Missing data also may have an impact on effect size estimates; those with indeterminate family history statuses were no more or less likely to be obese than others in the NLAES or NESARC, but those with missing BMI data were more likely to report a family history of alcoholism, an effect that was larger in the NESARC. It is difficult to speculate on how this correlation might impact the results, but if social-desirability is a component of missing BMI data (i.e., passive refusal to report high weight), this may result in slight underestimates for both the association between FH-Alc and obesity, and the secular trend.
