Sex differences in spirometric measures and its association with basal metabolic rate in obese and healthy normal weight middle-aged subjects

Abstract

Context: Reduced basal metabolic rates (BMRs) are said to be common in obese or sedentary adults. Very few investigations have analyzed the BMR relationship with that of respiratory functions in middle-aged obese individuals. Objectives: We aimed to determine the sex differences in BMR and spirometric measures in obesity and evaluate the association of BMR with respiratory functions in middle-aged people. Methods: This analytical study was undertaken in healthy normal-weight and obese men and women (50 each) of age 35–55 years. Body mass index (BMI), percentage of body fat, fat mass, and fat-free mass were estimated and BMR was calculated using predicted equations. Spirometric measures such as forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, peak expiratory flow rate, mean forced expiratory flow during the middle of FVC (FEF25%–75%), and maximum voluntary ventilation were assessed in both sexes. Independent two-sample t-test and Pearson's correlation were used as tests of significance with P ≤ 0.05 affirming the statistical significance. Results: BMR among men showed significantly higher mean scores than females. In obese group, most of the respiratory function parameters except FEV1/FVC ratio were significantly reduced in females compared to men. An inverse correlation existed between BMR and FEV1/FVC ratio, whereas BMR observed a positive correlation with all other respiratory function measures among both obese and nonobese. Conclusions: To study the early lung function alterations in the obese, it is necessary to take into account the sex differences, BMR, and body composition instead of BMI alone.

Keywords

• anthropometrics
• basal metabolism
• lung functions
• obesity
• sex differences