For total and ER + breast cancer, there was significant interaction between nut intake and BMI-level, with decreased HRs observed in the subgroup BMI 18.5–< 25 [Total breast cancer: HR 0.79 (0.61–1.02); ER+: HR 0.84 (0.61–1.15)], and (significantly) increased HRs observed for BMI ≥ 25 kg/m2 [Total: HR 1.32 (0.96–1.81); ER+: HR 1.50 (1.03–2.18)]. Here, ESR1 is linked to breast cancer.