Risk factors for the development of diethylstilbestrol-associated clear cell adenocarcinoma: a case-control study

Factors related to the risk of developing clear cell adenocarcinoma in diethylstilbestrol-exposed women were investigated in 156 patients in the United States with clear cell adenocarcinoma and documented diethylstilbestrol exposure (Registry cases) and 1848 diethylstilbestrol-exposed women of similar age without cancer (National Cooperative Diethylstilbestrol Adenosis Project). Diethylstilbestrol dosage patterns, the use of other hormones, mother's age and pregnancy history, and daughter's birth month, birth weight, and age at menarche were compared. The relative risk was higher for those whose mothers began diethylstilbestrol before the twelfth week of pregnancy and for those who were born in the fall (winter conception). Maternal history of at least one prior spontaneous abortion elevated the risk. Supportive evidence for the difference in birth month distribution was also found by a comparison with United States vital statistics. Each factor was confirmed to be significant in a multivariate logistic model that examined all of them with region and year of birth adjusted.