Serum high-density lipoprotein cholesterol level and lifestyle habits among Japanese junior high school students

Abstract

Purpose: Many epidemiological studies have revealed a consistent inverse association between High-Density Lipoprotein Cholesterol (HDL-C) level and the risk of coronary heart disease in adults. Frequent Japanese style diet, which is characterized by adequate total calories, increased intake of fish and plant foods, and decreased intake of animal fat, has been shown to cause an elevation of HDL-C level. The present study was designed to examine the relationship between serum HDL-C level and dietary patterns and habits and physical activity in a sample of healthy Japanese junior high school students. Methods: Between April 2006 and March 2009, we conducted a cross-sectional study of 1064 Japanese junior high school students (570 boys and 494 girls, aged 12.1 to 15.0 years) who had annual school health examinations and received care programs for prevention of lifestyle-related diseases. The students underwent measurements of resting blood pressure, waist circumference, and weight and provided overnight fasting venous blood samples. Each participant was then asked to complete a simple self-administered questionnaire addressing lifestyle factors, such as dietary patterns and habits and physical activity, as well as the co-existence of cardiometabolic risk factors. Results: Students in the lowest quartile of HDL-C (< 55 mg/dL for boys and < 56 mg/dL for girls) showed increased prevalence of abdominal obesity, hypertriglyc-eridemia, and increased fasting plasma glucose compared with the highest quar-tile (> 74 mg/dL for boys and > 75 mg/dL for girls). In both genders, the ratios of students who were often commuting to and from school by car were significantly higher and who were liking exercise and doing sports outside of school were lower in the lowest quartile of the students compared with those who showed HDL-C level more than these values. The ratio of students who were watching television during meals was significantly higher in boys with lower HDL-C level than those without. There was no significant difference in other dietary patterns or habits between students with and without low HDL-C level in both genders. Conclusions: Serum lower HDL-C level was strongly associated with reduced daily physical activity among junior high school students. This study may provide insights into the role of HDL-C in the school screening system for the development of more effective educational programs on prevention of lifestyle-related diseases in the Japanese population of school children