Dietary intake of branched-chain amino acids and risk of colorectal cancer
Menée à partir des données des cohortes "the Nurses’ Health Study", "the Nurses’ Health Study II" et "the Health Professionals Follow-Up Study" portant sur 170 001 femmes et 47 255 hommes (durée de suivi : 28 ans), cette étude analyse l'association entre un apport alimentaire en acides aminés à chaîne ramifiée et le risque de cancer colorectal (1 660 cas)
Branched chain amino acids (BCAAs) are essential amino acids, and emerging evidence suggests that BCAAs may mediate pathways related to cancer progression, possibly due to their involvement in insulin metabolism. We investigated the association between dietary intake of BCAAs with colorectal cancer (CRC) risk in three prospective cohorts: the Nurses' Health Study I [(NHS), number of participants (n) at baseline =77,017], NHS II (n=92,984), and the Health Professionals Follow-up Study [(HPFS) n=47,255]. Validated food frequency questionnaires were administered every four years and follow-up questionnaires on lifestyle biennially. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models. Pooled HRs were obtained using random effect models. After up to 28 years of follow-up, 1660 cases were observed in NHS, 306 in NHS II and 1343 in HPFS. In multivariable adjusted models, we observed a weak inverse association between BCAA intake and CRC [highest vs. lowest quintile, pooled HR including all three cohorts (95% CI): 0.89 (0.80-1.00), Ptrend=0.06, HR per standard deviation (SD) increment 0.95 (0.92-0.99)]. However, after including dairy calcium to the models, BCAA intake was no longer associated with risk of CRC [HR 0.96 (0.85-1.08), Ptrend=0.50, HR per SD increment 0.97 (0.93-1.01)]. We did not find evidence that higher dietary BCAA intake is associated with higher risk of CRC. As this is the first prospective study to examine the association between BCAA intake and CRC, our findings warrant investigation in other cohorts.