Validation of pediatric height estimation formulae in suburban communities in South-east Nigeria: a cross-sectional study

BACKGROUND: Height measurement is one of the common essential anthropometric measurements in clinical pediatrics. The most accurate method of determining a child’s height is to measure the height. However, in emergency situations and some resource limited settings, obtaining the actual height of a child may not be feasible hence the need to estimate. The most common age-based formulae for height estimation in children is the Nelson-Wheech formula, 6n + 77 where n = age in years. The accuracy of this height estimation formulae has not been assessed in a developing setting like ours with high prevalence of malnutrition. This study therefore sought to evaluate the accuracy of the height estimation formula in children in communities across Enugu southeast Nigeria. METHOD: Children 2-12 years old who met the inclusion criteria were enrolled over 12 months from three of the 17 Local Government Area of Enugu State. Height was measured using a standard stadiometer and estimated height was calculated 6n + 77. Data collected was analyzed using SPSS. RESULT: Of the 4046 children enrolled, majority (86.1%) were of normal height. The formula underestimated height of children in the two, 3, 4, 5, 6, 7, 9 and 10 years old categories by a factor of 1.2%-10.0% while overestimating height in 8-year old children by 5.1%, 11-year old by 0.2% and 12-year by 2.9%. Overall, the estimated height using the formula was within ± 10% agreement of the actual height of surveyed children in 77.0% of children surveyed. CONCLUSION: The 6n + 77 formula is a reasonable but not entirely accurate for height estimation for children in our setting.