Associations of overweight, obesity, and underweight with high serum total cholesterol level over 30 years among the Japanese elderly: NIPPON DATA 80, 90, and 2010

Background: The trend of association between overweight and high serum total cholesterol (TC) among the elderly is unclear. In addition, there is little evidence of risk of underweight for high TC. Therefore, we examined the trend of association of overweight or underweight with high TC among Japanese elderly people using nationwide population-based data. Methods: Data of the National Survey on Circulatory Disorders and National Health and Nutrition Survey for 1980, 1990, 2000, and 2010 were used in the analysis. High TC was defined as 220mg=dL and above. For participants aged =50 years, sex-specific odds ratios (ORs) of overweight or underweight compared with normal body mass index participants for high TC were calculated using a logistic regression model adjusted for age, smoking, drinking, exercise, food, and treatment of hyperlipidemia. Results: A total of 5,734, 4,673, 5,059, and 2,105 participants enrolled in these surveys in 1980, 1990, 2000, and 2010, respectively. Although overweight was positively and significantly associated with high TC in 1980, the association has gradually weakened since (ORs in 1980 and 2010 were 2.44; 95% confidence interval [CI], 1.83-3.24 and 0.92; 95% CI, 0.66-1.27 among men and 1.43; 95% CI, 1.18-1.72 and 1.08; 95% CI, 0.81-1.44 among women, respectively). While underweight was inversely and significantly associated with high TC in 1980, the association also gradually weakened among women (ORs in 1980 and 2010 were 0.28; 95% CI, 0.12-0.60 and 0.37; 95% CI, 0.10-1.28 among men and 0.39; 95% CI, 0.26-0.57 and 0.96; 95% CI, 0.58-1.57 among women, respectively). Conclusions: These findings provide evidence that high TC prevention efforts must expand the target to not only overweight but also to normal and underweight people.