Relationship between the nutritional status of breastfeeding Mayan mothers and their infants in Guatemala

A case-control study was conducted to determine the association between maternal height and infant length-for-age, and to evaluate how this association is modified by either maternal or infant nutritional status. We hypothesised that maternal excess caloric intake [measured as body mass index (BMI)] would increase the association, while infant nutrition (measured in main meals consumed in addition to breastfeeding) will diminish the effect. Mother and infant pairs in Chimaltenango, Guatemala, were measured for anthropometric values and nutritional status, and mothers were interviewed to elicit nutritional and socio-economic information. Infant length was converted into z-scores based on the World Health Organization's (WHO) standards. Odds ratios (ORs), associated 95% confidence intervals (CIs) and the relative excess risk due to interaction (RERI) were calculated. Cases were infants below 2 z-scores of the WHO's length-for-age, while controls were infants within the -2 to 2 z-score range. Cases (n=84) had an increased odds (OR: 3.00, 95% CI: 1.57-5.74) of being born to a stunted mother (below 145cm) when compared with controls (n=85). When adjusted for potential confounders, the OR decreased to 2.55 (95% CI: 1.30-5.02). Negative RERI values were produced for the joint exposure of maternal BMI25 and maternal stuntedness (RERI: -0.96), as well as for the joint exposure of maternal stuntedness and infant nutrition (RERI: -2.27). Our results confirm that maternal stuntedness is a significant contributor to infant stuntedness; however, this association is modified negligibly by maternal nutritional status and significantly by infant nutritional status, each in a protective manner.