Effect of cigarette smoking on evolution of ventilatory lung function in young adults: an eight year longitudinal study

Impact of Cigarettes Smoking on Undergraduates' Lung Health and Functional Performance: Observational Cross-Sectional Study

Background

Cigarettes Smoking is a major social and global health problem. Cigarette smoking continues to be a major contributor to deteriorated health status across different age categories. Clarifying the impact of the cigarette smoking on young adults' lungs health and functional aspects can serve eliminating further deterioration in health status and establishing proper management regimens. This study aimed to investigate the impact of cigarette smoking on lung health (age and functions) and functional performance in the university smoker students.

Methods

One hundred and Thirty eligible volunteer, current smoker students participated in this study to objectively evaluate their pulmonary functions (including forced vital capacity "FVC", forced expiratory volume in one second "FEV1", FEV1/FVC, peak expiratory flow rate "PEFr"), lung age and functional performance (via the 6-minutes' walk test "6MWT") and compare "the observed" with "the predicted normal" mean values. Data were analyzed via SPSS program using the student t-test.

Results

There were significant differences (P < 0.05) between the "observed" and the "predicted normal" FVC, FEV₁, FEV1/FVC, PEFr, lung age, and the 6MWT mean values. The "observed" and the "predicted normal" FVC, FEV₁, FEV1/FVC, PEFr, lung age and the 6MWT mean values were [(4.47 ± 0.53, 4.77 ± 0.5 liter), (3.95 ± 0.42, 4.08 ± 0.4 liter), (88.74 ± 7.17, 85.59 ± 4.91%), (550.75 ± 114.96, 572.72 ± 53.02 liter/minute), (32.77 ± 9.44, 21.55 ± 1.37 year), (387.06 ± 56.47, 466.82 ± 18.45 meter)], respectively.

Conclusions

Cigarette smoking negatively impacts the lung age, functions, and functional performance of the university smoker students; the concept that can be used to encourage prevention and early smoking cessation.

The long-term health effects of initiating smoking in adolescence: Evidence from a national longitudinal survey

We estimate the long-term effect of initiating smoking in adolescence on a range of health outcomes later in life. We use the second wave (1996) and the fifth wave (2016-2018) of the National Longitudinal Study of Adolescent to Adult Health (Add Health) and estimate instrumental variables models with school-level fixed effects, where the instruments are the average rate of smoking among friends and the respondents' perceptions about their friends' smoking. We find that smoking in adolescence has a negative impact on 15 of the 28 self-reported, diagnosed, and self-identified health outcomes approximately 20 years later.

Diagnosis and Treatment of Early Chronic Obstructive Lung Disease (COPD)

Chronic obstructive lung disease (COPD) is responsible for substantial rates of mortality and economic burden, and is one of the most important public-health concerns. As the disease characteristics include irreversible airway obstruction and progressive lung function decline, there has been a great deal of interest in detection at the early stages of COPD during the “at risk” or undiagnosed preclinical stage to prevent the disease from progressing to the overt stage. Previous studies have used various definitions of early COPD, and the term mild COPD has also often been used. There has been a great deal of recent effort to establish a definition of early COPD, but comprehensive evaluation is still required, including identification of risk factors, various physiological and radiological tests, and clinical manifestations for diagnosis of early COPD, considering the heterogeneity of the disease. The treatment of early COPD should be considered from the perspective of prevention of disease progression and management of clinical deterioration. There has been a lack of studies on this topic as the definition of early COPD has been proposed only recently, and therefore further clinical studies are needed.

Clinical and Radiologic Disease in Smokers With Normal Spirometry

IMPORTANCE

Airflow obstruction on spirometry is universally used to define chronic obstructive pulmonary disease (COPD), and current or former smokers without airflow obstruction may assume that they are disease free.

OBJECTIVE

To identify clinical and radiologic evidence of smoking-related disease in a cohort of current and former smokers who did not meet spirometric criteria for COPD, for whom we adopted the discarded label of Global Initiative for Obstructive Lung Disease (GOLD) 0.

DESIGN, SETTING, AND PARTICIPANTS

Individuals from the Genetic Epidemiology of COPD (COPDGene) cross-sectional observational study completed spirometry, chest computed tomography (CT) scans, a 6-minute walk, and questionnaires. Participants were recruited from local communities at 21 sites across the United States. The GOLD 0 group (n = 4388) (ratio of forced expiratory volume in the first second of expiration [FEV1] to forced vital capacity >0.7 and FEV1 ≥80% predicted) from the COPDGene study was compared with a GOLD 1 group (n = 794), COPD groups (n = 3690), and a group of never smokers (n = 108). Recruitment began in January 2008 and ended in July 2011.

MAIN OUTCOMES AND MEASURES

Physical function impairments, respiratory symptoms, CT abnormalities, use of respiratory medications, and reduced respiratory-specific quality of life.

RESULTS

One or more respiratory-related impairments were found in 54.1% (2375 of 4388) of the GOLD 0 group. The GOLD 0 group had worse quality of life (mean [SD] St George's Respiratory Questionnaire total score, 17.0 [18.0] vs 3.8 [6.8] for the never smokers; P < .001) and a lower 6-minute walk distance, and 42.3% (127 of 300) of the GOLD 0 group had CT evidence of emphysema or airway thickening. The FEV1 percent predicted distribution and mean for the GOLD 0 group were lower but still within the normal range for the population. Current smoking was associated with more respiratory symptoms, but former smokers had greater emphysema and gas trapping. Advancing age was associated with smoking cessation and with more CT findings of disease. Individuals with respiratory impairments were more likely to use respiratory medications, and the use of these medications was associated with worse disease.

CONCLUSIONS AND RELEVANCE

Lung disease and impairments were common in smokers without spirometric COPD. Based on these results, we project that there are 35 million current and former smokers older than 55 years in the United States who may have unrecognized disease or impairment. The effect of chronic smoking on the lungs and the individual is substantially underestimated when using spirometry alone.

Occupational exposure to petroleum products and respiratory health: a cross-sectional study from Algeria

OBJECTIVE

To investigate the possible impact of long-term occupational exposure to hydrocarbons on respiratory health.

METHODS

Respiratory health was assessed by questionnaires, spirometry, and exhaled nitric oxide in 250 male workers from a company handling and distributing refined petroleum products (exposed) and 250 electricians (controls). Exposure to hydrocarbons was assessed by personal air monitoring.

RESULTS

Aerial exposure to hydrocarbons was low. Respiratory and nasal symptoms were significantly more frequent among exposed subjects than among controls. Although forced vital capacity and forced expiratory volume in 1 second did not differ, ratio of forced expiratory volume in 1 second to forced vital capacity and maximal expiratory flows were significantly lower in exposed than in control subjects, adjusting for smoking. Exhaled nitric oxide was significantly higher among exposed subjects (30.1 ppb) than among controls (21.6 ppb), adjusting for age and smoking.

CONCLUSIONS

Even low exposure to petroleum-derived hydrocarbons is associated with more respiratory and nasal symptoms, lower pulmonary function, and airway inflammation.

Pulmonary function tests and respiratory symptoms among smokers in the city of Mashhad (north east of Iran)

The prevalence of smoking was studied using a questionnaire. Pulmonary function tests and respiratory symptoms were evaluated in 176 smokers. The total studied population with family and co-workers were 13289. The number of smokers among studied population was 11.7%. The rate of smoking among male subjects was 17.2% and in female 2.5%. All values of PFTs in smokers were significantly lower (p<0.001) and respiratory symptoms higher than in non smokers (p<0.05 for cough and p<0.001 for wheeze and tightness). There were significant negative correlations between smoking duration and rate with values of PFT (p<0.05-p<0.001). In this study the prevalence of smoking in population of Mashhad city was shown. The prevalence of smoking was higher among male than females. Smoking leads to increased respiratory symptoms and reduction of PFTs values.

Systematic review of the evidence relating FEV1 decline to giving up smoking

BACKGROUND

The rate of forced expiratory volume in 1 second (FEV1) decline ("beta") is a marker of chronic obstructive pulmonary disease risk. The reduction in beta after quitting smoking is an upper limit for the reduction achievable from switching to novel nicotine delivery products. We review available evidence to estimate this reduction and quantify the relationship of smoking to beta.

METHODS

Studies were identified, in healthy individuals or patients with respiratory disease, that provided data on beta over at least 2 years of follow-up, separately for those who gave up smoking and other smoking groups. Publications to June 2010 were considered. Independent beta estimates were derived for four main smoking groups: never smokers, ex-smokers (before baseline), quitters (during follow-up) and continuing smokers. Unweighted and inverse variance-weighted regression analyses compared betas in the smoking groups, and in continuing smokers by amount smoked, and estimated whether beta or beta differences between smoking groups varied by age, sex and other factors.

RESULTS

Forty-seven studies had relevant data, 28 for both sexes and 19 for males. Sixteen studies started before 1970. Mean follow-up was 11 years. On the basis of weighted analysis of 303 betas for the four smoking groups, never smokers had a beta 10.8 mL/yr (95% confidence interval (CI), 8.9 to 12.8) less than continuing smokers. Betas for ex-smokers were 12.4 mL/yr (95% CI, 10.1 to 14.7) less than for continuing smokers, and for quitters, 8.5 mL/yr (95% CI, 5.6 to 11.4) less. These betas were similar to that for never smokers. In continuing smokers, beta increased 0.33 mL/yr per cigarette/day. Beta differences between continuing smokers and those who gave up were greater in patients with respiratory disease or with reduced baseline lung function, but were not clearly related to age or sex.

CONCLUSION

The available data have numerous limitations, but clearly show that continuing smokers have a beta that is dose-related and over 10 mL/yr greater than in never smokers, ex-smokers or quitters. The greater decline in those with respiratory disease or reduced lung function is consistent with some smokers having a more rapid rate of FEV1 decline. These results help in designing studies comparing continuing smokers of conventional cigarettes and switchers to novel products.

Asthma patients who smoke have signs of chronic airflow limitation before age 45

BACKGROUND

The frequency of smokers among asthma patients often mirrors the frequency of smokers among healthy individuals. Smoking has been shown to increase the lung function decline in adult asthma patients and change the composition of the bronchial inflammation.

OBJECTIVE

To examine the consequences of smoking in a large cohort of young asthma patients.

METHODS

Seven hundred ninety-three asthma patients, aged 14 to 44, were examined using lung function measurements, bronchial provocations, clinical interviews, and questionnaires.

RESULTS

Forty-five percent of participants were smokers; smokers had significantly lower forced expiratory volume in one second (FEV(1)), FEV(1) in percent of predicted value (FEV(1)% pred), and FEV(1)/forced vital capacity (FVC) values compared with nonsmokers, and there was a dose-response relationship between tobacco exposure and these lung function measures. Smoking seemingly affected the FEV(1) growth already in adolescence, and before the age of 45, significantly more smokers than nonsmokers had signs of airflow limitation, with FEV(1)/FVC ratios below 0.70. Smokers had more asthma symptoms despite receiving inhaled corticosteroid (ICS) treatment as frequently as did nonsmokers.

CONCLUSION

The additive effect of smoking on lung function decline in asthma patients is detectable at early ages and leads to signs of airflow limitation before the age of 45 years.

Longitudinal evaluation of airway function 21 years after preterm birth

RATIONALE

There are limited longitudinal data about respiratory morbidity and lung function after preterm birth into adulthood.

OBJECTIVES

To determine the evolution of respiratory symptoms, spirometry, and airway hyperresponsiveness of ex-preterm subjects from childhood into adulthood.

METHODS

Ex-preterm subjects (median birth weight, 1,440 g; median gestation, 31.5 wk), recruited at birth (not treated with surfactant), had excess respiratory symptoms, airway obstruction, and increased airway hyperresponsiveness in mid-childhood. At a median age of 21.7 years, 60 of these subjects (the index study group) and 50 healthy term control subjects were recruited to determine respiratory morbidity and spirometry.

MEASUREMENTS AND MAIN RESULTS

Respiratory symptom questionnaire, spirometry, and methacholine challenge test. The index study group had significantly more respiratory symptoms (16 of 60) than did control subjects (4 of 50) (odds ratio, 4.2; 95% confidence interval, 1.3 to 13.5; P = 0.01), but no significant difference in measured spirometry. Specifically, in the index study group and control subjects, the mean z scores (95% confidence interval of the group difference) for the FEV(1) were -0.60 and -0.58 (-0.44 to 0.49), respectively (P = 0.92); for the forced mid-expiratory flow they were -1.02 and -0.86 (-0.33 to 0.64), respectively (P = 0.52); and for the FVC they were -0.29 and -0.33 (-0.46 to 0.38), respectively (P = 0.85). Ex-preterm adults did not show evidence of increased airway hyperresponsiveness compared with control subjects, 23 and 19%, respectively (P = 0.89).

CONCLUSIONS

There are still excess respiratory symptoms 21 years after preterm birth. Reassuringly, this longitudinal study did not show evidence of persistent airway obstruction or airway hyperresponsiveness in ex-preterm adults.

Early growth and adult respiratory function in men and women followed from the fetal period to adulthood

BACKGROUND

While some studies suggest that poor fetal growth rate, as indicated by lower birth weight, is associated with poor respiratory function in childhood, findings among adults remain inconsistent. A study was undertaken to determine the association between early growth and adult respiratory function.

METHODS

A longitudinal birth cohort study was performed of 5390 men and women born full term and prospectively followed from the fetal period to adulthood. Weight at birth and infancy were recorded, and forced expiratory volume in 1 s (FEV(1)) and forced vital capacity (FVC) were assessed by standard spirometry at age 31 years.

RESULTS

Adult FEV(1) and FVC increased linearly with higher birth weight in both men and women with no apparent threshold. After adjustment for sex, adult height and other potential confounders operating through the life course, every 500 g higher birth weight was associated with a higher FEV(1) of 53.1 ml (95% CI 38.4 to 67.7) and higher FVC of 52.5 ml (95% CI 35.5 to 69.4). These positive associations persisted across categories of smoking, physical activity and body mass index, with the lowest respiratory function noted among those with lower birth weight who were smokers, led a sedentary lifestyle or were overweight. Weight gain in infancy was also positively associated with adult lung function.

CONCLUSION

Birth weight is continuously and independently associated with adult respiratory function. It is plausible that poor growth in early life may restrict normal lung growth and development, which could have long-term consequences on lung function later in life.

COPD: a dust-induced disease?

Various reports have demonstrated the importance of small airway inflammation in the development of airflow limitation and progression of COPD. This hypothesis proposes that the pathogenesis of COPD mirrors a chronic inhalational dust-induced disease. The putative inorganic dust in cigarette smoke is aluminum silicate or kaolinite, a common component of clay soils. Kaolinite has been recovered in the alveolar macrophages of smokers and has been reported as a constituent of tobacco products. The origin of kaolinite in tobacco products remains unknown, and possible potential sources are proposed. On inhalation, kaolinite deposition in the distal lung may promote macrophage accumulation within the terminal airways leading to a respiratory bronchiolitis. In the susceptible smoker, important genetic, environmental, immunologic, and mechanical factors interact and modulate this small airway inflammation, ultimately leading to the pathologic lesion of emphysema. Further studies into the effects of kaolinite on macrophage function and the subsequent development of respiratory bronchiolitis could lead to prevention of COPD at its precursor lesion.

Tobacco Use and Health in Young Adulthood

In this prospective longitudinal study, the authors investigated the association between lifetime tobacco use and subsequent health problems by age 30. The authors interviewed a community group of 749 participants from upstate New York at mean ages of 14, 16, 22, and 27 years. Daily tobacco use during any of the time periods, as well as the number of periods of daily tobacco use, were significantly associated with increased risk for respiratory ailments, neurobehavioral and cognitive problems, and general malaise. The results suggested that daily tobacco use, either during childhood, adolescence, the early 20s, or a combination of those times, predicted health problems by age 30. Effective smoking prevention programs that begin in childhood are imperative to prevent the occurrence of later health problems.

Childhood smoking is an independent risk factor for obstructive airways disease in women

OBJECTIVE

To assess whether starting to smoke in childhood increases the risk of obstructive airways disease (OAD) in adult life.

METHODS

A retrospective cohort analysis was undertaken of 12 504 current and ex-smokers in the EPIC-Norfolk cohort. The main exposure was starting to smoke during childhood (age <16 years). Three definitions of OAD were used: doctor diagnosed asthma, doctor diagnosed bronchitis/emphysema, and "any OAD" (doctor diagnosed asthma or bronchitis/emphysema, or taking medication used in the treatment of OAD).

RESULTS

Childhood smokers had significantly more pack years of exposure and poorer lung function than subjects who started to smoke in adulthood (>/=16 years). Compared with starting in adulthood, starting to smoke in childhood was associated with a greater risk of bronchitis/emphysema in female smokers (OR 1.79, 95% CI 1.25 to 2.56) and ex-smokers of both sexes (OR 1.29, 95% CI 1.07 to 1.55 in men and OR 1.40, 95% CI 1.05 to 1.85 in women), and of "any OAD" in female smokers (OR 1.72, 95% CI 1.24 to 2.38) and male and female ex-smokers (OR 1.20, 95% CI 1.03 to 1.40 in men and 1.34, 95% CI 1.07 to 1.57 in women). After adjustment for pack years, childhood smoking was associated with poorer lung function (FEV(1) 92.3% predicted in adult smokers and 89.5% in childhood smokers, p = 0.03) and a greater risk of bronchitis/emphysema (adjusted OR 1.55, 95% CI 1.08 to 2.24) and for "any OAD" (OR 1.54, 95% CI 1.10 to 2.13) in female smokers but not in male and female ex-smokers.

CONCLUSION

Starting to smoke in childhood is associated with an increased risk of airways disease because of the extra pack years smoked. In women, childhood smoking is itself an independent risk factor for the development of airways disease.

Short-term smoke exposure attenuates ovalbumin-induced airway inflammation in allergic mice

Little is known about effects of smoking on airway inflammation in asthma. We tested the hypothesis that smoking enhances established airway inflammation in a mouse model of allergic asthma. C57Bl/6j mice were sensitized to ovalbumin (OVA) and challenged with OVA (OVA-mice) or sham-sensitized to phosphate-buffered saline (PBS) and challenged with PBS aerosols (PBS-mice) for 7 wk. At 4 wk, mice were additionally exposed to air (nonsmoking controls) or mainstream smoke for 3 wk. Using whole body plethysmography, we found OVA-induced bronchoconstriction to be significantly inhibited in smoking OVA-mice as compared with nonsmoking OVA-mice (1 +/- 2% increase versus 22 +/- 6% increase in enhanced pause, respectively). Smoking did not change airway hyperresponsiveness (AHR) to methacholine in PBS-mice, yet significantly attenuated AHR in OVA-mice 24 h after OVA challenge as compared with nonsmoking mice. This was accompanied by reduced eosinophil numbers in lung lavage fluid and tissue of smoking OVA-mice compared with nonsmoking OVA-mice. In contrast to our hypothesis, short-term smoking reduced responsiveness to OVA and methacholine in OVA-mice and decreased airway inflammation when compared with nonsmoking mice. This effect of smoking may be different for long-term smoking, in which remodeling effects of smoking can be expected to interrelate with remodeling changes caused by asthmatic disease.

Gender differences in the impact of adolescent smoking on lung function and respiratory symptoms. the Nord-Trøndelag Health Study, Norway, 1995-1997

Girls take up smoking at least as frequently as boys. Few studies have focused on gender differences in the impact of adolescent smoking. We evaluated the sex-specific effect of adolescent smoking on respiratory symptoms and lung function. All students in junior high and high schools in Nord-Trøndelag County Norway, 1995-97, were invited to participate in a cross-sectional study. Information on smoking habits and respiratory symptoms was obtained by self-administered questionnaires. Spirometry was performed in accordance with ATS standards. Eight-thousand-three-hundred and five students (83%) completed both questionnaire and spirometry. Among 6811 students aged 13-18 years (50.3% girls) with no history of asthma, 2993 (43.9%) reported never smoking, 665 (98%) reported occasional smoking, and 667 (9.9%) reported daily smoking (mean initiation age: 13.9 years). More boys than girls were heavy smokers. In all smoking categories, smokers reported a higher prevalence of respiratory symptoms than nonsmokers; symptoms increased with smoke burden. Girls reported more symptoms compared to boys with comparable smoke burden. A dose-response relation between smoking and reduced lung function was found only in girls. Girls were more vulnerable than boys to the impact of smoking on respiratory symptoms and lung function.

Environmental tobacco smoke and lung function in employees who never smoked: the Scottish MONICA study

OBJECTIVES

To investigate the relation between lung function in employees and exposure to environmental tobacco smoke (ETS) at work and elsewhere.

METHODS

Never smokers in employment (301) were identified from the fourth Scottish MONICA survey. They completed a self administered health record, which included details of exposure to ETS, and attended a survey clinic for physical and lung function measurements, and for venepuncture for estimation of serum cotinine. Differences in lung function in groups exposed to ETS were tested by analysis of variance (ANOVA), the exposure-response relation by a linear regression model, and a case-control analysis undertaken with a logistic regression model.

RESULTS

Both men and women showed effects on forced expiratory volume in the first second (FEV(1)) and forced vital capacity (FVC) from exposure to ETS-higher exposure going with poorer lung function. This was found at work, and in total exposure estimated from ETS at work, at home, and at other places. Linear regression showed an exposure-response relation, significant for ETS at work, total exposure, and exposure time/day, but not at home or elsewhere. Compared with those not exposed to ETS at work, those who were exposed a lot had a 254 ml (95% confidence interval (95% CI) 84 to 420) reduction in FEV(1), and a 273 ml (60 to 480) reduction in FVC after adjusting for confounders. Although lung function was not significantly associated with serum cotinine in all the data, a significant inverse relation between cotinine concentration and FVC occurred in men who had had blood collected in the morning. Case-control analysis also showed a significant exposure-response relation between ETS, mainly at work, and lung function. A higher exposure measured both by self report and serum cotinine went with lower lung function.

CONCLUSION

The exposure-response relation shows a reduction in pulmonary function of workers associated with passive smoking, mainly at work. These findings endorse current policies of strictly limiting smoking in shared areas, particularly working environments.

Occupational inhalant exposure and respiratory disorders among never-smokers referred to a hospital pulmonary function laboratory

BACKGROUND

Multiple reports have described associations between occupational inhalant exposure and lung disease. Previous occupational lung disease investigations have studied populations consisting of both smokers and nonsmokers. Smoking complicates interpretation of toxicant exposure-response relationships. The objective of this study was to determine whether, among never-smokers, occupational exposure to gases, dusts, or fumes is associated with a history of respiratory disorders and pulmonary function test defined obstructive lung disease.

METHODS

We performed a retrospective analysis of 517 never-smoker patients who underwent pulmonary function testing in our clinical laboratory between 1986 and 1999. We calculated the relative risks of developing adverse respiratory health outcomes given a history of exposure to occupational inhalants.

RESULTS

Compared with persons with a negative occupational exposure history, exposed persons had an increased risk of reporting a history of bronchitis [relative risk (RR), 1.59; 95% confidence interval (CI), 1.20-2.12], recurrent lung infections (RR, 2.09; 95% CI, 1.14-3.82), and bronchodilator use (RR, 1.61; 95% CI, 1.26-2.06). There was also a statistically significant association between a history of inhalant exposure and the finding of an obstructive ventilatory defect on pulmonary function testing (RR, 1.79; 95% CI, 1.12-2.85). A history of inhalant exposure was not associated with self-reported asthma (RR, 1.08; 95% CI, 0.83-1.41). The population attributable risk estimates for respiratory disorders due to inhalant exposure were: bronchitis, 23.6%; recurrent lung infection, 36.3%; bronchodilator use, 24.3%; and obstructive lung disease, 29.6%.

CONCLUSIONS

Occupational inhalant exposure is a strong risk factor for lung disease in this population of never smokers. A significant burden of respiratory disease in this population may be attributable to occupational inhalant exposure.

Rise and fall of the FEV(1)

BACKGROUND

Most studies of the rate of decline in ventilatory capacity in normal subjects take into account a relatively restricted number of factors, such as age, smoking, and dust exposure. There is increasing evidence to suggest that such a limited approach is inadequate.

OBJECTIVE

To carry out a prospective study of those factors influencing the rate of decline of the ventilatory capacity in a cohort of automobile workers.

DESIGN

Prospective cohort study.

SETTING

Southern Ontario, Canada.

PARTICIPANTS

A cohort of 181 workers employed in assembling and spray painting the chassis of new cars, a minority of whom used paints containing isocyanates.

MEASUREMENTS

All participants underwent annual anthropometric measurements. Spirometry was carried out at yearly intervals, and a questionnaire relating to respiratory symptoms and smoking habits was completed annually by all participants. Daily monitoring of the isocyanate levels was carried out.

RESULTS

There was no indication of any effect from isocyanate exposure. The annual decline in the FEV(1) was similar to that found in other studies, with the respective annual decrements for smokers, ex-smokers, and nonsmokers being 0.055 L, 0.046 L, and 0.035 L, respectively. The decline of the FEV(1) in those > 35 years old and < 35 years old differed appreciably. The decrements in the FEV(1) in subjects < 35 years old were influenced as much by excessive weight gain as by cigarette smoking. Loss of weight in those significantly overweight was frequently associated with improved lung function.

CONCLUSIONS

While age and smoking play an important role in determining the rate of decline in the ventilatory capacity, it is clear that body weight plays a significant role and needs to be taken into account in all epidemiologic studies of the ventilatory capacity.

Correlation of hematologic markers of inflammation and lung function: a comparison of asymptomatic smokers and nonsmokers

Increased inflammation of the peripheral airways has been implicated as a cause of pulmonary function impairment. However, little information is available on the correlation between subclinical decrements of pulmonary function and inflammation in asymptomatic individuals. A relationship between markers of inflammation and lung function may be useful in predicting the early onset of lung function impairment. The purpose of this study was to investigate the correlation of hematologic markers of inflammation and spirometry in asymptomatic smokers and nonsmokers. The specific objectives of this study were twofold. The first objective was to quantify and compare the spirometric measures of lung function in smokers and nonsmokers having similar demographic and lifestyle characteristics. The second objective was to define the correlation between these spirometric measurements and hematologic markers of inflammation (white blood cells, monocytes, basophils, PGE1, IgG, and IgE). Systemic blood samples and spirometric measurements were obtained from 61 age-matched (33 +/- 9 years) healthy, asymptomatic smokers and nonsmokers, with similar self reported lifestyles (i.e., food, alcohol, vitamin consumption and exercise). Both male and female smokers self reported a higher coffee consumption (P < 0.05) compared to nonsmokers. Male smokers self-reported a trend toward current blue-collar versus white-collar occupation when compared with the nonsmokers. Body weight (77.6 +/- 16.6 kg) did not differ between the smokers and nonsmokers. The male nonsmokers were taller than the male smokers (P < 0.05). All subjects were asymptomatic and had clinically normal spirometry. Compared to male nonsmokers, the male smokers had lower FEF25-75% and FEF75-45% values (P < 0.05). No additional spirometric measurements, including FEV1/FVC, FEV1 and FVC were significantly different. The female smokers did not differ from the female nonsmokers (P < 0.05) in any of the spirometric endpoints measured. Thirteen statistically significant (P < 0.05) correlations involving inflammatory (white blood cells, monocytes, basophils, and PGE1) or immunologic endpoints (IgE) and spirometric measurements were observed in female smokers, female nonsmokers and male nonsmokers. No statistically significant correlations involving immunologic or inflammatory endpoints were observed in the male smokers. A better mechanistic understanding of the observed relationship between elevated hematologic inflammatory endpoints and reduced lung function may provide valuable insight into the clinical significance of these correlations.

Effect of passive smoking on the development of respiratory symptoms in young adults: an 8-year longitudinal study

The evidence of an association between passive smoking and occurrence of respiratory symptoms is relatively strong in children, whereas studies conducted in adult populations have provided inconsistent results. The objective of the present study was to examine the relations between exposure to environmental tobacco smoke (ETS) and development of respiratory symptoms in young adults during a study period of 8 years, with emphasis on the evaluation of potential dose-response pattern of the relations. The study population consisted of 117 "never smokers," who were 15 to 40 years of age at the time of initial examination, when they answered a standardized questionnaire on respiratory health, and who were reexamined 8 years later. ETS exposure at home and at work during the study period was recorded at the 8-year examination with a structured questionnaire. The symptoms studied as outcomes included wheezing, dyspnea, cough, and phlegm production. The relations between ETS exposure and development of respiratory symptoms were studied in multivariate logistic regression models controlling for age, gender, atopy, and the presence of other respiratory symptoms. Cumulative incidences of the respiratory symptoms, except of phlegm production, were consistently greater among subjects exposed to ETS compared with the reference group. A significant dose-related increase in the risk of developing dyspnea was observed in relation to ETS exposure, with an OR of 2.37 for an average exposure of 10 cigarettes/day (95% confidence interval, 1.25-4.51). The risk of developing other respiratory symptoms, apart from phlegm, was also related to ETS exposure, but these relations did not achieve statistical significance. The results provide evidence of adverse respiratory effects of ETS exposure in the home and office work environments in young adults. These findings emphasize the need for effective measures in the prevention of involuntary smoking during young adulthood.

Respiratory symptoms in young adults should not be overlooked

The purpose of this study was to examine the relation between development of respiratory symptoms and the rate of change in ventilatory lung function in young adults during a study period of 8 yr. The study population consisted of 391 subjects who were 15 to 40 yr of age at initial examination, when they underwent spirometry and an interviewer-administered ATS-DLD-78-A questionnaire on respiratory health, and who were reexamined 8 yr later. The association between the development of symptoms and the rate of change in FEV1 over time (delta FEV1, ml/yr) was studied in a linear regression model that included the potential confounders and other determinants of the outcome. The presence of modification by such factors as smoking, childhood exposure to environmental tobacco smoke, gender, or atopy was assessed by the significance of interaction terms between potential modifiers and incident symptoms. Subjects who developed wheezing and dyspnea and in whom a doctor diagnosed asthma had a significantly greater average annual change in FEV1 compared with those without respiratory symptoms or asthma (-12.3 ml/yr, SE 5.0; -16.2 ml/yr, SE 5.5; and -42.6 ml/yr, SE 11.5, respectively). When focusing on subjects without a diagnosis of asthma, the associations with appearance of wheezing and dyspnea remained significant. The associations were in general stronger in never smokers compared with smokers and were strongest in ex-smokers. The presence of atopy was a significant modifier, so that in subjects with atopy there was a stronger negative association between the onset of cough and asthma and delta FEV1 than in those without.(ABSTRACT TRUNCATED AT 250 WORDS)