Introduction Children’s growth status is an important measure commonly used as a proxy indicator of advancements in a country’s health, human capital and economic development. We aimed to assess the feasibility of using Super-Imposition by Translation And Rotation (SITAR) models for summarising population-based cross-sectional height-by-age data of children under 5 years across 64 countries.
Methods Using 145 publicly available Demographic and Health Surveys of children under 5 years across 64 low-income and middle-income countries from 2000 to 2018, we created a multicountry pseudo-longitudinal dataset of children’s heights.
Results SITAR models including two parameters (size and intensity) explained 81% of the between-survey variation in mean boys’ height and 80% in mean girls’ height. Size parameters for boys and girls (relative to the WHO child growth standards) were distributed non-normally around a mean of −5.2 cm for boys (range: −7.9 cm to −1.6 cm) and −4.9 cm for girls (range: −7.7 cm to −1.2 cm). Boys exhibited 10% slower linear growth compared with the WHO (range: 19.7% slower to 1.6% faster) and girls 11% slower linear growth compared with the WHO (range: 21.4% slower to 1.0% faster). Variation in the SITAR size parameter was ≥90% explained by the combination of average length within the first 60 days of birth (as a proxy for fetal growth) and intensity, regardless of sex, with much greater contribution by postnatal intensity (r≥0.89 between size and intensity).
Conclusions SITAR models with two random effects can be used to model child linear growth using multicountry pseudo-longitudinal data, and thereby provide a feasible alternative approach to summarising early childhood height trajectories based on survey data. The SITAR intensity parameter may be a novel indicator for specifically tracking progress in the determinants of postnatal growth in low-income and middle-income countries.
- child health
- public health
- other study design
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Handling editor Sanni Yaya
Contributors EOO, DER and DGB designed the research. HQ performed data manipulation, cleaning and data curation. EOO conducted the research and analysed the data with input from DER, DGB, HQ and SY. EOO wrote the paper with input from all authors. EOO had primary responsibility for final content. All authors have read and approved the final manuscript.
Funding EO was supported by the Sick Kids Centre for Global Child Health Growth and Development Fellowship.
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Competing interests None declared.
Patient consent for publication Not required.
Ethics approval This work is a secondary analysis of publicly available de-identified data which are exempt from ethical review at the Hospital for Sick Children Ethics Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available in a public, open access repository. The data used are DHS and are publicly available at https://dhsprogram.com/data/available-datasets.cfm.
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