β-hexachlorocyclohexane as a risk for Alzheimer’s disease: A pilot study in North Indian Population

Abstract

The notion of potential existence of gene environment interaction (GxE) in Alzheimer's disease (AD) has substantial impact on understanding the role of genetic and non-genetic contribution to this disorder. Keeping in mind this background we examined the genetic and environmental factors which may determine their relative contribution to AD. Based on well defined inclusion and exclusion criteria this study includes 70 AD patients and 75 age-matched controls. Organochlorine Pesticides (OCPs) were analyzed in blood by using gas chromatography and serum metals were analyzed by using an autoanalyser. The LRPAP1 and APOE gene polymorphism were determined by polymerase chain reaction and restriction fragment length polymorphism respectively. The frequency of APOE ε4 allele and LRPAP1 I allele were significantly high (p=0.000 for both allele) in AD patients as compared to controls. The significantly high levels of β-hexachlorocyclohexane (β-HCH) and dieldrin are risk factors for AD independent of the genetic risk factor, recording an odds ratio of 2.777 and 2.344 respectively. This study suggests that out of the environmental factors, high β-HCH levels were the best predictor of presence of AD independent of the genetic component and low levels of serum iron play a protective role against AD.