Height, Early Life Body Size and Breast Cancer Subtypes

Height and body size in childhood and young adulthood have been consistently associated with breast cancer risk; whether associations differ across molecular subtypes is unclear. In a pooled analysis of the Nurses' Health Studies, we prospectively examined the association of four exposures: height, body mass index (BMI) at the age of 18 years, childhood and adolescent somatotypes, with breast cancer risk according to molecular subtypes defined by immunohistochemical markers. We used multivariable-adjusted Cox proportional hazards regression to estimate HRs and 95% confidence intervals (CI). We identified 2,983 luminal A, 1,281 luminal B, 318 HER2-enriched, 408 basal-like, and 128 unclassified tumors. Height was positively associated with all subtypes (Pheterogeneity = 0.78). BMI at the age of 18 (Pheterogeneity = 0.001), childhood (Pheterogeneity = 0.51), and adolescent somatotype (Pheterogeneity = 0.046) were inversely associated, but with differences in magnitude of association. BMI at the age of 18 of ≥25 kg/m2 (compared with 20–21.9 kg/m2) was associated with a 52% decreased risk of HER2-enriched (HR, 0.48; 95% CI, 0.26–0.91; Ptrend < 0.0001) and 39% reduced risk of basal-like tumors (HR, 0.61; 95% CI, 0.36–1.02; Ptrend = 0.008). Compared with the lowest category, women in the highest adolescent body size category were 71% less likely to develop HER2-enriched (HR, 0.29; 95% CI, 0.10–0.85; Ptrend = 0.0005) and 60% less likely to develop basal-...
Source: Cancer Prevention Research - Category: Cancer & Oncology Authors: Tags: Research Articles Source Type: research