A dynamic perspective on maternal employment and early childhood overweight: evidence from the German Socio-Economic Panel

Michael Kühhirt, University of Cologne

In this paper I study the effect of maternal employment history in the first five years after birth on children’s body mass index and overweight around age six. Theoretical arguments exist for both a positive and a negative effect of maternal employment on children’s physiological development, the former resulting from additional resources provided by the mother, the latter from diminishing the time available for preparing healthy food and engaging in physical activity. Most earlier research has measured maternal employment at a particular point in time, thereby neglecting the dynamic character of children’s development where outcomes at one time are likely to depend on current as well as on past context conditions. Studies that did consider complete employment histories used simple duration measures that do not capture important aspects of employment history like timing and (in)stability. Moreover, studying the effects of time-varying predictors such as maternal employment poses specific analytical challenges that standard methods cannot readily address, particularly if time-varying confounders of the relationship of interest are themselves affected by earlier values of the predictor. In the present study, I use sequence analysis to derive measures that identify typical timing patterns and (in)stability of early maternal employment in addition to duration measures used in previous research. Furthermore, I use inverse probability weighting of marginal structural models to estimate the association of these different measures with body mass index and overweight at age six, a method developed specifically for studying the effects of time-varying exposures. Using data on around 900 children from the German Socio-Economic Panel, I find no differences in body weight for children that have experienced very different maternal employment histories but are similar with regard to observed characteristics like maternal education, number of siblings, and household income.