Several limitations of this study should be noted. First, our method of data collection relied on self report, thus recall bias may affect data accuracy. Drinking behavior and SLE occurrence were based on retrospective report for a 1-year period prior to the interview and for an even longer duration for drinking onset. Although questions were asked in different sections of the interview to avoid priming participants of potential links between drinking and SLE, it is possible that biased recall could spuriously account for part of the association. Age at drinking onset might be confounded by “telescoping” bias, when older individuals recall events as occurring closer in time than they actually occurred, as we observed that late-onset drinkers tended to be older at the time of the interviews than early- and middle-onset drinkers (see Table 1). However, we did not find evidence for (linear) age effects on past-year drinking, nor that current age altered the association between onset age and past-year drinking patterns, as would have suggested systematic recall bias. Second, our sample comprises Caucasian twins born in Virginia. Our findings
