Plasma apolipoprotein B in middle-aged Finnish men. Evidence for a regional gradient of apo B and lack of negative correlation between apo B and dietary linoleate in hyperapobetalipoproteinemia.

Plasma apolipoprotein B (apo B) concentrations were determined in 178 randomly selected 40-49-year-old men from Eastern and Southwestern Finland and compared with the concentrations of plasma lipids and the fatty acid composition of plasma and adipose tissue determined previously from the same populations. The plasma apo B concentrations ranged from 50 to 209 mg/dl. Although men from the two regions had similar mean concentrations of plasma triglyceride, total cholesterol and high density lipoprotein (HDL)-cholesterol, men from Eastern Finland had significantly higher mean apo B levels (139 +/- 25 mg/dl) and a lower ratio of total cholesterol to apo B (1.85 +/- 0.25) than the Southwestern men (125 +/- 33 mg/dl and 2.05 +/- 0.40, respectively). In the whole population, apo B and total cholesterol had significant negative correlations with the percentages of linoleate in the fatty acids of plasma and adipose tissue, which are known to reflect the quality of dietary fat. As the percentages of linoleate have previously been shown to be lower in the Eastern population, part of the regional difference in apo B is obviously explained by differences in the quality of dietary fat. On the other hand, men (n = 59) who had high plasma apo B (greater than 130 mg/dl) but low density lipoprotein (LDL)-cholesterol within the reference values (less than 5.17 mmol/l) showed no correlation between linoleate and apo B. This suggests that other factors than dietary fat determine the concentration of apo B in this group of men.