RELATIONS OF BODY-FAT AND FAT DISTRIBUTION TO THE SERUM-LIPID, APOLIPOPROTEIN AND INSULIN CONCENTRATIONS OF SAMOAN MEN AND WOMEN

OBJECTIVE: To examine relations between obesity and serum concentratio ns of lipoprotein cholesterol, apolipoproteins, triglycerides and insu lin in American and Western Samoans. Associations are also described b etween these CHD risk factors and abdominal adiposity, and the potenti al mediating role of insulin in these relationships is examined. DESIG N: Cross-sectional, using a sub-sample from an observational epidemiol ogical study of cardiovascular disease risk factors among Samoans. MEA SUREMENT: Obesity is estimated by the body mass index (BMI), and fat d istribution by the abdomen-hip circumference ratio (AHR). All biochemi cal parameters were measured in the fasted stated. SUBJECTS: The sub-s ample is 178 men and 147 women who were free from hypertension, diabet es and heart disease. RESULTS: In multivariate linear regression analy ses in men the BMI was positively associated with levels of total chol esterol, the total-HDL cholesterol ratio, apolipoprotein B, and the lo g of triglyceride and insulin concentrations, and negatively associate d with HDL and HDL2 cholesterol. The quadratic term for BMI was also f ound to be significantly predictive of all metabolic parameters in men , except for the log of serum insulin concentrations. Among the women, in contrast, BMI levels were significantly associated only with conce ntrations of HDL2 cholesterol, triglyceride and insulin. In men, the a ssociations between the AHR and the metabolic parameters were similar to those described for the BMI, but showed no indication of non-linear ity. Addition of the log of insulin to these models had little effect on the relations between the AHR and the lipid parameters, with the ex ceptions of total cholesterol and triglycerides. As with BMI, the AHR was much res predictive of metabolic parameters in women than in men, with a significant relation existing only with the log of insulin conc entrations. CONCLUSIONS: These cross sectional data indicate that over all and abdominal adiposity are important correlates of serum lipid pa rameters among Samoan men, though the associations with BMI are attenu ated at higher levels. Neither anthropometric indicator has much relat ion with these CHD risk factors among the women, perhaps due to extrem ely high levels of obesity in this group.