Our study also had several limitations. As noted previously, our study did not capture drinking among all baby boomers, just the early part of that generation (born 1946–1954). Inherent confounding between birth cohort and age may have occurred in our main results as individuals in the earliest birth cohort are also older at any given point in time. This issue is what led us to examine birth cohorts stratified by age groups. However, in that examination, there remains the issue of period, i.e., secular effects. Among women, our results for binge drinking were truncated in 2013. The 1997–2013 NHIS defined binge drinking for men and women as 5 or more drinks per day. Starting in 2014, NHIS changed the binge drinking definition to 4 or more drinks per day for women and will continue to use that definition in future years; had we included the 2014 data for women, their binge drinking prevalence would have been artificially inflated by the lowered criterion relative to prior years. The NHIS response rate has dropped over time which can bias results and effect
