We determined the adjusted hazard ratios (HR) for all-cause mortality based on frequency of drinking for drinkers of 1–2 drinks per day in both the NHIS data and in the VA data. Frequency of low-level drinking is modeled as a continuous variable in the NHIS dataset and as a discrete variable in the VA dataset. Although our primary variable of interest was frequency of low-level drinking, all statistical models were also adjusted for typical drinking quantity and frequency of binge drinking. Fractional polynomial modeling was used in the NHIS dataset to allow for flexible parameterization of non-linear associations. Using a stepwise approach, frequency of low-level drinking in the NHIS resulted in a model containing terms for frequency and frequency cubed. Other polynomial terms, including (frequency)2, log(frequency), (frequency)−1, and (frequency)−2, were not statistically significant. Estimated hazard ratios for alcohol-related variables are given in supplementary Supplementary table S2, and are plotted in Figure 2.
