Total body water adjustment of mean alcohol intakes

Total body water volume (TBW) is one factor that determines the functional effect of a standard dose of alcohol. Because women and the elderly generally have lower TBW values than men and younger persons, respectively, less alcohol needs to be consumed by women and elders to achieve the same or higher blood alcohol levels compared to men and younger persons. An existing data set on elderly drinkers was analyzed with and without TBW adjustment of intakes using mean TBW estimates per decade for each gender. The estimates were obtained from a published report that pooled cross-sectional data to produce mean TBW values and TBW prediction equations applicable to Western populations. As the analyses confirm, the use of cutoff points of alcohol intake not adjusted for TBW results in drinking-level misclassification and findings biased towards younger males. This report supports the standard use of TBW-adjusted alcohol intakes in analyses of samples with both genders and/or a wide age range.