RESUMO
Resistance to insulin action is a well-established feature of type II (non-insulin-dependent) diabetes and is believed by many to contribute to the etiology of this condition. We therefore characterized restriction-fragment-length polymorphisms of the insulin-receptor gene with the restriction enzyme Rsa 1 in 242 Mexican Americans and non-Hispanic Whites with type II diabetes and 202 age-, sex-, and ethnicity-matched control subjects who participated in a population-based study in San Antonio. Alleles of 6.7 kilobases (kb) (A allele), 6.2 kb (B allele), and 3.4 kb (C allele) were identified. The C allele was observed in Mexican Americans only, where its frequency among nondiabetic control subjects was 17.7%. Diabetic Mexican Americans were twice as likely as control subjects to be homozygous for the C allele. The crude odds ratio for diabetes in CC homozygotes compared with the other two genotypes was 2.22, although this result was not statistically significant (chi 2 = 1.57, P = .21). The Mantel-Haenszel odds ratio, adjusting for age, however, indicated a 4.71-fold increased risk of diabetes among Mexican Americans with the CC genotype compared with Mexican Americans without this genotype (chi 2 = 5.38, P = .020). The age of onset of diabetes was also slightly younger in CC homozygote cases (45.4 +/- 9.2 yr) than in CX or XX cases (47.7 +/- 9.0 and 48.6 +/- 9.6 yr, respectively), although this difference was not statistically significant (P .467).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Diabetes Mellitus Tipo 2/genética , Hispânico ou Latino/genética , Polimorfismo Genético , Receptor de Insulina/genética , Adulto , Alelos , DNA/genética , Diabetes Mellitus Tipo 2/etiologia , Genótipo , Humanos , Pessoa de Meia-Idade , Polimorfismo de Fragmento de Restrição , Fatores de RiscoRESUMO
The authors hypothesized that increased socioeconomic status and acculturation of Mexican Americans to mainstream US society would be accompanied by a progressive lessening of obesity and non-insulin-dependent diabetes mellitus. This hypothesis was tested in 1979-1982 in the San Antonio Heart Study, a population-based study of 1,288 Mexican Americans and 929 non-Hispanic whites, aged 25-64 years, randomly selected from three San Antonio neighborhoods: a low-income barrio, a middle-income transitional neighborhood, and a high-income suburb. Socioeconomic status was assessed by the Duncan Socioeconomic Index, a global measure of socioeconomic status based on occupational prestige. Acculturation was assessed by three scales which measure functional integration with mainstream society, value placed on preserving Mexican cultural origin, and attitude toward traditional family structure and sex-role organization. In Mexican-American men, increased acculturation was accompanied by a statistically significant, linear decline in both obesity and diabetes, while socioeconomic status had no significant effect on either outcome. In Mexican-American women, on the other hand, increased acculturation and increased socioeconomic status were accompanied by statistically significant, linear declines in both outcomes. However, the effects of acculturation on obesity and diabetes prevalence in women were stronger than the effects of socioeconomic status. In women, obesity also appeared to be a more important mediator of the relation between socioeconomic status and diabetes than of the relation between acculturation and diabetes. The results of this study suggest that culturally mediated factors exert a more pervasive influence on obesity and diabetes in Mexican Americans than do socioeconomically mediated factors. The influence of socioeconomic status in women, however, cannot be ignored, particularly with regard to obesity.
Assuntos
Aculturação , Diabetes Mellitus Tipo 2/etnologia , Hispânico ou Latino , Obesidade/etnologia , Adulto , Métodos Epidemiológicos , Feminino , Humanos , Masculino , México/etnologia , Pessoa de Meia-Idade , Fatores Socioeconômicos , TexasRESUMO
Mexican Americans are the second largest minority group in the United States (8.73 million people according to the 1980 US census) and are known to have an excess prevalence of obesity and non-insulin-dependent diabetes mellitus, but similar or lower rates of hypertension when compared with non-Hispanic whites. To our knowledge, no data are available on incidence of end-stage renal disease in this population. Using a data base from the Texas Kidney Health Program, a division of the Texas Department of Health, and the 1980 US census for the state of Texas, the authors calculated age-adjusted incidence of treatment of end-stage renal disease in Mexican Americans, non-Hispanic whites, and blacks for the years 1978-1984. Mexican Americans and blacks have an excess of treatment of end-stage renal disease (all etiologies combined) compared with non-Hispanic whites (incidence ratios of 3 and 4, respectively). For diabetes-related end-stage renal disease, Mexican Americans have an incidence ratio of 6, while blacks have an incidence ratio of 4 compared with non-Hispanic whites. For Mexican Americans, this excess is higher than would be expected on the basis of their underlying prevalence of diabetes. The incidence of hypertensive end-stage renal disease in Mexican Americans was 2.5 times higher than in non-Hispanic whites, which is higher than expected given the lack of excess in their underlying prevalence of hypertension. The high prevalence of diabetes in Mexican Americans explains some, but not all, of the excess of treatment of end-stage renal disease in this population.
Assuntos
Nefropatias Diabéticas/epidemiologia , Hispânico ou Latino , Falência Renal Crônica/epidemiologia , Adulto , Idoso , População Negra , Nefropatias Diabéticas/terapia , Feminino , Humanos , Falência Renal Crônica/terapia , Masculino , México/etnologia , Pessoa de Meia-Idade , Diálise Renal , Texas , População BrancaRESUMO
Although the decline in ischemic heart disease mortality is now entering its third decade, there has been no definitive information on the experience of Mexican Americans, the nation's second largest minority group. Earlier studies carried out in the 1970s were hampered by the unavailability of satisfactory population data beyond 1970. In the present study we have used 1970 and 1980 census data to compute death rates in Mexican Americans and non-Hispanic whites from Texas for the periods 1969-1971 and 1979-1981. All four sex-ethnic groups showed statistically significant declines in death rates due to all causes, due to total ischemic heart disease, and due to acute myocardial infarction between 1969-1971 and 1979-1981. Declines in the latter two causes of death were least marked in Mexican American men. This sex-ethnic group was also the only one that failed to show a decline in death rates due to chronic ischemic heart diseases. The fact that Mexican Americans have been shown to be less well informed about and less likely to adopt lifestyle changes aimed at reducing heart disease risk than non-Hispanic whites may account for the less striking mortality decline observed in Mexican American men, but is harder to reconcile with the apparent equal decline in Mexican American women compared with non-Hispanic whites.
Assuntos
Doença das Coronárias/mortalidade , Hispânico ou Latino , Adulto , Idoso , Doença das Coronárias/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fatores Sexuais , TexasRESUMO
This study examined whether currently employed women are at increased risk of coronary heart disease relative to full-time homemakers. Subjects were 1,041 Mexican-American and non-Hispanic white women aged 25-64 years, residing in households randomly selected from three socioculturally distinct neighborhoods in San Antonio, Texas. No statistically significant differences between employed women and homemakers were found for obesity, total serum cholesterol, low density lipoprotein cholesterol, systolic and diastolic blood pressures, or cigarette smoking. Highly significant differences favoring employed women over homemakers were found for both Mexican Americans and non-Hispanic whites in high density lipoprotein (HDL) cholesterol, ratio of HDL cholesterol to total cholesterol, and triglycerides. These differences were not explained by obesity, exercise, cigarette smoking, alcohol consumption, use of exogenous estrogens, and use of oral contraceptives, or by the healthy worker effect, and were observed at all occupational levels. Employed women ate a less atherogenic diet than full-time homemakers, but it is not clear that this nutritional factor could explain the differences in HDL cholesterol and triglycerides found in this study. The magnitude of the employment status difference in HDL cholesterol for both ethnic groups was in a range (3-4 mg/100 ml) associated with protection against coronary heart disease.
Assuntos
Doença das Coronárias/etiologia , Emprego , Hispânico ou Latino , Adulto , Glicemia , Pressão Sanguínea , Doença das Coronárias/epidemiologia , Dieta , Métodos Epidemiológicos , Feminino , Humanos , Casamento , Menopausa , México , Pessoa de Meia-Idade , Obesidade/complicações , Risco , Fumar , Fatores Socioeconômicos , Texas , Triglicerídeos/sangueRESUMO
Because the issue of how to empirically identify Mexican Americans in health-related research is still unresolved, the authors compared the performance of three indicators for identifying Mexican Americans across five distinct population subgroups: men and women in two age strata, and residents in low, middle, and high socioeconomic neighborhoods. Individual surname had the lowest sensitivity, specificity, and predictive values in the pooled population sample and varied the most widely on these parameters across population subgroups. Parental surnames, which are available on vital statistics and could easily be added to other health records used in secondary analyses, offered a significant improvement over individual surname in classifying persons as Mexican American. The San Antonio Heart Study (SAHS) algorithm, a nine-item indicator which uses parental surnames, birthplace of both parents, self-declared ethnic identity, and ethnic background of grandparents, had the highest sensitivity, specificity, and predictive values and varied the least on these parameters across different sex, age, and socioeconomic status population subgroups. The performance of all indicators was lower at the higher socioeconomic status levels. The findings suggest that it may be useful to use parental surnames as an indicator for Mexican-American ethnicity in research involving vital statistics and to add parental surnames to other health records frequently used in secondary analyses. Since the SAHS algorithm can be adapted for use with non-Mexican origin Hispanic subgroups, it may be a useful indicator for Mexican-American (or other Hispanic) ethnicity in survey research.
Assuntos
Métodos Epidemiológicos , Hispânico ou Latino/classificação , Adulto , Fatores Etários , Feminino , Humanos , Masculino , México/etnologia , Pessoa de Meia-Idade , Fatores Sexuais , Fatores Socioeconômicos , TexasRESUMO
Evidence for bimodality in the distribution of two hour post oral glucose challenge plasma glucose concentrations has come previously primarily from native American and Pacific Island populations having high non-insulin dependent diabetes mellitus (NIDDM) prevalence. Because the National Diabetes Data Group (NDDG) criteria for diagnosing NIDDM rely in part upon the assumption of bimodality, it is important to determine the generality of this phenomenon. We looked for bimodality among Mexican Americans in San Antonio, a population having greater than 50% Caucasian admixture. By fitting both a single normal distribution model and a mixture model of two normal distributions, for each age decade, we found that the mixture model was preferred to the single normal model (p less than 0.001) and that this model fit the data well. The proportion in the upper component (hyperglycemics) increased with each successive age decade. The minimum misclassification cutpoints decreased with age, but all were higher than the 200 mg/dl cutpoint recommended by the NDDG. Use of the NDDG cutpoint, however, improved sensitivity with only a minimal deterioration of specificity. Our findings further generalize the bimodality phenomenon and support the NDDG criteria.
Assuntos
Glicemia/metabolismo , Teste de Tolerância a Glucose , Hispânico ou Latino , Adulto , Fatores Etários , Diabetes Mellitus Tipo 2/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Texas , Fatores de TempoRESUMO
We have estimated the prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in Mexican Americans and Anglos in three San Antonio neighborhoods. The age-adjusted NIDDM rates (both sexes pooled) for Mexican Americans were 14.5%, 10%, and 5% for residents of a low-income barrio, a middle-income transitional neighborhood, and a high-income suburb, respectively. In Mexican American women, though not in men, obesity also declined from barrio to suburbs. We have previously shown, however, that, although obesity is an important cause of NIDDM in Mexican Americans, there is a two- to fourfold excess in the rate of NIDDM in this ethnic group over and above that which can be attributed to obesity. We therefore speculated that genetic factors might also contribute to excess NIDDM in this ethnic group. The percent native American admixture of Mexican Americans as estimated from skin color measurements was 46% in the barrio, 27% in the transitional neighborhood, and 18% in the suburbs. The NIDDM rates in Mexican Americans thus paralleled the proportion of native American genes. Furthermore, the San Antonio Mexican American rates were intermediate between the NIDDM rates of "full-blooded" Pima Indians (49.9%), who presumably have close to 100% native American genes, and the San Antonio Anglo population (3.0%) and the predominantly Anglo HANES II population (3.1%), both of which presumably have few if any native American genes. The association of genetic admixture with NIDDM rates suggests that much of the epidemic of NIDDM in Mexican Americans is confined to that part of the population with a substantial native American heritage.