(HealthDay News) — People exposed to elevated levels of the metabolite of the pesticide dichlorodiphenyltrichloroethane (DDT) are at higher risk of Alzheimer’s disease (AD), particularly if they carry a particular apolipoprotein E (APOE) genotype, according to a study published online January 27 in JAMA Neurology.
Jason R. Richardson, PhD, from Rutgers University in Piscataway, NJ, and colleagues measured dichlorodiphenyldichloroethylene (DDE) levels, the metabolite of DDT, in 79 controls and 86 patients with AD and examined whether APOE genotype affected the association.
The researchers found that serum DDE levels were 3.8-fold higher in patients with AD, and patients in the highest tertile of DDE levels had a significantly higher risk of AD (odds ratio, 4.18). These patients also had significantly lower Mini-Mental State Examination scores, which were significantly lower in patients with the APOE ε4 allele compared with the APOE ε3 allele. Serum and brain levels of DDE were highly correlated, and both DDT and DDE increased the levels of amyloid precursor protein in neuroblastoma cells.
“Elevated serum DDE levels are associated with an increased risk for AD and carriers of an APOE4 ε4 allele may be more susceptible to the effects of DDE,” Richardson and colleagues conclude.