[Surveillance of hyperlipidemia among young adults in an occupational setting]

This study was conducted to contribute to the improvement of occupational health surveillance. The subjects of the study were 461 young male workers born between April 1959 to March 1969, who worked at two plants in Tokyo, and who do not usually undergo examination of blood lipid levels at a routine health check-up program. The screening procedure was mainly based on the second report of the National Cholesterol Education Program Expert Panel (Adult Treatment Panel, ATP II). The proportion of the subjects with low HDL-cholesterol level (< 35 mg/dl) was 5.2% for workers in their late twenties (W20) and 8.4% for those in their early thirties (W30). For high LDL-cholesterol (130+ mg/dl), the proportion (underestimated due to non-fasting blood collection) was 7.2% for W20 and 13.5% for W30, and the difference was statistically significant (p < 0.05). Among subjects with low HDL, the proportion of subjects with total cholesterol (TC) being < 200 mg/dl was 94% (15/16) for W20 and 54% (7/13) for W30. This implies that it is difficult to detect subjects with low HDL from values for TC only especially among W20. Hence it is useful to examine HDL in combination with TC. Among subjects with TC being 200-239 mg/dl, the proportion (underestimated) of the subjects with high LDL was 40% for W20 and 26% for W30, and ATP II procedure would fail to incorporate most of them into a treatment program. Thus, accurate estimation of LDL is necessary for subjects with TC being 200+ mg/dl. Relationships of high HDL (60+ mg/dl) to exercise as well as low HDL to obesity (p < 0.05) were found among both age groups. The high prevalence of LDL and HDL abnormality found among the study subjects would imply that it is necessary to initiate evaluation of hyperlipidemia at younger ages and also ATP II procedure needs to be modified for proper surveillance.