RESUMEN
BACKGROUND: The familial aggregation of coronary heart disease can be in large part accounted for by a clustering of cardiovascular disease risk factors. To elucidate the determinants of cardiovascular disease, many epidemiological studies have focused on the behavioral and lifestyle determinants of these risk factors, whereas others have examined whether specific candidate genes influence quantitative variation in these phenotypes. METHODS AND RESULTS: Among Mexican Americans from San Antonio (Tex), we quantified the relative contributions of both genetic and environmental influences to a large panel of cardiovascular risk factors, including serum levels of lipids, lipoproteins, glucose, hormones, adiposity, and blood pressure. Members of 42 extended families were studied, including 1236 first-, second-, and third-degree relatives of randomly ascertained probands and their spouses. In addition to the phenotypic assessments, information was obtained regarding usual dietary and physical activity patterns, medication use, smoking habits, alcohol consumption, and other lifestyle behaviors and medical factors. Maximum likelihood methods were used to partition the variance of each phenotype into components attributable to the measured covariates, additive genetic effects (heritability), household effects, and an unmeasured environmental residual. For the lipid and lipoprotein phenotypes, age, gender, and other environmental covariates accounted in general for < 15% of the total phenotypic variance, whereas genes accounted for 30% to 45% of the phenotypic variation. Similarly, genes accounted for 15% to 30% of the phenotypic variation in measures of glucose, hormones, adiposity, and blood pressure. CONCLUSIONS: These results highlight the importance of considering genetic factors in studies of risk factors for cardiovascular disease.
Asunto(s)
Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/genética , Americanos Mexicanos , Adulto , Factores de Edad , Anciano , Antropometría , Apolipoproteínas A/sangre , Glucemia , Presión Sanguínea , Enfermedades Cardiovasculares/complicaciones , HDL-Colesterol/sangre , Sulfato de Deshidroepiandrosterona/sangre , Complicaciones de la Diabetes , Diabetes Mellitus/epidemiología , Salud de la Familia , Femenino , Humanos , Insulina/sangre , Masculino , Persona de Mediana Edad , Linaje , Fenotipo , Prevalencia , Factores de Riesgo , Factores Sexuales , Globulina de Unión a Hormona Sexual/metabolismo , Texas/epidemiologíaAsunto(s)
Fertilidad , Indígenas Sudamericanos , Dinámica Poblacional , Adolescente , Adulto , Factores de Edad , Niño , Preescolar , Demografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , SurinameAsunto(s)
Análisis Actuarial , Mortalidad , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Crecimiento Demográfico , SurinameRESUMEN
Mating patterns in the population of St. Barthélémy, French West Indies, are examined to evaluate the expected genetic consequences of consanguinity avoidance and of failure to mate due to celibacy and emigration. Nearly 60% of all individuals reaching mating age on "St. Bart" never contribute to the gene pool of succeeding generations. This greatly reduces the effective population size and, therefore, increases genetic drift or random inbreeding. The consequent loss of heterozygosity is partially countered by the fact that the individuals who fail to reproduce within the population tend to be more closely related to the population than are those who do reproduce. This nonrandom failure to mate results in nonrandom inbreeding, which reduces total pedigree inbreeding. Total inbreeding is also reduced by consanguinity avoidance. However, the effect of avoiding close consanguineous matings is, to some extent, reversed by an apparent preference for more distant relationships, especially with second cousins. Generally similar results are found for the related Northside French population of St. Thomas. U.S. Virgin Islands. A recently developed mathematical model predicts the expected effect on heterozygosity of partial or complete avoidance of, or preference for, any combination of consanguineous matings, and also takes into account nonrandom failure to mate. Application of this model to these two populations suggests that under some circumstances nonrandomness in celibacy and emigration may have a greater influence on genotype distributions than does consanguinity avoidance.