Estimating missing concentrations of p,p′- DDT in the 1999–2004 National Health and Nutrition Examination Survey using multiple imputation

Abstract

We investigated the association between diabetes and p,p′-DDT (dichlorodiphenyltrichloroethane) in blood of Mexican Americans who participated in the 1999–2004 National Health and Nutrition Examination Survey (NHANES). In this sample, p,p′-DDT were missing in 50% of subjects and we used multiple imputation (MI) to address the problem. Compared to ignoring the missing data, MI led to a more robust threshold for the p,p′-DDT reference category. Whereas previously p,p′-DDT ≤ 0.0860 ng/g was used as the reference category, using MI, we were able to use p,p′-DDT < 0.0574 ng/g as the reference category to study the association between p,p′-DDT and diabetes via logistic regression. In this analysis, p,p′-DDT ≥ 0.0750 ng/g was associated with an odds ratio of 1.99 (95% CI 1.09–3.61) for diabetes and 4.20 (95% CI 1.93–9.12) for diabetic nephropathy. The reference category for diabetes without nephropathy outcome stayed consistent after MI but our analysis confirmed that p,p′-DDT > 0.0860 ng/g was associated with diabetes without nephropathy with an odds ratio of 1.89 (95% CI 1.09–3.27). Our study showed that MI can be effectively used to deal with missing at random data in persistent organic pollutants measured in the 1999–2004 NHANES.

from Climate Change Skeptic Blogs via hj on Inoreader http://bit.ly/2H0nWSD