Anthropometric estimation of undernutrition among rural adolescents in Tanzania: A comparison of three international growth references

Introduction: International growth references based on body mass index were developed for the classification of undernutrition in adolescents. Few studies have examined differences in the estimation of undernutrition among adolescents across different international growth standards. This comparative study examines variations in the estimated prevalence of undernutrition using WHO (2007) and two other growth standards in a sample of Tanzanian adolescents.

Methods: This cross-sectional study examined data from 687 adolescents (10-19 years) from  Kilosa District, Tanzania. Using three international growth standards, adolescents were classified as undernourished if their body mass index for age and gender was <-2 SD of the WHO 2007 reference, <5^th percentile of the NCHS/WHO reference, or <grade 2 of the International Obesity Task Force (IOTF) reference. Descriptive analysis was used to examine the prevalence of undernutrition across growth standards.

Results: Using WHO 2007 growth standards, 11.7% of the sample was classified as undernourished compared to 21.1% and 7.7%, respectively, by NCHS/WHO and IOTF standards. The NCHS/WHO charts categorize as undernourished 10.9% of those individuals considered healthy using the WHO 2007 reference. The NCHS/WHO growth standards identify more adolescents as undernourished than either the WHO 2007 or the IOTF growth standards.

Conclusion: Undernutrition is a public health concern in developing countries, and has direct implications for maternal and child health. Evaluation of child growth patterns and nutrition interventions are based on the growth charts used. Different estimates of undernutrition across international growth charts raise questions about the accuracy of reported prevalence rates and strategies for improving targeting.