Estimating age-specific breast cancer risks: a descriptive tool to identify age interactions

摘要: Clarifying age-specific female breast cancer risks and interactions may provide important etiologic clues. Using a population-based case–control study in Poland (2000–2003) of 2,386 incident cases 2,502 control subjects aged 25–74 years, we estimated incidence rates according to risk factors. Breast were elevated among women with positive family history (FH), younger age at menarche, older first full-term birth, nulliparity, exogenous hormonal usage, reduced physical activity (PA). Notwithstanding overall risks, observed statistically significant quantitative (non-crossover) qualitative (crossover) for all factors except FH PA. For example, nulliparity compared parity ages 25–39 years then crossed or reversed, after which increased relative 40–74 years. Though could be expected, somewhat counterintuitive. If confirmed other populations, continuous covariate such as will difficult reconcile sequential (multistep monolithic) ‘stochastic’ model. Alternatively, the reversal suggests subgroup heterogeneity different mechanisms early-onset late-onset types.