Time trends in population cholesterol levels 1986-2004: influence of lipid-lowering drugs, obesity, smoking and educational level. The northern Sweden MONICA study

OBJECTIVES: To explore time trends in population total cholesterol. DESIGN AND SETTING: Five population-based cross-sectional surveys, 1986-2004 in the northern Sweden MONICA study included 8827 men and women. RESULTS: Age-adjusted cholesterol level declined in men, 25-64 years old, from 6.38 to 5.78 mmol L(-1) and in women from 6.32 to 5.51 mmol L(-1). Between 1994 and 2004, subjects 65-74 years old were included, and their levels also decreased, in men from 6.35 to 5.76 mmol L(-1) and in women from 7.11 to 6.24 mmol L(-1). The decrease was continuous over surveys and age groups, except in young and middle-aged men where no further decline was found after 1999. Cohorts born 1920-1939 showed decreased cholesterol over the period, whilst no change was noted for those born thereafter. In 2004, one-fourth of men and one-third of women 25-74 years achieved levels below 5.0 mmol L(-1). Subjects with low educational level, body mass index > or =25 or smokers all had higher cholesterol levels which persisted during the 18-year period. In 2004, the 9% who used lipid-lowering drugs are estimated to contribute, at most, to 0.13 mmol L(-1) lower cholesterol in the population. CONCLUSION: Large decreases in cholesterol levels occurred in the 18-year period. Less smoking may contribute to, and increasing obesity attenuate, this trend whilst lipid-lowering drugs have had little effect until recently. Socio-economic inequalities persist.