Background & Objective: Human milk oligosaccharides (HMOs) have been associated with several child growth metrics, but there was no difference in the associations according to child sex. Here, we present clinic-based cross-sectional data on the relationship between specific HMOs in the milk of Ugandan mothers and growth in their breastfed children as a group and as males and females separately. Method: Human milk samples were manually collected from 127 lactating mothers. Levels of human milk oligosaccharides (HMOs) were analyzed by high-performance liquid chromatography (HPLC). Childrens weight and length were measured using a portable digital scale and length board, respectively. Weight-for-age (WAZ), height-for-age (HAZ) and weight for height (WHZ) Z scores were calculated. The relationships between HMOs and untransformed weights and heights and between WAZ, HAZ and WHZ subcategories were analyzed for all children and for males and females separately by Spearmans correlation and Kruskal Wallis and Mann Whitney U tests. Results: There were positive and negative correlations between the concentrations of specific HMOs and the heights and weights of children according to mothers secretor status. Tall infant stature was associated with higher concentrations of 6SL, LSTc, DFLNH, DSLNH, LNnT and total HMOs in secretor or nonsecretor mothers; short infant stature was associated with higher concentrations of 3FL and DFLac; overweight was associated with higher concentrations of 6SL, LSTc and LNnT in secretor and nonsecretor mothers; and normal weight was associated with higher concentrations of 3FL. The associations between maternal HMO levels and childrens heights and weights or between the LAZ, WAZ and WHZ subcategories significantly differed between male and female children. Conclusions: There are sex differences in the associations between high concentrations of some HMOs and stature and weight in Ugandan children born to secretor and nonsecretor mothers.

The authors have declared no competing interest.

Thomas Egwang received funding from the Global Innovation Fund, and Grand Challenges Canada. The funders played no role in the study design, data collection and analysis, preparation of the manuscript or decision to publish this paper.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Uganda National Council for Science and Technology and the Research Ethics Committee of the Vector Division, Ministry of Health, approved the original HD4MC study. All mothers who donated milk samples and brought infants to the study clinic for weight and height measurements and health assessment signed or thumb-printed an informed consent form.

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The datasets supporting the conclusion of this article will be made available upon request from TGE.