Later onset of hypertension increased the risk of dementia in Mild Cognitive Impairment in community

Objective To investigate the effect of later onset of hypertension on the progression of MCI in community. Methods Participants are from The Study (NO.PKJ2010-Y26, 2011), a population-based longitudinal cognition survey of people aged 55+, sampled by probability proportional to size cluster. Hypertension onset age was estimated by self-reported information and medical insurance card records, then classified into two groups: the middle-age group (onset age < 65 years) and the old-age group (onset age ≥ 65 years). In order to study the effect of later onset of hypertension on dementia, the incidence of dementia was compared between the two groups. Results A total of 277 hypertensive mild cognitive impairment (MCI) participants without dementia were followed for 6 years. 56 MCI participants (20.22%) progressed to dementia (MCIp). The proportion of MCIp participants in the old-age onset hypertension group (≥ 65 years) was higher than that of middle-age onset one (27.0% vs 15.4%; X2 = 5.538, P = 0.019). And in the old-age onset hypertension group, the proportion of MCIp without diabetes mellitus was higher than those with diabetes mellitus (24.7% vs 12.6%; X2 = 5.321, P = 0.021), and the proportion of MCIp with increased pulse pressure was higher than those without increased pulse pressure (33.3% vs 15.4%; X2 = 3.902, P = 0.048). However, the multivariate logistic regression analysis showed that older age was the only risk for MCIp (OR=0.732, p=0.029). Conclusions These results suggest that, later onset hypertension was harmful to cognition even in cases where the level of blood pressure maintained at 130/80mmHg with antihypertensive management. It is necessary to expand the research sample and improve the experimental methods for further confirmation.