Migrant and native South Asians appear to be at increased risk of Type II
diabetes mellitus and
coronary disease. The aim of the present study was to determine the relationship between the most accurate summary index of the
lipoprotein-related risk of
vascular disease, the
apoB (
apolipoprotein B-100)/
apoA-I (
apolipoprotein A-I) ratio, and body composition in established migrant South Asians and white Caucasians living in Canada. Men and women living in Montreal, Canada between the ages of 20-60 years were recruited for participation in the study. Subjects were excluded if they had a history of
cardiovascular disease or were taking
lipid-lowering medication. Individuals identified themselves as Asian Indian or Caucasian. Anthropometric measurements were collected, including weight, height, waist circumference, hip circumference and body fat percentage. Plasma samples were analysed for total
cholesterol, HDL-C (
high-density lipoprotein-cholesterol),
apoA-I and
apoB. Indian subjects had a substantially higher WHR (waist-to-hip ratio) than Caucasian subjects [men, 0.93+/-0.01 compared with 0.86+/-0.01 respectively (P<0.001); women, 0.88+/-0.01 compared with 0.77+/-0.01 respectively (P<0.0001)]. WHR correlated strongly with body fat percentage in Caucasians (men, r=0.63, P=0.0002; women, r=0.74, P<0.0001). By contrast, there was no correlation in Indians (men, r=0.22, P value not significant; women, r=0.23, P value not significant). In addition, Indian men and women had a higher
apoB/A-I ratio than Caucasians [men, 0.85+/-0.04 compared with 0.66+/-0.04 respectively (P=0.001); women, 0.73+/-0.04 compared with 0.56+/-0.03 respectively (P=0.0003)]. Of interest, there were also significant correlations between the
apoB/
apoA-I ratio and WHR in all of the groups, except the Indian women, which were stronger than the correlation of the
apoB/
apoA-I ratio with BMI. On the other hand, there was no significant relationship between the
apoB/
apoA-I ratio and the body fat percentage in any of the groups. In conclusion, the present study confirms that, as body fat percentage increases, the distribution of body fat differs between migrant Indians and Caucasians living in Canada. It also relates differences in body fat distribution to differences in the
apoB/
apoA-I ratio, providing at least part of the answer as to why South Asians may be at increased risk of
vascular disease.