The Use of Mid-Upper Arm Circumference (MUAC) as a Nutrition Indicator for Adolescents in Tanzania

Background: While adolescent nutrition has not historically garnered attention in public health programming, assessing adolescent nutrition is necessary in addressing cycles of chronic disease, intergenerational malnutrition, and poor developmental trajectory. Mid-upper arm circumference (MUAC), while mostly used as a tool to screen for undernutrition in children under 5, has the potential to offer a simple, low-resource alternative or supplement to BMI in assessing nutrition in adolescent populations. This study seeks to generate more data on adolescent nutrition in Tanzania, to understand the relationship between BMI and MUAC among adolescents, and to consider current age-specific cutoffs for adolescents.

Methods: This study analyzed anthropometric data from a sample of adolescents in primary school in Bagamoyo, Tanzania. A Spearman’s correlation coefficient was used to determine the relationship between BMI and MUAC and bivariate analysis was used to explore whether anthropometric categories of height, BMI, and MUAC vary according to pubertal and food security status. Additional post-hoc analysis was conducted to explore stunting among this population.

Results: The majority of adolescents in this population were of normal nutritional status. Thirty-eight percent of males compared to 3% of females were stunted. BMI and MUAC were significantly correlated (r=0.6530, p=0.000), with a

stronger correlation among females (r= 0.7736, p=0.000) than males (r=0.5878, p=0.000) and a stronger correlation among non-stunted (r=0.7797, p=0.000) when stunted individuals were removed from the sample. There was no correlation between BMI and MUAC among individuals categorized at overweight according to BMI (r=0.088, p=0.868). There were no significant differences in age-specific anthropometric categories according to self-reported pubertal status or food-insecurity status.

Conclusion: MUAC is a promising measure to be used for determining undernutrition when BMI calculation is not possible. More research is needed on a more nutritionally diverse population to better understand the relationship between BMI and MUAC in under and overnourished individuals and between stunted and non-stunted individuals. More country level data collection on adolescent nutrition including BMI and MUAC is needed to inform programmatic and policy decisions.