The genetics of obesity and obesity-related factors among Samoans.

摘要

Samoans are well known for their massive weight and muscularity. The general aim of this dissertation is to examine the genetic contributions to obesity and obesity related phenotypes among Samoans while additionally describing where fat is deposited, and how fat distribution may have changed during the lifespan, and over different time periods.; Univariate genetic analysis of adult Samoans, indicates that heritability estimates (29%–58%) exist for overall fat measurements and blood pressure, but not for central fat measurements. The bivariate analysis among adults indicates that significant genetic (pleiotropic) effects exist between general fat measures and blood pressures. Genetic analysis among juvenile Samoans reveals significant heritability estimates (19%–100%) and genetic correlations for anthropometric measurements that are stronger than corresponding adult ones. However, even though a significant central fat heritability can be found among juveniles, they do not statically differ from adult estimates. Significant but weaker genetic effects also exist between blood pressures and anthropometric measurements among juveniles.; Using cross sectional data spanning 24 years, the prevalences, means and principal components analysis indicate that American Samoans have increased both overall fat and central fat in the early 1990s. Comparison to published reports of other populations indicate that American Samoans have more overall fat and more central fat with the exception of Spanish/Hispanic origin populations. It is possible however, that the central fat that is deposited is mostly subcutaneous and not visceral as Samoans have been shown to have more muscle mass for given body mass indices.