Relationship between Obesity and Osteoporosis

Purpose/Aims

This study aims to evaluate the incidence of osteoporosis in patients with a BMI higher than 25 and to observe whether it offers a protective role against osteoporosis

Rationale/Background

The prevalence of obesity and the diagnosis of osteoporosis have accelerated over the past decade. The relationship between obesity and bone metabolism is complex and not well understood. Historically, obesity was thought to be protective against osteoporosis; however, several studies have challenged this belief. Even though a majority of the studies suggest that obesity has a favorable effect on bone density, it is unclear what effect obesity has on skeletal microarchitecture.

Methods

Researchers observed data from 388 patients from a community-based primary care clinic who had undergone screening for bone density or DEXA scan. The criteria for identifying individuals as having osteoporosis was based on International Osteoporosis Foundation criteria, which states that the threshold for qualification is a T-Score of less than or equal to -2.5 in one or more regions or the occurrence of a fragility fracture of the hip or vertebra. BMI values were recorded for the patients at the time of the bone density scan and patients were classified according to WHO weight criteria with underweight being a BMI less than 18.5 kg/m2, normal weight being a BMI between 18.5–24.9 kg/m2, and overweight being a BMI between 25.0–29.9 kg/m2. Of the 388 total patients, 134 were confirmed to have had osteoporosis based on the criteria.

Results

There were 134 patients who were diagnosed with osteoporosis, and the average age of a person in that group was 71 (70 for females and 81 for males). The average T-Score on a bone density scan for those individuals was -2.8. There was no preference for which region (lumbar vs. hip) was most affected within the group studied. Of the 134 patients screened for Osteoporosis, 21.6% (29/134) patients were of the ‘Obese’ BMI category, 31.3% of patients were of the ‘Overweight’ BMI category (42/134), and 23.8% (32/134) of patients were of the ‘Normal’ BMI category. Only two of the patients were underweight. Furthermore, the Chi- square test was used to evaluate Osteopenia and Osteoporosis as categories and the Obese, Overweight, Normal, and Underweight as groups. The p Value was set at 0.05, and the study found p-value to be 4.04.

The result is not significant.

Implications

From the data collected above, there appears to be no indication that obesity has a protective effect against osteoporosis. In fact, there was a higher incidence of osteoporosis in individuals with a BMI of 25 or higher when compared to other respective groups. Further studies, with a larger sample group, may be needed to effectively evaluate the relationship between BMI and osteoporosis.