RESUMO
Objective To explore the relationship between baseline urinary protein levels and the onset of chronic obstructive pulmonary disease (COPD). Methods A questionnaire survey, blood and urine sample collection, physical examination, and pulmonary function test were conducted among permanent residents over 40 years old in Pudong New Area, Shanghai. The subjects were divided into four groups based on the baseline urine albumin-to-creatinine ratio (ACR) quartiles (0~1.65 mg/g, 1.65~4.89 mg/g, 4.89~10.78 mg/g, and ≥10.78 mg/g). Cox regression analysis was used to explore the relationship between ACR levels and the incidence of COPD in middle-aged and elderly people. Results Among the 3 105 subjects, the median follow-up time was 3.212 years (P25~P75：3.102~3.473). 116 new cases of COPD were observed, with an incidence density of 10.423 per 1000 person-years. The incidence densities for COPD at four ACR levels were 7.922 per 1 000 person-years, 8.300 per 1 000 person-years , 11.419 per 1 000 person-years, and 13.843 per 1 000 person-years, respectively. Cox regression analysis revealed that as the ACR level increased, there was a rising trend in the incidence rate of COPD (χ2=4.396, P=0.036). After adjusting for gender, age, education level, occupational exposure to dust, history of childhood pneumonia, smoking, family history of COPD, central obesity, and hypertension, the risk of developing COPD was 2.499 times higher (95% CI: 1.460~4.276) for ACR levels ≥10.78 mg/g compared to the reference group with a baseline ACR level of 0~1.65 mg/g. Conclusion Elevated ACR levels in middle-aged and elderly population may increase the risk of COPD, and early monitoring of urine protein levels is beneficial for COPD prevention.