Genetic admixture and gallbladder disease in Mexican Americans.

Gallbladder disease is a common source of morbidity in the Mexican American population. Genetic heritage has been proposed as a possible contributor, but evidence for this is limited. Because gallbladder disease has been associated with Native American heritage, genetic admixture may serve as a useful proxy for genetic susceptibility to the disease in epidemiologic studies. The objective of our study was to examine the possibility that gallbladder disease is associated with greater Native American admixture in Mexican Americans. This study used data from the Hispanic Health and Nutrition Examination Survey and was based on 1,145 Mexican Americans who underwent gallbladder ultrasonography and provided usable phenotypic information. We used the GM and KM immunoglobulin antigen system to generate estimates of admixture proportions and compared these for individuals with and without gallbladder disease. Overall, the proportionate genetic contributions from European, Native American, and African ancestries in our sample were 0.575, 0.390, and 0.035, respectively. Admixture proportions did not differ between cases and noncases: Estimates of Native American admixture for the two groups were 0.359 and 0.396, respectively, but confidence intervals for estimates overlapped. This study found no evidence for the hypothesis that greater Native American admixture proportion is associated with higher prevalence of gallbladder disease in Mexican Americans. Reasons for the finding that Native American admixture proportions did not differ between cases and noncases are discussed. Improving our understanding of the measurement, use, and limitations of genetic admixture may increase its usefulness as an epidemiologic tool as well as its potential for contributing to our understanding of disease distributions across populations.

Diagnóstico de la diabetes mellitus: ¿Necesitamos nuevos criterios? / Diagnosing diabetes mellitus-do we need new criteria?

La clasificación actual y los criterios diagnósticos para la diabetes mellitus fueron hechos por el Grupo Nacional de Datos de Estados Unidos (United States National Data Group) en 1979 y aprobados por la Organización Mundial de la Salud en 1980, con modificaciones en 1985 y 1994. Los criterios, elegidos para reflejar el riesgo de las complicaciones, fueron la síntesis del debate y la experiencia, representando un consenso útil por igual para todas las personas relacionadas con la diabetes- el médico clínico, el investigador y el epidemiólogo. Es bien sabido que la prueba de tolerancia oral a la glucosa (PTOG) esincómoda, variable y no fisiológica. A pesar de estas limitaciones, la glucosa plasmática de 2 hs. postcarga sigue siendo el estándar contra el cual se evalúan el resto de las pruebas. En este artículo se hace una revisión sobre la justificación original de la PTOG y a la luz de investigaciones epidemiológicas más recientes, se busca colocar los actuales criterios diagnósticos para diabetes dentrode una perspectiva fisiopatológica, diagnóstica y pronóstica (AU)

Diagnóstico de la diabetes mellitus: ¿Necesitamos nuevos criterios? / Diagnosing diabetes mellitus-do we need new criteria?

La clasificación actual y los criterios diagnósticos para la diabetes mellitus fueron hechos por el Grupo Nacional de Datos de Estados Unidos (United States National Data Group) en 1979 y aprobados por la Organización Mundial de la Salud en 1980, con modificaciones en 1985 y 1994. Los criterios, elegidos para reflejar el riesgo de las complicaciones, fueron la síntesis del debate y la experiencia, representando un consenso útil por igual para todas las personas relacionadas con la diabetes- el médico clínico, el investigador y el epidemiólogo. Es bien sabido que la prueba de tolerancia oral a la glucosa (PTOG) esincómoda, variable y no fisiológica. A pesar de estas limitaciones, la glucosa plasmática de 2 hs. postcarga sigue siendo el estándar contra el cual se evalúan el resto de las pruebas. En este artículo se hace una revisión sobre la justificación original de la PTOG y a la luz de investigaciones epidemiológicas más recientes, se busca colocar los actuales criterios diagnósticos para diabetes dentrode una perspectiva fisiopatológica, diagnóstica y pronóstica

The magnitude and origin of European-American admixture in the Gila River Indian Community of Arizona: a union of genetics and demography.

Complementary genetic and demographic analyses estimate the total proportion of European-American admixture in the Gila River Indian Community and trace its mode of entry. Among the 9,616 residents in the sample, 2,015 persons claim only partial Native American heritage. A procedure employing 23 alleles or haplotypes at eight loci was used to estimate the proportion of European-American admixture, m(a), for the entire sample and within six categories of Caucasian admixture calculated from demographic data, md. The genetic analysis gave an estimate of total European-American admixture in the community of 0.054 (95% confidence interval [CI] .044-.063), while an estimate from demographic records was similar, .059. Regression of m(a) on md yielded a fitted line m(a) = .922md, r = .959 (P = .0001). When total European-American admixture is partitioned between the contributing populations, Mexican-Americans have provided .671, European-Americans .305, and African-Americans .023. These results are discussed within the context of the ethnic composition of the Gila River Indian Community, the assumptions underlying the methods, and the potential that demographic data have for enriching genetic measurements of human admixture. It is concluded that, despite the severe assumptions of the mathematical methods, accurate, reliable estimates of genetic admixture are possible from allele and haplotype frequencies, even when there is little demographic information for the population.

Prevalence of diabetes in Mexican Americans, Cubans, and Puerto Ricans from the Hispanic Health and Nutrition Examination Survey, 1982-1984.

The purpose of this study was to estimate the prevalence of diagnosed and undiagnosed diabetes among Mexican Americans, Cubans, and Puerto Ricans in the United States and compare these estimates to data from prior surveys for U.S. non-Hispanic whites and blacks. Data for this study are from the Hispanic Health and Nutrition Examination Survey, a multipurpose cross-sectional survey of three U.S. Hispanic populations conducted in 1982-1984. The interviewed sample of people aged 20-74 yr included 3935 Mexican Americans in the southwest, 1134 Cubans in Florida, and 1519 Puerto Ricans in the New York City area. The diabetes component consisted of interview questions on diabetes diagnosis and treatment and an oral glucose tolerance test administered to a subsample. The prevalence of diabetes was two to three times greater for Mexican Americans and Puerto Ricans than for non-Hispanic whites surveyed in 1976-1980. In Cubans, the prevalence was similar to that for non-Hispanic whites. In men and women 45-74 yr of age, the prevalence of diabetes was extremely high for both Mexican Americans (23.9%) and Puerto Ricans (26.1%) compared with Cubans (15.8%) or non-Hispanic whites (12%). The total prevalence of diabetes was not significantly different for Mexican Americans and Puerto Ricans but was significantly lower for Cubans. The relatively lower prevalence of diabetes among Cubans and the high prevalence in both Mexican Americans and Puerto Ricans may be related to socioeconomic, genetic, behavioral, or environmental factors.

Risk factors for gallstone disease in the Hispanic populations of the United States.

The 1982-1984 Hispanic Health and Nutrition Examination Survey used ultrasonography to investigate risk factors for gallstone disease (gallstones or cholecystectomy). Mexican American, Cuban American, and Puerto Rican men (n = 968) and women (n = 1,325) aged 20-74 years were selected from household samples in nine states. Among men, the risk of gallstone disease increased with age, education, and subscapular skinfold thickness. Among women, the risk of gallstone disease increased with age, body mass index, four skinfold measures, diabetes, impaired glucose tolerance, and oral contraceptive usage, but not with parity. Women currently using oral contraceptives were also found to be at increased risk of current gallstones. Menopause was a risk factor for gallstone disease and cholecystectomy. Alcohol consumption was negatively related to the risk of gallstone disease. In men, the cholesterol/high density lipoprotein cholesterol ratio was positively related to gallstone disease and, in women, this ratio was negatively related. This interaction between the effect of sex and the cholesterol/high density lipoprotein cholesterol ratio on gallstone disease was highly significant (p = 0.002). Mexican Americans were at increased risk of gallstone disease even when other risk factors were controlled in multiple logistic regression analysis.

Self-reported diabetes in Mexican Americans: HHANES 1982-84.

In the Hispanic Health and Nutrition Examination Survey (HHANES) of 3,928 Mexican Americans ages 20-74 years, the age-adjusted prevalence of self-reported diabetes was 6.8 percent among men and 7.6 percent among women. Comparable age-adjusted rates for the US population in a national survey were 2.9 percent in men and 3.8 percent in women. The prevalence of diabetes in Mexican Americans is greater in older age groups, was similar in men and women, and among women only was inversely associated with education.