Objective: To determine the population distribution of apolipoproteins A-I and B, and the relationship of apolipoprotein B to lipid risk factors for coronary artery disease.
Design: A stratified random sample of men and women aged 18 to 74 years selected from the provinces of Saskatchewan and Quebec in 1989 and 1990.
Outcome measures: Plasma concentrations of apolipoproteins A-I and B, triglycerides, low density lipoprotein cholesterol, high density lipoprotein cholesterol and nonhigh density lipoprotein cholesterol for subjects who provided a fasting blood sample.
Main results: Apolipoprotein B mean values increased with age from 0.80 g/L at age 18 to 24 years to a maximum of 1.16 g/L in the 45 to 54 year age group for men. For women, the values increased more gradually from 0.81 g/L for ages 18 to 24 to 1.19 g/L at ages 65 to 74 years. The distribution of apolipoprotein A-I was unrelated to age. Means for men varied from 1.35 g/L to 1.42 g/L and for women from 1.50 g/L to 1.61 g/L. Apolipoprotein B was strongly correlated with nonhigh density lipoprotein cholesterol (r2=0.89), and this was used to define apolipoprotein B concentrations less than 1.04 g/L as indicating low risk for coronary artery disease, from 1.04 g/L to less than 1.22 g/L as moderate risk, from 1.22 g/L to less than 1.40 g/L as high risk, and 1.40 g/L or greater as very high risk. The prevalence of high risk plasma apolipoprotein B levels was higher in men and women with triglycerides greater than 2.3 mmol/L. Apolipoprotein A-I was strongly correlated with high density lipoprotein cholesterol (r2=0.67), and this was use to identify apolipoprotein A-I concentrations of less than 1.20 g/L as a risk factor and 1.65 g/L or greater as an antirisk factor for coronary artery disease. The prevalence of apolipoprotein A-I of less than 1. 20 g/L was 19% in men and 6% in women, whereas the prevalence of apolipoprotein AI 1.65 g/L or greater was 9% in men and 28% in women.
Conclusion: Reference values for plasma apolipoproteins A-I and B in a Canadian population random sample are given. Plasma apolipoprotein B and apolipoprotein A-I provide information that is complementary to that provided by low density lipoprotein and high density lipoprotein cholesterol levels.