FRIDAY, March 22, 2019 (HealthDay News) -- An earlier age at menopause is associated with a higher risk for bladder cancer, according to a study presented at the annual meeting of the European Association of Urology, held from March 15 to 19 in Barcelona, Spain.
Mohammad Abufaraj, M.D., from the Medical University of Vienna, and colleagues investigated the impact of hormonal and reproductive factors on bladder cancer risk using data from 106,138 female registered nurses participating in the Nurses' Health Study (NHS) and 113,974 who participated in NHSII.
During a follow-up period of up to 36 years, researchers found 441 incident bladder cancer cases. In the NHS, 21.3 percent of women were menopausal at baseline versus 2.4 percent in the NHSII. Younger age at menopause (≤45 years) was associated with an increased risk for bladder cancer (multivariable-adjusted incidence risk ratio [IRR], 1.41; Ptrend = 0.01), particularly among ever smokers (IRR, 1.53; Pinteraction = 0.16) compared with women participating in NHS with menopause onset at ≥50 years. There was no association between bladder cancer risk and age at menarche, parity, age at first birth, oral contraceptive use, or postmenopausal hormone use.
"The potential protective impact of longer reproductive years on bladder cancer risk adds new evidence to our understanding of sexual dimorphism in bladder cancer," the authors write.