Maternal characteristics associated with milk leptin content in a sample of Filipino women and associations with infant weight for age.

BACKGROUND Human milk contains many metabolic hormones that may influence infant growth. Milk leptin is positively associated with maternal adiposity and inversely associated with infant growth. Most research has been conducted in populations with higher leptin levels; it is not well understood how milk leptin may vary in lean populations or the associations that reduced leptin may have with infant size for age. It is also largely unknown if associations between maternal body composition and milk leptin persist past 1 year of age. OBJECTIVES We investigated the association between maternal body composition and milk leptin content in a sample of lean Filipino women and the association between milk leptin content and infant size for age. METHODS Milk samples were collected at in-home visits from 113 mothers from Cebu, Philippines. Milk leptin content was measured using EIA techniques; anthropometric data, dietary recalls, and household information were also collected. RESULTS Mean ± standard deviation (SD) milk leptin in this sample was 300.7 ± 293.6 pg/mL, among the lowest previously reported. Mean ± SD maternal percentage body fat was 24.8% ± 3.5%. Mean ± SD infant age was 9.9 ± 7.0 months, and mean ± SD weight for age z-score was -0.98 ± 1.06. Maternal percentage body fat was a significant, positive predictor of milk leptin content. Milk leptin was a significant, inverse predictor of infant weight and body mass index z-scores in infants 1 year old or younger. CONCLUSION The association between maternal body composition, milk leptin, and infant growth persists in mothers with lean body composition. Milk leptin is not associated with growth in older infants.