Changes in serum lipid levels during a 10 year period in a large Japanese population. A cross-sectional and longitudinal study.

To determine the recent secular trends in serum lipid levels and characterize their influence on the aging process, we examined a large cohort of Japanese cross-sectionally and longitudinally. The participants included 80331 Japanese men and women 20-79 years of age, who had received annual health examinations from 1989 to 1998. In cross-sectional analysis, an increase in total and LDL cholesterol as well as triglyceride levels was observed in the population during the period of 1989-1998. The longitudinal changes showed that total and LDL cholesterol increased with age in men between the birth cohorts of the 1920s and 1960s. In women, these cholesterol levels increased in the 1930s and younger cohorts. HDL cholesterol decreased in men of all birth cohorts. However, HDL cholesterol increased in women of the 1940s and younger cohorts. Triglyceride levels increased in men of the 1940s and younger cohorts but decreased in the 1930s and older. Triglyceride levels increased in women of the 1930s and younger. Longitudinal analysis also suggested a birth cohort effect except for the triglyceride level for women. These results suggest that Japanese serum lipid levels continue to increase and that there exist birth cohort effects regarding serum lipid levels in the Japanese population.