Prevalence of Self-Reported Diabetes and Exposure to Organochlorine Pesticides among Mexican Americans: Hispanic Health and Nutrition Examination Survey, 1982-1984
Cox, Shanna, Niskar, Amanda Sue, Narayan, K. M. Venkat, Marcus, Michele, Environmental Health Perspectives
A Hispanic individual in the United States has one chance in two of developing diabetes sometime during his or her lifetime (Narayan et al. 2003). Hispanics represent the fastest-growing minority group in the United States. Among the Hispanic population, two-thirds are of Mexican origin (Ramirez and de la Cruz 2002). The prevalence of diabetes is twice as high for Mexican Americans than for non-Hispanic whites (Haffner 1998).
In the United States, serum levels of organochlorine pesticides and metabolites are highest in Mexican Americans and those who reside in the southwestern regions of the United States [Centers for Disease Control and Prevention (CDC) 2005; Stehr-Green 1989]. The U.S. Environmental Protection Agency (EPA) banned most uses of these compounds during the 1970s and 1980s, and serum levels of organochlorine pesticides in the United States have decreased over time; however, exposure among the general population persists through bioaccumulation of these compounds in the food chain (CDC 2005). DDT (dichlorodiphenyltrichloro-ethane) continues to be used for malaria vector control in parts of Africa and India.
Evidence of an association between persistent environmental contaminants and diabetes has begun to accumulate. Accidental environmental releases (Pesatori etal. 1998) and occupational exposures related to the manufacture or application of organochlorines has been associated with diabetes morbidity and mortality (Beard et al. 2003; Laws et al. 1967; Morgan etal. 1980; Vena etal. 1998). Limited and inconclusive data have linked higher serum levels of polychlorinated biphenyls (PCBs) with increased risk of type I diabetes (Longnecker et al. 2001). In 1999, the Institute of Medicine (2000) concluded that there was limited, suggestive evidence of an association between exposure to herbicides contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and type II diabetes. A study among an elderly Swedish cohort found that diabetics had significantly higher serum levels of persistent organochlorine pollutants than nondiabetic control subjects (Rylander et al. 2005). More recently, cross-sectional studies of a nationwide probability sample representative of the general population of the United States have found a strong association between diabetes and a range of persistent environmental contaminants including dioxins, PCBs, and organochlorine pesticides (Everett et al. 2006; Lee et al. 2006). Serum levels of PCBs measured before the development of adult-onset diabetes among a cohort of Michigan women were significantly associated with diabetes incidence (Vasiliu etal. 2006).
Because exposure to persistent environmental contaminants differs by place and has changed over time, population and period effects are plausible (Porta 2006). The association between diabetes and exposure to persistent organic pollutants was found to be stronger among Mexican Americans (Lee et al. 2006) than among non-Hispanic whites or African Americans. The Hispanic Health and Nutrition Examination Survey (HHANES) is the largest and most comprehensive Hispanic health survey in the United States (Delgado et al. 1990). This cross-sectional study investigates the relationship between individual serum organochlorine pesticide concentrations and the prevalence of self-reported diabetes among the 1980 Mexican-American population residing in the southwestern region of the country.
Materials and Methods
Study population. The HHANES was conducted by the CDC National Center for Health Statistics in 1982-1984 (Delgado et al. 1990). The HHANES was a stratified multistage probability sample of three Hispanic subgroups of the population: Mexican Americans residing in Arizona, California, Colorado, New Mexico, and Texas; Puerto Ricans residing in the New York City metropolitan area (including parts of New York, New Jersey, and Connecticut); and Cuban Americans residing in Dade County, Florida (Delgado et al. …