Effects of ambient ozone on respiratory function in healthy adults exercising outdoors

The effect of exposure to ozone (O3) in ambient air on respiratory function was studied in 30 healthy adult nonsmokers engaged in a regular daily program of outdoor exercise in Tuxedo, NY during the summer of 1985. Each subject did the same exercise each day, but exercise intensity and duration varied widely between subjects, with minute ventilation ranging from 20 to 153 L and duration ranging from 15 to 55 min. Spirometry was performed immediately before and after each exercise period. O3 concentrations during exercise ranged from 21 to 124 parts per billion (ppb). All measured functional indexes showed significant (p less than 0.01) O3-associated mean decrements with FVC at -2.1 ml/ppb, FEV1 at -1.4 ml/ppb, PEFR at -9.2 ml/s/ppb, FEF25-75 at -6.0 ml/s/ppb, and FEV1/FVC at -0.038%/ppb. Mean decrements were smaller for 10 subjects with minute ventilations greater than 100 L than for 10 other subjects with minute ventilations between 60 and 100 L or for the 10 subjects with minute ventilations below 60 L. Overall, the functional decrements were similar in magnitude to those we have seen in children engaged in supervised recreational programs in summer camps. For 10 subjects with minute ventilations comparable to those used in controlled 1- and 2-h exposures to O3 in purified air in chambers (50 to 80 L), the effects were about twice as large as those reported for the chamber studies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute lower respiratory illness in childhood as a predictor of lung function and chronic respiratory symptoms

This study investigated the relationship of acute lower respiratory illness (LRI) to level and change in level of forced expiratory volumes in a cohort of 801 children, followed longitudinally for a maximum of 13 yr. The co-occurrence of respiratory illness before 2 yr of age and two or more LRI during a single surveillance year was associated with a 20.3% lower mean cross-sectional level of FEF25-75, and with reduced longitudinal change in level of FEF25-75. The effect of LRI on lung function was uniformly stronger for boys than for girls. Of the children with illness before 2 yr of age and two or more LRI, six of 14 were male asthmatics with mean levels of FEF25-75 that were lower than those of other asthmatic children. Pneumonia and/or hospitalization for respiratory illness prior to the onset of study were associated with lower cross-sectional levels of forced expiratory volumes at entry to the study, even when asthmatics/persistent wheezers were eliminated from the analysis (6.1% lower level of FEV1 for a nonasthmatic boy with previous hospitalization versus a nonasthmatic boy without hospitalization). In the longitudinal analysis, pneumonia and/or hospitalization were associated with slower increase in level of forced expiratory volumes, even after adjusting for "ever diagnosis of asthma/current any wheeze" (starting at the same leve, after eight years a boy with hospitalization would develop a 5.0% lower FEV1 than a boy without hospitalization). Acute LRI also was evaluated as a predictor of chronic respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)     

The relationship between airway responsiveness to histamine and pulmonary function level in a random population sample

The association of nonspecific bronchial responsiveness (BR) with pulmonary function level has been studied in a random population sample of 2,156 male and female subjects 15 to 64 yr of age participating in the Vlagtwedde-Vlaardingen field survey on chronic obstructive pulmonary disease (COPD) being conducted in the Netherlands. About 25% of the subjects responded with a decrease in baseline FEV1 of 10% or more after challenge with histamine in a concentration of 16 mg/ml or less inhaled over 30 s (PC10). In a stratified analysis, pulmonary function level appeared to be associated with BR in a dose-response relationship. The mean %FEV1 was consistently lower in the more responsive subjects. This relationship was confirmed in linear regression analyses, adjusting for age, sex, area of residence, and smoking habits. Exclusion of subjects with %FEV1 less than 80% diminished but did not change the association between FEV1 and BR. The magnitude of the effect of responsiveness on level of pulmonary function was considerable and statistically significant. In the subjects older than 21 yr of age, male responders (PC10 at less than or equal to 16 mg/ml) on average had an adjusted FEV1 of 32.5 centiliters less than nonresponders, and female responders had an adjusted FEV1 of 30.5 centiliters less (p less than 0.001). BR appeared to be an independent predictor of pulmonary function level after adjustment for age, sex, area of residence, respiratory symptom prevalence, and cigarette smoking. The effect of cigarette smoking on pulmonary function level in this population sample was significant only in men older than 21 yr of age.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case-control study of lung cancer and diesel exhaust exposure in railroad workers

A case-control study of deaths among U.S. railroad workers was conducted to test the hypothesis that lung cancer is associated with exposure to diesel exhaust. Employed and retired male workers with greater than or equal to 10 yr of service who were born on or after January 1, 1900 and who died between March 1, 1981 and February 28, 1982 were eligible. We collected 87% of the death certificates from 15,059 deaths reported to the U.S. Railroad Retirement Board (RRB). Cases of lung cancer (1,256) were matched to controls by age (+/- 2.5 yr) and date of death (+/- 31 days). Potential exposure to diesel exhaust was assigned based on an industrial hygiene evaluation of jobs and work areas. Each subject's work history was determined from a yearly job report filed by his employer with the RRB from 1959 until death or retirement. Asbestos exposure prior to 1959 was categorized by the job held in 1959, the end of the steam locomotive era, or by the last job held if retirement occurred before 1959. Smoking histories were obtained by questionnaire from next of kin. Using multiple conditional logistic regression analysis to adjust for smoking and asbestos exposure, workers 64 yr of age or younger at the time of death with work in a diesel exhaust exposed job for 20 yr had a significantly increased relative odds (odds ratio = 1.41, 95% Cl = 1.06, 1.88) of lung cancer. No effect of diesel exhaust exposure was seen in workers 65 yr of age or older because many of these men retired shortly after the transition to diesel-powered locomotives.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prospective Study of Short Stature and Newly Diagnosed Asthma in Women

The authors tested the hypothesis that short stature predicts adult-onset asthma independent of obesity among women in the Nurses' Health Study. Height, weight, and physician-diagnosed asthma were assessed with validated questionnaire items. Proportional hazard models adjusted separately for weight and body mass index. The rate of newly diagnosed asthma was 1.55 times greater in the shortest versus the tallest quintile after adjustment for weight (95% CI, 1.26–1.91). After adjustment for body mass index, the rate ratio was 1.16 (95% CI, 0.94–1.42). Short stature predicted adult-onset asthma in a large cohort of women, but this association was not independent of obesity.     

Oral contraceptive use and risk of melanoma in premenopausal women.

Melanoma has been increasing in white populations. Incidence rates rise steeply in women until about age 50, suggesting oestrogen as a possible risk factor. Oestrogens can increase melanocyte count and melanin content and cause hyperpigmentation of the skin. We examined prospectively the association between oral contraceptive (OC) use and diagnoses of superficial spreading and nodular melanoma among 183,693 premenopausal white women in the Nurses' Health Study (NHS) and the Nurses' Health Study II (NHS II) cohorts. One hundred and forty six cases were confirmed in NHS during follow-up from 1976 to 1994, and 106 cases were confirmed in NHS II from 1989 to 1995. Skin reaction to sun exposure, sunburn history, mole counts, hair colour, family history of melanoma, parity, height and body mass index were also assessed and included in logistic regression models. A significant twofold increase in risk of melanoma (relative risk (RR) = 2.0, 95% confidence interval (CI) 1.2-3.4) was observed among current OC users compared to never users. Risk was further increased among current users with 10 or more years of use (RR = 3.4, 95% CI 1.7-7.0). Risk did not appear elevated among past OC users, even among those with longer durations of use, and risk did not decline linearly with time since last use. In conclusion, risk of premenopausal melanoma may be increased among women who are current OC users, particularly among those with longer durations of use. Further research is needed to determine whether low-dose oestrogen pills in particular are associated with an increase in risk and to describe possible interactions between OC use and sun exposure or other risk factors for melanoma.     

Colorectal neoplasms: accuracy of US in demonstrating the depth of invasion

Six normal and 16 neoplastic colorectal specimens were examined with 8.5-MHz ultrasound (US). An articulated system facilitated precise spatial correlation between US and histologic sections. Images were blindly interpreted and then compared with histologic results. All six normal specimen showed five distinct echo layers and were distinguished from neoplastic specimens by all the observers. The central echogenic layer, corresponding to the submucosa, is useful in determining the depth of origin of a neoplasm and the presence of submucosal invasion. US had an accuracy of 92.5% in demonstrating invasion of the submucosa and 77% for invasion of the muscularis externa. For mucosal neoplasms with invasion through the muscularis externa and extension into the subserosal tissues, nearly 90% of US interpretations were correct. High-frequency US may be useful in determining the depth of invasion of mucosal tumors with respect to the submucosa and in differentiating mucosal from extramural masses.     

Health effects of acid aerosols on North American children: respiratory symptoms.

We examined the respiratory health effects of exposure to acidic air pollution among 13,369 white children 8 to 12 years old from 24 communities in the United States and Canada between 1988 and 1991. Each child's parent or guardian completed a questionnaire. Air quality and meteorology were measured in each community for a 1-year period. We used a two-stage logistic regression model to analyze the data, adjusting for the potential confounding effects of sex, history of allergies, parental asthma, parental education, and current smoking in the home. Children living in the community with the highest levels of particle strong acidity were significantly more likely [odds ratio (OR) = 1.66; 95% confidence interval (CI) 1.11-2.48] to report at least one episode of bronchitis in the past year compared to children living in the least-polluted community. Fine particulate sulfate was also associated with higher reporting of bronchitis (OR = 1.65; 95% CI 1.12-2.42). No other respiratory symptoms were significantly higher in association with any of the air pollutants of interest. No sensitive subgroups were identified. Reported bronchitis, but neither asthma, wheeze, cough, nor phlegm, were associated with levels of particle strong acidity for these children living in a nonurban environment.