Characterising school-age health and function in rural Zimbabwe using the SAHARAN toolbox

Abstract: Introduction: School-age health, growth and development are poorly characterised in low- and middle-income countries. We developed the School-Age Health, Activity, Resilience, Anthropometry and Neurocognitive (SAHARAN) toolbox to measure growth, cognitive and physical function in rural Zimbabwe. Methods: The SAHARAN toolbox was developed using a stepwise approach, with tool selection based on COSMIN principles. Growth was measured with anthropometry, skinfold thicknesses and bioimpedance analysis to obtain lean mass index (LMI) and phase angle. Cognition was assessed using a fine motor finger tapping task, school achievement test (SAT), and the Kaufmann Assessment Battery for Children (KABC-2) to determine the mental processing index (MPI). Physical function combined grip strength, broad jump and the 20m shuttle run test to produce a total physical score (TPS). A detailed caregiver questionnaire was performed in parallel. Results: 80 Zimbabwean children with mean (SD) age 7.6 (0.2) years had mean height-for-age (HAZ) and weight-for-age Z-scores (WAZ) of -0.63 (0.81) and -0.55 (0.85), respectively. For growth measures, LMI and total skinfold thicknesses were highly related to both WAZ and BMI Z-score, but not to HAZ. For physical function, TPS was associated with unit rises in HAZ (1.29, 95%CI 0.75,1.82, p<0.001), and LMI (0.50, 95%CI 0.16,0.83, p=0.004), but not skinfold thicknesses. For cognition, the SAT was highly associated with unit increases in the MPI (0.9 marks, 95%CI 0.4,1.3, p<0.001) and a child socioemotional questionnaire (8.2 marks, 95%CI 2.9,13.5, p=0.003). Phase angle was associated with 3.5 seconds quicker time to complete the finger tapping task (95%CI 0.6,6.4, p=0.02). No child outcomes were associated with socioeconomic status, nurturing, discipline, food and water insecurity, or household adversity. Conclusions: We found clear associations between growth, height-adjusted lean mass and physical function, but not cognitive function, in a cohort of Zimbabwean children. The SAHARAN toolbox could be deployed to characterise school-age growth, development and function in sub-Saharan Africa.