Decrements in spirometry values associated with chlorine gassing events and pulp mill work.

In a previous study of older pulp and paper workers in Berlin, New Hampshire, decrements in spirometry results associated with accidental exposures to high levels of irritant gases depended on cumulative levels of pulp mill exposure and cigarette smoking. Many of those subjects were older and retired. A new study was initiated to assess whether gassing events were a problem among current workers. Three hundred white male pulp and paper workers from the mill in Berlin, New Hampshire, were surveyed in 1992. Testing included spirometry and questionnaires. The mean age was 40.4 yr, and the mean tenure with the company was 18.5 yr. A total of 105 of the 300 subjects (35%) reported ever having an episode of high exposure to chlorine gases (i.e., being gassed). The percentage gassed was 51% for pulp mill workers and only 13% for other employees. For subjects with no more than 26 pack-years of cigarette smoking, obstruction (i.e., abnormally low FEV1 and FEV1/FVC) was observed only among those with a history of gassing. Also, the combination of high cigarette smoking (i.e., > 26 pack-years) and gassing had a greater than additive effect on obstruction. These findings suggest that additional controls are needed to minimize the number of gassing events in this and other chemical pulp mills.

Acute effects of summer air pollution on respiratory symptom reporting in children.

A daily diary of respiratory symptoms was collected from the parents of 1,844 school children in six U.S. cities to study the association between ambient air pollution exposures and respiratory illness. A cohort of approximately 300 elementary school children in each of six communities were asked to keep a daily log of the study child's respiratory symptoms for one year. Daily measurements of ambient sulfur dioxide, nitrogen dioxide, ozone, inhalable particles (PM10), respirable particles (PM2.5), light scattering, and sulfate particles were made, along with integrated 24-h measures of aerosol strong acidity. The analyses were limited to the five warm season months between April and August. Significant associations were found between incidence of coughing symptoms and incidence of lower respiratory symptoms and PM10, and a marginally significant association between upper respiratory symptoms and PM10. There was no evidence that other measures of particulate pollution including aerosol acidity were preferable to PM10 in predicting incidence of respiratory symptoms. Significant associations in single pollutant models were also found between sulfur dioxide or ozone and incidence of cough, and between sulfur dioxide and incidence of lower respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

A longitudinal study of the effects of parental smoking on pulmonary function in children 6-18 years.

The association between parental cigarette smoking and children's pulmonary function was investigated in 8,706 nonsmoking white children, followed annually by questionnaire and spirometry between 6 and 18 yr. Exposure to maternal and paternal smoking was each divided into three components: exposure in the first 5 yr of life, cumulative exposure between age 6 and the year prior to each visit; parental smoking status reported at each visit. Regression splines were used to assess the effects of parental smoking on the level and growth rate of pulmonary function adjusting for age, height, city of residence, and parental education. Models best predicting pulmonary function level included current maternal smoking and exposure to maternal smoking in the first 5 yr of life but did not include the other measures of parental smoking. After adjusting for early exposure, current maternal smoking for each pack/d was associated with a reduced level of FEV1 (-0.4%, 95% CI: -0.9, 0.1), FEV1/FVC (-0.6%, 95% CI: -0.9, -0.4), and FEF25-75% (-2.3%, 95% CI: -3.6, -1.0) in children 6 to 10 yr. These effects were slightly smaller in children 11 to 18 yr. Adjusting for current maternal smoking, those exposed to maternal smoking in the first 5 yr of life had higher FVC (+0.5%, 95% CI: -0.1, 1.2) and lower FEV1/FVC (-0.7%, 95% CI: -1.1, -0.4) and FEF25-75% (-2.8%, 95% CI: -4.4, -1.2) than those not exposed in children 6 to 10 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentration of indoor particulate matter as a determinant of respiratory health in children.

The effect of passive exposure to environmental tobacco smoke in the home on respiratory symptoms and pulmonary function level was studied in a cohort of white children aged 7-11 years examined in six US cities in 1983-1988. For 2,994 children with questionnaire-based exposure data, passive exposure to an additional pack of cigarettes smoked daily in the home was associated with increased incidence of lower respiratory symptoms (odds ratio (OR) = 1.25, 95% confidence interval (CI) 1.10-1.42). For 1,237 children with two consecutive 1-week measurements in both winter and summer, a 30-micrograms/m3 increase in the annual average indoor concentration of respirable particulate matter with an aerodynamic diameter of < 2.5 microns (PM2.5)--that is, approximately the effect of one pack per day of smoking--was marginally associated with an increased cumulative incidence of lower respiratory symptoms (OR = 1.13, 95% CI 0.99-1.30). Indoor measurements of PM2.5 showed no direct association with children's pulmonary function measurements. Children whose mothers smoked during pregnancy showed a reduction of -2.6% (95% CI -5.2% to 0.1%) in volume-adjusted forced expiratory flow rates. Therefore, current indoor exposure to PM2.5 increases the cumulative incidence of lower respiratory symptoms, but is only weakly associated with decreased pulmonary function level in preadolescent children.

Gender- and race-specific effects of asthma and wheeze on level and growth of lung function in children in six U.S. cities.

The gender-and race-specific effects of asthma/wheeze on pulmonary function level and annual growth velocity were studied in a cohort of 10,792 white and 944 black children 6 to 18 yr of age, examined annually between 1974 and 1989 in six U.S. cities. In comparison with white boys who never reported asthma or wheeze, FEV1 levels were 5.7% lower and FEF 25-75 levels were 16.9% lower for white boys with a diagnosis of asthma who reported wheeze symptoms in the past year. White girls with asthma and wheeze had FEV1 levels that were 3.4% lower and FEF25-75 levels that were 13.6% lower than white girls with never-asthma/wheeze. Asthma with wheeze was associated with a greater percent deficit in FEV1 level in boys than in girls (p < 0.01) and, particularly in preadolescence, with a significant percent increment in FVC level (1.6%) for girls but not for boys. The diagnosis of asthma with or without wheeze in the past year was associated with a greater deficit in level of lung function than the reporting of wheeze symptoms in a child without the diagnosis of asthma. The prevalence of asthma and wheeze was higher among blacks, but no race differences were found in the effects of asthma or wheeze on level of FEV1 and FEF25-75. Compared with white adolescent female ever asthmatics with no medication use, FEV1 level was 5.8% lower for those with routine medication use and 7.8% lower for those with routine and additional medication use. Although white girls with wheeze but no diagnosis of asthma had slightly slower growth of FEV1 (0.3% per year) than did white girls without asthma or wheeze, children with asthma did not have slower annual growth in percent terms. In absolute terms, growth of FEV1 was 14.7 ml/yr and FEF25-75 was 47 ml/s/yr slower for asthmatic white boys with wheeze than for those without asthma; for girls with asthma and wheeze growth of FEF25-75 was 29 ml/s/yr slower. We conclude that in absolute terms, but not in percent terms, the pulmonary function deficits associated with asthma and wheeze increase throughout childhood. In the preadolescent and adolescent years, the mechanical properties of the lungs and the inflammatory process in asthmatics may differ by gender, leading to gender differences in their pulmonary function. We also conclude that lung function may not return to normal, even when asthmatics become asymptomatic.

Pulmonary function growth velocity in children 6 to 18 years of age.

Pulmonary function growth rate varies with a child's stage of growth. Since attained pulmonary function reflects the cumulative effects of growth, insults, and repair, rate of growth may be a more sensitive indicator of a child's current pulmonary health status. The sample for analyses included 2,478 white boys and 2,785 white girls followed annually by questionnaire and spirometry. Empirically derived annual growth velocities, peak velocity (Vpk), and age at which peak velocity occurred (Agepk) were determined for height, FVC, FEV1, and FEF25-75 for each child. Mean velocity curves for height, FVC, FEV1, and FEF25-75, stratified by sex and Agepk of height (an indicator for early, middle, or late maturity) were produced as a function of age. The differences between Agepk of FVC, FEV1, and FEF25-75 and Agepk of height (i.e., the lag period) were compared by sex and by the indicator of maturity. Linear regression analyses were performed to investigate associations between Vpk and Agepk of height, as well as between the lag period and Agepk of height. As is generally observed in height growth, there were considerable variations in the age of onset and magnitudes of the adolescent growth spurts of the pulmonary function parameters both between sexes and among children of the same sex. The duration of adolescent growth spurt appeared to be similar for all children, regardless of early, middle, or late maturity. Thus, those who matured earlier had shorter total growth periods than those who matured later. On the other hand, early maturers had greater growth velocities during preadolescence and greater adolescent Vpk than later maturers.(ABSTRACT TRUNCATED AT 250 WORDS)

An association between air pollution and mortality in six U.S. cities.

BACKGROUND: Recent studies have reported associations between particulate air pollution and daily mortality rates. Population-based, cross-sectional studies of metropolitan areas in the United States have also found associations between particulate air pollution and annual mortality rates, but these studies have been criticized, in part because they did not directly control for cigarette smoking and other health risks. METHODS: In this prospective cohort study, we estimated the effects of air pollution on mortality, while controlling for individual risk factors. Survival analysis, including Cox proportional-hazards regression modeling, was conducted with data from a 14-to-16-year mortality follow-up of 8111 adults in six U.S. cities. RESULTS: Mortality rates were most strongly associated with cigarette smoking. After adjusting for smoking and other risk factors, we observed statistically significant and robust associations between air pollution and mortality. The adjusted mortality-rate ratio for the most polluted of the cities as compared with the least polluted was 1.26 (95 percent confidence interval, 1.08 to 1.47). Air pollution was positively associated with death from lung cancer and cardiopulmonary disease but not with death from other causes considered together. Mortality was most strongly associated with air pollution with fine particulates, including sulfates. CONCLUSIONS: Although the effects of other, unmeasured risk factors cannot be excluded with certainty, these results suggest that fine-particulate air pollution, or a more complex pollution mixture associated with fine particulate matter, contributes to excess mortality in certain U.S. cities.

Race and gender differences in respiratory illness prevalence and their relationship to environmental exposures in children 7 to 14 years of age.

Race and gender differences in respiratory illness prevalence rates were assessed in a cohort of 8,322 white children and 1,056 black children 7 to 14 yr of age from four U.S. cities. Boys had higher rates of wheeze, asthma, cough, phlegm, and bronchitis than girls. Black children had higher rates of persistent wheeze, shortness of breath with wheeze, asthma, chronic cough, and chronic phlegm than white children. We examined whether the racial disparity in respiratory illness prevalence could be accounted for by environmental exposures and socioeconomic factors. The proportion of families without a parent who had graduated from high school was higher for blacks than for whites, as was the proportion of single-parent households. Black children took up smoking less frequently; their mothers smoked fewer cigarettes. Personal and maternal smoking predicted higher rates of persistent wheeze, chronic cough, chronic phlegm, and chest illness. The relative odds for persistent wheeze were 1.34 (1.07, 1.69) for smoking children compared with nonsmoking children. The relative odds for persistent wheeze were 1.35 (1.13, 1.60) for children whose mother smoked > 30 cigarettes per day versus children with no maternal smoke exposure. Other predictors of respiratory illnesses included parental respiratory illness, parental education, only-child status, single-parent household, air conditioner use, and body mass index. Nevertheless, adjustment for socioeconomic factors, environmental exposures, and body habitus did not significantly reduce the excess respiratory illness prevalence observed among black children. The adjusted relative odds were 1.47 (1.25, 1.74) for persistent wheeze and 1.57 (1.17, 2.10) for asthma for black children versus white children.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidental gassing incidents and the pulmonary function of pulp mill workers.

A previous investigation of white male workers from a pulp and paper company in Berlin, New Hampshire identified decrements in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) associated with work in the pulping operations. A subset of those data were reanalyzed to consider another type of occupational exposure: gassing incidents in which workers were accidentally exposed to high levels of irritant gases, such as chlorine (Cl2) or sulfur dioxide (SO2). A total of 230 current and former workers (all white male) were included in the analysis. Gassing events were more common among pulp mill workers (34%) than workers from other parts of the company (9%). Average changes of -291.9 ml in FEV1 (p < 0.05) and -5.00% in FEV1/FVC (p < 0.05) were associated with gassing. Also, in each of the regression models for the three measures of pulmonary function (FEV1, FVC, and FEV1/FVC), there was a three-way interaction of cumulative smoking, cumulative pulp mill exposure, and gassing. The greatest decreases in FEV1 and FEV1/FVC associated with gassing were evident in the dual smoking/pulp mill exposure categories of none/high and high/none. The changes in pulmonary function appeared to be chronic effects that persisted beyond cessation of the exposure. Only limited information about the gassing episodes was requested from the subjects, and future research is discussed that will address some of the limitations.

Pulmonary function between 6 and 18 years of age.

Pulmonary function of children aged 6-18 years is described based on 82,462 annual measurements of forced vital capacity (FVC), forced expired volume in 1 second (FEV1), and forced expiratory flow between 25% and 75% of FVC (FEF25-75%) from 11,630 white children and 989 black children. Median height, FVC, FEV1, FEV1/FVC, and FEF25-75% for each 3 months of age are compared among race and sex subgroups. Race- and sex-specific percentile distributions of FVC, FEV1, FEV1/FVC, and FEF25-75% are presented for each centimeter of height (growth curves). For the same height, boys have greater lung function values than girls, and whites have greater ones than blacks. Lung function increases linearly with age until the adolescent growth spurt at about age 10 years in girls and 12 in boys. The pulmonary function vs. height relationship shifts with age during adolescence. Thus, a single equation or the pulmonary function-height growth chart alone does not completely describe growth during the complex adolescent period. Nevertheless, race- and sex-specific growth curves of pulmonary function vs. height make it easy to display and evaluate repeated measures of pulmonary function for an individual child. Race-, sex-, and age-specific regression equations based on height are provided, which permit the evaluation of growth during adolescence with improved accuracy and, more importantly, in comparison with previous observations for the same child.

Effects of cigarette smoking on rate of loss of pulmonary function in adults: a longitudinal assessment.

Data from a random sample of 8,191 men and women selected in six U.S. cities and examined on three occasions over a 6-yr follow-up period were analyzed by longitudinal methods to describe the effects of smoking history and current smoking behavior on rate of loss of pulmonary function during adult life. Former smokers had age- and height-adjusted rates of decline (34.3 ml/yr for men and 29.6 ml/yr for women) comparable with those of never smokers (37.8 ml/yr for men and 29.0 ml/yr for women) but much smaller than those of continuing smokers (52.9 ml/yr for men and 38.0 ml/yr for women). The accelerated rate of loss of FEV1 among smokers depended linearly on the number of cigarettes smoked per day during the interval between examinations. The estimated increase in rate of loss associated with smoking was 12.6 ml/yr per pack/day for men and 7.2 ml/yr per pack/day for women. These longitudinal estimates of the effects of smoking were approximately 50% larger than estimates obtained from cross-sectional analysis of the initial pulmonary function examination. Men who started smoking had accelerated rates of loss (55.9 ml/yr) as did women (43.1 ml/yr). Smokers who stopped smoking between examinations had reduced declines (41.2 ml/yr for men and 28.7 ml/yr for women) compared with continuing smokers. The age-specific rates of loss suggest that the benefits of cessation may be greatest among the youngest smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

Longitudinal lung function decline in subjects with respiratory symptoms.

The relation of respiratory symptoms and lung function has not been extensively investigated. To determine better the rate of FEV1 decline in subjects reporting persistent wheeze, chronic cough, chronic phlegm, and/or dyspnea, longitudinal data from an adult population sample of 3,948 subjects (1,757 men; 2,191 women) followed for 12 yr were analyzed. At the initial and subsequent follow-up visits, subjects completed a standardized respiratory questionnaire and performed spirometry using the same methods and spirometers. Subjects were categorized based on the presence or absence of self-reported respiratory symptoms (persistent wheeze, chronic cough, chronic phlegm, or shortness of breath) at the initial visit. Six-specific linear regression models were fitted to determine the effect of these respiratory symptoms on lung function. In both men and women, reporting of any respiratory symptoms was associated with both a reduction in initial lung function and more rapid decline in height-adjusted FEV1. Furthermore, after adjustment for height, age, and cigarette smoking, men with cough or phlegm and women with cough alone showed accelerated loss in FEV1. Clinicians should be aware of the predictive value of these respiratory symptoms, because therapeutic intervention may modify the associated decline in lung function.

Association of indoor nitrogen dioxide with respiratory symptoms and pulmonary function in children.

The effect of indoor nitrogen dioxide on the cumulative incidence of respiratory symptoms and pulmonary function level was studied in a cohort of 1,567 white children aged 7-11 years examined in six US cities from 1983 through 1988. Week-long measurements of nitrogen dioxide were obtained at three indoor locations over 2 consecutive weeks in both the winter and the summer months. The household annual average nitrogen dioxide concentration was modeled as a continuous variable and as four ordered categories. Multiple logistic regression analysis of symptom reports from a questionnaire administered after indoor monitoring showed that a 15-ppb increase in the household annual nitrogen dioxide mean was associated with an increased cumulative incidence of lower respiratory symptoms (odds ratio (OR) = 1.4, 95% confidence interval (95% Cl) 1.1-1.7). The response variable indicated the report of one or more of the following symptoms: attacks of shortness of breath with wheeze, chronic wheeze, chronic cough, chronic phlegm, or bronchitis. Girls showed a stronger association (OR = 1.7, 95% Cl 1.3-2.2) than did boys (OR = 1.2, 95% Cl 0.9-1.5). An analysis of pulmonary function measurements showed no consistent effect of nitrogen dioxide. These results are consistent with earlier reports based on categorical indicators of household nitrogen dioxide sources and provide a more specific association with nitrogen dioxide as measured in children's homes.

Sensitive subgroups and normal variation in pulmonary function response to air pollution episodes.

The Clean Air Act requires that sensitive subgroups of exposed populations be protected from adverse health effects of air pollution exposure. Hence, data suggesting the existence of sensitive subgroups can have an important impact on regulatory decisions. Some investigators have interpreted differences among individuals in observed pulmonary function response to air pollution episodes as evidence that individuals differ in their sensitivity. An alternative explanation is that the differences are due entirely to normal variation in repeated pulmonary function measurements. This paper investigates this question by reanalyzing data from three studies of children exposed to air pollution episodes to determine whether the observed variability in pulmonary function response indicates differences in sensitivity or natural interoccasion variability. One study investigated exposures to total suspended particulates (TSP), the other two investigated exposure to ozone. In all studies, each child's response to air pollution exposures was summarized by regressing that child's set of pulmonary function measurements on the air pollution concentrations on the day or days before measurement. The within-child and between-child variances of these slopes were used to test the hypothesis of variable sensitivity. Regression slopes did not vary significantly among children exposed to episodes of high TSP concentration, but there was evidence of heterogeneity in both studies of ozone exposures. The finding of heterogeneous response to ozone exposure is consistent with the epidemiologic and chamber studies of ozone exposures, but the lack of evidence for heterogeneous response to TSP exposures implies that observed variation in response can be explained by sampling variability rather than the presence of sensitive subgroup.

Longitudinal and cross-sectional estimates of pulmonary function decline in never-smoking adults.

This paper describes methods for simultaneous cross-sectional and longitudinal analysis of repeated measurements obtained in cohort studies with regular examination schedules, then uses these methods to describe age-related changes in pulmonary function level among nonsmoking participants in the Six Cities Study, a longitudinal study of air pollution and respiratory health conducted between 1974 and 1983 in Watertown, Massachusetts; Kingston and Harriman, Tennessee; St. Louis, Missouri; Steubenville, Ohio; Portage, Wisconsin; and Topeka, Kansas. The subjects, initially aged 25-74, were examined on three occasions at 3-year intervals. Individual rates of loss increased more rapidly with age than predicted from the cross-sectional model. For example, for a male of height 1.75 m, the cross-sectional model predicted an increase in the annual rate of loss of FEV1 from 23.7 ml/yr at age 25 to 39.0 ml/yr at age 75, while the longitudinal model gave rates of loss increasing from 12.9 ml/yr at age 25 to 58.2 ml/yr at age 75. These results contrast with those of other studies comparing longitudinal and cross-sectional estimates of pulmonary function loss.

Pulmonary function among pulp and paper workers in Berlin, New Hampshire.

Pulmonary function was studied among pulp and paper workers from a production facility in New Hampshire. Subjects were first tested in the 1960s and then surveyed at regular intervals up to 1985. The current study examined results for the 339 subjects who participated in at least one of the two most recent follow up surveys in 1979 and 1985. For the 171 subjects who were tested in both surveys, the pulmonary function values were higher and the effect of pulp mill work was diminished compared with the findings for the 168 subjects who were tested in just one of the two surveys. To avoid the loss of less healthy subjects and the subsequent bias in effect estimate, the 1985 data were analysed cross sectionally with the inclusion of data from 1979 for those subjects who had not been followed up in the last survey. The subjects with work experience in the pulp mill had mean levels of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) lower than those of unexposed subjects who had never worked in the pulp or paper production areas. Based on parameter estimates from regression analysis, each year of employment in the pulp operation was associated with a -5.8 ml change in FEV1 (p = 0.08) and a -7.2 ml change in FVC (p = 0.04). Ninety one per cent of the subjects with pulp mill experience had terminated employment in that area of the company, so the association with decreased lung function appears to be a non-reversible effect that persisted after the cessation of exposure.

Home dampness and respiratory morbidity in children.

This study examined the relationship between measures of home dampness and respiratory illness and symptoms in a cohort of 4,625 eight- to 12-yr-old children living in six U.S. cities. Home dampness was characterized from questionnaire reports of mold or mildew inside the home, water damage to the home, and the occurrence of water on the basement floor. Symptoms of respiratory and other illness were collected by questionnaire. Pulmonary function was measured by spirometry. Signs of home dampness were reported in a large proportion of the homes. In five of the six cities, one or more of the dampness indicators were reported in more than 50% of the homes. The association between measures of home dampness and both respiratory symptoms and other non-chest illness was both strong and consistent. Odds ratios for molds varied from 1.27 to 2.12, and for dampness from 1.23 to 2.16 after adjustment for maternal smoking, age, gender, city of residence, and parental education. The relationship between home dampness and pulmonary function was weak, with an estimated mean reduction of 1.0% in FEF25-75 associated with dampness and 1.6% with molds. We conclude that dampness in the home is common in many areas of the United States and that home dampness is a strong predictor of symptoms of respiratory and other illness symptoms among 8- to 12-yr-old children.

Mortality among pulp and paper workers in Berlin, New Hampshire.

Cause specific mortality was analysed among 883 white male workers from a paper company in Berlin, New Hampshire. Subjects were assigned to different exposure groups on the basis of their having worked in the pulp mill, the paper mill, or elsewhere in the paper company. A standardised mortality ratio (SMR) analysis was used to compare death rates for each of the exposure groups with United States national rates. For all the subjects, deaths due to all causes, all malignant neoplasms, and lung cancer were close to the number expected and excesses were noted for cancers of the digestive system and leukaemia. Among pulp mill workers, the number of cancers of the digestive system was raised and the SMR for pancreatic cancer was especially high (SMR = 305, 95% CI = 98-712). Among paper mill workers, more deaths were due to leukaemia and cancers of the digestive system than expected. These results are consistent with the findings from other studies that employment in pulp and paper mills is associated with excess mortality due to digestive and lymphopoietic cancers.

Chronic obstructive pulmonary disease mortality in six U.S. cities.

Results are presented from a 9- to 12-yr mortality follow-up of 8,427 white adults in six U.S. cities between 25 and 74 yr of age at enrollment. Survival analyses were performed for all causes on 941 confirmed deaths, and for specific primary causes for the subset of 851 death with death certificates. Relative level of FEV1 compared with predicted was a strong predictor of sex-specific chronic obstructive pulmonary disease (COPD), cardiovascular (CV), and all-cause mortality, even after adjusting for age, respiratory symptoms, and smoking. Even in this relatively large cohort, the total number of respiratory deaths was small, and no trend in COPD mortality could be determined over the period of study.