US Immigrants From India At Higher Risk Of Diabetes Due To Previous Exposure Of Pesticide DDT In India
Source: Thailand Medical News Nov 21, 2019 5 years, 1 day, 14 hours, 56 minutes ago
A study conducted by University of California, Davis found that previous exposure to the pollutant
DDT (dichlorodiphenyltrichloroethane) may contribute to the risk of
diabetes among Asian
Indian immigrants to the United States.
The recent study in the American Chemical Society's journal
Environmental Science & Technology, linked high levels of
DDT, or
dichlorodiphenyltrichloroethane, in
Indian immigrants with risk factors for
metabolic disease.
Dr Michele La Merrill, an associate professor in the UC Davis Department of Environmental Toxicology and lead author told
Thailand Medical News, "Our findings evoke a new interpretation of Rachel Carson's famous book Silent Spring, in that the high
DDT exposures of South Asian immigrants in the U.S. currently fall on deaf ears in the U.S. Although
DDT remains in use in other nations and migration globalizes these exposures, people in the U.S. often mistakenly regard
DDT exposure as no longer relevant to our society due to its ban in this country nearly 50 years ago."
Dr La Merrill said that high exposure levels in these immigrants may be causing their increased risk of obesity and other
metabolic diseases, but medical doctors are often not aware of that possible link.
Asians from
India have a higher risk of
diabetes than other populations, and this risk extends to Indian immigrants in the U.S., Europe and elsewhere.
The United Nations Stockholm Convention in 2004 banned the production and use of many persistent organic pollutants, or POPs, such as
DDT and polychlorinated biphenyls, or PCBs. However, POP production and use continue in some nations that did not ratify the treaty, including
India and other South Asian countries such as Cambodia, Vietnam, Thailand, Malaysia, Myanmar and also China. Past studies have found
DDT in samples taken from the environment, food and people of the
Indian subcontinent and also in other South East Asian countries. DDT was rampant in the whole system from foods, water supplies to even blood samples.
Dr La Merrill and colleagues wondered whether prior exposure to
DDT and other POPs could influence Asian I
ndians'
diabetes risk, even after they had immigrated to the U.S. Based on results from animal studies, the researchers hypothesized that POPs could contribute to
diabetes by causing excess fat deposition in the liver, which in turn can lead to insulin resistance.
To confirm and test their hypothesis, the researchers examined the levels of 30 environmental pollutants in blood plasma samples from 147 Asian
Indian participants, 45 to 84 years old, living in the San Francisco Bay Area. The researchers detected levels of numerous POPs that were much higher than levels previously found in other U.S. populations.
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The findings showed that people with higher levels of
DDT in their blood were more likely to be obese, store excess fat in their livers and show increased insulin resistance compared to people with lower levels.
Though more research is needed to establish a causal relationship, these findings could help explain the increased
diabetes risk for
Indian immigrants and have public health implications for the approximately 1.8 billion South Asians throughout the world, the researchers said.
The problem is not only unique to
India but also to many other countries in Asia that is still using
DDT as a pesticide in the agricultural and livestock industries.
Reference: Michele A. La Merrill et al. Exposure to Persistent Organic Pollutants (POPs) and Their Relationship to Hepatic Fat and Insulin Insensitivity among Asian Indian Immigrants in the United States, Environmental Science & Technology (2019). pubs.acs.org/doi/abs/10.1021/acs.est.9b03373 
