The contribution of change in ethnic composition to prevalence of obesity and overweight

Objective. The prevalence of overweight and obesity differs substantially among children of different ethnic origin in the United States. The objective of this project is to estimate to what extent changes in ethnic composition since 1980 have contributed to the current general “obesity epidemic” in the childhood population of the United States.^ Methods. Populations by single year of age, 0 to 19, male and female, for Hispanics, non-Hispanic whites, and non-Hispanic blacks, from the US Census’ July estimates for 1985, 1990, 1995, 2000 and 2005 were taken and compared to the population and percentage of those groups from 1980. Age, sex, and ethnicity specific prevalence rates for overweight in 1980 were then applied to the populations by age for the specified year and differences in expected and actual overweight populations were assessed.^ Result. The results from this investigation provide estimates of the contribution that different ethnic groups have made to the overall prevalence of overweight and obesity in the childhood population of the United States. Assuming that the 1976-1980 prevalence rates had remained unchanged, and then comparing the population had there been no change in ethnic composition with the population given the actual change in ethnicity, the percentage increase was 1.06% in 1985, 1.72% in 1990, 2.57% in 1995, 3.95% in 2000, and 4.39% in 2005.^ Conclusion. The changes in ethnic composition of the population, independent of changes in ethnicity-specific prevalence, have contributed substantially to the current overall prevalence of obesity in the United States childhood population. There are a number of factors that may be responsible for the apparent susceptibility of Mexican-Americans and non-Hispanic blacks to overweight and obesity. Further research is needed on specific characteristics of those populations.^

Attributing inpatient care to diabetes: The case of Medicare for the elderly in Texas, 1995

Specific aims. This study estimated the accuracy of alternative numerator methods for attributing health care utilization and associated costs to diabetes by comparing findings from those methods with findings from a benchmark denominator method. ^ Methods. Using Medicare's 1995 inpatient and enrollment databases for the elderly in Texas, the researcher developed alternative estimates of costs attributable to diabetes. Among alternative numerator methods were selection of all records having diabetes as a principal or secondary diagnosis, and a complex ICD-9-CM sorting routine as previously developed for study of diabetes costs in Texas. Findings from numerator methods were compared with those from a benchmark denominator method based on attributable risk and adapted from a study of national diabetes costs by the American Diabetes Association. This study applied age, gender and ethnicity specific estimates of diabetes prevalence taken from the 1987–94 National Health Interview Surveys to person-months of Medicare Part A, non-HMO enrollment for Texas in 1995. Outcome measures were number of persons identified as having diabetes using alternative definitions of the disease; and number of hospital stays, patient days, and costs using alternative methods for attributing care and costs to diabetes. Cost estimates were based on Medicare payments plus deductibles, co-pays and third party payments. ^ Findings. Numerator methods for attributing costs to diabetes produced findings quite different than those from the benchmark denominator method. When attribution was based on diabetes as principal or secondary diagnosis, the resulting estimates were significantly higher than those obtained from the denominator method. The more complex sorting routine produced estimates near the lower boundary for the confidence interval associated with estimates from the benchmark method. ^ Conclusions. Numerator methods employed by previous researchers poorly estimate the costs of diabetes. While crude mathematical adjustment can be made to the respective numerator approaches, a more useful strategy would be to refine the complex sorting routine to include more hospitalizations. This report recommends approaches to improving methods previously employed in study of diabetes costs. ^

Predictors of weight stability in women and men: The aerobic center longitudinal study, 1987--1995

It is estimated that more than half the U.S. adult population is overweight or obese as classified by a body mass index of 25.0–29.9 or ≥30 kg/m 2, respectively. Since the current treatment approaches for long-term maintenance of weight loss are lacking, the National Institutes of Health state that an effective approach may be to focus on weight gain prevention. There is a limited body of literature describing how adults maintain a stable weight as they age. It is hypothesized that weight stability is the result of a balance between energy consumption and energy expenditure as influenced by diet, lifestyle, behavior, genetics and environment. The purpose of this research was to examine the dietary intake and behaviors, lifestyle habits, and risk factors for weight change that predict weight stability in a cohort of 2101 men and 389 women aged 20 to 8 7 years in the Aerobic Center Longitudinal Study regardless of body weight at baseline. At baseline, participants completed a maximal exercise treadmill test to determine cardiorespiratory fitness, a medical history questionnaire, which included self-reported measures of weight, dietary behaviors, lifestyle habits, and risk factors for weight change, a three-day diet record, and a mail-back version of the medical history questionnaire in 1990 or 1995. All analyses were performed separately for men and women. Results from multivariate regression analyses indicated that the strongest predictor of follow-up weight for men and women was previous weight, accounting for 87.0% and 81.9% of the variance, respectively. Age, length of follow-up and eating habits were also significant predictors of follow-up weight in men, though these variables only explained 3% of the variance. For women, length of follow-up and currently being on a diet were significantly associated with follow-up weight but these variables explained only an additional 2% of the variance. Understanding the factors that influence weight change has tremendous public health importance for developing effective methods to prevent weight gain. Since current weight was the strongest predictor of previous weight, preventing initial weight gain by maintaining a stable weight may be the most effective method to combat the increasing prevalence of overweight and obesity. ^

Hazardous air pollutants and childhood lymphohematopoietic cancer in Southeast Texas, 1995--2004

Southeast Texas, including Houston, has a large presence of industrial facilities and has been documented to have poorer air quality and significantly higher cancer rates than the remainder of Texas. Given citizens’ concerns in this 4th largest city in the U.S., Mayor Bill White recently partnered with the UT School of Public Health to determine methods to evaluate the health risks of hazardous air pollutants (HAPs). Sexton et al. (2007) published a report that strongly encouraged analytic studies linking these pollutants with health outcomes. In response, we set out to complete the following aims: 1. determine the optimal exposure assessment strategy to assess the association between childhood cancer rates and increased ambient levels of benzene and 1,3-butadiene (in an ecologic setting) and 2. evaluate whether census tracts with the highest levels of benzene or 1,3-butadiene have higher incidence of childhood lymphohematopoietic cancer compared with census tracts with the lowest levels of benzene or 1,3-butadiene, using Poisson regression. The first aim was achieved by evaluating the usefulness of four data sources: geographic information systems (GIS) to identify proximity to point sources of industrial air pollution, industrial emission data from the U.S. EPA’s Toxic Release Inventory (TRI), routine monitoring data from the U.S. EPA Air Quality System (AQS) from 1999-2000 and modeled ambient air levels from the U.S. EPA’s 1999 National Air Toxic Assessment Project (NATA) ASPEN model. Further, once these four data sources were evaluated, we narrowed them down to two: the routine monitoring data from the AQS for the years 1998-2000 and the 1999 U.S. EPA NATA ASPEN modeled data. We applied kriging (spatial interpolation) methodology to the monitoring data and compared the kriged values to the ASPEN modeled data. Our results indicated poor agreement between the two methods. Relative to the U.S. EPA ASPEN modeled estimates, relying on kriging to classify census tracts into exposure groups would have caused a great deal of misclassification. To address the second aim, we additionally obtained childhood lymphohematopoietic cancer data for 1995-2004 from the Texas Cancer Registry. The U.S. EPA ASPEN modeled data were used to estimate ambient levels of benzene and 1,3-butadiene in separate Poisson regression analyses. All data were analyzed at the census tract level. We found that census tracts with the highest benzene levels had elevated rates of all leukemia (rate ratio (RR) = 1.37; 95% confidence interval (CI), 1.05-1.78). Among census tracts with the highest 1,3-butadiene levels, we observed RRs of 1.40 (95% CI, 1.07-1.81) for all leukemia. We detected no associations between benzene or 1,3-butadiene levels and childhood lymphoma incidence. This study is the first to examine this association in Harris and surrounding counties in Texas and is among the first to correlate monitored levels of HAPs with childhood lymphohematopoietic cancer incidence, evaluating several analytic methods in an effort to determine the most appropriate approach to test this association. Despite recognized weakness of ecologic analyses, our analysis suggests an association between childhood leukemia and hazardous air pollution.^

First -year mortality and survival among infants with selected congenital anomalies in Texas, 1995 to 1997

Congenital anomalies have been a leading cause of infant mortality for the past twenty years in the United States. Few registry-based studies have investigated the mortality experience of infants with congenital anomalies. Therefore, a registry-based mortality study was conducted of 2776 infants from the Texas Birth Defects Registry who were born January 1, 1995 to December 31, 1997, with selected congenital anomalies. Infants were matched to linked birth-infant death files from the Texas Department of Health, Bureau of Vital Statistics. One year Kaplan-Meier survival curves, and mortality estimates were generated for each of the 23 anomalies by maternal race/ethnicity, infant sex, birth weight, gestational age, number of life-threatening anomalies, prenatal diagnosis, hospital of birth and other variables. ^ There were 523 deaths within the first year of life (mortality rate = 191.0 per 1,000 infants). Infants with gastroschisis, trisomy 21, and cleft lip ± palate had the highest first year survival (92.91%, 92.32%, and 87.59%, respectively). Anomalies with the lowest survival were anencephaly (5.13%), trisomy 13 (7.41%), and trisomy 18 (10.29%). ^ Infants born to White, Non-Hispanic women had the highest first year survival (83.57%; 95% CI: 80.91, 85.88), followed by African-Americans (82.43%; 95% CI: 76.98, 86.70) and Hispanics (79.28%; 95% CI: 77.19, 81.21). Infants with birth weights ≥2500 grams and gestational ages ≥37 weeks also had the highest first year survival. First year mortality drastically increased as the number of life-threatening anomalies increased. Mortality was also higher for infants with anomalies that were prenatally diagnosed. Slight differences existed in survival based on infant's place of delivery. ^ In logistic regression analysis, birth weight (<1500 grams: OR = 7.48; 95% CI: 5.42, 10.33; 1500–2499 grams: OR = 3.48; 95% CI: 2.74, 4.42), prenatal diagnosis (OR = 1.92; 95% CI: 1.43, 2.58) and number of life-threatening anomalies (≥3: OR = 22.45; 95% CI: 11.67, 43.18) were the strongest predictors of death within the first year of life for all infants with selected congenital anomalies. To achieve further reduction in the infant mortality rate in the United States, additional research is needed to identify ways to reduce mortality among infants with congenital anomalies. ^