Estimation equations for the height of Colombian elders using knee height.

Introduction: The height in the elderly does not reflect their real size as young adults due to the aging of their spine, among other aspects. Objective: To estimate the equations to predict the height in Colombian elders according to their ethnic group and sex using the knee height measurement. Materials and methods: We conducted a secondary analysis of the SABE, 2015, crosssectional study using a multistage probabilistic sampling design in people aged 60 years and over in Colombia. We randomly selected two groups from the study’s database: A development group and a validation group of the equations. Age and anthropometric characteristics were similar in both groups. We performed a multiple linear regression analysis to predict the height using knee height measurement in the different ethnic groups (Indigenous, Afro-descendant, and white-mestizo groups) by age and sex; the results were validated in each selected subgroup. Results: We designed six equations by sex (men=3,665; women=3,019) and ethnic group. The adjusted R2 of the equations in men from the three ethnic groups oscillated between 64% and 75% and the standard errors, between 3,09 and 3,93 cm while in women, the R2s of the three equations ranged between 53% and 73% and the EEs, between 2,96 and 3,90 cm. Conclusion: The equation with the best predictive capacity of the height of Colombian elders was obtained for African descendants of both sexes. The lowest coefficients of determination were obtained for the indigenous population.