Household solid fuel use and pulmonary function in an urban population in Shanghai, China.

OBJECTIVES: We examined the association between household solid fuel exposure and lung function in a densely populated district in urban Shanghai, China. METHODS: Spirometry was performed in 12 506 subjects, aged 18 and over, residing in the Putuo District in Shanghai, China, in a cross-sectional survey. Exposure to solid fuel use at home was assessed by an administered questionnaire, estimating duration and total amount of solid fuel use at home during the lifetime. RESULTS: After adjusting for confounders, the subjects with exposure to household solid fuel had a 1.3% (95% CI 0.57 to 2.02) decrease in forced expiratory volume in 1 s (FEV(1)) percent predicted and 3.5% (95% CI 2.74 to 4.18) decrease in forced vital capacity (FVC) percent predicted, respectively. Trends towards decreased pulmonary function measures were seen for longer duration and greater amount of household fuel use at home, in the highest compared with lowest tertile (p values for trend <0.001). We observed decrease in FEV(1) and FVC percent predicted across increase in tertile of body mass index in association with in-home solid fuel exposure. CONCLUSIONS: This study suggests that in-home solid fuel exposure is associated with reduced lung function in an urban population.

In-home solid fuel use and cardiovascular disease: a cross-sectional analysis of the Shanghai Putuo study.

BACKGROUND: Although recent research evidence suggests an association between household air pollution from solid fuel use, such as coal or biomass, and cardiovascular events such as hypertension, little epidemiologic data are available concerning such exposure effects on cardiovascular endpoints other than hypertension. We explored the association between in-home solid fuel use and self-reported diagnoses of cardiovascular endpoints, such as hypertension, coronary heart disease (CHD), stroke, and diabetes. METHODS: We analyzed 14,068 Chinese adults, aged 18 years and older. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were estimated using logistic regression models for the risk of each outcome after adjusting for potential confounders. RESULTS: The use of solid fuel in home was significantly associated with an increased risk for hypertension (OR 1.70, 95% CI 1.40 to 2.07), CHD (OR 2.58, 95% CI 1.53 to 4.32), and diabetes (OR 2.48, 95% CI 1.59 to 3.86), after adjusting for potential confounders. Compared with individuals in the lowest tertile of the duration of solid fuel exposure, those in the highest tertile of the duration of solid fuel exposure had an increased odds of hypertension (OR 1.73, 95% CI 1.45 to 2.06), stroke (OR 1.87, 95% CI 1.03 to 3.38), and diabetes (OR 3.18, 95% CI 2.11 to 4.78). CONCLUSIONS: Our data suggest that in-home solid fuel exposure maybe associated with increased risk for hypertension, CHD, stroke, and diabetes in the Chinese adult population. Further large-scale longitudinal studies are warranted to confirm these findings.

Long-term effects of work cessation on respiratory health of textile workers: a 25-year follow-up study.

RATIONALE: The degree to which chronic respiratory health effects caused by exposures to cotton dust and endotoxin is reversible after cessation of textile work is unknown. OBJECTIVES: To investigate changes in lung function and respiratory symptoms after cessation of textile work and to determine whether past exposure to cotton dust and endotoxin or smoking history modify the associations. METHODS: We performed a prospective cohort study consisting of 447 cotton textile workers exposed to cotton dust and 472 unexposed silk textile workers, with a 25-year follow-up. Spirometry testing and respiratory questionnaires were conducted at 5-year intervals. Generalized estimated equations were used to model the average 5-year change in FEV(1) and odds ratios of respiratory symptom prevalence. MEASUREMENTS AND MAIN RESULTS: Years since cessation of textile work was positively associated with 11.3 ml/yr and 5.6 ml/yr gains in 5-year FEV(1) change for cotton and silk workers, respectively. Among male cotton workers, smokers gained more FEV(1) per year after cessation of exposure than did nonsmokers, and the risk of symptoms of chronic bronchitis and byssinosis was larger for smoking than for nonsmoking male cotton workers. CONCLUSIONS: Cessation of textile work was significantly associated with improvement in lung function and respiratory symptoms. The positive effect of work cessation was greater for cotton workers than for silk workers. For cotton workers, the improvement in lung function loss after cessation of textile work was greater among smokers, but no differences were observed for silk workers.

Cross-shift airway responses and long-term decline in FEV1 in cotton textile workers.

RATIONALE: Acute airway response, measured as cross-shift change in FEV(1), to cotton dust may lead to subsequent chronic loss of lung function in exposed workers. OBJECTIVES: To explore the association between the magnitude and frequency of cross-shift change and chronic loss of FEV(1). METHODS: Four hundred eight cotton workers and 417 silk workers from Shanghai textile mills were observed prospectively for 20 years, with cross-shift measurements at baseline and follow-up surveys at approximate 5-year intervals. To account for repeated measures of 5-year change, generalized estimating equations were used to estimate the relationship between the magnitude of cross-shift change in FEV(1) (DeltaFEV(1)) and subsequent 5-year annualized change. Linear regression models were used to examine the association between the number of drops in cross-shift FEV(1) (DeltaFEV(1) < 0) and annualized change over the entire study period. MEASUREMENTS AND MAIN RESULTS: Exposure to cotton dust was associated with a 10 ml/year decrement in 5-year annualized FEV(1) decline. In addition, every 10 ml in DeltaFEV(1) drop was associated with an additional 1.5 ml/year loss in annualized FEV(1) decline. The association between the frequency of drops and annualized decline was stronger for cotton workers than for silk workers over the entire study period. CONCLUSIONS: Cotton workers had larger and more frequent drops, as well as excessive chronic declines in FEV(1), than did silk workers. The magnitude and frequency of cross-shift drops were associated with chronic loss in FEV(1) over the entire 20-year period examined.

Is chronic airway obstruction from cotton dust exposure reversible?

BACKGROUND: Exposure to cotton dust is known to cause chronic airway obstruction, but there is little information on whether the obstructive impairment is reversible after the exposure stops. METHODS: Longitudinal changes in lung function were evaluated among 429 cotton textile workers and 449 silk workers in Shanghai, China, beginning in 1981. Both active and retired workers were tested every 4 to 6 years for 15 years. RESULTS: Overall, cotton workers had greater annual declines in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Compared with active workers, retired cotton workers had lower annual loss of FEV1, although the retired workers had a greater loss during their active employment than the currently active workers. No such trends were detected in silk workers. Annual declines in FEV1 in retired cotton workers were smaller with increasing time since retirement. Multivariate analysis showed that retirement was a substantial contributing factor for improved FEV1 and FVC in the cotton workers, especially among those who did not smoke. Correspondingly, remission of airflow obstruction, defined as a ratio of FEV1 and FVC of less than 70%, was more common in retirees than in the active workers, and more common in nonsmokers than in smokers. CONCLUSION: Chronic airway obstruction related to long-term exposure to cotton dust may be partially reversible after the exposure ceases, although lung function does not return to the level found in unexposed workers.

Lung function, airway reactivity, and atopy in newly hired female cotton textile workers.

To assess changes in lung function and airway reactivity resulting from exposure to cotton dust, and the role of atopic status in these changes, the authors observed a group of 225 newly hired Chinese textile workers for 1 yr. All workers were female, lifelong nonsmokers, and none of them had been exposed previously to cotton or other occupational dust. Atopic status was determined at baseline. Spirometry, response to methacholine challenge, and total serum immunoglobulin E level were examined at baseline and again after subjects began work in the cotton mills. Obvious cross-shift drops in forced expiratory volume in 1 sec (FEV1.0), and declines in forced vital capacity and FEV1.0 over 1 yr, were observed. Atopic workers had a significantly greater acute drop in FEV1.0 than did nonatopic workers. Both atopic and nonatopic workers had slightly increased airway reactivity at 1 yr, compared with baseline values. The results suggest that exposure to cotton dust is responsible for acute and longitudinal declines in lung function, as well as for slightly increased airway reactivity. Atopy may interact with cotton dust to accentuate the acute lung function response.

Follow-up study of respiratory health of newly-hired female cotton textile workers.

BACKGROUND: Numerous studies have investigated adverse effects of exposure to cotton dust on respiratory health, but very limited longitudinal data are available with regard to the early pulmonary response to cotton dust. Moreover, the adverse effects of occupational exposure to cotton dust have been difficult to separate from the confounding effects of smoking. This setting provided a unique opportunity to evaluate early respiratory effects in newly hired and non-smoking female textile workers. METHODS: To identify early pulmonary responses to cotton dust exposure and associated gram-negative bacterial endotoxin, respiratory symptoms and pulmonary function in 225 newly-hired textile workers were assessed at work initiation, and at three and twelve months later. RESULTS: All the workers were females and nonsmokers, with an average age of 18 years. Symptom incidence at three months was 3.6% for usual cough with phlegm, and 6.7% for usual dry cough. Lung function changes were detectable at one year: FEV1 declined by 70 ml and FVC by 124 ml over the year, and workers reporting respiratory symptoms at three months showed a significantly greater cross-shift drop in FEV1 (- 2.3%) than those without the symptoms (- 0.7%). CONCLUSIONS: These results suggest that the occurrence of respiratory symptoms represents the earliest response to cotton dust exposure, followed by lung function changes. Early respiratory symptoms may be a risk factor for subsequent loss of pulmonary function in cotton textile workers.