Objective: To study the relationship between body mass index (BMI), hypertension and all-cause mortality in the elderly population in Beijing.
Methods: In 1992, a cohort of 3 257 people above 55 years old was selected from 3 different areas of Beijing, i.e. urban and suburbs (both plain and mountain areas). Information on physical condition, history of chronic diseases, self-perceived health, as well as smoking and drinking status was collected. Blood pressure, body height and weight were measured among 2 086 of 3 257 subjects.
Results: BMI was decreasing with age, while the prevalence of hypertension increased with age. Meanwhile the prevalence of hypertension increased with age as well as with BMI. There was a reverse relationship between BMI and all-cause mortality, i.e. the risk of death was 39.0% lower for those with BMI = 20.0 - 24.9 kg/m(2) (Hazard ratio: 0.61, 95% Confidence interval: 0.49 - 0.75) and 62% lower for those with BMI >/= 25.0 kg/m(2) (Hazard ratio: 0.38%, 95% Confidence interval: 0.29 - 0.49) than those with BMI < 20.0 kg/m(2). After controlling for age, gender, residential place, hypertension as well as self-perceive health status and cognition function, low BMI remained a significant and independent predictor to death.
Conclusion: The distribution of BMI was different in elderly from the youth. The findings suggested that it was important to control the body weight among the elderly hypertensives.