The article "A 20-year follow-up study on chronic respiratory effects of exposure to cotton dust" evaluates the long-term impact of cotton dust exposure on respiratory health. It followed a cohort of Chinese cotton and silk workers from 1981 to 2001, comparing lung function and symptoms. Results showed that cotton workers experienced greater declines in lung function and persistent respiratory symptoms compared to silk workers. The study found that exposure to airborne endotoxins in cotton dust was strongly linked to chronic respiratory impairment. It highlighted that stopping exposure helped improve lung function, particularly in non-smoking men, while smokers continued to show negative effects.