Journal of General Practice

Is Chronic Obstructive Pulmonary Disease a Risk Factor for Osteoporosis A Structural Equation Modeling (SEM) Analysis

Abstract

Amy Olver and Lawrence Leung

Background: Osteoporosis (OP) is reported to be far more prevalent in those with Chronic Obstructive Pulmonary Disease (COPD) than in healthy patients. While these two diseases share many common risk factors, studies suggest that COPD itself may be a contributing factor for poor bone health and thus could serve as a useful indicator to institute treatment for osteoporosis. Our study set out to further elucidate this correlation using structural equation modeling (SEM) in a population attending an academic family health team in Kingston, Ontario. Methods: With ethics approval, data was collected from the existing electronic medical record system of the Queen's University Family Health Team in Kingston, Ontario. A path model with both structural and measurement components testing our hypothesis was constructed using the Structural Equation Modeling (SEM) software (SPSS AMOS 21©) using various latent and manifest variables that include the basic demographics, smoking status, alcohol usage and confirmed diagnoses of COPD and/or OP. Regression and covariance analyses were then performed and results were tabulated for discussions. Results: Our proposed SEM model exhibited a goodness of fit index (GFI) of 0.88, which met the threshold (>0.85) of a good fit for our hypothesis. The correlation between poor lung function and poor bone health showed a statistically significant (p<0.05) positive regression coefficient of 5.753, indicating that poor lung function is indeed indicative of poor bone health. Alternatively, vitamin D and calcium intake in our population were found to have a statistically significant (p<0.001) negative regression coefficient of -0.342, -0.776 respectively, paradoxically implying that positive intake of both vitamin D and calcium is inversely correlated with poor lung function. Moreover, known risk factors for poor lung function such as age and smoking were confirmed with our model, and other factors like gender and alcohol intake were not. Limitations of our study included errors in documentation in the EMR and a biased sample that may not be representative for the general population. Conclusions: Other studies have speculated a correlation between COPD and osteoporosis but definitive data is lacking. We performed a SEM analysis basing on electronic medical record data from an academic family health team in Kingston, Ontario, and our data supported a statistically significant correlation between poor lung function upon poor bone health with due regard to other factors including age, smoking, vitamin D and calcium intake.