Photo credit: Global Panorama

While scientists have established a clear link between a diagnosis of hypertension and high blood pressure during midlife and an increase in Alzheimer’s disease and dementia, the linkage between hypertension and mental impairment in the elderly is not consistent. To better understand how outside factors may influence these results, a study published in PLOS ONE attempted to factor in the effect that exposure to organochlorine pesticides may be influencing results. The study investigated 644 participants ages 60-85 who were given a cognitive test, tested for hypertension and submitted blood samples to test for exposure to six different organochlorine pesticides. When associations between only hypertension and low cognition were tested for, researchers found that participants with hypertension were slightly more likely to exhibit lower cognition. However, when participants were exposed to organochlorine pesticides, p,p'-DDT, p,p'-DDE and b-hexachlorocyclohexane and had hypertension, they were 2.5 – 3.5 times more likely to score lower on cognition tests. These results help explain why simple associations between patients with hypertension and cognitive impairment yield mixed results and suggest “the possibility of a certain role of OC pesticides in the development of hypertension-induced dementia.”