Environment and Health

Estrogen and Progesterone in Waterways

2011-11-17T09:49:00.001-06:00

In the last post, I was speculating about how estrogens from effluent might end up in way water ways and end up increasing the incidence of prostate cancer. I wondered if the problem (if it there is anything more than a chance association) might be progesterone from birth control pills rather than estrogen. Progesterone is markedly non-soluble in water so it seemed unlikely at first thought. Poking around a little, progesterone might end up in sewage effluent after all. The three studies below report on fecal and/or urinary progesterone, conjugated progesterone or "progesterone metabolites" in animals. So . . . maybe progesterone contamination of water might be relevant. And, not all sewage is filtered and treated. I recently watched someone emptying a truckload of portapotties into one of our local creeks. (Yes, I called the police, who told me it was not their problem.) Don't know if anyone has looked at this or not. If you know, please have at it in comments.

deCatanzaro D, Muir C, Beaton EA, & Jetha M (2004). Non-invasive repeated measurement of urinary progesterone, 17beta-estradiol, and testosterone in developing, cycling, pregnant, and postpartum female mice. Steroids, 69 (10), 687-96 PMID: 15465115Kinoshita K, Inada S, Seki K, Sasaki A, Hama N, & Kusunoki H (2011). Long-term monitoring of fecal steroid hormones in female snow leopards (Panthera uncia) during pregnancy or pseudopregnancy. PloS one, 6 (5) PMID: 21559303Brown JL, Wasser SK, Wildt DE, & Graham LH (1994). Comparative aspects of steroid hormone metabolism and ovarian activity in felids, measured noninvasively in feces. Biology of reproduction, 51 (4), 776-86 PMID: 7819459

Response to a friend on significance of Triclosan in drinking water

2011-11-16T10:36:00.003-06:00

Sorry Friend. That was a poor response to your question about the significance of Triclosan following news of the chemical as an androgen blocker in water.

Triclosan is a thyroid disruptor and according to recent reports, an androgen blocker. As an anti-androgen, exposure could be important to male fetuses, since it could potentially interfere with development of the genito-urinary system, which could mean birth defects like hypospadias, small phallus, or non-obvious problems like changes in numbers and proportions of cells that would, later in life, produce sperm and testosterone. Thyoid inhibition has its own effects on development of the male reproductive system as well. So there might be some interesting interactive effects if both thyroid hormones and androgens are impacted. If that would occur you'd see reduced fertility. In an adult lowered testosterone would lead to other problems.

Blocking androgens, on the upside, might lead to less prostate cancer. It would be interesting to see if Dial Soap or other triclosan-containing products use this as a marketing point. "protects against body odor, gingivitis AND prostate cancer" Let's guess not.

Lastly, there was also an article out recently that associates rates of prostate cancer with presumed levels of estrogen (presumably from urine from women on birth control) in water supplies (Margel & Fleshner 2011). This was unexpected to me, until I thought about the pathway through which testosterone is produced. Testosterone can be synthesized from Progesterone, which is also present in birth control pills. So, it may be the progesterone, rather than estrogen, that is causing the problem. Progesterone is not water soluble, so its unlikely to be found in water systems unless conjugated to something else or incorporated in something else, so this is just speculation on my part.

Back to Triclosan. You can find some basic information on what kinds of products contain Triclosan at the Environmental Working Group Website. Its dated 2008, but the basic information may be useful.

For all of this, note that, for Triclosan, the picture is far from clear, as recent papers also report Triclosan enhancing androgenic activity in vitro (Christen et al. 2010) and as having estrogenic activity (Jung et al. 2011). Neither of those qualities is desirable in an environmental contaminant.
Best wishes,

Margel, D., & Fleshner, N. (2011). Oral contraceptive use is associated with prostate cancer: an ecological study BMJ Open, 1 (2) DOI: 10.1136/bmjopen-2011-000311

Christen V, Crettaz P, Oberli-Schrämmli A, & Fent K (2010). Some flame retardants and the antimicrobials triclosan and triclocarban enhance the androgenic activity in vitro. Chemosphere, 81 (10), 1245-52 PMID: 20943248

Jung EM, An BS, Choi KC, & Jeung EB (2011). Potential estrogenic activity of triclosan in the uterus of immature rats and rat pituitary GH3 cells. Toxicology letters PMID: 22062131

Rostkowski, P., Horwood, J., Shears, J., Lange, A., Oladapo, F., Besselink, H., Tyler, C., & Hill, E. (2011). Bioassay- directed identification of novel antiandrogenic compounds in bile of fish exposed to wastewater effluents. Environmental Science & Technology DOI: 10.1021/es202966c

"The Demon, Gluten"

2011-06-05T08:11:00.003-05:00

The fear of gluten, for most people, may be the "fear of the moment," with 25% of the population concerned about gluten intake (Associated Press, 2010) and less than 1% actually sensitive to it (Rubio-Tapia et al. 2009), but the evidence for increased auto-immune diseases as a whole, and this includes diabetes, lupus, etc., is strong. It does appear that the prevalence of celiac disease, (an auto-immune disorder triggered by gluten) along with many other autoimmune diseases is increasing (again Rubio-Tapia et al.) The Rubio-Tapia study shows a large increase (keeping in mind that the percentage of the population affected is very small) in prevalence of celiac disease based on evaluation of blood samples collected between WWII and the present day. What is causing such increased incidence of reactions? Why would gluten sensitivity have increased since WWII? I can only imagine what people with the immune disorder known as celiac disease experience, and I can understand their fear and desire to demonize gluten, .

But, what, if anything, is driving changes in autoimmune diseases? Immunotoxic chemicals, fetal programming, excessive hygiene (the hygiene hypothesis), viruses? It would seem that the demon is this driver, rather than some particular trigger like gluten.

Rubio-Tapia A, Kyle RA, Kaplan EL, Johnson DR, Page W, Erdtmann F, Brantner TL, Kim WR, Phelps TK, Lahr BD, Zinsmeister AR, Melton LJ 3rd, Murray JA (2009). Increased prevalence and mortality in undiagnosed celiac disease. Gastroenterology Gastroenterology, 137 (1), 88-93 DOI: 10.1053/j.gastro.2009.03.059

Environmental Chemicals Review

2011-05-06T11:43:00.002-05:00

This post is intended as a review of the chemicals presented (Benzene link) and discussed by Environmental Science students at UNT.

Hexavalent Chromium: A natural element in its Hexavalent state. This particular state is very toxic. It has occurred as a water contaminant, and causes a wide range of adverse health effects, including cancer.

Arsenic: Another natural element, found in the earth’s crust. It is water soluble and has been a problem when drinking water sources have been contaminated, or in areas where the concentration is naturally high. Its most well-known adverse effect is skin cancer (in chronic exposures). It has also been used as a pesticide, especially before the synthesis and widespread availability of organochlorine and organophosphate pesticides.

Beryllium: also an element present naturally in the earth’s crust. It has been a problem for human health when workers are exposed in occupational settings, or when the families of workers have been exposed by contaminated clothing. Exposure occurs through respiratory routes, and can make the immune system hypersensitive. Such hypersensitivity can result in overly strong allergic responses, or in autoimmune diseases such as asthma, thyroid disorders, and rheumatoid arthritis.

Cadmium: an element, not normally an environmental problem unless it has been concentrated by human activities. Cadmium fumes can cause lung and kidney damage. It also causes cancer.

Mercury: more elemental evil. It is rare in the earth’s crust, but is concentrated anthropogenic means (by human activities), where it has become a problem for humans as well as other species. When methylated (by anaerobic bacteria) it bioaccumulates and targets the nervous system. It can also be hazardous when inhaled.

Flouride: appears to increase bone strength at low levels, but at higher levels may make them brittle, and will cause stained splotched teeth. There have been some correlative studies looking at high fluoride intake and reduced IQ in children, but the jury is still out. This will be an interesting issue to follow. For more information try:
http://dels.nas.edu/resources/static-assets/materials-based-on-reports/reports-in-brief/fluoride_brief_final.pdf

Benzene: is a volatile compound that may be found naturally in gas deposits, may form in combustion, but is also synthesized for commercial uses. Environmental exposures are associated with increased incidence of Spina Bifida in infants. Industrial exposures are associated with Leukemia and Aplastic Anemia (this is often fatal as well). Although benzene is non-polar and lipophilic it does not bioaccumulate. This is because of its volatility, which allows it to be exhaled in breath. It also undergoes biotransformation, which means it is not as persistent as other cyclic compounds such as lindane. For more info: http://www.atsdr.cdc.gov/ToxProfiles/tp3-c6.pdf This is for your interest, and will not be on the exam.

Asbestos: a natural mineral that causes micro-damage and inflammation in human tissues. This is especially problematic for lungs, as inhalation is the primary route of exposure.

Oxybenzone: Not to be confused with Benzene. It is used in sunscreen and other personal care products. It is an endocrine disruptor, and also appears to be damaging to coral reefs. For more information try: http://www.ewg.org/news/can-sunscreen-lead-hormone-damage-kids

Particulate matter: is a hot topic right now, and you can be sure there will be a lot of interesting studies coming out in the near future as people try to figure out how particulates may adversely impact human health. Exposure to particulates is associated with increased cardiovascular disease, increased risk of arthritis and other immune disorders, and number of other problems.

Estrogens in aquatic systems: causes induction of intersex in fish, and may cause problems for humans and other organisms as well.

Organophosphates: These are a class of synthetic pesticides (and nerve agents) that target the nervous system. Exposures, if sufficiently high, will produce the SLUDGE syndrome (salivation, lacrimation, urination, defection, Gastrointestinal distress and emesis). Chronic, lower level exposures, may cause Delayed Onset Peripheral Neuropathy and are associated with increased risk of Parkinson’s disease.

Formaldehyde: used in fraking and in personal care products, as well as in various other industrial applications. Formaldehyde is classified as a “probably carcinogen”. Exposures have occurred industrially, but also in people exposed to off-gassing of formaldehyde-contaminated temporary housing.
It is also a respiratory irritant and may induce asthma. For more info try:
http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@rn+@rel+50-00-0
If you would rather get depressed try:
http://junkscience.com/2011/04/10/victory-lap-junkscience-com-knocks-off-another-junk-scientist/

Selenium, Brazil Nuts and Testosterone

2011-05-01T15:25:00.007-05:00

There seems to be a lot out in the popular press or online material that incresing selenium intake will increase a healthy man's testosterone production (example and example II from Forbes Magazine: what were they thinking?), but little, if anything, in the scientific literature to support that idea. (I like the scientificky approach used by that website, especially the graph that shows no effect, and no indication of variability in the data points). However, elevated testosterone, long term, will increase risk of testicular and prostate cancer. There has also been recent emphasis on consumption of brazil nuts as a natural source of selenium that will boost testosterone and increase virility.

Selenium is protective against prostate cancer, and good for testicular development (fetal period . . . sorry guys) and possibly protective against other oxidative-stress-induced ailments, testicular or not. On the other hand, selenium, at high concentrations can result in DNA damage, and thus increase risk of cancer. The problem with supplementing, either through tablets, or through consumption of a natural product high in selenium, is that we do not know where the lines of good and evil cross.

As for Brazil nuts, selenium concentrations in any plant should be dependent on the concentration of selenium in the soil in which it grows, therefore, the concentration of selenium in Brazil nuts probably varies. This turns out to be the case, with nuts grown in Manaus-Belem more than ten times higher in selenium than those grown in Acre-Rondia. Someone consuming Brazil nuts may or may not be making a significant increase in selenium intake.
Chang, J. (1995). Selenium content of Brazil nuts from two geographic locations in Brazil Chemosphere, 30 (4), 801-802 DOI: 10.1016/0045-6535(94)00409-N

ATIF, F., YOUSUF, S., & AGRAWAL, S. (2008). Restraint stress-induced oxidative damage and its amelioration with selenium European Journal of Pharmacology, 600 (1-3), 59-63 DOI: 10.1016/j.ejphar.2008.09.029

Brozmanová J, Mániková D, Vlčková V, & Chovanec M (2010). Selenium: a double-edged sword for defense and offence in cancer. Archives of toxicology, 84 (12), 919-38 PMID: 20871980
Henderson, B. (2000). Hormonal carcinogenesis Carcinogenesis, 21 (3), 427-433 DOI: 10.1093/carcin/21.3.427

Schistosomiasis may be protective against Auto-Immune Disease

2011-02-09T09:14:00.004-06:00

Following up here on the associations between parasite infection and reduced incidence of autoimmune diseases such as diabetes, thyroid disorders, arthritis and possibly asthma, this time with a specific focus on Schistosome infection. Schistosomias is a common infection in many areas of the developing world, and is thought to be the second most important human parasite after malaria. Infection may be sub-clinical with little or no indication of infection.

Osada et al. (2009) reported on lower inflammation and less arthritic response in infected mice. Arthritis can be induced in mice by injecting them with Collagen II. A recent publication by Xiao-Ping Chen's group (He et al. 2010) further report that the inhibitory effect of schistosomiasis is dependent on the life stage of the schistosomes. Schistosomes have a very complex life cycle and apparently some phases are more protective or induce different physiological responses in the host than others. Acute infection and egg-laying by the parasite are associated with less response to the collegen injections. Very interesting.

However, it is not advised that people run out and attempt to infect themselves, which can be pretty horrible and disfiguring. Malnutrition, anemia and lowered IQ have been observed in infected children, and increased incidence of bladder cancer is seen among infected adults. Still, it will be interesting to see where this work goes, and what treatments may be eventually developed. Thank you Osada et al. and He et al.

He, Y., Li, J., Zhuang, W., Yin, L., Chen, C., Li, J., Chi, F., Bai, Y., & Chen, X. (2010). The inhibitory effect against collagen-induced arthritis by Schistosoma japonicum infection is infection stage-dependent BMC Immunology, 11 (1) DOI: 10.1186/1471-2172-11-28

Araújo, M., Hoppe, B., Medeiros Jr, M., & Carvalho, E. (2004). Schistosoma mansoni infection modulates the immune response against allergic and auto-immune diseases Memórias do Instituto Oswaldo Cruz, 99 DOI: 10.1590/S0074-02762004000900005

OSADA, Y., SHIMIZU, S., KUMAGAI, T., YAMADA, S., & KANAZAWA, T. (2009). Schistosoma mansoni infection reduces severity of collagen-induced arthritis via down-regulation of pro-inflammatory mediators International Journal for Parasitology, 39 (4), 457-464 DOI: 10.1016/j.ijpara.2008.08.007

Did Intestinal parasites and poor hygiene protect us from autoimmune diseases?

2011-01-22T15:16:00.002-06:00

Autoimmune diseases are troubling, and often frustrating and painful for health care practitioners and patients. As far as I know, celiac disease is the only autoimmune disorder with a specific and identified trigger: the protein gluten. It has also been pointed out that the incidence of Celiac Disease, the formal name for gluten-triggered autoimmune reactions in the bowel, appears to have been increasing. Some have claimed that humans are not adapted to consumption of plant proteins like gluten, and that inflammatory bowel disorders are the result of the development of agriculture. However, there are a few other possibilities. One is that autoimmune disorders in general have been increasing and that Celiac disease is not increasing at a uniquely faster rate.

A major hypothesis in the development of allergies (inappropriate immune responses to non-pathogens, such as glutten or pollen or dog hair) is lack of exposure to potential allergens early in life. This, perhaps, is the root of the problem: soap, lysol, and a generally high level of cleanliness. Also, a huge change in human habit is the widespread introduction of infant formula to replace breast milk, and early introduction of other foods into infant diets. The ideal window of exposure to gluten is now considered to be between 4 and 7 months and that exposure should be concurrent with continuing breast milk consumption. Introduction to wheat cereals during this period is thought to be protective against celiac disease. Those raising their young children on gluten-free diets in the hope of protecting them from celiac disease, or the adverse effects of inflammation in general, may be taking the wrong route. (See Pinier et al. 2010 and Lopez-Serrano et al. 2010). Let them get a little dirty

Another possiblity, proposed by Elliot and Weinstock (2009) is the current rarity of helminth infection in the Western World. These authors propose that helminth infection was protective against autoimmune diseases like celiac disease by stimulating immune circuits that lower inflammation. I suppose if one were to choose between a gluten-free diet and helminth infection, most would go with the gluten-free diet. However, before you consider loss of bread as the price some pay for the protection of all against intestinal parasites, note that Elliot and Weinstock also propose exploration of the use of helminths for clinical treatment of auto-immune disease.

Elliott, DE and Weinstock JV (2009). Inflammatory bowel disease and the hygiene hypothesis: an argument for the role of helminths Progress in Inflammation Research, 149-178 DOI: 10.1007/978-3-7643-8903-1_9

Pinier M, Fuhrmann G, Verdu E, & Leroux JC (2010). Prevention measures and exploratory pharmacological treatments of celiac disease. The American journal of gastroenterology, 105 (12) PMID: 20877349

López-Serrano P, Pérez-Calle JL, Pérez-Fernández MT, Fernández-Font JM, Boixeda de Miguel D, & Fernández-Rodríguez CM (2010). Environmental risk factors in inflammatory bowel diseases. Investigating the hygiene hypothesis: a Spanish case-control study. Scandinavian journal of gastroenterology, 45 (12), 1464-71 PMID: 20704469

Ketogenic Diets

2011-01-15T14:01:00.014-06:00

I would advocate moderation in just about everything. Ketogenic diets have proven helpful to people with uncontrolled epilepsy and may be of benefit to epileptics in general, to victims of stroke and other forms of brain injury and possibly cancer. They come with other effects that may not be worth the discomfort or unintended risks to healthy people. This includes kidney stones and, in women and girls, amenorrhea. Amenorrhea is associated with bone loss, increasing risk of osteoporosis, and indicates problems in hormone balance. Supplementation with calcium may help with this, but then again, it might not. Physiology can be quite complex, and consumption does not necessarily indicate absorption is occurring. It is quite possible that something that causes hormonal imbalance in women may also cause hormonal imbalance in men. Playing with one’s physiology, when we don’t know the unintended outcomes of such play, may be inadvisable, especially long-term.

I have been a vegetarian for 30 years and an athlete all my life. I have excellent bone density, low blood pressure, low resting heart rate, low fasting blood sugar, excellent blood lipid profile and great strength to body weight ratio. I'm happy and healthy, even though I thoroughly understand I represent but a single data point. I do get a lot of advice from well-meaning friends that I need to eat meat and would be much healthier if I followed a ketogenic diet. Vegetarians, as described in some current diet books, are weak and "skinny-fat". I will leave it at this: The "optimal diet" for one person may not be the "optimal diet" for another, nor the optimal diet for all conditions. Humans are omnivores and physiologically polymorphic and adaptable. This has given us tremendous abilitity to survive in wildly different climes and environments, and has made us such a resilient species. It is also quite possible, that our individual resilience allows our bodies to adjust to dietary and environmental change.

The current state of research indicates no harm though, from short-term ketogenic diets. I have not found much in the way of research on the risks and benefits of long-term ketogenic diets in healthy adults. Anyone who wishes to add a citation, please feel free.

Kossoff, E., Zupec-Kania, B., & Rho, J. (2009). Ketogenic Diets: An Update for Child Neurologists Journal of Child Neurology, 24 (8), 979-988 DOI: 10.1177/0883073809337162

Bergqvist AG, Chee CM, Lutchka L, Rychik J, & Stallings VA (2003). Selenium deficiency associated with cardiomyopathy: a complication of the ketogenic diet. Epilepsia, 44 (4), 618-20 PMID: 12681013

Brinkworth GD, Buckley JD, Noakes M, Clifton PM, & Wilson CJ (2009). Long-term effects of a very low-carbohydrate diet and a low-fat diet on mood and cognitive function. Archives of internal medicine, 169 (20), 1873-80 PMID: 19901139

Role of Hormones, Genes, Hybrid Cars and Environmental Factors in Human Cryptorchidism

2011-01-07T21:40:00.002-06:00

Undescended testicles (Cryptorchidism) appear to be of complex origin . . . one of those cases where there are genetic and environmental components, and therefore difficult to figure out. You can consider genetics, exposures to environmental estrogens and anti-androgens and the relations among risk factors. You will not be bored trying to figure this one out. Added to this mix is a previously unconsidered variable: Hybrid Cars.

I teach a course called "Introduction to Research" which is somewhat like boot camp for aspiring academics. I would now only encourage people to go into academia if they are so driven by love or fascination for a subject that they are willing to sacrifice a signifant amount material comfort in its pursuit. I described my 16 year old minivan as dented and rusty, with an interior re-upholstered piece-meal with green fluorescent duct-tape. The starstruck response: a breathless and drawn out "cool . . . " I went on to describe my leaky roof and deceased dishwasher, and received this: "Dr. K, I will come to your house and fix your dishwasher" followed by "and I will drape my body over the hole in your roof next time it rains" from yet another. Undergraduates can be absolutely amazing.

So, to the hybrid part of the cryptorchidism story. The minivan leaks oil, gets not-so-good mileage and I drive about 120 miles a day to commute to the University. This is horrible for the environment, and costs about 1/7th of my income in gasonline alone. It suddenly struck me, during a quiet conversation with a good friend, and sometimes nemesis, that I could get a used Prius and maybe come out ahead financially on the reduction in gas expenditures. "Oh No! I'm Emasculating!" (that wasn't exactly how it was phrased, but you get the point: he has just become cryptorchidic). I only struck up a conversation with him in the first place because he looked like a hippie and a good environmentalist. Just another reminder not to speak to strangers even if they look "nice".

So what's the deal with hybrids and environmentalism that threatens the masculinity of men in Texas? A simple question, that could be answered with a simple "beats the hell out of me" until I started considering bumper stickers:

This is a question that should be posed to an historian, psychologist and/or poli sci person.

Foresta, C., Zuccarello, D., Garolla, A., & Ferlin, A. (2008). Role of Hormones, Genes, and Environment in Human Cryptorchidism Endocrine Reviews, 29 (5), 560-580 DOI: 10.1210/er.2007-0042

Hearing, Reading Disabilities and PCB exposures

2011-01-06T11:09:00.000-06:00

I found this article very exciting. Serum PCB Concentrations and Cochlear Function in 12-Year-Old Children. by Trnovec et al. 2010, in which they describe associations between hearing function and PCB exposures in Slovakian kids. (In regular terms: PCB exposure in children probably causes hearing deficits). My forebears were deaf, graduated from the American School for the Deaf, were members of Deaf Baseball and Football teams, and from all the old pictures we have, seem to have had absolutely fun and wonderful lives, so I've never really considered Deafness a disability. However, hearing deficits make it hard for children to learn to read, and they do not get the full range of information available to children without hearing deficits. This can be a problem that may put them at a disadvantage in terms of conventional measures of school and life success. See Banai et al. 2009 for some recent interesting work in this area.

Trnovec et al. also observed differences between ears (no, not that some kids heads were filled with Kapok and some weren't) with the left ear showing a stronger deficit than the right. This does lead one to wonder if people are left earred or right-earred and that the same effect might not be seen if they had recruited only right-handed or left-handed children. This is also more complex than it seems because you can be right handed and "goofy footed" i.e. left foot dominant. I am goofy footed, but its only apparent when I'm out surfing.

Here is a link for understanding the systems through which Trnovec are evaluating correlations of PCB exposure with hearing. http://www.est-med.com/OAE/understanding-using_OAE%20von%20Kemp.pdf

Trnovec, T., Šovčíková, E., Pavlovčinová, G., Jakubíková, J., Jusko, T., Husťák, M., Jurečková, D., Palkovičová, L., Kočan, A., Drobná, B., Lancz, K., & Wimmerová, S. (2010). Serum PCB Concentrations and Cochlear Function in 12-Year-Old Children Environmental Science & Technology, 44 (8), 2884-2889 DOI: 10.1021/es901918h

Triclosan induces hypothyroidism and is transfered to infants during lactation.

2010-12-30T19:40:00.003-06:00

Triclosan is used in many personal care products as an anti-bacterial agent. You can find it in soaps, toothpaste etc. It is also an endocrine disruptor that effects at least two different (albeit interrelated) systems. Triclosan has some estrogenic effects. Paul et al. (Dec 2010) have demonstrated that triclosan alters thyroid hormone levels early in lactation. Thyroid hormones are especially important during fetal and infant development because they play crucial roles in brain development. Early thyroid hormone deficiency alters neurological function in animals, and in human, reduces IQ and increases ADHD-like behavior. There are many environmental contaminants that interfere with thyroid hormones including PCBs, PBDEs, perchlorate, and nitrate. It is difficult to study the impact of exposures to these chemicals in humans because its hard to know how much people are exposed to over time, and people are probably never exposed to just one agent at a time. Its important to consider additive (or synergistic or antagonistic) effects and not consider them individually. For now, its probably best for pregnant and lactating women to limit their exposure to triclosan. Thank you, Paul et al., for your hard work, and for fitting yet another piece into the puzzle. Here is the U.S. FDA's position on Triclosan safety.
as of today.

Paul KB, Hedge JM, Devito MJ, & Crofton KM (2010). Developmental triclosan exposure decreases maternal and neonatal thyroxine in rats. Environmental toxicology and chemistry / SETAC, 29 (12), 2840-4 PMID: 20954233

Fried food may cause diabetes in thin people too.

2010-12-24T06:41:00.003-06:00

A Taiwanese research group published on the effects of high oxidized frying oil on insulin secretion (reduces insulin secretion)in 2007. In this study they (Chiang et al. 2010) attempt to determine the cause by experimenting with mice. They used three treatment groups:

Low Fat Diet
High Fat Diet
High Oxidized Frying Oil Diet.

The mice fed high oxidized frying oil exhibited reduced insulin secretion and high blood glucose levels. Very important here: their islets of langerhans (the tissue that produces insulin, as well as glucagon) showed evidence of oxidative damage. Glucagon and insulin work together to keep blood sugar stable. It seems likely that oxidative damage would occur throughout the body, so its probably best to avoid fried food even if diabetes or metabolic syndrome is not one of your concerns.

The High Fat diet mice did not show such changes. This implies that a diet high in fried food may put people at risk of diabetes or metabolic disorder by interfering with production of hormones regulating blood sugar, while a high fat diet of unoxidized oil might be just fine. Vitamin E is an important anti-oxidant and is protective against the effects of High Oxidized Frying Oil. Chiang et al. found that adding Vitamin E to the diet reduced the effects of the Oxidized Fat diet. Thanks to all for their hard work.

Ya-Fan Chiang, Huey-Mei Shaw, Mei-Fang Yang, Chih-Yang Huang, Cheng-Hsien Hsieh and Pei-Min Chao (2010). Dietary oxidised frying oil causes oxidative damage of pancreatic islets and impairment of insulin secretion, effects associated with vitamin E deficiency British Journal of Nutrition : 10.1017/S0007114510005039

Chao, P., Huang, H., Liao, C., Huang, S., & Huang, C. (2007). A high oxidised frying oil content diet is less adipogenic, but induces glucose intolerance in rodents British Journal of Nutrition, 98 (01) DOI: 10.1017/S000711450769000X

Autoimmune disease and inhalation of particulates

2010-12-23T07:07:00.003-06:00

Airborne particulate matter appears to increase risk of diabetes, as discussed a few posts down and diabetics appear to have altered immune function according to a number of parameters. Diabetics have now been observed to have stronger indicators of immune response when air pollution levels (particulate matter in this case) are high. Schneider and Alexis (2010 . . . two first authors, congratulations all) observed increased blood levels of endogenous promotors of Activated Protein C Resistance. Diabetics who were also obese, or who did not express GSTm1, (not having this, by the way, increases risk of a wide array of cancers) or who already had elevated HbA1C (this is an indicator of longer-term blood glucose levels) had the strongest response to particulate matter. So, are diabetics more vulnerable to challenges to the immune system? Do these challenges contribute to development of diabetes? Or is there an interplay in each (diabetes and immune response)alters the pattern of the other. Lets hope they don't progressively spiral over time and continued exposure. The cohort was small with only 20 subjects, but it would be interesting to look at response to particulate matter by age, or time since diagnosis of type II diabetes.

Schneider A, Alexis NE, Diaz-Sanchez D, Neas LM, Harder S, Herbst MC, Cascio WE, Buse JB, Peters A, & Devlin RB (2010). Ambient PM2.5-Exposure Up-regulates the Expression of Co-Stimulatory Receptors on Circulating Monocytes in Diabetic Individuals. Environmental health perspectives PMID: 21169129

Inflammation, autoimmune disease, diabetes and gum disease

2010-12-20T10:26:00.000-06:00

The other day I wrote about environmental agents increasing risk of obesity, diabetes and insulin resistance and mentioned an article associating exposure to particulate matter with increased incidence of diabetes and wondered about it. If, as the authors suggest, exposure to particulates results in low-level chronic inflammation, then other causes of chronic inflammation (like gum disease) should also be associated with increased risk of diabetes, insulin resistance or similar. A little poking around, and yes, looks like a hit: Increased Prevalence of Cardiovascular and Autoimmune Diseases in Periodontitis Patients: A Cross-Sectional Study. Just out last month by Nesse et al. at the University of Groningen in The Netherlands. Very cool guys. Congrats on the publication.

Nesse W, Dijkstra PU, Abbas F, Spijkervet FK, Stijger A, Tromp JA, van Dijk JL, & Vissink A (2010). Increased prevalence of cardiovascular and autoimmune diseases in periodontitis patients: a cross-sectional study. Journal of periodontology, 81 (11), 1622-8 PMID: 20583916

A Little More on Lipophilic Chemicals, Diabetes and Obesity

2010-12-17T12:50:00.000-06:00

This is just a little continuation of the post made yesterday in which I wondered if associations between intake of animal protein (vs. vegetable protein) and waist circumference had anything to do with increased exposure of consumers of animal products to environmental contaminants. This is not my area of research . . . but it is an area of research for a lot of other people. Diabetes and/or Insulin Resistance is associated with exposure to Brominated Flame Retardants, Persistent Organic Pollutants, polychlorinated diphenyl ethers, and, interestingly (perhaps because I don't understand the mechanism by which this would occur . . . will have to look into it) airborn particulates. A brief and very readable review of environmental (chemical) causes of diabetes was made in 2008 by Oliver et al.

Jones, O., Maguire, M., & Griffin, J. (2008). Environmental pollution and diabetes: a neglected association The Lancet, 371 (9609), 287-288 DOI: 10.1016/S0140-6736(08)60147-6
Lee, D., Lee, I., Jin, S., Steffes, M., & Jacobs, D. (2007). Association Between Serum Concentrations of Persistent Organic Pollutants and Insulin Resistance Among Nondiabetic Adults: Results from the National Health and Nutrition Examination Survey 1999-2002 Diabetes Care, 30 (3), 622-628 DOI: 10.2337/dc06-2190
Lim, J., Lee, D., & Jacobs, D. (2008). Association of Brominated Flame Retardants With Diabetes and Metabolic Syndrome in the U.S. Population, 2003-2004 Diabetes Care, 31 (9), 1802-1807 DOI: 10.2337/dc08-0850
Pearson JF, Bachireddy C, Shyamprasad S, Goldfine AB, & Brownstein JS (2010). Association between fine particulate matter and diabetes prevalence in the U.S. Diabetes care, 33 (10), 2196-201 PMID: 20628090

Animal vs. Plant Protein, Adiposity, Persistent Organic Pollutants and Endocrine Disruption

2010-12-16T06:23:00.006-06:00

This looks like the second step of a tangent and I want to get back to endocrine disruption, but here is another bit of data that supports the benefits of vegetable protein. Intake of vegetable protein is negatively correlated with waist circumference and BMI. In contrast, intake of animal protein is positively correlated with waist circumference and BMI, at least in Belgians. There are a lot of questions to raise with this including the possibility that people who eat less animal protein consume less animal fat which can be a rich source of bioactive, lipophilic contaminants which may also be endocrine disruptors that increase adiposity or alter blood lipids. Note Ruzzin et. al.'s April 2010 paper "Persistent Organic Pollutant Exposure Leads to Insulin Resistance Syndrome." (Very nice work! Congratulations to all authors.) Also possible that people who eat a lot of vegetable protein also eat fewer calories, are less sedentary etc. There is also the argument that lean, grass-fed animals (happy cattle, miserable chickens) would eliminate this vulnerability in meat eaters. I don't know how many purist animal protein people are out there, and this is probably not a viable option for a heavily populated planet, but that would be an interesting study. BMI and blood lipid profiles in matched cohorts of grass-fed/organic animal protein eaters vs. regular grocery store consumers. Anyone . . . ?
Ruzzin J, Petersen R, Meugnier E, Madsen L, Lock EJ, Lillefosse H, Ma T, Pesenti S, Sonne SB, Marstrand TT, Malde MK, Du ZY, Chavey C, Fajas L, Lundebye AK, Brand CL, Vidal H, Kristiansen K, & Frøyland L (2010). Persistent organic pollutant exposure leads to insulin resistance syndrome. Environmental health perspectives, 118 (4), 465-71 PMID: 20064776
Lin, Y., Bolca, S., Vandevijvere, S., De Vriese, S., Mouratidou, T., De Neve, M., Polet, A., Van Oyen, H., Van Camp, J., De Backer, G., De Henauw, S., & Huybrechts, I. (2010). Plant and animal protein intake and its association with overweight and obesity among the Belgian population British Journal of Nutrition, 1-11 DOI: 10.1017/S0007114510004642

Nutritional Stuff, Protein and Vegetarianism

2010-12-06T23:36:00.007-06:00

This is not my field but, late at night, when I can't sleep, I sometimes look at articles dealing with nutrition and here are two that piqued my curiosity.
One is that high protein maternal diets may predispose infants (at least rats anyway) to greater risk of obesity later in life. Maternal consumption of high-prebiotic fibre or -protein diets during pregnancy and lactation differentially influences satiety hormones and expression of genes involved in glucose and lipid metabolism in offspring in rats, British Journal of Nutrition. Of course there are lots of questions. The young rats were switched to a "normal" diet after weaning. What if they had stayed on the same diet their mothers had been on? For review of fetal programming see Godfrey et al. 2007. Is the problem when diet changes after an infant as been "programmed" to a particular nutritional condition? i.e. is it mismatch between fetal expectation and the reality of later life, or is it a problem created by a high protein diet?

The other is that creatine supplements appear to increase cognitive function in vegetarians: The influence of creatine supplementation on the cognitive functioning of vegetarians and omnivores also just out in the British Journal of Nutrition. I'm a vegetarian with ADHD-like traits. Time to try a supplement? Opposed on principle, but what the hey, I can use all the cognitive function I can get.

Godfrey KM, Lillycrop KA, Burdge GC, Gluckman PD, & Hanson MA (2007). Epigenetic mechanisms and the mismatch concept of the developmental origins of health and disease. Pediatric research, 61 (5 Pt 2) PMID: 17413851

Ototoxicity

2010-12-04T12:15:00.002-06:00

You don't hear much about ototoxicity (pun completely intended), but I think it is fascinating (what???). Hearing is relatively easy to evaluate and can serve as marker of neurological effect for chemicals targetting the developing nervous system (i.e. harm nerve development in general and you may see poor functioning in general, including poor hearing). Like other cells in the body, cells involved in hearing are vulnerable to oxidative stress. Oxidative attack can result in damage to a cell's DNA, which can lead to development of a cancerous cell or, if you are a fetus, in the development of a birth defect. Your body is not completely defenseless against a cancerous cell. Abnormal cells normally self-destruct in a process called "apoptosis". Its when a cell loses the ability to undergo apoptosis that you may have a serious problem.

When you combine something like Arsenic, which is a great creator of oxidative stress, with exposure to loud noise you get more hearing loss than you would if you were not also exposed to Arsenic. Heavy metals, mercury and lead, are classic ototoxicants as are some antibiotics and drugs for erectile dysfunction.

Hearing loss is also seen when environmental chemicals interfere with neurodevelopment. There is some very interesting work being done in this area by Tomas Trnovec (Slovakia) et al. that focuses on hearing deficits in children exposed to PCBs. PCBs were bannned in the US decades ago, but continued to be produced by the Soviet Block. Poor environmental regulation in Eastern Europe has left those countries with some major environmental health problems. Best wishes to all working in this area.

High Fructose Corn Syrup

2010-11-14T07:41:00.008-06:00

I have been detecting a bit of concern about high fructose corn syrup in my local atmosphere (gas chromatography, of course), and there is a simple solution: avoid regular indulgence, as you would for popcorn balls, frosting and jolly ranchers. However, small amounts are extremely unlikely to cause any harm (Please note that as a scientist I have been trained not to make absolute statements. There is always the possibility that new information will come along, even for very well-established theories like "gravity"). Be rational. Read widely. You should neither let those who enjoy fanning flames keep you from enjoying your life, nor let those intent on obscuring truth keep you from making good decisions.

For a recent review of the current state of the debate about high fructose corn syrup take a look at this publication: Fructose and Cardiometabolic Disorders: the controversy will, and must, continue by Wiernsperger, Geoloen and Rapin from October 2010. Nice work gentlemen, and very much appreciated. Another review has been published this month by Dekker et al., but I don't yet have access. Thanks to all for their work in this area.

For a well-crafted response from the Corn Syrup interests click this link. Wiernsperger et al., Dekker et al. . . . it will be hard to compete.

Here's a plea for rationalism, unbiased information, recognition of unknowns, and conservative judgement:

2010-11-12T08:44:00.001-06:00

And also for a very important factor in health that is often overlooked, perhaps because the technical details cannot be argued: friendship, community and laughter.

Politics, Money, Chemicals, Health and the Environment

2010-10-17T16:45:00.002-05:00

Oh Canada
has declared BPA . . . (fit that into the music for the national anthem) to be a toxicant. That does make sense, given the growing body of evidence that it is an endocrine disruptor that produces wide-ranging effects in test animals and is positively correlated with adverse effects in humans. It is also usual for industries involved in production, use and distribution of chemicals found to have strong potential for causing health problems in humans to argue with scientists and regulatory personnel and to try to convince the population at large that there is nothing wrong with their products. I wonder if this is simply characteristic of democracies. I'm sure graft and favoritism plays a role in other systems of government (and in ours as well). Part of me is just morbidly fascinated with how truth, logic and fairness are knotted up into some very twisted wads.

A spokesman for the BPA people is claiming that BPA is safe and that Canada's decision will only alarm and confuse the public. (I do agree that no one should have to go grocery shopping in an alarmed and confused state of mind . . . that's how products like "Lunchables" are purchased). You can read the American Chemistry Council statement here where it claims that the European Food Safety Authority (EFSA) confirms the safety of BPA and that Canada's decision flies in the face of "World Wide Scientific Evidence". Funny Funny. In fact the EFSA is stating that there is no compelling evidence that the Tolerable Daily Intake should be changed from its current level. This is a far cry from stating that BPA is safe.

Some legitimate arguments in BPAs favor is that it makes food packaging and transport safer and more economical. This does have economic and social value. But please, let's honor good work done and the validity of concerns for human and environmental health.

Diabetes and Bisphenol A (BPA)

2010-09-30T06:10:00.000-05:00

There is increasing evidence that chemicals in the environment may be contributing to diabetes and obesity. For current reviews and discussion take a look at:

Here is specific evidence on the relationship between exposure to bisphenol A and risk of diabetes: Bisphenol A Exposure during Pregnancy Disrupts Glucose Homeostasis  in Mothers and Adult Male Offspring. As discussed in previous posts, nearly everyone is exposed to Bisphenol A (BPA) through consumption of food and beverages packaged in plastic.

Atrazine

2010-07-03T06:38:00.001-05:00

Congratulations to Walid D. Fakhouri, Joseph L. Nuñez, and Frances Trail for their recently published work on reduction of growth hormone production by the herbicide Atrazine. Growth hormone is important, as will sound obvious, because it plays a key role in growth (cell proliferation) but also because it influences production of many other hormones including those important in sexual development and reproduction. Changes in growth hormone produce a range of effects that extend far beyond body size.

The battles over Atrazine have been politically intense and, at times, highly entertaining to those on the sidelines. It was banned in Europe in 2004, but remained in use in the US after studies were provided to the EPA through Syngenta, the company that manufactures Atrazine, that contradicted studies by independent scientist Tyrone Hayes at the University of California at Berkeley.

Understanding Atrazine's mechanism of action will be invaluable in making informed well-reasoned decisions for protection of human health and the environment.

Fakhouri, W., Nuñez, J., & Trail, F. (2010). Atrazine Binds to the Growth Hormone–Releasing Hormone Receptor and Affects Growth Hormone Gene Expression Environmental Health Perspectives, 118 (10), 1400-1405 DOI: 10.1289/ehp.0900738

The Environmental Health Store

2010-06-03T14:32:00.002-05:00

There's only one design, but you can get a
"Phthalates Phthuck"
water bottle or T-Shirt.

Mercury

2010-04-12T16:10:00.005-05:00

Just out, news that rice is a major pathway for methylmercury exposure in a mining community in Inland China. This is big news because fish consumption has been the focus of exposure assesments for mercury exposure. Mercury, when methylated (hence methylmercury) can be devastating to developing fetuses, causing severe brain damage. For a detailed history of a methylmercury incident look up "Minimata, Japan". Keep in mind this was an unusual tragedy and human exposures are normally much lower than those that occurred there.

Would have to search to see if anyone has done similar work to test produce or other agricultural projects near US coal plants, but it would be interesting to know (hopefully soon). Mercury uptake by plants apparently varies by species, with most of it remaining in roots, and most mercury detected in/on plant leaves may be from simple settling of dust. To the right is a USGS map of wet mercury deposition in the (on the) US. Above is the link for further information. Health effects are minimal for unmethylated mercury, with methylation being performed by anaerobic bacteria in oxygen poor environments . . . which you would see in swamp bottoms, ocean floor etc. . . and would probably not (to the best of my knowledge) be occurring in common agricultural conditions. Rice fields, being flooded and marsh-like, may provide good conditions for methylated microorganisms.

Further note, China does not export much rice and mercury in rice may be only a local problem.

Zhang H, Feng X, Larssen T, Qiu G, Vogt RD, 2010 In Inland China, Rice, rather than Fish is the Major Pathway for Methylmercury Exposure. Environ Health Perspect doi:10.1289/ehp.1001915

Environmental Chemicals, Obesity and Diabetes

2010-04-01T12:05:00.004-05:00

Exposure to chemicals may change the way people (and other creatures) deposit fat within their bodies which may play a role in obesity. Since Obesity is also associated with diabetes, cancer and heart disease it is also possible that the same chemicals play a role in development of these diseases as well.

A study published in this month's (April) issue of Environmental Health Perspectives by Ruzzin et al.describes the effects of exposure to Persistent Organic Pollutants (POPs) on insulin and lipid profiles in rats. POPS is a term usually used to describe a set of chemicals that are very slow to degrade, accumulate in body fat, and concentrate as you move up the food chain. The POPs in this study were isolated from farmed Salmon, and it is thus not much of a stretch to expect that people consuming farmed salmon would be exposed to a similar mixture of this particular soup.
It is important to keep in mind that anything with animal fat will contain POPs, so avoiding salmon consumption may not be particularly protective. An earlier and equally intriguing paper by Somme et al. 2009 showed altered fat deposition when newborn rats were exposed to Bisphenol A. So what's going on with the current obesity epidemic? Are chemical exposures playing a role? Hopefully further research will elucidate this mystery.
For those interested in protecting their health: eat low on the food chain (bugs, shrimp, vegetables). And, avoiding drinking or eating things that have been packaged in BPA-containing plastics would be a simple way to reduce BPA exposure.

The original "dirty dozen" POPs have been banned in the US. Exposure, however, is universal because POPs accumulate in fat, and we pass them on to our children during pregnancy and lactation. Anyone interested in a multi-generational fat biopsy study? Bisphenol A is not banned and is believed to be rapidly excreted in urine (Yeah!).

Plastic water bottles

2010-02-27T05:49:00.000-06:00

Yes, it is true. There is very little point in using these unless you live in an area where drinking water is contaminated with sewage/agricultural run-off (West Bank, Palestine), high arsenic (areas of India and Bangladesh) or nitrate concentrations (any of the above places, and possibly agricltural areas in the US.). Bisphenol A, a major ingredient in many plastics is an endocrine disruptor. The health effects of Bisphenol A are still under investigation. How much is safe is not known. Biological systems effected are not well understood. How much is coming off the water bottle and into the water it contains is unknown.

On environmental impact level, plastic water bottles just use petroleum and create mountains of waste. Yes, they can be recycled, but recycling is not cost free. Someone pays for it (whether through taxes, higher costs, or energy consumption and more pollution).

Carry a glass bottle, carry a cup, use a drinking fountain.

Dipping into Psychology, but keeping focus on Oxytocin and Cortisol

2010-02-23T05:23:00.001-06:00

Briefly here, on today's NY Times article on touch , and that warm touches (and who knows, maybe the playful punch in the arm or slap to the back of the head) results in release of oxytocin and reduction of cortisol. Oxytocin is released within the brain and triggers feelings of relaxation, well-being and warmth towards others. For more info look that hormone up on Wikipedia. Cortisol is elevated in people who are under prolonged stress and is associated with a range of undesirable health effects like cancer, elevated blood pressure, cardiovascular disease and if I remember correctly possibly diabetes. Oxytocin is probably signalling "its OK. You are not alone" "The threat is gone", or "we will fight this battle together".

So, reach out and support your friends, colleagues, team-mates and loved ones. It is likely to do a statistically significant world of good

Science can accomplish whatever you want. The choice is yours.

2010-02-15T05:56:00.002-06:00

Enjoyed this Youtube video: Haber Process, World War I and the Green Revolution which describes the development of the Haber Process for the fixation of Nitrogen from air, its use in manufacture of chemical weapons during WWI, and its subsequent use as synthetic fertilizer that helped drive the Green Revolution. Love the final message. May use the book, The Poisonous Cloud, by Haber's son Ludwig and/or Enriching the Earth by Vaclav Smil.

This week's topic is Androgen/Estrogen Disruption

2010-02-06T06:54:00.004-06:00

Could write a book here, but will be brief for now. First listen to (and watch if you want) this clip: Tone setting music. Endocrine disruptors are chemicals that mimic or interfere with "signals" from the endocrine system (glands). Examples of hormones are androgens (such as testosterone), estrogens, thyroid hormones, epinephrine (aka adrenaline) etc. Examples of endocrine disrupting chemicals in the environment (and/or food and drinking water) are phthalates, bisphenol A (BPA) and perchlorate. You can read numerous articles on endocrine disruption in Environmental Health Perspectives, including that of Reproductive Toxicology Rock Star Shanna Swan. This is a great source of information because its peer-reviewed and you can get the entire article for free.

Phthalates and BPA are part of many plastics and they interfere with sex hormones (in this case estrogen mimics). This is hugely important during fetal development as organsystems (including brain) are being formed. Had a student ask if increased exposures to estrogenic compounds would results in higher rates of homosexuality. Not sure that this is appropriate to discuss here, but estrogen is the hormone that masculinizes the brain, so you might see a tendency towards masculinization and associated behavioral traits. Yes, sex hormones are important for brain development. A lot of other chemicals may have similar effects. Will link to an interesting article reporting on prenatal exposure to phthalates and aggressive, disruptive behavior during childhood.
Click "manufacturer's point of view" for information on industry response. Businesses often put their own interests first. There is nothing wrong with that as long as it doesn't hurt anyone else. My opinion.

Climate change and the hoax question I get in class

2010-01-30T13:48:00.001-06:00

There are a number of planetary patterns such as the Milankovich cycles that influence climate in relatively predictable ways. Volcanic outputs of particulates and sulfer dioxide also influence global climate, as may the billion tons of dust swept from the Sahara each year. However human activities add large quantities of material to the atmosphere as well. This is something over which we have some degree of control. I will agree that modelling future events is something done with risk of error and it is foolish not to acknowledge this simple fact. Any scientist will freely discuss this in reports and publications unless he or she is a complete messianic whacko. I think the press often oversimplifies science articles either because they don't fully understand what they are writing about, or because they assume most readers won't be able to understand any degree of complexity. However, as intelligent beings we CAN attempt to understand what drives our world, evaluate relative risks, make decisions and plan for the future.

It is fun to get attention and make people upset (believe me, I know this from personal experience). One can make people upset by bringing bad news. Attention and fun can also be had by going against the deeply held (and sometimes rational) belief's of others. This is especially true with scientists, who expect any attacks to be well-thought out, supported by hard data, and properly cited. Our culture requires that all opinions be heard and given equal consideration. I support listening to others, but do not support believing whatever happens to be most forcefully expressed.

Reading about Health and Science

2010-01-30T06:42:00.002-06:00

Sometimes a health or science story comes up in the news that catches people's interest. Here is some simple advice:

go find the original publication or read the abstract on PubMed( http://www.pubmed.gov/).

Often a journalist will pick up on one aspect of a study and not mention other aspects, or limitations, or may misinterpret the conclusions of the study authors. So take a look at the original yourself. Peer-reviewed articles published in highly-ranked journals put out quality work. Getting through peer-review is a rigorous process as exemplified in this video Scientific Peer Review ca. 1945.

Telomeres, aging and exercise

2010-01-28T16:25:00.002-06:00

An interesting bit of research has been picked up by the press. Telomere length has been reported to be longer in older endurance athletes than in older couch potatos Telomeres are thought to be important in aging. You can find the abstract and access the full text through: http://www.pubmed.gov/. This is hopefully good news for older endurance athletes and an encouragement to others to get moving. (It is also possible that people with more resistant telomeres are the ones able to continue intense exercise into middle age and that the exercise did not change the nature of the telomeres.) But interesting . . . Take a look at table 1. There are a number of other variables aside from telomere length that you'd think would have been statistically significant but weren't. More research?

Congratulations to authors Larocca, Seals and Pierce. And thank you for publishing this, Mechanisms of Ageing and Development (journal).

Light

2010-01-17T09:53:00.001-06:00

Light controls our circadian rhythms. These determine our daily pattern of waking and sleeping, and probably how our energy levels vary throughout the day as well. In the modern environment, most of us spend most of our time indoors with artificial light. The signals our brains get from light are no longer triggered exclusively by the rising and setting of the sun. A number of health effects from altered light exposure have been noted including

Increased incidence of cancer (esp. breast and colorectal cancer in shift workers)
Insomnia
Obesity
Diabetes
Depression
Timing of onset of puberty

For more detailed discussion, references to specific papers and the above image see: http://ehp03.niehs.nih.gov/article/info:doi/10.1289/ehp.117-a20

AND

http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.118-a22 for a more detailed discussion with emphasis on blue light and photoreceptors.

Human Health and Environmental Factors

2010-01-17T09:42:00.000-06:00

There are a lot of things that influence health beyond diet and exercise, and many ways in which our health may be influenced by the world we create.

Exposure to light:
Temperature control
Psychological stress (traffic, kids, job etc.)
Quality of friendships and community
Exposure to environmental agents
Drugs
Air Quality
Water Quality

and etc. It is important to keep in mind that all of these things can impact your physical health, and that they can all influence each other.