These analyses did not control for years of AUD exposure. To investigate this question, our next model examined both age and years since first AUD registration divided into 4 periods. Our model again fit the data well (AIC of model vs raw data: 4 002 503.9 vs 4 002 519.9). The estimated parameters from this model illustrated 2 major trends (Figure 3). First, aside from the anomalous results (likely due to small sample sizes) for ages 65 to 70 years within 1 to 5 years of first registration, we saw the general trend observed in Figure 2: the slopes of the mHRs in the general population and increasingly close relatives were steeper at younger ages and gradually approached horizontal at older ages. Second, from age 40 years onward, within age periods, the differences in mHR across groups tended to decline with increasing years from first registration. However, this trend was less consistent in the oldest groups. We illustrate these trends in Figure 4, which depicts the GS of the mHRs across the 4 groups (general population and discordant half-siblings, full-siblings, and MZ twins) as a function of years since first AUD registration and age.
