Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries

Introduction Although boys tend to be more affected by linear growth faltering than girls, little is known about sex differences across distinct age groups. We aimed to compare sex differences in linear growth throughout the first 5 years of life among children from low-income and middle-income coun...

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Main Authors: Cesar Victora, Janaína Calu Costa, Cauane Blumenberg
Format: Article
Language:English
Published: BMJ Publishing Group 2021-11-01
Series:BMJ Global Health
Online Access:https://gh.bmj.com/content/6/11/e007152.full
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author Cesar Victora
Janaína Calu Costa
Cauane Blumenberg
author_facet Cesar Victora
Janaína Calu Costa
Cauane Blumenberg
author_sort Cesar Victora
collection DOAJ
description Introduction Although boys tend to be more affected by linear growth faltering than girls, little is known about sex differences across distinct age groups. We aimed to compare sex differences in linear growth throughout the first 5 years of life among children from low-income and middle-income countries.Methods We analysed 87 cross-sectional Demographic and Health Surveys and Multiple Cluster Indicator Surveys (2010–2019). Growth was expressed as height-for-age z-scores (HAZ) based on the 2006 WHO Growth Standards. Sex-specific means were estimated for each country and results were pooled through random-effects meta-analysis for all children and by 12-month age groups. Using linear regression, we assessed the association between sex differences in HAZ and gross domestic product as a proxy for national economic development.Results Boys presented lower mean HAZ than girls in the first 30 months. Sex differences were mostly absent between 30 and 45 months, and in several countries, girls had lower HAZ at ages over 45 months. The pooled sex difference (boys minus girls) for the whole sample was −0.10 (95% CI −0.12 to −0.08). The difference was −0.17 (95% CI −0.20 to −0.14) at 0–11 months and −0.22 (95% CI −0.25 to −0.19) at 12–23 months. This was followed by a narrowing of the sex gap to −0.10 (95% CI −0.13 to −0.07) and −0.04 (95% CI −0.07 to −0.01) among children aged 24–35 and 36–47 months, respectively. At 48–59 months, there was evidence of female disadvantage; the mean height-for-age of boys was 0.02 (95% CI 0.00 to 0.05) SDs higher than for girls. Ecological analyses showed that in all age groups, male disadvantage decreased with increasing national income, and this was no longer present for the 4-year-old children, particularly in wealthier countries.Conclusion Male disadvantage in linear growth is most evident in the first years, but by the age of 4 years, the sex gap has mostly disappeared, and in some countries, the gap has been reversed.
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spelling doaj-art-8b0f3b0e64f9451db5f12f7719a2eedc2024-12-05T11:55:09ZengBMJ Publishing GroupBMJ Global Health2059-79082021-11-0161110.1136/bmjgh-2021-007152Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countriesCesar Victora0Janaína Calu Costa1Cauane Blumenberg2emeritus professor of epidemiologyInternational Center for Equity in Health, Federal University of Pelotas, Pelotas, RS, BrazilInternational Center for Equity in Health, Federal University of Pelotas, Pelotas, BrazilIntroduction Although boys tend to be more affected by linear growth faltering than girls, little is known about sex differences across distinct age groups. We aimed to compare sex differences in linear growth throughout the first 5 years of life among children from low-income and middle-income countries.Methods We analysed 87 cross-sectional Demographic and Health Surveys and Multiple Cluster Indicator Surveys (2010–2019). Growth was expressed as height-for-age z-scores (HAZ) based on the 2006 WHO Growth Standards. Sex-specific means were estimated for each country and results were pooled through random-effects meta-analysis for all children and by 12-month age groups. Using linear regression, we assessed the association between sex differences in HAZ and gross domestic product as a proxy for national economic development.Results Boys presented lower mean HAZ than girls in the first 30 months. Sex differences were mostly absent between 30 and 45 months, and in several countries, girls had lower HAZ at ages over 45 months. The pooled sex difference (boys minus girls) for the whole sample was −0.10 (95% CI −0.12 to −0.08). The difference was −0.17 (95% CI −0.20 to −0.14) at 0–11 months and −0.22 (95% CI −0.25 to −0.19) at 12–23 months. This was followed by a narrowing of the sex gap to −0.10 (95% CI −0.13 to −0.07) and −0.04 (95% CI −0.07 to −0.01) among children aged 24–35 and 36–47 months, respectively. At 48–59 months, there was evidence of female disadvantage; the mean height-for-age of boys was 0.02 (95% CI 0.00 to 0.05) SDs higher than for girls. Ecological analyses showed that in all age groups, male disadvantage decreased with increasing national income, and this was no longer present for the 4-year-old children, particularly in wealthier countries.Conclusion Male disadvantage in linear growth is most evident in the first years, but by the age of 4 years, the sex gap has mostly disappeared, and in some countries, the gap has been reversed.https://gh.bmj.com/content/6/11/e007152.full
spellingShingle Cesar Victora
Janaína Calu Costa
Cauane Blumenberg
Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries
BMJ Global Health
title Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries
title_full Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries
title_fullStr Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries
title_full_unstemmed Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries
title_short Growth patterns by sex and age among under-5 children from 87 low-income and middle-income countries
title_sort growth patterns by sex and age among under 5 children from 87 low income and middle income countries
url https://gh.bmj.com/content/6/11/e007152.full
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