DDT and its metabolites are linked to increased risk of type 2 diabetes among Saudi adults: a cross-sectional study

Organochlorine (OC) pesticides have recently been associated with type 2 diabetes in several non-Asian general populations. As there is currently an epidemic of type 2 diabetes mellitus in Asia. The prevalence and incidence of diabetes is increasing rapidly worldwide including many Arab Gulf countries. According to a community-based national epidemiological health survey, the overall prevalence of diabetes mellitus in Saudi adults (age group of 30–50 years) is 23.7 %. A recent study by Al-Daghri et al. (BMC Med 9:76, 2011) reported that the prevalence of diabetes mellitus in the Kingdom of Saudi Arabia (KSA) is 31.6 %. We investigated the associations between OC pesticides and type 2 diabetes in Saudi Arabia using a simple, sensitive, rapid, and selective gas chromatography coupled with mass spectrometry (GC-MS) method that has been recently developed. A total of 280 Saudi adults (136 diabetes mellitus (DM) patients and 144 non-DM controls) were randomly selected from the Riyadh Cohort Study for inclusion. The diagnosis of diabetes was based on established diagnosis and medications taken. Blood dichlorodiphenyltrichloroethane (DDT) and its derivatives were quantified using GC-MS. Residues of DDT and its derivatives were analyzed in serum by means of gas chromatography with a mass spectrometry detector. Associations between DDT exposure and T2DM were analyzed by logistic regression. DDT and its derivatives and serum concentrations of DDT and its derivative DDE showed the strongest and most significant association to type 2 diabetes in both cross-sectional and prospective studies. Associations of DDT and its derivatives varied across different diabetes-related components of the metabolic syndrome. It positively and significantly associated with four of the five of these components especially elevated triacylglycerol, high fasting glucose, high blood pressure, and HOMA-IR but negatively and significantly with HDL. Possible biological mechanisms are discussed. This study confirms previous reports relating organochlorine pesticide (OCP) exposure to diabetes and suggests possible hormonal pathways deserving further exploration. The study will be one of the first to shed light on the associations of serum levels of total DDTs and DDT derivatives among the Saudi Arab ethnicity, and diabetes type 2 chronic noncommunicable diseases are highly prevalent.