Objective ApoB exerts a pro-thrombotic and pro-atherogenic effect and promotes the progression of atherosclerotic lesions. In the present study, we investigated if elevated ApoB serum levels predicted the risk of premature cardiovascular events in a prospective Swedish cohort study of 60-year-old men and women from Stockholm.

Design A cohort consisting of every third man and woman turning 60 years of age in the large Stockholm area during the years 1997–1998 (n=4232).

Methods Incident cases of cardiovascular diseases have been recorded yearly by matching national registries. Exposure to high ApoB serum levels (≥0.9 g/l) was used to calculate the risk of cardiovascular diseases, and the time to the first cardiovascular event using Cox regression and Laplace regression, respectively.

Results Individuals exposed to high ApoB serum levels showed an increased risk of cardiovascular diseases over the 11 years of follow-up. The HR decreased over time from 2.49 at 4 years of study entry (95% CI 1.31 to 4.69) to 1.36 at 11 years (95% CI 1.01 to 1.83), after adjusting for gender, diabetes, hypertension, smoking, obesity, HDL and triglyceride serum levels. The first 5% of the individuals had a cardiovascular event nearly 2 years earlier among those with ApoB ≥0.9 g/l than among those with ApoB <0.9 g/l (p=0.001).

Conclusions Our data indicate that increased ApoB serum levels are important predictors of early cardiovascular events. It is possible that this reflects a shift over time in the effects of apoB from a more pro-thrombotic to a more pro-atherogenetic molecule.