Association of recalled age at menarche with risk of site-specific cancers in middle-aged women

The timing of pubertal events may have implications for disease risks in aging women. Pooled analysis of nine prospective U.S. and European cohorts found that each additional year in the recalled age at menarche was associated with reduced risks of endometrial cancer (HR 0.91; 95% CI 0.89-0.94), liver cancer (0.92; 0.85-0.99), melanoma (0.95; 0.93-0.98), bladder cancer (0.96; 0.93-0.99), colon cancer (0.97; 0.96-0.99), lung cancer (0.98; 0.96-0.99), and breast cancer (0.98; 0.93-0.99). The authors propose that early exposure to sex hormones increases mid-life cancer risks by altering functional capacities of stem cells with roles in systemic energy balance and tissue homeostasis.