Smoking habit changes and body weight: causal estimates from the British Household Panel Survey

This paper evaluates the causal relationship between smoking and body weight through two waves (2004-2006) of the British Household Panel Survey. We model the effect of changes in smoking habits, such as quitting or reducing, and account for the heterogeneous responses of individuals located at different points of the body mass distribution by quantile regression. We investigate the robustness of our results by means of a large set of control groups and the application of an instrumental variable (IV) estimator. Our results reveal the positive effect of quitting smoking on weight changes, which is also found to increase in the highest quantiles, whereas the decision to reduce smoking does not affect body weight. Lastly, cost-benefit analysis reveals that quitting smoking implies savings for the National Health Service which are much larger than the costs associated with increased obesity.