Relationship between hypertension and health in the elderly population of Japan

In general, the Japanese population is relatively healthy, with low rates of heart disease, obesity, diabetes, functioning difficulties, and the longest life expectancy in the world. At the same time, Japan has high rates of hypertension. Japan provides a unique opportunity to examine how various aspects of health influence each other and mortality in a relatively healthy population. The findings in the literature suggest that disease states might differentially influence health in different countries; compared to Japan, the United States has low life expectancy and higher rates of heart disease, obesity, diabetes, and functioning difficulties, however, the US has lower rates of hypertension compared to Japan. Using the Nihon University Japanese Longitudinal Study of Aging (NUJLSOA) (n=2195) this study examined the influence of hypertension on different aspects of health, namely mortality and cognitive performance, in the elderly population of Japan. Contrary to the literature on the US, in Japan hypertension was neither associated with mortality (OR: 0.91, 95% CI: 0.55-1.51) nor with cognitive performance using logistic and OLS-regression, respectively. Additionally, in a model that included hypertension, education, gender, and common hypertension comorbidities (diabetes, heart disease, and obesity) there was no association between the comorbidities and mortality. However, the female gender was associated with reduced mortality (OR: 0.50, 95% CI: 0.33-0.75). The findings suggest that aging may be conceptualized differently in different countries; in the US and other Western countries it appears that aging might be a constellation of diseases, whereas in Japan this is not the case.