ASSESSMENT OF THE IMPACT OF OBESITY ON BONE LOSS

Background: Most of the available evidence supports a lower risk of vertebral fracture in obese adults. This belief was partially suggested by the positive correlation between bone mineral density (BMD) and body mass index (BMI). Objectives: We aimed to assess the association of BMI with BMD and to explore their relation with age and gender. Methods: This is a cross-sectional study including Tunisian patients referred for an assessment of BMD through dual-energy X-ray absorptiometry (DXA). BMD was measured using standard methods over the lumbar spine L1-L4, the total proximal femur. The results were expressed as T-scores according to the World Health Organization definition. Patients were sub-grouped according to age (≤50 and >50 years). Association between BMD and age as well as BMI was also assessed (G1: obese patients and G2: non-obese patients). The level of significance was fixed for p<0.05 Results: The study included 100 patients with a female predominance (sex ratio =10.1). The mean age for women was 61.9 ±13 [18-83] years and the mean age for men was 59.7± 7.5 [47-72] years. The mean body mass index was 29.1± 5 kg/m [15-45] for women and 27.6 ±3.6 Kg/m [22.8-32.9] for men. Forty percent of all patients were obese with a mean BMI of 32.9 kg/m ± 4.3. Osteopenia was diagnosed in half of the men (55.5%) and most of the women (70%). Twenty-nine percent of patients suffered from osteoporosis. BMD of the spine was similar between men and women (p=0.53). Men had higher BMD of the hip than women (p=0,038). The mainstream of the subjects >50 years had more vertebral fractures, suffered more from osteoporosis and had a higher BMI than those < 50 years (95% % vs 5%; p=0.04), (92.3% vs 77 %; p=0.03) and (82.5% vs 17.5%; p=0.05) respectively. There was no correlation between BMD of the spine and higher BMI (0.94 in G1 vs 0.98 in G2, p=0.3). Similarly, there was no correlation between BMD of the hip and higher BMI (0.9 in G1 vs 0.84 in G2, p=0.2). Moreover, Obese patients had less a vertebral fracture but with no statistically significant correlation (21% in G1 vs 25% in G2; p=0.2). Conclusion: Our study showed that obesity was frequent among Tunisian patients but was not associated with a higher BMD. Older age was directly associated with a lower BMD and higher risk for vertebral fracture. Disclosure of Interests: None declared. Citation: Ann Rheum Dis, volume 80, supplement 1, year 2021, page 1342Session: Osteoporosis (Publication Only)