Abstract
We examined serum cholesterol and fatty-acid levels of cord blood and maternal blood samples collected from 193 Japanese fetuses and their mothers. Our study, which is the largest study of this kind ever conducted in Japan, is the first Japanese study reporting that total, high density lipoprotein (HDL) and non-HDL cholesterol levels in females were statistically significantly higher than those in males; the sex differences of total, HDL and non-HDL cholesterol levels were 8.5 mg/dl (P= 0.002), 4.5 mg/dl (P= 0.004) and 4.1 mg/dl (P= 0.045), respectively. The sex difference of total cholesterol was attributable to both HDL and non-HDL cholesterol. The sex of fetuses didn't show evident differences in cholesterol levels in maternal sera. Fatty-acid levels in cord blood were also higher in female fetuses than in male fetuses. However, none of the differences except for monoene fatty acids were statistically significant. Further investigations seem warranted to elucidate the mechanisms involved in our results. J Epidemiol, 1997; 7 : 226-231.