The Relation Between Calcaneus Stiffness Index as a Measure of Bone Density and Body Mass Index in an Egyptian Cohort

Background: Obesity and osteoporosis are two conditions that are associated with morbidity and mortality; there is contradictory evidence regarding this association. Purpose: The aim of the current study was to explore further the association between obesity and calcaneus stiffness index (CSI), as a measure of bone density, in a community-based cross-sectional study in an Egyptian population. Methods: A cross-sectional study was conducted among active subjects, aged >= 20 years old, over one year. CSI was measured by Quantitative ultrasound (QUS), in addition; QUS T-score and Z-score of the non-dominant heel scan were recorded. Results: Two hundred and eighty participants were recruited; 7 subjects were excluded because of Z score more than -2, mean age was 61 (+/- 11.9) years, and mean BMI was 29.7 (+/- 5.6). Female participants were 77.7%, with mean of age 60.3 (+/- 11.6); and age range 20-82 years. Male participants were 22.3%, with mean of age 63.6 (+/- 12.7); and age range 30-80 years. Older subjects (>55 years) had significantly lower CSI and worse T-score than the younger subjects (P < 0.001 for both). In the younger age group, BMI was not significantly associated with CSI, even after adjustment for gender (P= 0.52). However, in the older age group, BMI was significantly associated with stiffness index (P= 0.049, O.R.= 1.73), even after adjustment for gender (P= 0.041, O.R.= 1.7). Conclusion: Compared to young subjects, older subjects (>= 55 years) had significantly lower bone strength as measured by CSI, and their BMI was significantly positively associated with bone density. In younger people (<55 years), BMI was not associated with bone strength.