The relationship between body mass index and footprint parameters in older people

Background: The relationship of body mass index (BMI) with footprint parameters has been studied in paediatric populations, but there are limited data regarding the effects of BMI on parameters in the elderly. Objectives: To establish the relationship between BMI and static footprint parameters in the elderly population. Methods: 128 subjects aged 65 and above with no history of lower extremity surgical intervention and no significant lower extremity weakness were included in the current study. BMI and footprint parameters of arch angle, Chippaux-Smirak index (CSI), Staheli index (SI), arch index (AI) and footprint index (FI) were measured for each subject, and statistical analysis was done to investigate the correlation between BMI and the parameters. Results: Weak correlations detected between all calculated indices and angles with BMI, except the left foot arch angle. CSI, SI and AI of the right foot were found to be positively correlated with BMI, while a negative correlation between the arch angle and FI of right foot was shown with BMI. Conclusions: The results reveal a relationship between BMI and footprint parameters that are indicative of flatfoot in the elderly. This could be due either to confounding of the footprint measure by fat or possibly due to an as yet unknown structural change that requires further evaluation.