The labour market impact of body weight in China: a semiparametric analysis

While a positive wage effect of Body Mass Index (BMI) is widely observed in low-income developing countries, a negative wage effect of BMI is often observed in high-income developed countries. To fill the gap between these previous findings, we investigate the relationship between body weight and wages in transition economies. We focus on China, whose rapid economic growth of the 1990s was followed by a rapid increase in overweight and obesity while still experiencing significant food insecurity and underweight. we first use several parametric regression strategies to obtain a consistent estimate of the wage effects of weight. Second, we adopt a semiparametric partially linear model that allows for endogeneity of weight. Parametric regressions provide mixed results, and the sign and magnitude of their estimates are sensitive to the choice of samples and regression strategies. Semiparametric estimates provide evidence of a wage penalty for very heavy and thin persons among both men and women. The wage penalty is more significant among men than among women. Semiparametric results also indicate that parametric estimates can overstate and misrepresent the wage effects of weight for healthy weight persons due to their restrictive functional form assumptions.