Persistent organic pollutants (POPs), such as dichlorodiphenyltrichloroethane (
DDT) and other
organochlorine compounds, are abundant in the environment and in foodstuffs from the Indian subcontinent. These environmental contaminants have been associated with a higher risk of diabetes in numerous studies. Asian Indians are well known to have a high risk of diabetes compared with other populations, and this risk is also found in migrant populations of Asian Indians in the United States, Europe, and elsewhere. We hypothesized that high plasma concentrations of POPs in Asian Indian migrants are linked to a variety of diabetes-related pathologies and explored the mechanism for the induction of these effects. We measured 30
environmental pollutants in plasma samples obtained from 147 participants in the
Metabolic syndrome and
Atherosclerosis in South Asians Living in America pilot study using a gas chromatography-tandem mass spectrometry analytical method that uses less than 0.5 mL of plasma. We found that plasma levels of
o,p'-DDT and
p,p'-DDT were independently associated with both body mass index (BMI) and waist circumference. Doubling the levels of the sums of these DDTs was associated with
insulin insensitivity (-0.38 Matsuda index, p = 0.001), increased adiposity (1.26 kg/m2 BMI and 3.58 cm waist circumference increase, p < 0.0001), circulating
insulin (12.9 mIU/L, p = 0.002), hepatic fat (-0.051 HU, p = 0.001), as well as increased odds of
obesity (OR = 2.17, p < 0.001, BMI-based; OR = 2.37, p = 0.001, waist-based),
prediabetes (OR = 1.55, p = 0.02), diabetes (OR = 1.72, p = 0.01), and
fatty liver (OR = 1.66, p = 0.01) in multivariable models accounting for confounding by age, sex, years in the US, education, and
fish protein. Furthermore, levels of DDTs were associated with increased hepatic fat and circulating
insulin, independent of
obesity and confounders. These findings suggest that exposure to DDTs may contribute to the risk of
metabolic disease among Asian Indians by affecting hepatic fat levels independent of
obesity.