Appendicitis: higher risk in Mexican Americans?

OBJECTIVES: Mexican Americans (MAs), compared to white non-Hispanics (WNHs), have higher rates of biliary disease, noninsulin dependent diabetes, and endstage renal disease but lower rates of lung cancer, hip fractures, and mortality from coronary heart disease. Relatively little research has been done to identify other ethnic differences in disease incidence. We used surgical procedure rates to confirm known ethnic differences and to explore our clinical suspicion that MAs have higher rates of appendectomy than WNHs. METHODS: We used a registry of surgical procedures at two teaching hospitals in South Texas to calculate proportional operation ratios (PORs) for MAs versus WNHs. These two hospitals are the primary source of acute hospital care for the indigent in the area. The POR is arithmetically identical to proportional incidence and mortality ratios. RESULTS: MAs underwent appendectomy proportionally more often than WNHs at both hospitals (POR = 1.41 and 1.75, p < 0.0001). Other significant PORs were consistent with known ethnic disease differences in biliary tract operations, vascular access for chronic hemodialysis, lung cancer, and coronary artery bypass. CONCLUSIONS: These findings support the hypothesis that MAs may undergo appendectomy more often than WNHs and so may be at higher risk of appendicitis.

Prevalence of gallbladder disease and associated clinical variables in a low income population of Mexico City.

We present the results of a population-based survey carried out in a low income area of Mexico City. The aim of this study is to characterize the prevalence of clinically significant gallbladder disease (CSGD) using the self-reported history of cholecystectomy (CG) or cholelithiasis (CL) demonstrated by cholecystography and/or ultrasonography. The population of the studied area was 15,532 inhabitants, of whom 3505 (22.6%) were age eligible (35-64 year-old men and non-pregnant women). Home interviews were obtained in 2810 (80.2%). A physical and laboratory examination was performed in 2282 individuals (65.1%; 941 men and 1341 women). The prevalence of CSGD in men was 2.0% (95% confidence intervals 1.1-2.9%) and 9.2% in women (95% confidence intervals 7.7-10.7%). Patients with CSGD were older, men (p < 0.003) and women (p < 0.001). Women with CSGD had higher waist to hip circumference ratio (p < 0.06), higher fasting glucose (p < 0.03) as well as 2 h post challenge glycemia (p < 0.04) and insulinemia (p < 0.03). In the multiple logistic regression model only age (p < 0.001) and sex (p < 0.001) remained significantly associated. We conclude that CSGD is quite prevalent in this population. It is associated with age in both genders and in women, higher glucose and insulin levels. The prospective follow-up of this cohort is important since it could generate the information needed to implement a preventive program to diminish the impact of this condition.

Gallstone characteristics in Mexican Americans and non-Hispanic whites.

Mexican Americans have an elevated risk of gallstones. Their increased rates may be due to genetic admixture with Native Americans, who have extremely high prevalences of cholelithiasis. Native Americans are believed to have almost exclusively cholesterol stones, whereas only 73% of non-Hispanics are reported to have such stones. Hence we hypothesized that Mexican Americans would have a higher proportion of cholesterol stones than would non-Hispanic whites. We interviewed 398 Mexican Americans and 93 non-Hispanic whites undergoing cholecystectomy and analyzed the composition of their gallstones. Mexican Americans were younger than non-Hispanic whites (P < 0.05). However, the age-sex standardized proportion of cholesterol stones was 89.7% in Mexican Americans and 87.2% in non-Hispanic whites. We conclude that Mexican Americans and non-Hispanic whites have gallstones of similar composition. The higher stone prevalence of Mexican Americans may be due to factors that predispose to both cholesterol and pigment stones.

Increased prevalence of clinical gallbladder disease in subjects with non-insulin-dependent diabetes mellitus.

The association between non-insulin-dependent diabetes mellitus (NIDDM) and the prevalence of gallbladder disease remains controversial. The authors investigated this association in 1,250 men and 1,656 women from the San Antonio Heart Study (1984-1988) a population-based study of diabetes and cardiovascular disease. A total of 68% of the subjects were Mexican American, a population at high risk for both gallbladder disease and NIDDM. Gallbladder disease was assessed by self-report, and the prevalence of diabetes was determined using National Diabetes Data Group criteria. NIDDM was significantly associated with gallbladder disease in Mexican-American men and women and in non-Hispanic white women. After adjustment for age, body mass index, ratio of waist-to-hip circumference, and ethnicity, using multiple logistic regression, the odds of gallbladder disease in women was 1.6 times higher if NIDDM was present (odds ratio = 1.60, 95% confidence interval 1.08-2.37). Mexican-American women also had a significantly increased prevalence of gallbladder disease relative to non-Hispanic white women (odds ratio = 2.21, 95% confidence interval 1.50-3.28). In nondiabetic women, fasting insulin was significantly related to prevalence of gallbladder disease in univariate analyses, but not in multivariate analyses. The authors conclude that women with diabetes have an increased prevalence of gallbladder disease relative to nondiabetic women and that this association is not explained by the greater adiposity or unfavorable body fat distribution of the diabetic subjects.

Dietary intake and the prevalence of gallbladder disease in Mexican Americans.

Mexican Americans have a high prevalence of gallbladder disease. We examined the contribution of ethnic preferences in food intake to the risk of gallbladder disease in Mexican Americans and non-Hispanic whites. Participants in a population-based health survey were questioned about any history of gallbladder disease, and were interviewed to determine their dietary intake. After adjusting for age, body mass index, and ethnic group, we found that women with the highest intake of total fat and linoleic acid had reduced risks of gallbladder disease, although an opposite trend was observed in men. High levels of sucrose intake and low levels of cholesterol intake were associated with an increased risk for both sexes, but the odds ratios were not statistically significant. Although Mexican Americans and non-Hispanics differed in their intake of several nutrients, the elevated risk of gallbladder disease in Mexican American women was unchanged after ethnic differences in food intake were taken into account. Although the dietary preferences of Mexican Americans as reflected in 24-h diet recall interviews do not appear to explain their high prevalence of gallbladder disease, this finding should be interpreted with caution because of methodologic limitations in measuring habitual food intake.

Central adiposity and gallbladder disease in Mexican Americans.

Obesity is widely recognized as a risk factor for gallstones. However, to the authors' knowledge, only one study has examined the effect of body fat distribution on the prevalence of gallbladder disease. Mexican Americans are a population characterized by both a high prevalence of gallbladder disease and an unfavorable body fat distribution. The authors examined whether central adiposity (as measured by the ratio of subscapular-to-triceps skinfold) was related to clinically evident gallbladder disease in 1,202 Mexican Americans and 908 non-Hispanic whites in the San Antonio Heart Study from 1979 to 1982. After adjustment for overall adiposity (as measured by body mass index) and the ratio of subscapular-to-triceps skinfold, an increased prevalence of gallbladder disease was still observed in Mexican-American women. Both body mass index and the ratio of subscapular-to-triceps skinfold were positively and independently associated with gallbladder disease in women, while in men, body mass index, but not the subscapular-to-triceps skinfold ratio, was associated with gallbladder disease. Central adiposity is also related to the adverse pattern of cardiovascular risk factors observed in women with gallbladder disease.

Risk of postmenopausal hip fracture in Mexican American women.

To assess the risk of hip fracture in Mexican Americans, the ethnicity of 80 women aged 50 years and over admitted with hip fractures to a Texas hospital was compared with that of age-matched women hospitalized for other reasons. The risk of fracture for Mexican Americans was only 35 per cent that of Whites (95% CI = 19 per cent, 65 per cent). This finding was confirmed in a chart survey performed in a second hospital population. These results suggest that Mexican American women may receive less potential benefit from preventive measures for hip fracture than Whites.

Socioeconomic status and the prevalence of clinical gallbladder disease.

The prevalence of clinical gallbladder disease was determined in a cross-sectional survey of Mexican Americans and non-Hispanic whites. The study population was randomly selected from three urban neighborhoods representing different socioeconomic strata. Gallbladder disease was defined as a history of cholecystectomy, or of stones on cholecystography. Mexican American women had an age-standardized prevalence of 16.9%, vs 8.7% for non-Hispanic whites (p less than 0.0001). Prevalences in men were 4.2 and 3.4%, respectively. The ethnic differences in women persisted after stratification by age, parity, and body mass index. Gallbladder disease prevalence was inversely related to four measures of socioeconomic status. After controlling for age, obesity, parity, and ethnicity, the prevalence in women was inversely related to levels of education, income, occupational status, and neighborhood. These socioeconomic differences, if not the result of detection bias, suggest that environmental factors may play a role in gallstone pathogenesis. Identification of such factors may lead to the development of preventive strategies.

A simple language-based acculturation scale for Mexican Americans: validation and application to health care research.

A simple scale for quantifying English use among Mexican Americans was constructed from four brief questions which proved to have excellent scaling characteristics by Guttman Scalogram Analysis in two independent data sets. Construct validity was established by significant associations of the scale with ethnicity, place of birth, generation within the United States, and type of neighborhood. Highly significant associations were found between scale scores and use of oral contraceptives, parity, "fatalism" regarding health, and attitudes toward folk healers. These associations remained significant (though weak) after controlling for education and family income. The language scale thus appears to be reliable and valid, to be capable of distinguishing meaningful subsets among the Mexican American population, and to be applicable to health care investigation.

Prevalence of clinical gallbladder disease in Mexican-American, Anglo, and black women.

Clinical observations have suggested that gallstones are increased in frequency in Mexican-Americans compared to other ethnic groups. Past autopsy surveys have demonstrated a low prevalence in blacks compared to whites. We retrospectively reviewed 1,018 charts to study the prevalence of cholelithiasis in ambulatory women of these three racial/ethnic backgrounds. Mexican-American women were found to have a prevalence of gallbladder disease approximately three times that of black women, with Anglo prevalences falling in an intermediate range. The prevalence of cholelithiasis was also positively associated with increasing age and diabetes, but not with serum cholesterol, use of oral contraceptives or conjugated estrogens, parity, hypertension, menstrual status, or smoking. An association with obesity was shown but could not be shown to be independent of other risk factors.