Coronary heart disease risk factors in relation to the menopause

The incidence of coronary heart disease increases after the menopause, but the mechanism is unclear. We assessed the relationship of age to fasting plasma insulin, total triglycerides, total cholesterol, total high density lipoprotein (HDL) cholesterol, including HDL2 and HDL3 subfractions, total/HDL cholesterol ratio, body mass index and waist-hip circumference ratio in 394 women and 824 men aged 40-69 years who participated in an epidemiological survey in East Bristol. Women over the age of 50 years were assumed to be post-menopausal, this being the median age of the menopause in Britain. Compared to younger women, post-menopausal women had higher plasma triglycerides by 0.31 mmol/l (95 per cent confidence interval 0.10-0.43), higher cholesterol by 1.0 mmol/l (0.77-1.24), higher total/HDL cholesterol ratio by 0.42 (0.15-0.69), higher insulin by 2.0 mU/l (0.02-0.11), higher body mass index by 0.9 kg/m2 (0.02-1.68), and higher waist-hip ratio by 0.02 (0.01-0.03). Age-related changes in men were absent or less marked. On multiple regression analysis the increases in plasma total triglycerides, total cholesterol, high density lipoprotein cholesterol, HDL3 cholesterol and total/HDL cholesterol ratio in postmenopausal women were independent of body mass index, waist-hip ratio, cigarette habits, alcohol consumption and antihypertensive therapy. On analysis of covariance sex had a significant effect on all variables which was independent of age. We conclude that there is an increase in coronary heart disease risk factors in women as they pass through the menopause, and insulin may play a central role.