Early childhood linear growth faltering in low-income and middle-income countries as a whole-population condition: analysis of 179 Demographic and Health Surveys from 64 countries (1993–2015)

Abstract

SummaryBackgroundThe causes of early childhood linear growth faltering (known as stunting) in low-income and middle-income countries remain inadequately understood. We aimed to determine if the progressive postnatal decline in mean height-for-age Z score (HAZ) in low-income and middle-income countries is driven by relatively slow growth of certain high-risk children versus faltering of the entire population.MethodsDistributions of HAZ (based on WHO growth standards) were analysed in 3-month age intervals from 0 to 36 months of age in 179 Demographic and Health Surveys from 64 low-income and middle-income countries (1993–2015). Mean, standard deviation (SD), fifth percentiles, and 95th percentiles of the HAZ distribution were estimated for each age interval in each survey. Associations between mean HAZ and SD, fifth percentile, and 95th percentile were estimated using multilevel linear models. Stratified analyses were performed in consideration of potential modifiers (world region, national income, sample size, year, or mean HAZ in the 0–3 month age band). We also used Monte Carlo simulations to model the effects of subgroup versus whole-population faltering on the HAZ distribution.FindingsDeclines in mean HAZ from birth to 3 years of age were accompanied by declines in both the fifth and 95th percentiles, leading to nearly symmetrical narrowing of the HAZ distributions. Thus, children with relatively low HAZ were not more likely to have faltered than taller same-age peers. Inferences were unchanged in surveys regardless of world region, national income, sample size, year, or mean HAZ in the 0–3 month age band. Simulations showed that the narrowing of the HAZ distribution as mean HAZ declined could not be explained by faltering limited to a growth-restricted subgroup of children.InterpretationIn low-income and middle-income countries, declines in mean HAZ with age are due to a downward shift in the entire HAZ distribution, revealing that children across the HAZ spectrum experience slower growth compared to the international standard. Efforts to mitigate postnatal linear growth faltering in low-income and middle-income countries should prioritise action on community-level determinants of childhood HAZ trajectories.FundingBill & Melinda Gates Foundation.

Adolescent Undernutrition: Global Burden, Physiology, and Nutritional Risks

“…Linear growth faltering is commonly seen in LMICs in the first 2 years of life [26]. Catch-up growth is possible in children older than 2 years, although stunting is often well established by this age in many LMICs.…”

Disentangling basal and accrued height‐for‐age for cross‐population comparisons

“…Fourth, we followed WHO guidelines in excluding the cases with HAZ magnitudes greater than 6 SD. Future work should examine the sensitivity of these findings to changing these cutoffs (Roth et al, ). We also focused on HAZ because they are the most commonly used metric for assessing stunting and growth faltering internationally.…”

“…First, the 3 SD cutoff is biologically arbitrary (Leroy & Frongillo, ; Perumal et al, ). Second, stunting prevalence is more appropriately interpreted as an indicator of deprivation for the entire population (not only among those classified as stunted) (Roth et al, ). Nonetheless, we conduct this exercise to illustrate further issues with using a universal standard.…”

“…Stunting, or impaired linear growth due to undernutrition and deprivation, has numerous negative consequences for health, cognitive ability, and long‐term academic and economic achievement (De Onis, Blössner, & Borghi, ; Prendergast & Humphrey, ; Victora et al, ). With an estimated 165 million children under the age of five currently suffering from stunting (Angood et al, ; De Onis et al, ; Kim, ), monitoring, targeting, and preventing stunting at the individual and population level has become a key global health priority (De Onis et al, ; Frongillo, Leroy, & Lapping, ; Leroy & Frongillo, ; Osgood‐Zimmerman et al, ; Perumal, Bassani, & Roth, ; Roth et al, ; Stevens et al, ). The underlying metric for assessing stunting—height‐for‐age z ‐scores (HAZ)—is also frequently used in anthropology and the social sciences to compare relative deprivation and healthy growth across individuals and populations (Gaur & Kumar, ; Hermanussen, Bogin, & Scheffler, ; Schillaci, Sachdev, & Bhargava, ; Sterling et al, ; Tanner, Leonard, & Reyes‐García, ; Vercellotti et al, ).…”

The charade of socioeconomic body-mass index determinants

“…This is an interesting idea that was previously explored for growth faltering among children. 5 In their study, 5 Roth and colleagues recognised that the changes observed in the height-for-age distribution in the first 3 years of life could not be explained solely by individual determinants (eg, wealth).…”