PARENTAL AGE AND BREAST-CANCER MORTALITY

Because older ages of both mothers and fathers have been hypothesized by others to increase the subsequent risk of breast cancer in female b abies, we analyzed the association between maternal and paternal age a t birth and mortality from breast cancer in a cohort of 384,796 Americ an women. Cox proportional hazards modeling accounted for age, family history of breast cancer in first-degree relatives, age at menarche, a ge at first pregnancy, and parity. We found little association between paternal age at birth and death from breast cancer. Although there wa s no clear linear trend for higher risk with increasing age of the mot hers at birth, women born to mothers age 45 years or older had a relat ive hazard of 1.30 (95% confidence interval = 0.85-1.98), compared wit h women born to mothers under the age of 20 years. Although these find ings are of little public health significance, they may indicate a hor monal profile in older mothers that predisposes female offspring to a higher risk of breast cancer in later years.