Objective: To examine 44-year trends in height, weight and BMI, and the prevalence of overweight/obesity and underweight in the elderly Japanese population because Japan, the country with the longest life expectancy, has the highest ageing population.
Design: Using the nationally representative cumulative data from the Japan National Health and Nutrition Survey 1973-2016, sex-specific and age-adjusted mean height, weight and BMI, and the prevalence of overweight/obesity and underweight were calculated for each year. Trend analyses were performed using the Joinpoint Regression Program. Next, changes in height, weight and BMI, and the prevalence of overweight/obesity and underweight were estimated for each age group (65-69, 70-79 and >80 years) according to the birth year groups.
Setting: Japan.
Participants: Individuals aged ≥65 years with complete data on height and body weight measurements (N 94 508).
Results: Trends in average height and weight increased over the four decades in both men and women. The prevalence of overweight/obesity dramatically increased and nearly tripled in men, accompanied with significantly decreased underweight prevalence. Furthermore, the increasing trend in average BMI and overweight/obesity prevalence in women reached a peak in 2002 and showed a decreasing trend thereafter, while a downward trend in underweight prevalence showed a gradual increase in women since 2003.
Conclusions: Trends in height, weight and BMI among the elderly population should continue to be closely monitored in parallel with the effects of dietary changes, energy intake and physical activity (step counts).
Keywords: BMI; Elderly; Japan; National Health and Nutrition Survey (NHNS).