Oral Contraceptive Use and Risks of Cancer in the NIH-AARP Diet and Health Study.

Oral Contraceptive Use and Risks of Cancer in the NIH-AARP Diet and Health Study. Am J Epidemiol. 2018 Jan 31;: Authors: Michels KA, Brinton LA, Pfeiffer RM, Trabert B Abstract Although use of oral contraceptives (OC) is common, their influence on carcinogenesis is not fully understood. We used Cox proportional hazards models to examine OC use (never/<1 year (reference), 1-4, 5-9, 10+ years) and development of incident cancers across body sites within the same base population: women in the prospective NIH-AARP Diet and Health Study (enrolled 1995-1996, followed until 2011). Adjustment for confounding varied by outcome; all models accounted for age, race, body mass index, and smoking status and included ≥100,000 women. Any OC use conferred a 3% reduction in the risk for any cancer (hazard ratio = 0.97, 95% confidence interval: 0.95, 0.99). Expected risk reductions that strengthened with duration of use were identified for ovarian and endometrial cancers and were suggested for kidney cancer (P-trends < 0.05). We noted reduced risk for non-Hodgkin lymphoma (hazard ratio = 0.79, confidence interval: 0.64, 0.97) with 10+ years of use. We observed a 37% reduced risk for bladder cancer and 46% increased risk for pancreatic cancer among long-term users who were ≤60 at baseline. OC use did not influence risks for most other cancers evaluated. Given the high prevalence of use and changing formulations, future studies are warran...
Source: Am J Epidemiol - Category: Epidemiology Authors: Tags: Am J Epidemiol Source Type: research