Interaction of Body Mass Index and Sex on Pulmonary Function Tests among patients with Chronic Obstructive Respiratory Disease: An Observational study from a Tertiary Centre in India

Introduction: Obesity has unique role in chronic disease like Chronic Obstructive Respiratory Disease; Patients with higher obesity have been reported to have better life expectancy than underweight patients. But this particular obesity paradox has been studied very less among the Indian population. The interaction of obesity with sex is an important factor as the fat distribution varies differently among male and females. Methods: Hospital based observational study. Here the anthropometric parameters and pulmonary function testing were recorded from 951 chronic respiratory disease patients. The relation and association were studied through Correlation, Regression and MANOVA. Results: A significant interaction effect between sex and BMI was observed for both FVC and FEV1, indicating that the impact of BMI on pulmonary function differs by Sex. Specifically, underweight males had disproportionately lower FVC and FEV1 values compared to their female counterparts. This suggests a possible synergistic vulnerability of respiratory function in underweight males Conclusion: In summary, this study reinforces the significant influence of sex on pulmonary function and highlights the nuanced role of BMI, particularly in its interaction with sex. These findings underline the importance of individualized interpretation of PFTs that account for both anthropometric and sex-based physiological differences. Further research is needed to explore underlying mechanisms and potential clinical implications in diverse populations.