From 1980 until 2008, 7690 cases of invasive breast cancer were diagnosed among 2.4 million years of person-time. Table 1 illustrates the characteristics of the study population according to cumulative average alcohol intake in 1994, the midpoint of the follow-up period. Breast cancer risk factors were distributed fairly evenly across the groups except that higher alcohol consumers were more likely to have had natural menopause, have a lower body mass index, and be current smokers. Although tumor characteristics, current use of hormone therapy and compliance with mammography/clinical breast exams did vary slightly across groups, none of these variables nor any other of the standard breast cancer risk factors displayed a consistent linear trend across categories of increasing alcohol use.
