Reference values of plasma apolipoproteins A-I and B, and association withnonlipid risk factors in the populations of two Canadian provinces: Quebecand Saskatchewan

OBJECTIVE: To determine the population distribution of apo lipoproteins 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 sel ected from the provinces of Saskatchewan and Quebec in 1989 and 1990. OUTCOME MEASURES: plasma concentrations of apolipoproteins A-I and B, trigl ycerides, low density lipoprotein cholesterol, high density lipoprotein cho lesterol and nonhigh density lipoprotein cholesterol for subjects who provi ded 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 gr oup for men. For women, the values increased more gradually from 0.81 g/L f or ages 18 to 24 to 1.19 g/L at ages 65 to 74 years. The distribution of ap olipoprotein A-I was unrelated to age. Means for men varied from 1.35 g/L t o 1.42 g/L and for women from 1.50 g/L to 1.61 g/L. Apolipoprotein B was st rongly correlated with nonhigh density lipoprotein cholesterol (r(2)=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 l ess 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 hig h risk plasma apolipoprotein B levels was higher in men and women with trig lycerides greater than 2.3 mmol/L. Apolipoprotein A-I was strongly correlat ed with high density lipoprotein cholesterol (r(2)=0.67), and this was use to identify apolipoprotein A-I concentrations of less than 1.20 g/L as a ri sk factor and 1.65 g/L or greater as an anti-risk factor for coronary arter y disease. The prevalence of apolipoprotein A-I of less than 1.20 g/L was 1 9% 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 Cana dian population random sample are given. Plasma apolipoprotein B and apolip oprotein A-I provide information that is complementary to that provided by low density lipoprotein and high density lipoprotein cholesterol levels.