Sociodemographic Correlates of Four Indices of Blood Pressure and Hypertension among Older Persons in Japan

Abstract

Background: High blood pressure is a significant risk factor for cardiovascular disease and mortality. Japan has traditionally had higher levels of measured blood pressure than many Western countries, and reducing levels of hypertension has been a major focus of Japanese health policy over recent decades. In the West, hypertension is strongly associated with sociodemographic and behavioral (smoking and body mass index, BMI) factors; studies of the association between sociodemographic factors and biological indicators have not been fully explored in the elderly population of Japan using nationally representative survey data. Objective: To describe hypertension prevalence rates with increasing age and to examine the link between sociodemographic and behavioral factors (including age, gender, education, residence, smoking, and BMI) and measures of blood pressure and overall hypertension in the Japanese population aged ≥68 years. Methods: Data were collected in 2006 during the fourth wave of the Nihon University Japanese Longitudinal Study of Aging, a nationally representative sample of those ≥68. The analytic sample includes 2,634 participants. Pulse pressure, systolic, diastolic, and mean blood pressure, as well as hypertension, were regressed on sociodemographic and behavioral factors. Results: There is no significant difference in the prevalence of overall hypertension by age for men and women from ages 68-69 to 90+. Higher BMI and older age were linked to higher blood pressure and higher chance of having hypertension. More years of education and being female were associated with a lower likelihood of measured hypertension. Smoking, rural residence, and living alone were not significantly associated with the outcome measures. Conclusion: The increase in hypertension with higher BMI raises concerns about future health in Japan as BMI increases. The lack of a relationship between smoking and any measure of blood pressure or hypertension is an indicator that smoking may have different effects in Japan than in other countries. Because there is no effect of living alone on blood pressure, compliance with drug regimes may not be enhanced by living with others in Japan.