Objective:To compare the differences in lung function between sanitation workers and the general population undergoing routine physical examinations, and to analyze the risk factors for restricted airflow and severity of the condition in sanitation workers.Methods:This study is a large cross-sectional study called "Shanxin Respiratory Health Screening for Ten Thousand People". A total of 1 036 sanitation workers (sanitation group) and 6 701 individuals from the general population undergoing routine physical examinations (control group) were selected as the original study subjects from June 2021 to April 2022 (before matching). Both groups underwent pre-bronchodilator lung function tests, and the differences in lung function characteristics between the two groups were compared. The sanitation group also completed a questionnaire survey. Multivariate and ordinal multinomial logistic regression analysis were used to analyze the risk factors for airflow limitation and its severity.Results:A total of 1 027 individuals from the sanitation group and 999 individuals from the control group were included in the study. There were no significant differences in age, gender, height, weight, and body mass index (BMI) between the two groups (all P>0.05). The rate of airflow restriction was significantly higher in the sanitation group compared to the control group (22.88% vs 8.81%, P<0.001). In the sanitation group, there was no statistically significant difference in a self-assessment test for chronic obstructive pulmonary disease (CAT) scores between individuals with airflow restriction (235 cases) and those without airflow restriction (792 cases) [(1.50±2.50) vs (1.15±2.03) points, P=0.084]. There were no statistically significant differences in forced vital capacity (FVC) as a percentage of predicted value (FVC%pred) between the two groups. However, the sanitation group had significantly lower %pred for forced expiratory volume in one second (FEV 1%pred), FVC/FEV 1 ratio (FEV 1/FVC%pred), forced expiratory flow at 50% of FVC (FEF 50%%pred), forced expiratory flow at 75% of FVC (FEF 75%%pred), and maximal mid-expiratory flow (MMEF%pred) compared to the control group (all P<0.05). The rates of abnormal FEF 50%%pred, FEF 75%%pred, and MMEF%pred were significantly higher in the sanitation group compared to the control group (17.62% vs 10.31%, 17.04% vs 10.01%, 27.26% vs 18.41%, all P<0.001). Small airway parameters and the rate of airflow restriction were significantly higher in past and current smokers of the sanitation group compared to never smokers (all P<0.05). Multifactorial analysis showed that high BMI ( OR=0.929, 95% CI: 0.885-0.974) was a protective factor for airflow restriction, while high smoking index was a risk factor ( OR=1.020, 95% CI: 1.011-1.030). Ordered multinomial logistic regression analysis showed that high BMI ( OR=0.925, 95% CI: 0.882-0.971) was a protective factor for the severity of airflow restriction, while high smoking index ( OR=1.020, 95% CI: 1.011-1.029) was a risk factor for the severity of airflow restriction. Conclusions:The incidences of airflow limitation and small airway abnormalities in sanitation workers are higher than that in general physical examination population. High smoking index and low BMI are independent risk factors for airflow limitation and its severity.