[Distribution patterns of body mass index and its associated factors in chinese patients with pneumoconiosis]

Objective: To analyze the distribution characteristics of body mass index (BMI) and its associated factors among pneumoconiosis patients in China. Methods: A cross-sectional survey was conducted among 12210 pneumoconiosis patients from 27 provinces, autonomous regions, and municipalities directly under the central government of China from March 2017 to December 2021 using stratified sampling combined with purposive sampling. Data were collected on sociodemographic characteristics, dust exposure history, disease severity, complications, economic and employment status, dietary pattern, and social insurance coverage. BMI was calculated and classified (underweight, normal weight, overweight, obesity) according to WS/T 428-2013 Criteria of weight for adults. Comparisons among different BMI groups were conducted using Pearson's χ(2) test. Binary logistic regression (forward method) was used to analyze factors associated with underweight, with underweight as the dependent variable (underweight=1, normal weight=0) . Results: The mean BMI of pneumoconiosis patients was (23.3±3.6) kg/m(2). The proportions of underweight, normal weight, overweight, and obesity were 6.9% (844/12210), 52.6% (6425/12210), 32.7% (3997/12210), and 7.7% (944/12210), respectively. Among respondents with valid data, underweight patients were predominantly distributed in western regions[44.3% (374/844) ] and rural areas [71.9% (605/841) ], and had higher proportions of silicosis [60.5% (506/836) ], stage Ⅲ pneumoconiosis [44.8% (376/839) ], and pulmonary complications (pulmonary tuberculosis 17.1%, pulmonary infection 29.9%, cor pulmonale 23.6%, chronic obstructive pulmonary disease 41.6%, pulmonary bullae or pneumothorax 26.1%). They also had lower personal income (47.5% earning ≤5000 yuan per year), lower coverage of urban employee medical insurance (26.1%), and lower daily egg intake (35.3%). Overweight and obese patients were mostly coal workers' pneumoconiosis and stage I, and had higher proportions of hypertension and diabetes (P<0.05). Multivariate logistic regression analysis showed that stage Ⅲ pneumoconiosis (OR=2.41, 95%CI: 1.94-2.99), silicosis (OR=1.27, 95%CI: 1.07-1.50), pulmonary complications (OR=1.36-1.55), and socioeconomic factors (lack of work-related injury insurance, lack of urban employee medical insurance, low income) were factors associated with underweight (P<0.05) . Conclusion: BMI level of pneumoconiosis patients in China is correlated with geographic region, disease severity, and social security. Individualized intervention strategies are recommended for different BMI strata.