Excess body fatness in late adulthood has been observed to increase ovarian cancer risk, but the association is relatively weak. Body fatness can change over time, and timing may differently influence risk. We used a life course epidemiology approach to identify whether the relation between body fatness and ovarian cancer risk is best described by a critical period, accumulation or sensitive period hypothesis. In a population-based case-control study of ovarian cancer in Montreal, Canada (2011-16), data on body mass index (BMI) at each decade starting at age 20 was available. Among 363 cases and 707 controls aged ≥ 50 years, we used a Bayesian relevant life course exposure model to estimate the relative importance of BMI for three pre-specified periods across the adult life course, i.e., early childbearing years, late childbearing years, and peri/postmenopause, on ovarian cancer risk. The accumulation hypothesis best described BMI in relation to ovarian cancer overall, with an odds ratio (OR) for the lifetime effect of BMI (per 5 kg/m² increase) of 1.10 (95% credible interval [CrI]: 0.90–1.35). For invasive ovarian cancer, the OR (95% CrI) for the lifetime effect was 1.16 (0.92–1.48), with BMI during early childbearing years showing the highest relative importance, suggesting this may be a sensitive period. For borderline cancer, the lifetime effect OR was not strongly supportive of an association (OR: 0.90, 95% CrI: 0.53–1.32). The results suggest that a sensitive period of early childbearing years is a candidate hypothesis for further investigation.

据观察，成年后期体脂过多会增加患卵巢癌的风险，但这种关联相对较弱。体脂会随着时间的推移而变化，时间可能会对风险产生不同的影响。我们使用生命历程流行病学方法来确定体脂与卵巢癌风险之间的关系是否最好地用关键期、积累期或敏感期假说来描述。在加拿大蒙特利尔一项基于人群的卵巢癌病例对照研究 （2011-16） 中，从 20 岁开始每十年的体重指数 （BMI） 数据可用。在 363 例 50 ≥ 例对照中，我们使用贝叶斯相关生命历程暴露模型来估计 BMI 在成年生命历程中三个预先指定时期的相对重要性，即早期生育期、晚期生育期和围绝经期/绝经后，对卵巢癌风险的影响。积累假说最好地描述了 BMI 与卵巢癌的整体关系，BMI 的终生效应（每 5 kg/m² 增加）的比值比 （OR） 为 1.10（95% 可信区间 [CrI]：0.90-1.35）。对于浸润性卵巢癌，终生效应的 OR （95% CrI） 为 1.16 （0.92-1.48），育龄早期的 BMI 显示出最高的相对重要性，表明这可能是一个敏感期。对于交界性癌症，终生效应 OR 并不强烈支持关联 （OR： 0.90， 95% CrI： 0.53–1.32）。结果表明，早期育龄期的敏感期是进一步研究的候选假设。