Secular Trends in Obesity and Serum Lipid Values among Children in Oita City, Japan, during a 27-Year Period.

Aims: We assessed 27-year trends in obesity and blood lipid levels of 10-year-old children to estimate the risk of metabolic syndrome in adulthood.
Methods: Based on a screening program for lifestyle-related diseases in school children in Oita City, Japan, we evaluated secular trends in height, weight, percentage of overweight (POW), total cholesterol (TC), triglyceride (TG), HDL cholesterol (HDL-C), and non-HDL cholesterol (non-HDL-C) of fifth graders (median age: 10.8 years) in Oita City from 1991 to 2017. We focused on the secular trend in the percentage of children with inappropriate serum levels of each lipid. We also evaluated the long-term trends in the 95 ^th , 50 ^th , and 5 ^th percentiles for each parameter, as dependent variables, with the calendar year as an independent variable. Percentages of children with mild obesity (POW-20), moderate obesity (POW-30), and severe obesity (POW-50) were set as dependent variables.
Results: A total of 58,699 boys and 56,864 girls were evaluated during the study period. The percentage of children with severe obesity (POW-50) consistently increased during these years, and the 95 ^th percentile of degree of obesity significantly increased in both boys and girls. The plot of percentages of children with inappropriate levels of TC, TG, and non-HDL-C showed a mild inverted U shape during the study period. The HDL-C level typically decreased in the study period, and the TC, TG, and non-HDL-C levels were markedly higher while the HDL level was lower in obese children than in non-obese children.
Conclusion: The number of children with severe obesity increased, and obese children had higher percentages of inappropriate lipid levels than non-obese children. The rate of dyslipidemia with low HDL levels gradually increased in all children in Oita City, Japan, over the past 27 years.