1. Prevalence of Self-Reported Diabetes and Exposure to Organochlorine Pesticides among Mexican-Americans: Hispanic Health and Nutrition Examination Survey
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

2. 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

3. 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

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

5. Survey Characteristics
Hispanic Health and Nutrition Examination Survey (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

6. Pesticide Laboratory Analysis
U.S. Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC)
Half sample of persons aged 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)

7. 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)

8. Study Design
Sample persons 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

9. Sample Characteristics
Select Demographics of Mexican Americans Aged by Self-Reported Diabetes Status, HHANES
BMI
Diabetic (n=89)
Non Diabetic (n=1214)
> 29.9 (obese)
35 (12.1%)
233 (87.9%)
(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%)

10. Sample Characteristics
Select Demographics of Mexican Americans Aged by Self-Reported Diabetes Status, HHANES
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%)

11. 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 ( )
0.0088
4.76 ± 0.08
0.0326
ppb (Below Median)
2.59 ( )
---
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

12. oxychlordane Self-reported diabetes Adjusted OR (95% CI) Trend p value
Non-fasting serum glucose
Mean ± SE
(mg/dL)
> ppb (Above Median)
3.25 ( )
0.0298
4.72 ± 0.11
0.2170
ppb (Below Median)
2.97 ( )
---
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

13. 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 ( )
0.0212
4.65 ± 0.05
0.2009
ppb (Below Median)
1.43 ( )
---
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

14. p, p’-DDE Self-reported diabetes Adjusted OR (95% CI) Trend p value
Non-fasting serum glucose
Mean ± SE
(mg/dL)
> ppb
(4th quartile)
2.63
( )
0.0151
4.64 ± 0.04
0.0805
ppb (3rd quartile)
2.43
( )
---
4.58 ± 0.02
0.7347
ppb (2nd quartile)
1.42
( )
4.59 ± 0.03
0.4474
< 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

15. 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 ( )
0.0625
4.72 ± 0.04
0.0029
ppb (Below Median)
1.73 ( )
---
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

16. 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 ( )
Values above median concentration compared to values below the minimum detectable limit

17. 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

18. 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

19. 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

20. 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