Quantitation of human serum apolipoprotein A-I by electroimmunoassay. Studies on some techniques for standardization of the assay and determination of serum apolipoprotein A-I levels in a random population sample of middle-aged men.

Serum apolipoprotein A-I levels have been determined in a population sample of seventy-six randomly selected men aged 41-48 years. Electroimmunoassay with a monospecific rabbit antiserum to human apoA-I was used. Different routes to standardization of the electroimmunoassay were exploited. Standardization was finally carried out with purified apoA-I and confirmed with LpA-I. The mean apoA-I level was 1.75 +/- 0.20 g/1 in the populaton sample, with a normal distribution of the values. A highly significant, positive correlation to alphalipoprotein cholesterol was observed. ApoA-I levels were negatively correlated to tobacco consumption. Significant correlations were also observed to the levels of serum cholesterol and physical activity during leisure time, but no significant correlations to serum triglycerides or body weight index were found.