Post-malnutrition growth and its associations with child survival and non-communicable disease risk: A secondary analysis of the Malawi ‘ChroSAM’ cohort

Abstract

Background: Rapid catch-up growth after prenatal undernutrition is associated with increased risk of non-communicable diseases (NCDs) in high-income countries. Severe malnutrition treatment programmes in low- and middle-income countries promote rapid post-malnutrition growth (PMGr) as desirable. Our aim was to explore patterns of PMGr during and in the year following treatment, and describe associations with survival and NCD risk seven years post-treatment. Methods: Secondary data analysis from a cohort of children treated for severe malnutrition in Malawi in 2006/7. Six definitions of PMGr were derived based on a variety of timepoints, weight, weight-for-age z-score (WAZ) and height-for-age z-score (HAZ). Three categorisation methods included: no categorisation, quintiles, and latent class analysis (LCA). Associations with mortality risk, and with eight NCD indicators were analysed visually using scatter plots and boxplots, and statistically using simple and multivariable linear regression. Findings: Faster weight gain was associated with lower risk of death (g/day during treatment aOR 0.99, 95%CI 0.99 to 1.00, p=0.04; after treatment g/kg/month aOR 0.91, 95% CI 0.87 to 0.94, p<0.001). In survivors, it was associated with greater hand grip strength in some instances (g/day during treatment 0.02, 95%CI 0.00 to 0.03, p=0.007) and larger HAZ 7-years post-discharge (adjusted Δ WAZ per day during treatment 6.62, 95%CI 1.31 to 11.9, p=0.02), both indicators of better health. However, faster weight gain in treatment was also associated with increased waist:hip ratio (adjusted g/day during treatment 0.02, 95%CI 0.01 to 0.03, p=0.003), a key indicator of later life NCD risk. The clearest patterns of association were seen when defining PMGr based on weight gain in g/day during treatment, and using the LCA method to describe growth patterns. Weight deficit at admission was a major confounder. Conclusion: We found a complex pattern of benefits and risks associated with faster PMGr with a possible trade-off between short- and long-term benefits/risks. Peripheral versus visceral weight distribution in particular requires further exploration. Both initial weight deficit and rate of weight gain have important implications for future health. Because conclusions from observational studies can go only so far, future randomised intervention trials are needed.