And the subgroup meta-analysis of APOE ε2/ε3/ε4 polymorphism by excluding the study of Srivastava et al. [53] didn’t produce any significant association of APOE ε2/ε3/ε4 with overweight/obesity (Additional file 3: Figure S2). Here, APOE is linked to obesity due to melanocortin 4 receptor deficiency.