Relationship between Body Mass Index and Bone Mineral Density in People with Osteoporosis: A Cross-Sectional Analytical Study

Background: Obesity and osteoporosis are prevalent global health problems. This study aims to investigate the relationship between bone density and body mass index (BMI) in patients with osteoporosis and osteopenia. Methods: Demographic data, BMI, bone mineral density (BMD), and T-scores of the lumbar spine (L1-L4) and neck of the left femur were collected using the files of individuals who were referred to the Bone Density Measurement Center, Nuclear Medicine Center, Abadan, Iran, from February 2022 to September 2023. The relationship between BMD of the lumbar spine and neck of the left femur and BMI in individuals with osteoporosis, osteopenia, and normal BMD, with varying weight categories ranging from underweight to obese or overweight, was investigated. Results: In this study, 475 people were included in three groups. The mean BMI was higher than normal. In the group with osteoporosis, the BMD of the lumbar spine of the overweight and obese group was higher than the underweight and normal weight groups (P < 0.001). There was a direct significant correlation between BMD of the spine and BMI in the group with osteoporosis (r = 0.389, P < 0.001). A direct and significant correlation was observed between BMI and BMD of the femur (r = 0.296) and between BMI and BMD of the lumbar spine (r = 0.233). Conclusion: BMI and BMD of the neck of the femur and lumbar spine were directly correlated.