“…In addition to HMOs, the levels of milk protein and lipids can also be affected by many maternal factors, including smoking, BMI, birth route, pregnancy weight gain, and energy intake during lactation. For example, Aksan et al ( 68 ) have detected significant correlations between body weight, length, and head circumference, respectively, and OPN levels after one ( r = 0.442, p = < 0.001; r = −0.284, p = < 0.001; r = −0.392, p = < 0.001) and 3 months ( r = 0.501, p = < 0.001; r = −0.450, p = < 0.001; r = −0.498, p = < 0.001) of lactation.…”