• Senahara Korsa Wake Department of Statistics, College of Science, Bahir Dar University, Bahir Dar, Ethiopia
  • Temesgen Zewotir School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa
  • Essey Kebede Muluneh School of Public Health, Bahir Dar University, Bahir Dar, Ethiopia
Keywords: Covariance structure, , Knot point, Mixed-effects model, nonlinear trajectory


Human physical growth consists of different growth phases. These growth phases are characterized by different growth rate changes. Therefore, this study aimed to examine differences in growth rate changes at different growth phases among children in four low- and middle-income countries. Physical height was measured in centimeters for children from infancy to middle adolescence. A total of 3401 males and 3200 females with measured height on five occasions were included in this study. A piecewise linear mixed-effects model was applied to analyze the data. There were significant differences in growth rate changes among children in Ethiopia, India, Peru and Vietnam. Males showed a higher increase in the rate of change during preschool (8.36 cm males and 8.23 cm females) and early adolescence (6.15 cm males and 3.44 cm females), while they showed a lower increase during school-age (5.16 cm males and 5.56 cm females). During school-age, children in Peru and Vietnam had a higher rate of changes (5.73 cm Peru, 5.83 cm Vietnam and 5.56 cm Ethiopia) than children in Ethiopia. However, differences in the rates of change were not significant during preschool and early adolescence among them. Children in India had a lower rate of change in both preschool and school-age, but they had a higher rate of change during early adolescence compared to children in Ethiopia. The study results may help to compare the growth status of children in low- and middle-income countries.


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How to Cite
Wake, S. K., Temesgen Zewotir, & Essey Kebede Muluneh. (2021). VARIATIONS IN PHYSICAL GROWTH TRAJECTORIES AMONG CHILDREN AGED 1-15 YEARS IN LOW AND MIDDLE INCOME COUNTRIES: PIECEWISE MODEL APPROACH. Malaysian Journal of Public Health Medicine, 21(3), 200-208.