We conducted a longitudinal study to determine the annual rate decline in pulmonary function measurements in male swine confinement workers. For comparison, a grain farming group and a nonfarming rural-dwelling control group were also chosen for the longitudinal study. Two hundred seventeen swine confinement workers, 218 grain farmers, and 179 nonfarming control subjects had valid pulmonary function measurements at the baseline observation conducted in 1990 to 1991 and at the second observation conducted in 1994 to 1995. The swine confinement workers were younger (mean age=38.3+/-11.7 [SD] years) than the nonfarming control subjects (42.6+/-10.4 years) and the grain farmers (44.5+/-11.9 years). When stratified by age, nonfarming control subjects had the lowest mean annual rate decline in FEV1 and FVC in all age categories. The swine confinement workers had the largest annual rate decline in FEV1 and FVC, and this was most obvious in the middle age categories. After controlling for age, height, smoking, and baseline pulmonary function, swine confinement workers had excess annual decline of 26.1 mL in FEV1 (p=0.0005), 33.5 mL in FVC (p=0.0002), and 42.0 mL/s in forced expiratory flow between 25% and 75% of FVC (FEF[25-75%]) (p=0.02) over nonfarming control subjects. Grain farmers had excess annual decline of 16.4 mL in FEV1 (p=0.03), 26.7 mL in FVC (p=0.002), and 11.2 mL/s in FEF(25-75%) (p=0.38) over control subjects. These findings suggest that workers engaged in the swine industry and grain farmers appear prone to accelerated yearly losses in lung function and may therefore be at risk for the future development of chronic airflow limitation.
Three surveys (1969/1970, 1979/1980 and 1989/1990) have examined the impact of acculturation to a sedentary lifestyle on the pulmonary function of a circumpolar native Inuit community. The sample comprised more than 50% of those aged 20-60 yrs, most recently 119 males and 92 females. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximal mid-expiratory flow (MMEF) were measured by standard spirometric techniques, and information was obtained on smoking habits and health. Multiple regression equations showed that lung function was affected by height and age, but usually not by age squared. Cross-sectional age coefficients for FVC and FEV1 increased over the period 1969/1970 to 1989/1990. Parallel longitudinal trends were seen in FEV1 (males only). Multiple analysis of variance (MANOVA) showed age-decade*cohort effects for FVC and FEV1 (males but not females). Almost all of the population now smoke (mean +/- SD males 13 +/- 8 cigarettes.day-1; females 11 +/- 7 cigarettes.day-1). However, smoking bears little relationship to lung function perhaps due to limited variance in consumption. About a third of the community have physician-diagnosed and/or radiographically visible chest disease, but with little effect upon pulmonary function. We conclude that an apparent secular trend to a faster ageing of lung function in men is not explained by disease or domestic air pollution. Possible factors include increased lung volumes in young adults, greater pack-years of cigarette exposure, nonspecific respiratory disease, increased inspiration of cold air or altered chest mechanics due to operation of high-speed snowmobiles, and loss of physical fitness.
The vital capacity in the 11- and 14-year old boys and 11- and 13-year old girls examined in 1996 to 1999 significantly reduced as compared in the children of the same age. The significant increase in the vital capacity in 15-16-old girls examined in 1996-1999 is due to that in their height, as compared with these indices in those examined in 1976 (by 4.64 and 4.87, respectively).
This study was designed to examine differences in the respiratory health status of preadolescent school children, aged 7-11 years, who resided in 10 rural Canadian communities areas of moderate and low exposure to regional sulfate and ozone pollution. Five of the communities were located in central Saskatchewan, a low-exposure region, and five were located in southwestern Ontario, an area with moderately elevated exposures resulting from long-range atmospheric transport of polluted air masses. In this cross-sectional study, the child's respiratory symptoms and illness history were evaluated using a parent-completed questionnaire, administered in September 1985. Respiratory function was assessed once for each child in the schools between October 1985 and March 1986, by the measurement of pulmonary function for forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1.0), peak expiratory flow rate (PEFR), mean forced expiratory flow rate during the middle half of the FVC curve (FEF25-75), and maximal expiratory flow at 50% of the expired vital capacity (V50max). The 1986 annual mean of the 1-hr daily maxima of ozone was higher in Ontario (46.3 ppb) than in Saskatchewan (34.1 ppb), with 90th percentile concentrations of 80 ppb in Ontario and 47 ppb in Saskatchewan. Summertime 1-hr daily maxima means were 69.0 ppb in Ontario and 36.1 ppb in Saskatchewan. Annual mean and 90th percentile concentrations of inhalable sulfates were three times higher in Ontario than in Saskatchewan; there were no significant differences in levels of inhalable particles (PM10) or particulate nitrates. Levels of sulfur dioxide (SO2) and nitrogen dioxide (NO2) were low in both regions. After controlling for the effects of age, sex, parental smoking, parental education, and gas cooking, no significant regional differences were observed in rates of chronic cough or phlegm, persistent wheeze, current asthma, bronchitis in the past year, or any chest illness that kept the child at home for 3 or more consecutive days during the previous year. Children living in southwestern Ontario had statistically significant (P 0.05).
To determine whether persons with intermediate value alpha1-antitrypsin phenotypes living in a polluted environment manifest significant abnormalities in lung function, a study was undertaken of an age-, sex- and smoking-stratified sample of 391 persons from the town of Fort Frances, Ont., which has elevated values of total dustfall, suspended particulates and hydrogen sulfide. Indices of pulmonary function were derived from the maximum expiratory flow and the single breath expiratory flow and the single breath expiratory nitrogen washout curves. The percentage frequency of the M, MS and MZ pheontypes was 91.7, 7.3 and 0.8, respectively. There was no significant difference between the M and MS groups as indicated by the nitrogen washout curve and maximum expiratory flow curve. There was no significant difference between the three MZ subjects and the M group. In both M and MS groups smokers displayed evidence of airflow obstruction when compared with nonsmokers. It would appear that, when compared with M subjects, persons with the MS phenotype living in a moderately polluted area show no changes in indicators of pulmonary function, including tests of early airway disease, that cannot be attributed to their smoking habit.
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Anticipation before the start of exercise may influence the cardiopulmonary responses during exercise. If anticipation influences the responses differently with maximal and submaximal exercises, normative values for submaximal responses will not be comparable unless exercise has been continued to the same end point.
Twelve healthy subjects (five men) aged 18-27 years had a maximal exercise test and a submaximal exercise test on a cycle ergometer on different days and in random order. They were not aware of the specific purpose of the study and were informed 15 min before the tests whether it should be maximal or submaximal. Workload increased with 15 W min(-1) until exhaustion or to 80% of predicted maximal heart rate (HR). HR, oxygen uptake (VO(2)), carbon dioxide production (VCO(2)), minute ventilation (V(E)) and tidal volume (V(T)) were averaged over 20 s intervals. Linear regression of the HR-VO(2) relationship and quadratic regression of the V(T)-V(E) relationship were performed for each individual, and the regression coefficients for maximal and submaximal tests were compared.
The regression models described the V(T)-V(E) responses with a R(2) > 0.85 in 23 of 24 tests, and the HR-VO(2) responses with a R(2) > 0.90 in all tests. The regression coefficients of the relationships were not significantly different with maximal and submaximal exercises.
Anticipation appears not to influence the responses to progressive maximal and submaximal exercise tests with the same rate of increase in load. Normative values at submaximal exercise levels are not influenced by the targeted end point of exercise.
K.G. Jebsen Center for Exercise in Medicine, Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU, Norwegian University of Science and Technology, Trondheim, Norway. firstname.lastname@example.org.
Although dynamic lung volume is not considered a limiting factor of peak oxygen uptake (VO2peak) in healthy subjects, an association between forced expiratory lung volume in one second (FEV1) and VO2peak has been reported in a healthy population aged 69 - 77?years. We hypothesized that a corresponding association could be found in a healthy general population including young and middle-aged subjects.
In a population-based study in Norway, we investigated the association between FEV1 above the lower limit of normal (LLN) and VO2peak using linear regression and assessed the ventilatory reserve (VR) in healthy subjects aged 20 - 79?years (n?=?741).
On average, one standard deviation (SD) increase in FEV1 was associated with 1.2?ml/kg/min (95% CI 0.7 - 1.6) higher VO2peak. The association did not differ statistically by sex (p-value for interaction?=?0.16) and was similar (0.9?ml/kg/min, 95% CI 0.2 - 1.5) in a sensitivity analysis including only never-smokers (n?=?376). In subjects below and above 45?years of age, corresponding estimates were 1.2?ml/kg/min (95% CI 0.5 - 1.8) and 1.2?ml/kg/min (95% CI 0.5 - 1.9), respectively. Preserved VR (= 20%) was observed in 66.6% of men and 86.4% of women.
Normal dynamic lung volume, defined as FEV1 above LLN, was positively associated with VO2peak in both men and women, in never-smokers and in subjects below and above 45?years of age. The majority of subjects had preserved VR, and the results suggest that FEV1 within normal limits may influence VO2peak in healthy subjects even when no ventilatory limitation to exercise is evident.
OBJECTIVE: To estimate the association between level of physical activity in 1984-1986 and 1995-1997 and lung function in 1995-1997 among Norwegian men and women aged 28-80 years. DESIGN: In 1984-1986 and 1995-1997, all residents of Nord-Trøndelag County, Norway, aged > or =20 years were invited to participate in the Nord-Trøndelag Health Studies. These analyses included a sample that took part in both studies and underwent spirometry (n = 8047). We used linear regression models adjusting for potential confounders stratified by sex and age groups (28-49 years, 50-69 years and > or =70 years) to estimate the association between forced expiratory volume in 1 second (FEV1) and physical activity. RESULTS: Men and women who were physically active in 1985 and 1995 had the highest lung function in both sexes and in all age groups. The reduction in FEV1 ranged from 20 ml to 170 ml, similar to 1-7% of predicted values dependent on physical activity level. Lung function was also associated with body mass index (BMI), height, smoking and subjective health. CONCLUSIONS: The findings show that a high level of physical activity corresponds to about 3-5 years of normal decline in FEV1 (30 ml/year), and may therefore overcome the disadvantages of a decline in FEV1 from increasing age.
Although reduced function of the respiratory system limits peak oxygen uptake in diseases affecting the lungs or airways, the healthy respiratory system is thought to have a spare capacity for oxygen transport and uptake, and is not considered a limiting factor for peak oxygen uptake in healthy people. However, lung function declines with age and could theoretically limit peak oxygen uptake in elderly. We examined the association between peak oxygen uptake and lung function indices in an elderly population with the hypothesis that lung function indices would be associated with VO2peak up to a threshold value situated above the lower limits of normal lung function for our population.
Spirometry, gas diffusion tests and incremental work tests were performed in 1443 subjects (714 women) aged 69-77 years. Association between lung function indices and peak oxygen uptake was studied with hockey-stick regression.
Forced expiratory volume in 1 s (FEV1) had a positive association with peak oxygen uptake up to, but not above, a threshold value of 2.86 l for men, and 2.13 l for women (lower limit of normal 2.73 and 1.77 l respectively). A corresponding threshold was found for diffusing capacity of the lung for carbon monoxide (DLCO) for men at 9.18 mmol/min/kPa (lower limit of normal 6.84 mmol/min/kPa). DLCO for women and DLCO divided by alveolar volume (DLCO/VA) for both sexes had a significant linear relationship to VO2peak (p