Comprehensive assessment of the impact of blood pressure, body mass index, smoking, and diabetes on healthy life expectancy in Japan: NIPPON DATA90.

Background: Healthy life expectancy (HLE) is a population health indicator that is widely used in developed countries, but little is known about its relationships with combinations of non-communicable disease risk factors. This study was conducted to examine HLE at age 65 according to combinations of blood pressure levels, body mass index, smoking status, and diabetes mellitus (DM) in a Japanese population.

Methods: In a nationwide cohort study (NIPPON DATA90), data on these risk factors were obtained from participants in 1990 through physical examinations, blood tests, interviews, and questionnaires. Subsequently, participants aged ≥65 years underwent surveys on activities of daily living in 1995 and 2000, and multistate life tables were used to calculate combination-specific HLEs and their 95% confidence intervals (CIs).

Results: The study population comprised 6,569 participants (men: 2,797; women: 3,772) who were followed-up until 2010. HLE at age 65 in men with grade II/III hypertension, obesity, current smoker status, and DM (HLE: 12.9 years, 95% CIs: 12.9-13.0 years) was 9.7 years shorter than men without these risk factors (HLE: 22.6 years, 95% CIs: 22.4-22.8 years). Similarly, HLE at age 65 in women with grade II/III hypertension, obesity, current smoker status, and DM (HLE: 16.2 years, 95% CIs: 15.9-16.5 years) was 10.1 years shorter than women without these risk factors (HLE: 26.3 years, 95% CIs: 26.3-26.3 years).

Conclusion: The large discrepancies in HLEs underscore the impact of non-communicable disease risk factors, which should be considered when formulating health interventions to improve HLE in Japanese older adults.