Effects of smoking and changes in smoking habits on the decline of FEV1

The aim of this study was to examine the effects of cigarette smoking and changes in smoking habits on the decline of forced expiratory volume in the first second of expiration (FEV1). We studied 7,764 men and women for 5 yrs. The subjects were grouped according to self-reported smoking habits during the observation period. We found that persistent cigarette smoking, in particular heavy smoking, accelerated the decline in FEV1. In 310 subjects who quitted smoking during the observation period, the decline of FEV1 was less pronounced than the decline observed in persistent smokers. In subjects younger than 55 yrs of age, smoking reduction was associated with a less pronounced FEV1 decline, while in the elderly subjects smoking reduction had no effect on the FEV1 decline. An increase in the number of cigarettes smoked was generally associated with a more rapid decline of FEV1, while the beginning of smoking during the 5 yrs of observation did not seem to influence the decline of FEV1. We conclude that smoking cessation or reduction may lead to a demonstrable beneficial effect on the FEV1 decline within a few years.     

Spirometry, rapid FEV1 decline, and lung cancer among asbestos exposed heavy smokers

We assessed whether spirometric measurements are associated with the development of accelerated FEV(1) decline and lung cancer among active and previous smokers with a wide range of lung function. Bivariate and multivariate analyses that adjusted for age, intervention arm, smoking status at enrollment and smoking history, years exposed to asbestos, and evidence of asbestosis were used to assess whether baseline FEV(1) and FEV(1)/FVC ratio were associated with accelerated FEV(1) decline and incident lung cancer. The 3,041 participants enrolled from 1985 to 1994 were followed through April 30, 2005. Baseline FEV(1)/FVC ratio<0.7 was significantly associated with an increased risk for rapid lung function decline (OR=1.73; 95% CI 1.31-2.28; p<0.001). Baseline FEV(1)/FVC ratio<0.7 was also significantly associated with an increased risk of developing lung cancer, even when baseline FEV(1) was >80%. Lung cancer risk among participants with baseline airflow obstruction and FEV(1)<60% was 4-fold higher than participants without baseline airflow obstruction and FEV(1)>80% (p<0.001), even among former smokers. These data indicate an FEV(1)/FVC<0.7 among smokers is significantly associated with faster airflow loss, and an increased risk for developing lung cancer, even among those individuals with a normal FEV(1).     

The FEV1/FEV6 predicts lung function decline in adult smokers

The use of FEV1/FEV6 in place of the traditional FEV1/FVC to detect airways obstruction during spirometry testing performed by primary care providers would reduce time and patient effort. We hypothesized that the FEV1/FEV6, would predict the subsequent decline in FEV1 in adult cigarette smokers who enrolled in the multicenter Lung Health Study. Ten clinical centers in the U.S. and Canada recruited 5887 male and female smokers, aged 35-60 years, with borderline to mild airways obstruction by spirometry. Those who successfully stopped smoking during the 5-yr study (usually as the result of the smoking cessation intervention) were excluded from this analysis. In those continuing to smoke, the relative strength of spirometric predictors of the change in FEV1 during 5 years of follow-up (DFEV1) was determined using a linear regression model. The following covariates were significant independent predictors of DFEV1: the baseline degree of airways obstruction, age, gender, cigarettes per day, years of education, and bronchial hyperresponsiveness. The FEV1/FEV6 was nearly as strong an independent predictor as was the FEV1/FVC (a traditional index of airways obstruction). The degree of airways obstruction, as determined by the FEV1/FEV6 from spirometry, is an independent predictor of subsequent decline in lung function; and therefore, may be used to detect smokers at higher risk of developing COPD.     

Smoking reduction and the rate of decline in FEV(1): results from the Lung Health Study.

Previous findings from the Lung Health Study have shown that smoking cessation and sustained abstinence substantially reduce the rate of decline in forced expiratory volume (FEV(1)) among smokers with early chronic obstructive pulmonary disease (COPD) when compared with continuing smoking. Intermittent quitters demonstrated rates of FEV(1) decline intermediate between those of sustained quitters and continuing smokers. In this study, data from 1,980 participants were analysed from 10 centres of the Lung Health Study in the USA and Canada. All participants were smokers with mild-to-moderate COPD who were unable to quit smoking at any time during the 1st yr of the study. No linear relationship was found between reduction in cigarettes per day and changes in FEV(1) during the 1st yr of the study. However, examination of the data revealed that this relationship was nonlinear. Further analysis found that smokers who reduced their cigarettes per day to very low amounts had smaller declines in FEV(1) than those who did not. Reduction in cigarettes per day was associated with only minimal changes in the presence of chronic respiratory symptoms. In conclusion, compensatory changes in smoking behaviour may account for the limited and unpredictable impact of smoking reduction on lung function decline and symptom prevalence when compared with smoking cessation.     

Methacholine responsiveness, smoking, and atopy as risk factors for accelerated FEV1 decline in male working populations.

Longitudinal lung function data from four occupational health surveys was used to explore the relationship between nonspecific bronchial responsiveness (NSBR) and the rate of decline of FEV1 (RDFEV) and to address other factors that may predict or influence RDFEV. Of the 1,203 subjects with baseline methacholine and lung function data, follow-up data were available for 733 individuals (61%). The data-available and data-unavailable groups were well matched with respect to baseline lung function, atopy, and smoking status. Compared with the unavailable group, those available for follow-up were younger (42.5 versus 37.7 yr; p less than 0.0001) and slightly less responsive to methacholine (p less than 0.01). Somewhat unexpectedly, RDFEV was lower in the 30 asthmatic subjects than in the nonasthmatics. Among the nonasthmatic subgroup (96% of those available for follow-up), age, occupational group, and baseline FEV1 (% predicted) were independent predictive factors for RDFEV. When these factors were included in the model, RDFEV was found to be increased among current smokers compared with never-smokers or ex-smokers. In the final regression model, a relationship was found between methacholine sensitivity (calculated as a dose-response slope) and RDFEV in nonasthmatics (p less than 0.05). Stratification by smoking status revealed that the relationship between RDFEV and bronchial responsiveness was confined to current smokers and that atopy was an additional risk factor in this subgroup only. This relationship was valid among current smokers in each of the three occupational groups studies. However, reinclusion of the 30 asthmatic subjects in the study population obscured the relationship between NSBR and RDFEV.(ABSTRACT TRUNCATED AT 250 WORDS)     

Low initial KCO predicts rapid FEV1 decline in pulmonary lymphangioleiomyomatosis

Pulmonary lymphangioleiomyomatosis (LAM) is a rare interstitial disorder affecting exclusively women, and leading to progressive deterioration of lung function. The disease course is highly variable from one patient to another, but no clinical predictor of rapid disease progression is currently available. To identify clinical variables, which could detect patients at risk for rapid lung function decline, we searched for correlations between the rate of forced expiratory volume in 1 s (FEV1) decline and clinical features at diagnosis in a retrospective series of 31 cases of LAM followed for > or = 1 yr. The mean FEV1 decline was 106+/-143 ml/yr or 3.4+/-4.6% predicted FEV1/yr. Among clinical features at diagnosis, only initial values of carbon monoxide transfer factor (TLCO, P = 0.006) and carbon monoxide transfer coefficient (KCO, P = 0.0001) were significantly correlated with the rate of FEV1 decline. Lung volumes and FEV1/forced vital capacity ratio at diagnosis were not predictive of rapid decline. No effect of previous smoking, contraceptive use or pregnancy on FEV1 decline could be detected. We conclude that low TLCO and KCO at the time of diagnosis are the best clinical predictors of rapid FEV1 decline in patients with LAM.     

Chronic respiratory symptoms, von Willebrand factor and longitudinal decline in FEV1

Although some risk factors for accelerated decline in forced expiratory volume in 1 s (FEV1) such as cigarette smoking, are well defined, it is not possible to identify those individuals with the most rapid rates of decline. Von Willebrand factor (vWF) is a product of both the pulmonary and systemic endothelium, and serum levels are raised during episodes of acute bronchitis. We hypothesized that raised serum levels of vWF may indicate sub-clinical pulmonary injury and so may predict subsequent accelerated decline in FEV1. The aims of this study were 1. to define the prevalence of chronic respiratory symptoms and obstructive airway disease in an inner-city British population and 2. to determine whether elevated levels of von Willebrand factor (vWF) identify those individuals at risk for more rapid decline in FEV1 over time. In 1987, all 2013 individuals aged 45 to 74 years at an inner-city general practice were mailed a respiratory symptom questionnaire. One in six of the responders were asked to attend for spirometry and for assessment of serum vWF. In 1996, those individuals who had spirometry and vWF assessed in 1987 were traced, and repeat spirometry was performed. In 1987, 1527 of 2013 (75.8%) individuals completed the questionnaire. Forty-two point two percent of responders reported shortness of breath on hills, 34.7% reported wheeze and 31.6% reported mucus hypersecretion. Smokers were more likely to report these symptoms. Two hundred and ten of the 251 (84%) individuals approached had spirometry and vWF assessed. Eleven percent of these had both an FEV1 < 75% predicted and a forced expiratory ratio (FEV1 forced vital capacity (FVC)) < 70%. Sub-normal spirometry was associated with wheeze, mucus hypersecretion, cigarette smoking and increasing age. By 1996, 32 (15%) of the original group of 210 individuals had died, and 117 of the remaining 178 (66%) had spirometry repeated. FEV1 < 75% predicted was a strong predictor of interim mortality, independent of age, sex and smoking history. The average decline in FEV1 was 46.7 ml yr-1. There was no significant correlation between serum vWF levels and subsequent decline in FEV1. Chronic respiratory symptoms and spirometric evidence of airflow limitation are common in inner-city residents of the U.K., and are associated with smoking history. Much of this disease is unrecognised by health professionals. An FEV1 < 75% predicted is a strong independent predictor of subsequent mortality. The measurement of serum vWF levels is unhelpful in identifying those individuals at increased risk of accelerated decline in FEV1.     

Tiotropium improves FEV1 in patients with COPD irrespective of smoking status

This study evaluated whether the effect of tiotropium on the change in trough forced expiratory volume in 1s (FEV1), vs. placebo, is affected by smoking status. In a 3-month, double-blind study in 31 centres in Portugal, 311 (289 completed) patients were randomised to tiotropium 18 microg once daily or placebo. Baseline mean (standard deviation (SD)) FEV1 was 1.11 (0.39) l in the tiotropium group and 1.13 (0.39) l in the placebo group. Patients had an average smoking history of 55 (25.7) pack-years; 80 (26%) were smokers and 224 (74%) were ex-smokers. The primary end-point was change in morning pre-dose (i.e. trough) FEV1 after 12 weeks. Trough FEV1 at 12 weeks was significantly improved with tiotropium vs. placebo: the difference in means was 102 ml, P=0.0011, 95% confidence interval (CI) (41, 164). The difference in means in smokers was 138 ml, P=0.0105, CI (32, 244); in ex-smokers it was 66 ml, P=0.0375, CI (3, 129). The difference between smokers and ex-smokers was not statistically significant (P=0.6982) and may be due to greater variability and differences in disease severity. The significant improvement in lung function in patients treated with tiotropium vs. placebo in both smokers and ex-smokers suggests that tiotropium is an effective and well-tolerated therapy in chronic obstructive pulmonary disease (COPD), regardless of smoking status.     

Blood lead levels of a population group not occupationally exposed to lead in Singapore

A survey was conducted between 1995 and 1997 to assess the impact of introduction of unleaded petrol and other public health measures on the blood lead level of the population. The geometric mean blood lead level of 269 government employees as determined by graphite furnace atomic absorption spectroscopy, was 66.0 microg/l, much lower than that recorded before introduction of lead-free petrol. Using multiple regression analysis, factors significantly associated with blood lead levels were: exposure to traffic, age (>50 years) and active smoking. Passive smoking, exposure to recent paint work, consumption of alcohol and traditional medicine were found not to be significantly associated with the blood lead level.     

Effect of smoking on FEV decline in a cross-sectional and longitudinal study of a large cohort of Japanese males

OBJECTIVE: The effects of cigarette smoking and smoking cessation on age-related pulmonary function decline was assessed in both cross-sectional and longitudinal studies. METHODOLOGY: In the cross-sectional study, pulmonary function data from 11,875 healthy asymptomatic males, aged between 35 and 74, were analysed and correlated with their smoking history and age. In the longitudinal study, changes in pulmonary function were monitored over a 5-year period in 1888 healthy males. RESULTS: The cross-sectional study showed that the difference in FEV(1) between male never smokers and current smokers was small at a younger age but increased with age. A beneficial effect on FEV(1) decline was observed in those who ceased smoking, even within the previous 12 months. Longitudinally, current smokers showed a more rapid decline in FEV(1) over the 5-year period than non-smokers. Those who ceased smoking had lower rates of decline in FEV(1) than those who continued to smoke. CONCLUSION: These results indicate that cigarette smoking is associated with a reduction in pulmonary function, and that smoking cessation has a beneficial effect on FEV(1) decline. Provision of a smoking cessation program for all smokers, especially those showing a rapid decline of FEV(1), should be considered as an important strategy to prevent progression of COPD.     

Change in C-reactive protein levels and FEV1 decline: a longitudinal population-based study

Reduced pulmonary function is an important predictor of cardiovascular morbidity and mortality. The mechanisms underlying this association are unknown but may involve systemic inflammation. We assessed the cross-sectional and longitudinal relationships between C-reactive protein (CRP) levels and forced expiratory volume in 1s (FEV1) and its decline in the general population, over a period of 8.5 years. The analyzes were based on 531 subjects (mean age at baseline: 37+/-7 years, 50% women and 42% non-smokers), recruited at two French centers participating in the European Community Respiratory Health Survey. Lung function was expressed as a percentage of predicted FEV1. CRP was measured centrally, by means of a highly sensitive assay. In cross-sectional analysis, FEV1 as a % of predicted values was negatively associated with serum CRP concentration (P=0.002). Multivariate adjustment did not alter these results (P=0.002). In longitudinal analysis, annual FEV1 decline tended to increase from the lower to the upper tertile for baseline CRP concentration but the association was borderline significant (P=0.14). Mean values of annual FEV1 decline were 26+/-32, 31+/-32, and 34+/-32 ml/year for the lower, middle and upper tertiles of baseline CRP concentration, respectively, after adjusting for potential confounders (P=0.09). Changes in CRP levels during follow-up were associated with annual FEV1 decline. The mean annual FEV1 declines in subjects with increasing CRP, in those with stable CRP and in those with decreasing CRP were 36+/-31, 30+/-31 and 24+/-31 ml/year, respectively (P<0.001). These findings were not affected by adjustment for potential confounders (P=0.002). In conclusion, increases in CRP levels over time were associated with a steeper FEV1 decline.     

Airway bacterial load and FEV1 decline in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by an accelerated decline in lung function and progressive airway inflammation. Bacteria have been isolated from the lower airway of stable COPD patients, and airway inflammation has been related to bacterial load and type. The relationship between bacterial colonization, airway inflammation, and lung function decline remains uncertain. We studied 30 patients with COPD, mean (SD) FEV1 0.947 (0.329), 34.8% (13.6%) predicted, for 12 months. Sputum collected at recruitment and the end of the study was analyzed for cytokines and for quantitative bacteriology. The decline in FEV1 was 57.6 (137.6) ml year-1. Bacterial growth was identified in all subjects, with an initial count of 107.47(0.91) cfu ml-1 rising to 107.93(0.81) cfu ml-1 at the end of the study (p = 0.019). FEV1 decline was related to this increase in airway bacterial load (r = 0.59, p = 0.001). FEV1 decline was greater in subjects who exhibited a change in the colonizing bacterial type compared with those with persistence of a single bacterial species over the study period (p = 0.017). Higher sputum interleukin (IL-8) was associated with greater declines in FEV1 (p = 0.03). Rising airway bacterial load and species changes are associated with greater airway inflammation and accelerated decline in FEV1. Bacterial colonization in COPD is an important factor in disease progression.     

A longitudinal study of alpha1-antitrypsin phenotypes and decline in FEV1 in a community population

BACKGROUND: It is well-known that the homozygous deficiency of alpha(1)-antitrypsin, phenotype PiZZ, is associated with an increased risk of COPD. However, studies evaluating the association between the heterozygous forms of the alpha(1)-antitrypsin phenotype PiMZ and rapid decline in lung function, both in patient and community populations, have yielded conflicting results. STUDY OBJECTIVE: To assess the relationship between alpha(1)-antitrypsin phenotypes and decline in FEV(1) values of 2,016 adult subjects in a community population in Tucson, AZ. Design and methods: Prospective cohort study. Standardized questionnaires and lung function measurements were administered 1.5 to 2 years apart during 12 surveys. RESULTS: The frequency distribution for PiMM, PiMS, and PiMZ phenotypes did not differ significantly by physician-confirmed diagnoses of emphysema, chronic bronchitis, or asthma. There was no statistically significant difference in mean FEV(1) slope values between PiMM, PiMS, and PiMZ phenotypes (-22.5, -21, and -7 mL per year, respectively). After controlling for smoking and other potential confounders, the FEV(1) slope was associated with an initial FEV(1) level and age for the initial questionnaire but not with the different phenotypes. Selecting cutoff values, we identified rapidly declining and nondeclining subgroups, based on the percent predicted changes in FEV(1). They also were not associated with alpha(1)-antitrypsin phenotypes. CONCLUSIONS: We conclude that the data from this longitudinal community study suggest that having the PiMZ phenotype is not a significant risk factor for an accelerated decline in FEV(1).