Virginia W. Chang

Weight Status and Restaurant Availability: A Multilevel Analysis

BACKGROUND Empiric studies find that contextual factors affect individual weight status over and above individual socioeconomic characteristics. Given increasing levels of obesity, researchers are examining how the food environment contributes to unhealthy weight status. An important change to this environment is the increasing availability of away-from-home eating establishments such as restaurants. METHODS This study analyzed the relationship between the restaurant environment and weight status across counties in the United States. Individual data from the 2002-2006 Behavioral Risk Factor Surveillance System (N=714,054) were linked with restaurant data from the 2002 U.S. Economic Census. Fast-food and full-service restaurant density, along with restaurant mix (the ratio of fast-food to full-service restaurants), were assessed. RESULTS Fast-food restaurant density and a higher ratio of fast-food to full-service restaurants were associated with higher individual-level weight status (BMI and the risk of being obese). In contrast, a higher density of full-service restaurants was associated with lower weight status. CONCLUSIONS Area-level restaurant mix emerged as an important correlate of weight status, with components of the restaurant environment exhibiting differential associations. Hence, it is the availability of fast-food relative to other away-from-home choices that appears salient for unhealthy weight outcomes. Areas with a high density of full-service restaurants were indicative of a more healthful eating environment, suggesting a need for research into the comparative healthfulness of foods served at different types of restaurants. Future prospective studies are required to delineate causal pathways.

Being Poor and Coping With Stress: Health Behaviors and the Risk of Death

OBJECTIVES Individuals may cope with perceived stress through unhealthy but often pleasurable behaviors. We examined whether smoking, alcohol use, and physical inactivity moderate the relationship between perceived stress and the risk of death in the US population as a whole and across socioeconomic strata. METHODS Data were derived from the 1990 National Health Interview Surveys Health Promotion and Disease Prevention Supplement, which involved a representative sample of the adult US population (n = 40335) and was linked to prospective National Death Index mortality data through 1997. Gompertz hazard models were used to estimate the risk of death. RESULTS High baseline levels of former smoking and physical inactivity increased the impact of stress on mortality in the general population as well as among those of low socioeconomic status (SES), but not middle or high SES. CONCLUSIONS The combination of high stress levels and high levels of former smoking or physical inactivity is especially harmful among low-SES individuals. Stress, unhealthy behaviors, and low SES independently increase risk of death, and they combine to create a truly disadvantaged segment of the population.

Substance P Innervation of Lumbar Spine Facet Joints

Sixteen adult human lumbar spine facet joints were harvested from patients undergoing various lumbar spine procedures. Diagnoses included degenerative disc disease, adult spinal deformity, facet joint degenerative arthritis, and degenerative spondylolisthesis. Facet joints were processed for routine hematoxylin and eosin staining. Immunohistochemical analysis was performed using a monoclonal antibody to substance P. All facets grossly exhibited evidence of degenerative disease, including cartilage surface irregularity and fibrillation. Histological examination of facets obtained from patients with degenerative spinal conditions demonstrated erosion channels extending through the subchondral bone and calcified cartilage into the articular cartilage. Immunostaining showed the presence of substance P-positive nerve fibers within these erosion channels, and also within marrow spaces. The presence of substance P nerve fibers within subchondral bone of degenerative lumbar facet joints implicates this type of joint in the etiology of low back pain.

Fundamental Cause Theory, Technological Innovation, and Health Disparities: The Case of Cholesterol in the Era of Statins

Although fundamental cause theory has been highly influential in shaping the research literature on health disparities, there have been few empirical demonstrations of the theory, particularly in dynamic perspective. In this study, we examine how income disparities in cholesterol levels have changed with the emergence of statins, an expensive and potent new drug technology. Using nationally representative data from 1976 to 2004, we find that income gradients for cholesterol were initially positive, but then reversed and became negative in the era of statin use. While the advantaged were previously more likely to have high levels of cholesterol, they are now less likely. We consider our case study against a broader theoretical framework outlining the relationship between technology innovation and health disparities. We find that the influence of technologies on socioeconomic disparities is subject to two important modifiers: (1) the nature of the technological change and (2) the extent of its diffusion and adoption.

Mortality Attributable to Obesity Among Middle-Aged Adults in the United States

Obesity is considered a major cause of premature mortality and a potential threat to the longstanding secular decline in mortality in the United States. We measure relative and attributable risks associated with obesity among middle-aged adults using data from the Health and Retirement Study (1992–2004). Although class II/III obesity (BMI _ 35.0 kg/m2) increases mortality by 40% in females and 62% in males compared with normal BMI (BMI = 18.5-24.9), class I obesity (BMI = 30.0-34.9) and being overweight (BMI = 25.0-29.9) are not associated with excess mortality. With respect to attributable mortality, class II/III obesity (BMI _ 35.0) is responsible for approximately 4% of deaths among females and 3% of deaths among males. Obesity is often compared with cigarette smoking as a major source of avoidable mortality. Smoking-attributable mortality is much larger in this cohort: about 36% in females and 50% in males. Results are robust to confounding by preexisting diseases, multiple dimensions of socioeconomic status (SES), smoking, and other correlates. These findings challenge the viewpoint that obesity will stem the long-term secular decline in U.S. mortality.

Weight change, initial BMI, and mortality among middle- and older-aged adults

Background: It is not known how the relationship between weight change and mortality is influenced by initial body mass index (BMI) or the magnitude of weight change. Methods: We use the nationally representative Health and Retirement Study (n = 13,104; follow-up 1992–2006) and Cox regression analysis to estimate relative mortality risks for 2-year weight change by initial BMI among 50- to-70-year-old Americans. We defined small weight loss or gain as a change of 1–2.9 BMI units and large weight loss or gain as a change of 3–5 BMI units. Results: Large and small weight losses were associated with excess mortality for all initial BMI levels below 32 kg/m2 (eg, hazard ratio [HR] for large weight loss from BMI of 30 = 1.61 [95% confidence interval = 1.31–1.98]; HR for small weight loss from BMI of 30 = 1.19 [1.06–1.28]). Large weight gains were associated with excess mortality only at high BMIs (eg, HR for large weight gain from BMI of 35 = 1.33 [1.00–1.77]). Small weight gains were not associated with excess mortality for any initial BMI level. The weight loss–mortality association was robust to adjustments for health status and to sensitivity analyses considering unobserved confounders. Conclusions: Weight loss is associated with excess mortality among normal, overweight, and mildly obese middle- and older-aged adults. The excess risk increases for larger losses and lower initial BMI. These results suggest that the potential benefits of a lower BMI may be offset by the negative effects associated with weight loss. Weight gain may be associated with excess mortality only among obese people with an initial BMI over 35.

Quality of Care Among Obese Patients

CONTEXT Clinicians often have negative attitudes toward obesity and express dissatisfaction in caring for obese patients. Moreover, obese patients often feel that clinicians are biased or disrespectful because of their weight. These observations raise the concern that obese patients may receive lower quality of care. OBJECTIVE To determine whether performance on common outpatient quality measures differs by patient weight status. DESIGN, SETTING, AND PARTICIPANTS Eight different performance measures were examined in 2 national-level patient populations: (1) Medicare beneficiaries (n = 36 122) using data from the Medicare Beneficiary Survey (1994-2006); and (2) recipients of care from the Veterans Health Administration (VHA) (n = 33 550) using data from an ongoing performance-evaluation program (2003-2004). MAIN OUTCOME MEASURES Performance measures among eligible patients for diabetes care (eye examination, glycated hemoglobin [HbA(1c)] testing, and lipid screening), pneumococcal vaccination, influenza vaccination, screening mammography, colorectal cancer screening, and cervical cancer screening. Measures were based on a combination of administrative claims, survey, and chart review data. RESULTS We found no evidence that obese or overweight patients were less likely to receive recommended care relative to normal-weight patients. Moreover, success rates were marginally higher for obese and/or overweight patients on several measures. The most notable differentials were observed for recommended diabetes care among Medicare beneficiaries: comparing obese vs normal-weight patients with diabetes, obese patients were more likely to receive recommended care on lipid screening (72% vs 65%; odds ratio, 1.37 [95% confidence interval, 1.09-1.73]) and HbA(1c) testing (74% vs 62%; odds ratio, 1.73 [95% confidence interval, 1.41-2.11]). All analyses were adjusted for sociodemographic factors, health status, clinical complexity, and visit frequency. CONCLUSIONS Among samples of patients from the Medicare and VHA populations, there was no evidence across 8 performance measures that obese or overweight patients received inferior care when compared with normal-weight patients. Being obese or overweight was associated with a marginally higher rate of recommended care on several measures.

Obesity and 1-year outcomes in older Americans with severe sepsis.

Objectives:Although critical care physicians view obesity as an independent poor prognostic marker, growing evidence suggests that obesity is, instead, associated with improved mortality following ICU admission. However, this prior empirical work may be biased by preferential admission of obese patients to ICUs, and little is known about other patient-centered outcomes following critical illness. We sought to determine whether 1-year mortality, healthcare utilization, and functional outcomes following a severe sepsis hospitalization differ by body mass index. Design:Observational cohort study. Setting:U.S. hospitals. Patients:We analyzed 1,404 severe sepsis hospitalizations (1999–2005) among Medicare beneficiaries enrolled in the nationally representative Health and Retirement Study, of which 597 (42.5%) were normal weight, 473 (33.7%) were overweight, and 334 (23.8%) were obese or severely obese, as assessed at their survey prior to acute illness. Underweight patients were excluded a priori. Interventions:None. Measurements and Main Results:Using Medicare claims, we identified severe sepsis hospitalizations and measured inpatient healthcare facility use and calculated total and itemized Medicare spending in the year following hospital discharge. Using the National Death Index, we determined mortality. We ascertained pre- and postmorbid functional status from survey data. Patients with greater body mass indexes experienced lower 1-year mortality compared with nonobese patients, and there was a dose-response relationship such that obese (odds ratio = 0.59; 95% CI, 0.39–0.88) and severely obese patients (odds ratio = 0.46; 95% CI, 0.26–0.80) had the lowest mortality. Total days in a healthcare facility and Medicare expenditures were greater for obese patients (p < 0.01 for both comparisons), but average daily utilization (p = 0.44) and Medicare spending were similar (p = 0.65) among normal, overweight, and obese survivors. Total function limitations following severe sepsis did not differ by body mass index category (p = 0.64). Conclusions:Obesity is associated with improved mortality among severe sepsis patients. Due to longer survival, obese sepsis survivors use more healthcare and result in higher Medicare spending in the year following hospitalization. Median daily healthcare utilization was similar across body mass index categories.

Secular Declines in the Association Between Obesity and Mortality in the United States

Recent research suggests that rising obesity will restrain future gains in US life expectancy and that obesity is an important contributor to the current shortfall in us longevity compared to other high-income countries. Estimates of the contribution of obesity to current and future national-level mortality patterns are sensitive to estimates of the magnitude of the association between obesity and mortality at the individual level. We assessed secular trends in the obesity/mortality association among cohorts of middle-aged adults between 1948 and 2006 using three long-running US data sources: the Framingham Heart Study, the National Health and Nutrition Examination Survey, and the National Health Interview Survey. We find substantial declines over time in the magnitude of the association between obesity and overall mortality and, in certain instances, cardiovascular-specific mortality. We conclude that estimates of the contribution of obesity to current national-level mortality patterns should take into account recent reductions in the magnitude of the obesity and mortality association.

The Lack of Effect of Market Structure on Hospice Use

OBJECTIVE To describe the relative importance of health care market structure and county-level demographics in determining rates of hospice use. DATA SOURCES Medicare claims data for a cohort of elderly patients newly diagnosed with lung cancer, colon cancer, stroke, or heart attack in 1993, followed for up to five years, and linked to Census and Area Resource File data. STUDY DESIGN Variation between markets in rates of hospice use by patients with serious illness was examined after taking into account differences in individual-level data using hierarchical linear models. The relative explanatory power of market-level structure and local demographic variables was compared. DATA COLLECTION METHODS The cohort was defined within the Medicare hospital claims data using validated algorithms to detect incident cases of disease with a three-year lookback. Use of hospice was determined by linkage at an individual level to the Standard Analytic Files for Hospice through 1997. Individual-level data was linked to the Area Resource File using county identifiers present in the Medicare claims. PRINCIPAL FINDINGS There is substantial variation in hospice use across markets. This variation is not explained by differences in the major components of health care infrastructure: the availability of hospital, nursing home, or skilled nursing facilities, nor by the availability of HMOs, doctors, or generalists. CONCLUSIONS Intercounty heterogeneity in hospice use is substantial, and may not be related to the set-up of the medical care system. The important local factors may be local preferences, differences in the particular mix of services provided by local hospices, or differences in community leadership on end of life-issues; many of these differences may be amenable to educational efforts.