Association of Organochlorine Pesticides with Peripheral Neuropathy in Patients with Diabetes or Impaired Fasting Glucose

OBJECTIVE Recent epidemiological studies have shown that background exposure to persistent organic pollutants (POPs)--xenobiotics accumulated in adipose tissue--is strongly associated with type 2 diabetes. Hyperglycemia is the cause of long-term complications of diabetes as well as diabetes itself, and POPs are well-known neurotoxicants. This study was performed to explore whether POPs are associated with peripheral neuropathy, a common long-term complication of diabetes, in people with glucose abnormalities. RESEARCH DESIGN AND METHODS We studied cross-sectional associations of peripheral neuropathy with 25 POPs, each of which were detectable in at least 60% of study subjects, in 246 subjects aged >or=40 years with diabetes or impaired fasting glucose (IFG) using National Health and Nutrition Examination Survey 1999-2002 datasets. RESULTS Among five subclasses of POPs, organochlorine pesticides showed a strong dose-response relation with prevalence of peripheral neuropathy; adjusted ORs were 1.0, 3.6, and 7.3 (P for trend <0.01), respectively, across three categories of serum concentrations of organochlorine pesticides. Furthermore, when we restricted the analyses to 187 participants with A1C <7%, the adjusted ORs were still 1.0, 3.9, and 6.7 (P for trend <0.01). Organochlorine pesticides were also strongly associated with the prevalence of A1C >or=7%; adjusted ORs were 1.0, 2.5, and 5.0 (P for trend <0.01). Specific POPs belonging to organochlorine pesticides showed similar positive associations. CONCLUSIONS This study suggests that background exposure to organochlorine pesticides may be associated with higher risk of peripheral neuropathic complications among those with glucose abnormalities, even beyond the influence of diabetes itself.