One-year anthropometric follow-up of South African preterm infants in kangaroo mother care: Which early-life factors predict malnutrition?

Background: Preterm infants often have poor short- and long-term growth. Kangaroo mother care supports short-term growth, but longer-term outcomes are unclear. Methods: This study analysed longitudinally collected routine clinical data from a South African cohort of preterm infants (born <37 weeks gestation) attending the outpatient follow-up clinic of a tertiary-level hospital (Tshwane District, South Africa) for 1 year between 2012 and 2019. At 1 year, small-for-gestational age (SGA) and appropriate-for-gestational age (AGA) infants were compared with regard to age-corrected anthropometric z-scores (weight-for-age [WAZ], length-for-age [LAZ], weight-for-length [WLZ] and BMI-for-age [BMIZ]) and rates of underweight (WAZ < -2), stunting (LAZ < -2), wasting (WLZ < -2) and overweight (BMIZ> + 2). Multiple regression analysis was used to investigate associations between maternal/infant characteristics and rates of underweight, stunting, wasting and overweight. Results: At 1 year, compared with AGA infants (n = 210), SGA infants (n = 111) had lower WAZ (-1.26 +/- 1.32 vs. -0.22 +/- 1.24, p < 0.001), LAZ (-1.50 +/- 1.11 vs. -0.60 +/- 1.06, p < 0.001), WLZ (-0.66 +/- 1.31 vs. 0.11 +/- 1.24, p < 0.001) and BMIZ (-0.55 +/- 1.31 vs. 1.06 +/- 1.23, p < 0.001), despite larger WAZ gains from birth (+0.70 +/- 1.30 vs. +0.05 +/- 1.30, p < 0.001). SGA infants had significantly more stunting (34.2% vs. 9.1%; p < 0.001), underweight (31.2% vs. 7.2%; p < 0.001) and wasting (12.6% vs. 4.3%, p = 0.012), with no difference in overweight (4.5% vs. 7.7%, p = 0.397). In multiple regression analysis, birth weight-for-GA z-score more consistently predicted 1-year malnutrition than SGA. Conclusion: Preterm-born SGA infants remain more underweight, stunted and wasted than their preterm-born AGA peers at 1 year, despite greater WAZ gains. Interventions for appropriate catch-up growth especially for SGA preterm infants are needed.