Causes and consequences of obesity: intergenerational transmission of bmi and its effect on cognive skills

In the last decades, obesity has become a real health plague in most of the developed and developing world, with serious economic and social consequences. Due to this reason, also the economists and social scientists recently focused their attention on this problem. The first chapter of this dissertation presents data that give an idea of the size of the obesity epidemics and surveys the medical, economic and social literature that deals with the causes and consequences of weight excess, both at the individual and macro level. In the second chapter, we shed new light on the intergenerational transmission of BMI and weight problems and study how the family environment, in particular parental education, influences this process. Thanks to the longitudinal structure of our data, we can follow individuals over time, from their childhood to adulthood, exploiting information about their BMI when 10, 16 and 34 years old and therefore studying the persistence of parental influence. We provide for the first time estimates of the intergenerational elasticity of BMI between both parents and their children and we find that it is extremely stable to the introduction of a large set of individual and family controls, suggesting a strong role for genetics in the transmission of weight. On the contrary, parental schooling seems to exert a minor influence on the persistence of BMI: only maternal education has a protective role, but exclusively for sons’ BMI. In the last chapter, we use again data from the BCS70 and we investigate whether obesity influences individuals’ cognitive ability when 10 years old and their literacy and numeracy skills at 34 years. In order to understand whether this relationship is causal, we employ instrumental variables, using both parents’ BMI as instruments for cohort members’ Body Mass. We perform our analysis using also dummies describing individual weight status instead of the continuous BMI variable and we exploit information about individuals’ BMI at different ages to study this issue from a dynamic point of view. Our results show that weight excess has a significant negative causal effect on both cognitive ability and basic skills.