Childhood and adolescent dietary patterns and incidence of benign breast disease

Childhood and adolescence may represent critical time windows for shaping future breast cancer risk. The association between early-life diet and breast cancer risk has been investigated, but few studies have examined the relation between adolescent diet and benign breast disease (BBD), an established breast cancer risk factor.

Among 11,422 female Growing Up Today Study participants followed from 1996 to 2016 who completed food frequency questionnaires, we investigated the associations between adherence to three dietary patterns (Alternative Healthy Eating Index [AHEI], the Empirical Dietary Inflammatory Pattern [EDIP], and the Empirical Dietary Index for Hyperinsulinemia [EDIH]) at ages 10 and 14 years and self-reported BBD diagnosis. Cox proportional hazards models were used to estimates hazard ratios (HRs) and 95% confidence intervals (CIs).

Over 20 years of follow-up, 554 BBD cases were ascertained, with 259 biopsy-confirmed cases. Non-significant inverse associations were observed between greater adherence to the AHEI at age 10 and BBD risk (HR for fourth vs. first quartile = 0.74; 95% CI = 0.50-1.10; p_trend = 0.09), and between AHEI at age 14 and biopsy-confirmed BBD (HR for fourth vs. first quartile = 0.70; 95% CI = 0.48-1.03; p_trend = 0.10). Non-significant positive associations were observed between adherence to the EDIH at age 10 and (HR for fourth vs. first quartile = 1.49; 95% CI = 0.91-2.43; p_trend = 0.09) age 14 (HR for fourth vs. first quartile = 1.33; 95% CI = 0.97-1.82; p_trend = 0.09) and BBD risk. No associations were observed for EDIP. In secondary analyses, the association between EDIH at age 10 and BBD became statistically significant after accounting for change in dietary pattern quartile from age 10 to 14 (HR for fourth vs. first quartile = 2.14; 95% CI = 1.04-4.41). Adjustment for adult diet also strengthened associations between EDIH at age 10 and BBD risk (HR = 1.94; 95% CI = 1.12-3.37; p_trend = 0.007), and showed a significant inverse trend for AHEI (p_trend = 0.04).

These findings may suggest that greater early-life adherence to a healthier dietary pattern (AHEI) is associated with lower BBD risk, while consuming a more insulinemic dietary pattern (EDIH) may be associated with increased risk. Associations for EDIH at age 10 were statistically significant in secondary analyses accounting for dietary change and adult diet. Further research is needed to confirm these findings and clarify potential mechanisms.