Height, sitting height and leg length in relation with breast cancer risk in the E3N cohort
Couplée à la cohorte française E3N incluant 50 704 participantes, cette étude évalue l'association entre la taille, la hauteur du tronc, la taille des jambes et le risque de cancer du sein
Background: If height is a well-established risk factor for breast cancer (BC), leg length and sitting height are usually considered as better candidate biomarkers of growth hormone exposure than height, respectively in pre- and postpuberty. Methods: Risk of BC associated with quartiles of height, sitting height and leg length were estimated in the French E3N cohort (N=50,704, including 2,065 BC cases), stratified on both menopausal and hormone receptor statuses. Results: Height was associated with an increased postmenopausal BC risk (HR=1.22[1.06-1.41] when comparing extreme categories, Ptrend=0.002) which was exclusively driven by the association with leg length (HR=1.21[1.05-1.39], Ptrend =0.013) and not sitting height (HR=1.03 [0.89-1.18], Ptrend=0.379). Leg length was associated with an increased ER+ BC risk in postmenopausal (HR=1.24[1.06-1.46], Ptrend =0.004) whereas sitting height was associated with a borderline decreased ER- premenopausal BC risk (HR=0.45[0.20-1.01], Ptrend =0.011). The positive associations observed in the overall population between leg length and BC risk were actually restricted to women who had a short birth length (HR=1.82[1.22-2.72], Ptrend =0.022) and those with a low birth weight (HR=1.43[1.00-2.04], Ptrend =0.054). Conclusion: The two components of height risk are differentially associated with BC risk: leg length with an increased risk of postmenopausal ER+ tumors and sitting height with a decreased risk of premenopausal ER- tumors. Impact: Future prospective studies should no longer consider height a single risk factor for BC risk.