BODY MASS INDEX AS A PREDICTOR OF MORTALITY IN OLDER PEOPLE IN TAIWAN (1982–2005)

Background: Obesity is associated with diverse health risks, but its role as a risk factor for death remains controversial
in the elderly. This study estimated the association of body mass index (BMI) with the risk of death
from any cause and from specific diseases in elderly Taiwanese.
Methods: The Six-Community Hypertension Intervention Project Study, a nationwide population-based cohort,
was conducted in 1982 and followed up for 23 years. Cause of death was ascertained by review of death certificate
files. Proportional hazards models were used to evaluate the association between the baseline BMI and
risk of death.
Results: Of 1,568 participants aged 65 years (range, 60–75 years) at study entry, 1,085 (69%) died during
follow-up. The relationship between death from any cause and BMI follows a J-shaped pattern. Increasing BMI
categories were associated with increased risk of all-cause mortality (BMI, 25–26.9: hazard ratio, HR, 1.36; 95%
confidence interval, CI, 1.11–1.67; BMI ≥ 27: HR, 1.46; 95% CI, 1.15–1.85). Death from diabetes, cardiovascular
diseases or cancer increased progressively with increasing categories of BMI, and HRs were significantly increased
at BMI levels >23.0 kg/m2 (BMI, 23–24.9: HR, 1.29; 95% CI, 1.05–1.60; BMI, 25–26.9: HR, 1.58; 95% CI, 1.21–2.05;
BMI ≥ 27: HR, 1.74; 95% CI, 1.29–2.35). These associations were more obvious in men than in women.
Conclusion: This study found that BMI > 25 kg/m2 was a significant independent predictor of all-cause mortality,
especially among older men. BMI > 23 kg/m2 also increased risk of mortality from cancer, cardiovascular
diseases and diabetes. The relationship was J-shaped in older Taiwanese. [International Journal of Gerontology
2009; 3(1): 39–46]
Key Words: body mass index, elderly, mortality, obesity, Taiwan