High lipid levels and coronary disease in women in Göteborg--outcome and secular trends: a prospective 19 year follow-up in the BEDA*study.

AIMS: To provide contemporary data on the effect of high cholesterol and high triglycerides on the risk of coronary heart disease (CHD) and mortality in Swedish women and to describe secular trends with respect to serum lipids, body mass index (BMI) and smoking in the source population.

METHODS: We followed 1372 women aged 39-64 years and without prior cardiovascular disease from 1980 to 1999 through record-linkage with the Swedish hospital discharge and cause-specific death registers. Risk factor measurements were done at baseline. Every fifth year between 1980 and 1995 coronary risk factors were assessed in independent samples of the source population.

RESULTS: In multivariate analyses, a 1 mmol increase in cholesterol was associated with a 51% increased risk of myocardial infarction (MI) and/or revascularisation (MI; p<0.0001) and a 30% increased risk of being hospitalised for CHD (p<0.0004). Women with cholesterol, 7-7.9 mmol/l, had a threefold risk of MI (HR 3.44 (1.63-7.23)) and hazard ratios in the highest cholesterol category, > or =8 mmol/l, was 4.49 (1.92-10.50) as compared to women with cholesterol below 6 mmol/l. A 1 mmol increase in triglycerides was associated with a 49% increased risk of MI (p=0.002) and a 45% increased risk of being hospitalised for CHD (p=0.001) after adjustment for major coronary risk factors. A moderate increase in triglycerides, 1.0-1.5 mmol/l, conferred no significant increase in risk of coronary events as compared to below 1.0 mmol/l. Women with high triglycerides, 1.5-1.9 mmol/l, had a doubled risk of MI (HR 2.55 (1.20-5.42)) and hazard ratios in the highest triglyceride category, > or =2.0 mmol/l, was 3.35 (1.48-7.60). Both high cholesterol and high triglycerides predicted mortality but the magnitude was smaller than for coronary events. During the study period the proportion of women with low cholesterol profile, below 6.0 mmol/l, increased on average from 49 to 68% and the proportion of women with low triglyceride levels, below 1.0 mmol/l, decreased from 59 to 36% in the source population. A modest increase in BMI was noted.

CONCLUSIONS: Both high fasting cholesterol and high fasting triglycerides strongly predicted coronary events in middle-aged Swedish women. The favourable decline in cholesterol levels and smoking rates during the study period was offset by a marked increase in triglyceride levels. The findings suggest that interventional strategies directed to correct abnormalities in the triglyceride metabolism may be specifically warranted in women.