A
workshop was organized by the National Institute of Environmental Health
Sciences (NIEHS) Division of the National Toxicology Program (NTP)
to assess whether and how exposure to environmental chemicals contribute to
obesity and diabetes. A group of more than 50 scientists from various medical
fields such as endocrinology, toxicology, epidemiology, bioinformatics and
other experts participated in the evaluation of current literature.
The
lead reviewers of the workshop were Kristina A. Thayer, Jerrold J. Heindel,
John R. Bucher, Michael A. Gallo. The workshop focused on the adverse effects
of arsenic, maternal smoking/nicotine, organotins, bisphenol A (BPA),
persistent organic pollutants (POPs), pesticides and phthalates on the health
of humans and experimental animals.
The
prime objective of the workshop was to formulate and forward recommendations
for a research program after a critical analysis of the environmental
chemicals.
In
order to assess the potential cellular pathways and hypothesize how certain
chemicals might hamper the biological processes concerned with diabetes and
obesity, high screening data from Tox21 were taken into account.
Existing
literature suggested that type-2 diabetes was affected by several environmental
chemicals. The hypothesis of 'developmental obesogen' was also supported. The
hypothesis suggests that exposure to certain chemicals may alter human
metabolism and lead to obesity.
Maternal Smoking and Nicotine: An
important finding of the workshop was that nicotine is a strong 'developmental
obesogen' in human beings.
Arsenic: An
association was found between
diabetes and arsenic in people from high-arsenic exposure regions such as
Taiwan and Bangladesh.
Organotins: No
epidemiological studies of organotin exposure and obesity or diabetes were
identified during the literature search.
POPs: Certain POPs
such as DDT, DDD, and polychlorinated
biphenyl (PCBs) showed positive association with diabetes.
Phthalates: Hatch
et al studied the exposure of phthalates on diabetes and obesity. The urinary
phthalate metabolite monoethyl phthalate was the common phthalate metabolite
associated with high body mass index (BMI).
BPA: One pilot study
suggests that bisphenol-A (BPA) pose a potential risk for childhood obesity.
BPA affects insulin release, glucose homeostasis, adipogenesis and cellular
signaling in pancreatic β cells.
Pesticides: Pesticide
acts as an important risk factor of obesity and diabetes.
It
is observed that the environmental chemical exposure produces more prominent
effects when combined with high-carbohydrate, high-fat or high-calorie diet.
The
workshop concluded on the hope that further researches would be done
internationally to better understand the impact of environmental pollutants on
the prevalence of obesity, metabolic syndrome and diabetes.
The
report highlights the need of further research and analysis regarding specific
exposures of environmental chemicals and their outcome.
Reference:
Role of Environmental Chemicals in Diabetes and
Obesity; Kristina et al; Environmental Health Prospectives 2012.
Source-Medindia