Chronic airflow limitation in a rural Indian population: etiology and relationship to body mass index

PURPOSE Respiratory conditions remain a source of morbidity globally. As such, this study aimed to explore factors associated with the development of airflow obstruction (AFO) in a rural Indian setting and, using spirometry, study whether underweight is linked to AFO. METHODS Patients > 35 years old attending a rural clinic in West Bengal, India, took a structured questionnaire, had their body mass index (BMI) measured, and had spirometry performed by an ancillary health care worker. RESULTS In total, 416 patients completed the study; spirometry was acceptable for analysis of forced expiratory volume in 1 second in 286 cases (69%); 16% were noted to exhibit AFO. Factors associated with AFO were: increasing age (95% confidence interval (CI) 0.004-0.011; P = 0.005), smoking history (95% CI 0.07-0.174; P = 0.006), male gender (95% CI 0.19-0.47; P = 0.012), reduced BMI (95% CI 0.19-0.65; P = 0.02), and occupation (95% CI 0.12-0.84; P = 0.08). The mean BMI in males who currently smoked (n = 60; 19.29 kg/m(2); standard deviation [SD] 3.46) was significantly lower than in male never smokers (n = 33; 21.15 kg/m(2) SD 3.38; P < 0.001). AFO was observed in 27% of subjects with a BMI <18.5 kg/m(2), falling to 13% with a BMI ≥18.5 kg/m(2) (P = 0.013). AFO was observed in 11% of housewives, 22% of farm laborers, and 31% of cotton/jute workers (P = 0.035). CONCLUSION In a rural Indian setting, AFO was related to advancing age, current or previous smoking, male gender, reduced BMI, and occupation. The data also suggest that being under-weight is linked with AFO and that a mechanistic relationship exists between low body weight, smoking tobacco, and development of AFO.