These findings demonstrate the feasibility and potential utility of identifying and reporting contextual factors. Involving diverse stakeholders in assessing context at multiple stages of the research process, examining their association with outcomes, and consistently reporting critical contextual factors are important challenges for a field interested in improving the internal and external validity and impact of health care research.

OBJECTIVES: The purpose of the study was to conduct a national multivariate analysis on poverty-area residence and mortality in the United States. METHODS: Proportional hazards analyses were performed of the effect of poverty-area residence on the risk of mortality among adult examinees in the 1971 through 1974 National Health and Nutrition Examination Survey who were followed through 1987. RESULTS: Poverty-area residence was associated with significantly elevated risk of all-cause mortality (rate ratio = 1.78, 95% confidence interval = 1.33, 2.38) and some cause-specific mortality among those aged 25 through 54 years, but not among those aged 55 through 74 years, at baseline after adjustment for several individual and household characteristics. CONCLUSIONS: Residence in poverty areas contributes to socioeconomic gradients in mortality among nonelderly adults in the United States.

Although per capita medical care utilization and expenditures are highest among children, adults constitute an important and growing share of the population living with spina bifida.

Before a 1996 US regulation requiring fortification of enriched cereal-grain products with folic acid, 3 economic evaluations projected net economic benefits or cost savings of folic acid fortification resulting from the prevention of pregnancies affected by a neural tube defect. Because the observed decline in neural tube defect rates is greater than was forecast before fortification, the economic gains are correspondingly larger. Applying both cost-benefit and cost-effectiveness analytic techniques, we estimated that folic acid fortification is associated with annual economic benefit of 312 million dollars to 425 million dollars. The cost savings (net reduction in direct costs) were estimated to be in the range of 88 million dollars to 145 million dollars per year.

The increase in income inequality in the United States over the past 20 years has been accompanied by a pronounced increase in economic segregation in urban areas. No research to date has analyzed the potential effects of such spatial segregation on mortality. To investigate these effects, the mortality experience of respondents aged 30 years and older on the 1986-94 National Health Interview Surveys residing in any one of 30 large metropolitan areas in the United States was analyzed. Concentrated poverty was associated with significantly elevated risk of mortality, even after controlling for individual household income. Concentrated affluence showed a consistent, protective effect only among the elderly. The effects were most pronounced among the poor, but were not confined to them. Urban planning should take into account the effects associated with economic residential segregation.

This study surveyed PKU patients and their primary caretakers to assess their current management practices, the barriers to effective management, and the potential utility of a home monitor in managing PKU. A survey instrument was mailed to caretakers of all 50 patients with PKU in Utah between the ages of 2 and 18 years in 1997 (response rate 64%). It included separate components for caretakers and patients aged 10 to 18 years. Although there was uneven compliance with recommended practices, caretakers universally recognized the negative consequences of not adhering to the low-protein diet. There was, however, disagreement regarding such consequences among the older children surveyed. The primary obstacles cited to better adherence were time constraints and stress associated with food preparation and record-keeping, and the restrictions imposed on social life. Phenylalanine test results were regarded as the principal signal for the need for dietary adjustment. Despite the facts that obstacles to dietary adherence are multifaceted and that no single intervention would therefore serve as a panacea, a large majority of respondents believed a home monitor would facilitate better management of PKU through more regular and timely feedback.

OBJECTIVES. The purpose of this study was to compare the economic costs and benefits of fortifying grain with folic acid to prevent neural tube defects. METHODS. A cost-benefit analysis based on the US population, using the human capital approach to estimate the costs associated with preventable neural tube defects, was conducted. RESULTS. Under a range of assumptions about discount rates, baseline folate intake, the effectiveness of folate in preventing neural tube defects, the threshold dose that minimizes risk, and the cost of surveillance, fortification would likely yield a net economic benefit. The best estimate of this benefit is $94 million with low-level (140 micrograms [mcg] per 100 g grain) fortification and $252 million with high-level (350 mcg/100 g) fortification. The benefit-to-cost ratio is estimated at 4.3:1 for low-level and 6.1:1 for high-level fortification. CONCLUSIONS. By averting costly birth defects, folic acid fortification of grain in the United States may yield a substantial economic benefit. We may have underestimated net benefits because of unmeasured costs of neural tube defects and unmeasured benefits of higher folate intake. We may have overestimated net benefits if the cost of neurologic sequelae related to delayed diagnosis of vitamin B12 deficiency exceeds our projection.

The purpose of this paper is to examine the hypothesis that marital and poverty status interact in their effects on mortality risks beyond their main effects. This study examines the epidemiological bases for applying an additive rather than a multiplicative specification when testing for interaction between two discrete risk factors. We specifically predict that risks associated with being nonmarried and with being poor interact to produce mortality risks that are greater than each risk acting independently. The analysis is based on men and women who were ages 25-74 during the 1971-1975 National Health and Nutrition Examination Survey I (NHANES I) and who were traced successfully in the NHANES I Epidemiologic Follow-Up Study in 1982-1984. Overall, being both poor and nonmarried places nonelderly (ages 25-64) men, but not women, at risk of mortality greater than that expected from the main effects. This study shows that for all-cause mortality, marital and poverty status interact for men but less so for women; these findings exist when interaction is assessed with either a multiplicative or an additive standard. This difference is most pronounced for poor, widowed men and (to a lesser degree) poor, divorced men. For violent/accidental deaths among men, the interaction effects are large on the basis of an additive model. Weak main and interaction effects were detected for the elderly (age 65+).