John Cawley

The Medical Care Costs of Obesity: an Instrumental Variables Approach

This paper is the first to use the method of instrumental variables (IV) to estimate the impact of obesity on medical costs in order to address the endogeneity of weight and to reduce the bias from reporting error in weight. Models are estimated using restricted-use data from the Medical Expenditure Panel Survey for 2000-2005. The IV model, which exploits genetic variation in weight as a natural experiment, yields estimates of the impact of obesity on medical costs that are considerably higher than the estimates reported in the previous literature. For example, obesity is associated with

The Impact of Obesity on Wages

656 higher annual medical care costs, but the IV results indicate that obesity raises annual medical costs by

Three observations on wages and measured cognitive ability

2741 (in 2005 dollars). These results imply that the previous literature has underestimated the medical costs of obesity, resulting in underestimates of the economic rationale for government intervention to reduce obesity-related externalities.

Patchy progress on obesity prevention: emerging examples, entrenched barriers, and new thinking

Previous studies of the relationship between body weight and wages have found mixed results. This paper uses a larger data set and several regression strategies in an attempt to generate more consistent estimates of the effect of weight on wages. Differences across gender, race, and ethnicity are explored. This paper finds that weight lowers wages for white females; OLS estimates indicate that a difference in weight of two standard deviations (roughly 65 pounds) is associated with a difference in wages of 9 percent. In absolute value, this is equivalent to the wage effect of roughly one and a half years of education or three years of work experience. Negative correlations between weight and wages observed for other gender-ethnic groups appear to be due to unobserved heterogeneity.

Cost Effectiveness of Community-Based Physical Activity Interventions

Abstract This paper summarizes our recent research on the relationship between wages and measured cognitive ability. In it, we make three main points. First, we find that wage payment by ability does vary across race and gender in the US, and that the fraction of wage variance explained by cognitive ability is modest. Second, measured cognitive ability and schooling are so highly correlated that one cannot separate their effects without imposing strong, arbitrary parametric structure in estimation which, when tested, is rejected by the data. Third, controlling for cognitive ability, personality traits (socialization skills) are correlated with earnings, although they primarily operate through schooling attainment.

Maternal Employment and Childhood Obesity: A Search for Mechanisms in Time Use Data

Despite isolated areas of improvement, no country to date has reversed its obesity epidemic. Governments, together with a broad range of stakeholders, need to act urgently to decrease the prevalence of obesity. In this Series paper, we review several regulatory and non-regulatory actions taken around the world to address obesity and discuss some of the reasons for the scarce and fitful progress. Additionally, we preview the papers in this Lancet Series, which each identify high-priority actions on key obesity issues and challenge some of the entrenched dichotomies that dominate the thinking about obesity and its solutions. Although obesity is acknowledged as a complex issue, many debates about its causes and solutions are centred around overly simple dichotomies that present seemingly competing perspectives. Examples of such dichotomies explored in this Series include personal versus collective responsibilities for actions, supply versus demand-type explanations for consumption of unhealthy food, government regulation versus industry self-regulation, top-down versus bottom-up drivers for change, treatment versus prevention priorities, and a focus on undernutrition versus overnutrition. We also explore the dichotomy of individual versus environmental drivers of obesity and conclude that people bear some personal responsibility for their health, but environmental factors can readily support or undermine the ability of people to act in their own self-interest. We propose a reframing of obesity that emphasises the reciprocal nature of the interaction between the environment and the individual. Todays food environments exploit peoples biological, psychological, social, and economic vulnerabilities, making it easier for them to eat unhealthy foods. This reinforces preferences and demands for foods of poor nutritional quality, furthering the unhealthy food environments. Regulatory actions from governments and increased efforts from industry and civil society will be necessary to break these vicious cycles.

The Economics Of Childhood Obesity

BACKGROUND Physical inactivity is associated with the increased risk of many chronic diseases. Such risks decrease with increases in physical activity. This study assessed the cost-effectiveness of population-wide strategies to promote physical activity in adults and followed disease incidence over a lifetime. METHODS A lifetime cost-effectiveness analysis from a societal perspective was conducted to estimate the costs, health gains, and cost-effectiveness (dollars per quality-adjusted life year [QALY] gained, relative to no intervention) of seven public health interventions to promote physical activity in a simulated cohort of healthy U.S. adults stratified by age, gender, and physical activity level. Interventions exemplifying each of four strategies strongly recommended by the Task Force on Community Preventive Services were evaluated: community-wide campaigns, individually adapted health behavior change, community social-support interventions, and the creation of or enhanced access to physical activity information and opportunities. Each intervention was compared to a no-intervention alternative. A systematic review of disease burden by physical activity status was used to assess the relative risk of five diseases (coronary heart disease, ischemic stroke, type 2 diabetes, breast cancer, and colorectal cancer) across a spectrum of physical activity levels. Other data were obtained from clinical trials, population-based surveys, and other published literature. RESULTS Cost-effectiveness ratios ranged between

Occupation-specific absenteeism costs associated with obesity and morbid obesity.

14,000 and

Cognitive Ability, Wages, and Meritocracy

69,000 per QALY gained, relative to no intervention. Results were sensitive to intervention-related costs and effect size. CONCLUSIONS All of the evaluated physical activity interventions appeared to reduce disease incidence, to be cost-effective, and--compared with other well-accepted preventive strategies--to offer good value for money. The results support using any of the seven evaluated interventions as part of public health efforts to promote physical activity.

Mobilisation of public support for policy actions to prevent obesity

A substantial body of research documents that maternal employment is associated with childhood obesity. This paper explores possible mechanisms for that correlation in the American Time Use Survey (ATUS). We find that maternal employment is associated with working mothers spending, per day, 4 fewer minutes grocery shopping, 17 fewer minutes cooking, 10 fewer minutes eating with children, 12 fewer minutes playing with children, 4 fewer minutes supervising children, and 37 fewer minutes caring for children. The differences tend to be greatest for mothers with young children (age 0-5 years). We explore the extent to which these findings differ by day of the week, whether a partner or spouse is present in the household, whether the mother works non-standard hours, and socioeconomic status. Only a small percentage (about 15%) of the fewer minutes spent in these activities by working mothers appears to be offset by increases in time by husbands and partners. These findings suggest plausible mechanisms for the association between maternal employment and childhood obesity.