Research line: Obesity

• General description

  The evidence on the effectiveness of many policies against obesity is limited, as the external validity of the results is unknown and because of the doubts on the classical assumptions of rationality of consumers and vendors, and thus the effectiveness of certain policies. Today, the economic science questions the assumptions of rationality of individuals whose decisions respond in part to their affective system and are shaped by various incentives from industry and government. In this sense, besides the traditional instruments to influence individual behavior, based on taxes and other economic incentives, others are becoming stronger incentives for the emotional part. Hence the most recent proposals advocate for changing the environment, making healthy behaviors more comfortable.

  The causal relationships between physical activity and risk factors for health are well established. The continued reduction in physical activity is responsible for 12-30% of the increase in the prevalence of obesity, hypertension, diabetes and ischemic heart disease in the US. The EU has defined "good practices", and in Spain there is a proposal for a standardized and uniform indicators to monitor the evolution of the practice of physical exercise, nutrition and obesity, defined within the NAOS strategy.

  On the other hand, the social contagion phenomenon and social interactions help explain the dynamics of lifestyles. In a previous study (Harris and Gonzalez Lopez-Valcarcel, 2008) we concluded that interactions could be asymmetrical. Among adolescents, to have a brother who smokes increases the likelihood of starting to smoke, but if you brother quits smoking your likelihood to quit does not change much. We have also recently quantified the phenomenon of contagion of obesity among adolescents in Catalonia (Mora and Gil, 2013). Because of social interactions group incentives for weight loss may be more effective than targeting individuals (Kullgren et al., 2013).

  We propose in this project a social experiment with children in schools, aimed at measuring the impact of information and promotion interventions. A consumer product to which literature and health policy is paying attention are sugary drinks. We will use laboratory experimentation techniques with teenagers in Catalonia to assess behavioral changes related to these drinks.

  The Household Budget Surveys have not been exploited so far to analyze dietary patterns of Spanish families, perhaps because they were in practice the exclusive preserve of economists. However, they could be a valuable source of information on the healthiness of the diet. We have previously linked different socioeconomic parameters with the consumption of different food groups and dietary patterns (Sánchez-Villegas et al., 2003; López-Azpiazu et al., 2003), as well as the prevalence of obesity (van Stralen et al. , 2012). In this project we will advance in this line in order to assess the effect of prices, own and cross, on consumtion, controlling for background information on the households. That analysis will provide important information for the analysis of the impact of possible tax changes.

  In practice, the effectiveness of taxes on the trend of obesity appears to be limited, precisely because of the complexities of consumer behavior. Thanks to new information provided by this project we will contribute to the design of an appropriate tax scheme.

  The association between obesity and productivity in the labor market has been studied by the scientific literature, to which members of our group have contributed and continue to (Vallejo-Torres and Morris, 2010, Mora, 2010, Morris 2007, Morris et al., 2012). It is well known the problem of reverse causation between obesity and labor productivity and socioeconomic status. We will contribute to enhance the design of policies by analysing these relationships with microeconometric models.

  We have shown that eating habits in Europe have an important social gradient (Lopez-Azpiazu et al, 2003, Sanchez Villegas et a). Hence the fight against obesity is ultimately a manifestation of equity policies, both interpersonal and territorial. Today there are a robust methodology for measuring inequality related to health, led globally by the group of Eddy VanDoorslaer (University Erasmus), in which our group is and will continue actively working (Vallejo-Torres et al., 2013 ).

  Since the beginning of the economic crisis the socioeconomic inequality in Spain (measured, for example, the Gini index of income concentration) is widening, and it has health consequences (van Doorslaer et al., 2013). Unemployment and poverty are becoming social health problems, with tangible effects on physical and mental health (Urban and Gonzalez Lopez-Valcarcel, 2013a, Urban and Gonzalez Lopez-Valcarcel , 2013b). In part the causes of these effects are changes in lifestyles.

  Feedback causations between lifestyles, health status and inequalities can only be broken by changing policies with emphasis on equity. This is the main focus of the project.

   

• Hypothesis on obesity and physical exercise

   

  1. The social gradient in obesity and sedentary lifestyle are increasing in Spain
  2. The individual cost of obesity in terms of opportunities in the labor market is also increasing
  3. Lifestyles are "contagious". Social interactions ultimately generate long term-differentiated clusters in the territory, with different prevalences of obesity and smoking. Well-designed policies can leverage this ability to spread
  4. It is possible to effectively promote the health of children and adolescents by analyzing their behavior (cause and effect) regarding the consumption of sugary drinks, and designing appropriate instruments based either on prices or on promotional campaigns and information
  5. In recent years of economic recession the decline in Spanish household budgets has led to changes in eating patterns, causing health effects
  6. Well-designed positive and negative economic incentives may be effective policy instruments related health lifestyles - snuff, exercise, and proper nutrition-. They need to be properly designed in order to minimize their side effects.

• Project coordinator

  •  Beatriz G Lopez-Valcarcel

Working Packages:

• WP2. Social gradient of obesity

  • To review the methodologies proposed in the literature to measure the social gradient of lifestyles and its dynamics
  • To review the evidence for the OECD (Spain in context)
  • To measure the gradient to Spain and its change between 2007 and 2012, focusing on the dimensions education, income, and unemployment, with microdata (Spanish National Health Survey among others). The methods we use to measure and monitor the social gradient in obesity are based on the specific literature, including the methods used in previous studies by members of our team. Specifically, we will use the concentration index and its decomposition. The use of the concentration index has been applied in numerous studies as a measure of inequality in health and lifestyles, providing advantages over other measures of social gradient. These advantages include the ability to break down and explore the reasons for changes observed in the level of inequality between different geographical areas or different time periods.

  PARTICIPANTS

  • Beatriz  González López-Valcárcel (Coordinadora)
  • Patricia Barber Pérez
  • Laura Vallejo Torres
  • Steve Morris
  • Colaboradora: Josefina Panetta

   

• WP3. Microeconometric model of obesity and productivity

  We will use econometric techniques on individual data from surveys such as the National Health Survey of Spain and the European project SHARE, in order to develop predictive models of obesity and measure the effects attributable to education, income and unemployment. We will consider the phenomenon of endogeneity; this phenomenon occurs due to reverse causation - lower socioeconomic levels cause obesity but obesity may impact on the socioeconomic level and the existence of unobservable variables that affect both obesity and socioeconomic level. In these cases, the coefficients obtained in conventional regression models will be biased. We will explore a number of econometric techniques have been developed to alleviate these problems, including the use of instrumental variables and systems of simultaneous equations. We will use these predictive models to explain obesity, and also to explain inequalities in obesity following the methodology described in the previous section. We will use indexes of concentration and decomposition factors in order to quantify the contribution of each of the variables in our models on the observed degree of inequality in obesity.

  • Simulating impact of different social gradients of obesity and sedentary lifestyle. We will calculate the causal attribution to differences in education, income and unemployment.

  PARTICIPANTS

  • Laura Vallejo Torres (Coordinadora)
  • Steven Morris
  • Beatriz González López-Valcárcel
  • Patricia Barber Pérez
  • Alejandro Rodríguez Caro

• WP4. Modeling social interactions and contagion of obesity

  Geostatistical mapping. Exploratory analysis of social interactions and spread of lifestyles. Application to the case of type 2 diabetes

  In other environments, it has been found that the spatial distribution of obese / normal weight is not homogeneous; there are territorial clusters that overlap with those of social class. In Spain, the north-south gradient in the prevalence of obesity is very significant (Basque Country vs Andalusia and the Canary Islands). Does it also occur in small areas? Is it because of contagion, as in other areas of the world?

  For this purpose we will use geospatial statistical methods (geostatistics), recently developed. These techniques have been widely used in the field of health, especially in problems related to the spread of disease. In recent years, Geographic Information Systems (GIS) allow a vision not only quantitative but also spatial of the phenomena studied. There are multiple applications of GIS in the field of Public Health. In Spain, the ATLAS poyect VPM (Variations in Medical Practice) has developed models of spatial statistics to analyze the geographic variability of certain medical practices (Orthopaedic Surgery, General Surgery, Pediatric Care, Cardiovascular Procedures or Hospitalizations for Mental Health, etc.). This project will use geostatistics to make an exploratory analysis of the study variables.

  Exploratory spatial data analysis is a set of techniques that allow, among other things, discover the existence of spatial association patterns (clusters) or spatially detect the existence of outliers (spatial outlier). When analyzing spatial trends two different methodologies can be used, global contrasts, for which the entire sample is used, and local contrasts that only use part of the sample chosen with neighborhood criteria.

  This project will use data from the Atlas of Mortality in Small Areas 1984-2004 (Benach and Martinez, 2013), recently introduced, which contains information for 2,218 geographic areas. We will analyse mortality from diabetes, which is little influenced by supply and will be used as an approximation to the distribution of obesity for small geographic areas. We will match the Atlas database with municipal databases of socioeconomic environment (http://www.cajaespana.es/pubweb/decyle.nsf) containing information on distribution, uses and value of land. We will use also other municipal databases to detect geographic patterns in the lifestyles related to health.

   

   

  PPARTICIPANTS

  • Jeff Harris (Coordinador)
  • Rafael Suárez Vega
  • Patricia Barber Pérez
  • Beatriz González López-Valcárcel
  • Alejandro Rodríguez Caro
  • Colaborador: Jaime Pinilla Domínguez

• WP5. School experiment. Sugared drinks

  This activity is intended to promote children's health thamks to the results obtained by laboratory experimentation. In particular, we will analyse the reactions of schoolchildren and adolescents in secondary schools in Catalonia to stimulae concerning sugary drinks. Because they are not autonomous in purchasing decisions, we will also collect information relating to the characteristics of the parents.

  To this end, we will get a representative sample of Catalonian schools of secondary education from the database of the population of schools in Catalonia provided by the Statistical Institute of Catalonia (IDESCAT). The sample, representative by school type in Barcelona, will be obtained through two-stage stratified sampling, with simple random sampling education groups (classes). As the sample size will be a function of the variables to be included in the study.

  This paper will contribute to the international literature by analyzing the causal impact from various determinants such as caloric input information, price changes and the peer influence. We will assess the impact of prices and the potential of an intervention consisting in nutritionist advice and information.

   

  PARTICIPANTS

  • Toni Mora (coordinador)
  • Beatriz González López-Valcárcel
  • Colabora: Carmen Cabezas

• WP6. Nutrition and Economics of Prevention

  We will explore the changes in nutritional patterns with the economic crisis in Spain. We will analyse data for each household participing in the Household Budget Surveys corresponding to two consecutive annual observations from 2007 to 2011. Therefore, we have five panel transitions (T = 2), and highly detailed food consumption data and consumption of other goods. By modeling these data, and from a standard definition of "optimal" diet (Example: Pattern Mediterranean Diet, Healthy Eating Index (HEI), Alternative HEI (AHEI), etc .), we estimate price elasticities of different food groups and "healthy" and unhealthy dietary patterns and cross elasticities, and measure the social gradient and the change in the wake of the economic crisis. Furthermore, the relationship between changes in food consumption and changes in the prevalence of obesity is discussed.

   

  PARTICIPANTS

  • Almudena  Sánchez Villegas (coordinador)
  • Jaime Pinilla Domínguez
  • Patricia Barber Pérez
  • Beatriz González López-Valcárcel

• WP7. Regulation. Designing fiscal tools and regulation of rights

  The objective is to design a proposal for taxing sugary drinks that is neutral to family income, in order to change unhealthy behavior patterns and to get a given reduction in obesity as defined by the tax target.

  Also, we will propose regulatory changes in the rights of use of obesogenic / unhealthy elements (salt, saturated fat) with measurable population health objectives, and prospectively assess their economic impact in the medium and long term.

  • Systematic review of the literature to identify which policies work to move the BMI distributions of the different deciles of income / education and to promote changes in lifestyles related to diet and physical activity
  • Optimal design of taxes on sugary drinks and fats. We will define alternative designs based on the literature and international evidence, and we will estimate their effects on changes in consumption, health and equity through microsimulation models

  Regulation and the markets of rights

  • We will design alternative regulation schemes of rights of use of unhealthy inputs (salt, fats, additives) by food businesses, and through microsimulation models we will quantitatively evaluate the expected consequences of changes in consumption, health and equity. This regulation considers the emergence of secondary markets for rights to use "bad calories" that some companies could sell to others.

   

   

  PARTICIPANTS

  • Vicente Ortún Rubio (coordinador)
  • Jaume Puig Junoy