Prevalence of Self-Reported Diabetes and Exposure to Organochlorine Pesticides among Mexican-Americans: Hispanic Health and Nutrition Examination Survey 1982-1984 Shanna Cox, MSPH1, Amanda Sue Niskar, DrPH, RN2, K.M. Venkat Narayan, MD1, PhD, Michele Marcus, PhD1 1 Rollins School of Public Health, Emory University 2 Department of Environmental and Occupational Health, School of Public Health, Tel Aviv University

Background Hispanics represent fastest growing minority group in United States The estimated lifetime risk of developing diabetes for Hispanic individuals in the U.S. is 50% Prevalence of diabetes twice as high for Mexican-Americans than non-Hispanic Whites Diabetes mellitus is an endocrine-related disorder

Background Endocrine disruptors are exogenous agents that interfere with the synthesis and/or action of natural hormones in the body Organochlorine compounds identified as potential endocrine disruptors Studies suggest diabetes may be associated with various organochlorine compounds (dioxins, PCBs, DDT, chlordane) Altered glucose transport activity proposed mechanism Serum levels of organochlorine pesticides highest in Mexican-Americans

Hypothesis Organochlorine pesticide exposure is associated with diabetes among Mexican-Americans in the Southwestern United States

Survey Characteristics Hispanic Health and Nutrition Examination Survey 1982-1984 (HHANES) Largest and most comprehensive Hispanic health survey in the United States Data were collected on 3 subgroups of the 1980 United States Hispanic population Bilingual interviewers collected socioeconomic, health and demographic data Physical examinations were administered

Pesticide Laboratory Analysis U.S. Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) Half sample of persons aged 20-74 years not scheduled for the oral glucose tolerance test Serum organochlorine concentrations were measured by electron capture gas chromatography Measurements are based on the minimum detectable limit (MDL) of laboratory method and reported in parts per billion (ppb)

Pesticide Laboratory Analysis 7 compounds found above the MDL in > 1% of HHANES serum samples dieldrin hexachlorobenzene (HCB) trans-nonachlor oxychlordane p, p’-DDT p, p’-DDE beta-hexachlorocyclohexane (beta-HCH)

Study Design Sample persons 20-74 years of age of Mexican or Mexican American ancestry (n=1303) 89 persons self-reported diabetes Do you have diabetes or sugar diabetes? Did a doctor tell you that you have it? Exposure categorized by distribution among self-reported diabetics Logistic regression models Least square means of non-fasting serum glucose levels

Sample Characteristics Select Demographics of Mexican Americans Aged 20-74 by Self-Reported Diabetes Status, HHANES 1982-1984 BMI Diabetic (n=89) Non Diabetic (n=1214) > 29.9 (obese) 35 (12.1%) 233 (87.9%) 25.0-29.9 (overweight) 40 (6.0%) 464 (94.0%) < 25.0 (normal or underweight) 14 (2.0%) 517 (98.0%) Age 55-74 53 (25.6%) 163 (74.4%) 45-54 21 (7.2%) 235 (92.8%) 20-44 15 (1.6%) 816 (98.4%)

Sample Characteristics Select Demographics of Mexican Americans Aged 20-74 by Self-Reported Diabetes Status, HHANES 1982-1984 Alcohol Diabetic (n=89) Non Diabetic (n=1214) Current 24 (2.56%) 631 (97.44%) Former Drinker 11 (16.43%) 51 (83.57%) Non Drinker 54 (8.39%) 530 (91.61%) Education > HS 6 (2.38%) 211 (97.62%) High school 20 (2.56%) 487 (97.44%) < HS 63 (10.39%) 497 (89.61%)

trans-nonachlor Self-reported diabetes Adjusted OR (95% CI) Trend p value Non-fasting serum glucose Mean ± SE (mg/dL) > 1.80 ppb (Above Median) 3.35 (1.42-7.89) 0.0088 4.76 ± 0.08 0.0326 1.00-1.80 ppb (Below Median) 2.59 (0.94-7.15) --- 4.70 ± 0.05 0.0270 < 1.00 ppb (Below MDL) 1.00 4.57 ± 0.01 MDL Minimum Detectable Limit Odds ratio adjusted for age at examination and body mass index Least-squares means adjusted for age at examination and body mass index

oxychlordane Self-reported diabetes Adjusted OR (95% CI) Trend p value Non-fasting serum glucose Mean ± SE (mg/dL) > 1.265 ppb (Above Median) 3.25 (1.21-8.68) 0.0298 4.72 ± 0.11 0.2170 1.00-1.265 ppb (Below Median) 2.97 (0.71-12.48) --- 4.65 ± 0.06 0.2246 < 1.00 ppb (Below MDL) 1.00 4.58 ± 0.01 MDL Minimum Detectable Limit Odds ratio adjusted for age at examination and body mass index Least-squares means adjusted for age at examination and body mass index

p, p’-DDT Self-reported diabetes Adjusted OR (95% CI) Trend p value Non-fasting serum glucose Mean ± SE (mg/dL) > 3.70 ppb (Above Median) 2.90 (1.24-6.80) 0.0212 4.65 ± 0.05 0.2009 2.00-3.70 ppb (Below Median) 1.43 (0.51-3.99) --- 4.64 ± 0.04 0.0505 < 2.00 ppb (Below MDL) 1.00 4.57 ± 0.01 MDL Minimum Detectable Limit Odds ratio adjusted for age at examination and body mass index Least-squares means adjusted for age at examination and body mass index

p, p’-DDE Self-reported diabetes Adjusted OR (95% CI) Trend p value Non-fasting serum glucose Mean ± SE (mg/dL) > 58.60 ppb (4th quartile) 2.63 (1.20-5.75) 0.0151 4.64 ± 0.04 0.0805 39.10-58.60 ppb (3rd quartile) 2.43 (1.03-5.72) --- 4.58 ± 0.02 0.7347 22.81-39.10 ppb (2nd quartile) 1.42 (0.55-3.65) 4.59 ± 0.03 0.4474 < 22.81 ppb (1st quartile) 1.00 4.57 ± 0.01 MDL Minimum Detectable Limit Odds ratio adjusted for age at examination and body mass index Least-squares means adjusted for age at examination and body mass index

beta-HCH Self-reported diabetes Adjusted OR (95% CI) Trend p value Non-fasting serum glucose Mean ± SE (mg/dL) > 2.10 ppb (Above Median) 2.71 (0.89-8.22) 0.0625 4.72 ± 0.04 0.0029 1.00-2.10 ppb (Below Median) 1.73 (1.08-2.76) --- 4.59 ± 0.02 0.0883 < 1.00 ppb (Below MDL) 1.00 4.56 ± 0.01 MDL Minimum Detectable Limit Odds ratio adjusted for age at examination and body mass index Least-squares means adjusted for age at examination and body mass index

Results Self-reported diabetes is significantly associated with exposure to trans-nonachlor, oxychlordane, p, p’-DDT, p, p’-DDE and beta-BHC Elevated serum glucose levels among those with highest exposure levels to trans-nonachlor and beta-BHC Upon correction for serum lipids, the relationship between p, p’-DDT and self-reported diabetes remained significant OR 2.31;95% CI (1.08-4.95) Values above median concentration compared to values below the minimum detectable limit

Limitations Cross-sectional survey design makes temporality unclear Occupations (work in pesticide processing plant and farm work) associated with higher prevalence of diabetes Do not have clinical confirmation of diabetes Missing data Lack of specificity

Strengths Consistency Results confirmed over various study designs, exposure levels, time periods and communities. One-to-one individual record linkage for laboratory and health self-report data

Conclusions Exposure to trans-nonachlor, oxychlordane, p, p’-DDT, p, p’-DDE and beta-BHC were associated with a higher prevalence of diabetes among Mexican Americans in the Southwestern United States Results suggest a dose-response relationship

Public Health Implications Widespread, long-term, chronic exposure to organochlorines in general population Obesity hypothesis Effect of association higher among obese individuals No association between obesity and diabetes among those without detectable levels of organochlorine compounds (Lee et al 2006, 2007 Diabetes Care) Need for longitudinal study Causality and mechanism of action unclear