Short and Long-run Effects of Obesity on Cognitive Skills: Evidence from an English Cohort

This paper investigates the consequences of obesity on individuals’ cognitive ability using data from the British Cohort Study. Specifically, it focuses on the outcomes of two cognitive tests: the B.A.S. (British Ability Scale), taken when cohort members are 10 years old, and a basic (literacy and numeracy) skills test, sit at age 34. The analysis is performed using both the individuals’ BMI (Body Mass Index) and an indicator for the obesity condition as measures of body weight and, for the test taken in adulthood, the impact of past weight status is also evaluated. In order to understand whether the influence of obesity is causal, we employ instrumental variables, using both parents’ BMI as instruments for cohort members’ BMI. Even after controlling for a large set of covariates describing individuals’ family environment, our results show that weight excess has a significant negative causal effect on cognitive skills, both in childhood and in adulthood. Moreover, childhood obesity has a long-run impact on skills at age 34