Available online 10 December 2023, 107794

To assess the association between childhood body fatness and epithelial ovarian cancer (EOC), and whether this association differs by type of EOC.

Using data from a population-based case-control study (497 cases and 902 controls) in Montreal, Canada conducted 2011–2016, we examined the association between childhood body fatness and EOC, overall and separately for invasive vs. borderline EOCs. A figure rating scale was used to measure body fatness at ages 5 and 10. Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (95% CI). Quantitative bias analyses were conducted to assess the impact of exposure misclassification and non-participation.

The aOR (95% CI) of overall EOC for high vs. low body fatness was 1.07 (0.85–1.34) at age 5 and 1.28 (0.98–1.68) at age 10. The associations were stronger for invasive EOC, specifically the endometrioid histological type. For borderline cancers, the aORs were below the null value with wide confidence intervals. Bias analyses did not reveal a strong influence of non-participation. Non-differential exposure misclassification may have biased aORs towards the null for invasive cancers but did not appear to have an appreciable influence on the aORs for borderline cancers.

Childhood body fatness may be a risk factor for invasive EOC in later adult life. Our study highlights the potential importance of examining early life factors for a comprehensive understanding of EOC development.

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