Physical activity levels objectively measured among older adults: a population-based study in a Southern city of Brazil
In an anthropometric nutritional assessment, elderly individuals are frequently unable to assume the positions needed for many measurements. This is especially true for stature, which is affected by mobility and skeletal deformities, and as a result measurements may be unreliable and inaccurate. An alternative is to use a surrogate value of stature. We developed predictive equations using data from elderly subjects in Cycle I of the National Health Examination Survey (NHES). The developed equations were cross-validated using two separate independent and more contemporary samples of elderly White men and women. The possible predictor variables were knee height and buttocks-knee length in the men and knee height and age in the women. For both the men and the women, the majority of the variance in stature was accounted for by knee height. Selected equation models were cross-validated, and a single equation was recommended for each elderly group that included knee height rather than buttocks-knee length as predictor variables. This selection was based upon the performance of the equations, and also upon the practical ease of collecting the possible predictor variables. Included with the recommended equations are the RMSEs and the standard error for predicting stature for an individual (SEI). The successful application of the recommended equations with two recent sets of elderly persons indicates the current utility of the recommended equations in White elderly Americans.