Long-term effects of severe acute malnutrition on lung function in Malawian children: a cohort study

Abstract

Early nutritional insults may increase risk of adult lung disease. We aimed to quantify the impact of severe acute malnutrition (SAM) on spirometric outcomes 7 years post-treatment and explore predictors of impaired lung function.Spirometry and pulse oximetry were assessed in 237 Malawian children (median age: 9.3 years) who had been treated for SAM and compared with sibling and age/sex-matched community controls. Spirometry results were expressed as z-scores based on Global Lung Function Initiative reference data for the African-American population.Forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) were low in all groups (mean FEV₁ z-score: -0.47 for cases, -0.48 for siblings, -0.34 for community controls; mean FVC z-score: -0.32, -0.38, and -0.15 respectively). There were no differences in spirometric or oximetry outcomes between SAM survivors and controls. Leg length was shorter in SAM survivors but inter-group sitting heights were similar. HIV positive status or female sex was associated with poorer FEV₁, by 0.55 and 0.31 z-scores, respectively.SAM in early childhood was not associated with subsequent reduced lung function compared to local controls. Preservation of sitting height and compromised leg length suggest "thrifty" or "lung-sparing" growth. Female sex and HIV positive status were identified as potentially high-risk groups.

FIGURE 1

Lung function results for cases, siblings and community controls. Solid line with error bars represent mean±sd. Dashed lines indicate the limits of normality as per Global Lung Function Initiative (GLI) spirometry reference data for the African–American population (i.e. mean (0) ±1.96 z-scores). There were no statistically significant differences in any of the spirometry outcomes among the three groups. Most results fall within the normal range; however, mean forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) were lower than predicted by the GLI reference for all three groups.

FIGURE 2

Recruitment flow diagram for spirometry results. Recruitment of sibling and community control only commenced at the time of 7-year follow-up; hence, their recruitment history starts after that of cases, who were enrolled at admission.