A significant limitation is the cross-sectional design. A general limitation of such designs is that reverse causality cannot be ruled out. In the present case, several candidate mediators (i.e., markers of disadvantage, unmarried status) could well be effects of respondent alcohol problems as well as (or instead of) causes. The cross-sectional design also presents difficulties in examining age/lifecourse effects. Accurate assessment of the impact of cumulative heavy drinking on racial/ethnic disparities (and causal analysis generally) is best achieved in the context of longitudinal data.
