Freudenheim and colleagues (1999) compared 315 breast cancer patients and 356 age-matched control subjects. Among premenopausal (but not postmenopausal) women, the researchers found that breast cancer risk was higher in women carrying two copies of the ADH1C*1 allele (i.e., homozygous for ADH1C*1) compared with women carrying only one or no copy of the ADH1C*1 allele (i.e., heterozygous or homozygous for the ADH1C*2 allele). Moreover, premenopausal women who were homozygous for ADH1C*1 and had a higher level of alcohol intake2 were at greater risk of breast cancer than were comparable women with moderate alcohol intake (odds ratio 3.6, 95% CI 1.5–8.8).
