Plasma and lipoprotein cholesterol and triglyceride concentrations in the Pima Indians: distributions differing from those of Caucasians.

Plasma and lipoprotein cholesterol and triglyceride concentrations were measured in Pima Indians, a genetically homogeneous population with a high prevalence of obesity and diabetes and a low frequency of coronary heart disease. The data for nondiabetic Pima Indians were compared with those of U.S. Caucasians measured during the Lipid Research Clinics Prevalence Study. Plasma total and low-density lipoprotein (LDL) cholesterol levels in Pima men older than 30 years of age and in women over 25 were lower than those of U.S. Caucasians, and in men the total and LDL cholesterol levels did not increase with age. In Pima male subjects of all ages high-density lipoprotein (HDL) cholesterol levels were lower than that in Caucasian male subjects, and in Pima female subjects HDL cholesterol levels averaged 11 mg/dl lower than those in female Caucasian subjects. On the other hand, plasma triglyceride levels in Pima male subjects up to 35 years of age and in female subjects up to 55 years old were higher than those of Caucasians. Comparison of plasma cholesterol and triglyceride levels in Pima male and female subjects showed the same relationships as those in Caucasians (i.e., higher in male subjects until the older age groups), but Pima male and female subjects had similar HDL cholesterol levels. There was a strong negative correlation between obesity and HDL cholesterol levels in Pimas. Obesity appeared to account for the lower HDL cholesterol levels in Pima male subjects compared with that in Caucasian male subjects, but obesity could not explain the lack of differences between the sexes in HDL levels in the Pimas. Triglyceride levels correlated positively with obesity in the Pimas, but the relationship was not as strong as that reported for Caucasians. The results indicate that there are differences in lipoprotein distributions between Pimas and U.S. Caucasians; the relationship between lipoprotein levels and the incidence of coronary disease in the Pimas must be determined.