Using Propensity Score Methods to Assess Causal Effects of Mothers' Dieting Behavior on Daughters' Early Dieting Behavior

Background: A high prevalence of dieting has been reported among preadolescent females. It is important to understand factors influencing the emergence of dieting because dieting is associated with increased likelihood of overeating, greater weight gain over time, and other chronic health problems. Previous studies suggest that mothers' own dieting behavior influences their daughters' dieting (i.e., modeling). Because it is not possible to randomly assign girls to a mother who is dieting versus not dieting, causal inference regarding the effects of mothers' modeling behaviors on daughters' dieting is not straightforward. Methods: In an observational study, data were collected on four occasions of measurement across a 6-year period, with 2-year intervals between assessments on 181 girls and their parents. Propensity score methods were used to estimate the causal effects of mothers' dieting on the emergence of daughters' dieting between ages 7 and 11, examining the moderating effect of weight status. Results: Girls whose mothers were currently dieting were significantly more likely to diet before age 11 than those whose mothers were not currently dieting, and this effect did not vary by girls' or mothers' weight status. Conclusions: We conclude by discussing the implications of the effects of mothers' dieting on daughters' early dieting as well as the potential of propensity score methods in the field of obesity compared with traditional methodology such as regression analysis.