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.
The influence of acculturation to a sedentary lifestyle upon the growth and development of lung volumes has been studied in Inuit children aged 9-19 years. Surveys were conducted in the circumpolar community of Igloolik (69 degrees 40'N, 81 degrees W) in 1969/70, 1979/80 and 1989/90. Over this period, the children showed little change of height or body mass at any given age, but a progressive loss of what initially had been a high level of health-related fitness. The sample for each survey comprised about 70% of children in the chosen age range: in the most recent study 87 males and 65 females. Respiratory data included forced vital capacity, one-second forced expiratory volume, maximal mid-expiratory flow rate (second and third surveys only), smoking habits and respiratory health. In each of the 3 surveys, many of the older children in the community were regular smokers. The average cigarette consumption currently rises progressively to 13 +/- 8 cigarettes/day in 87% of males and 11 +/- 7 cigarettes/day in 95% of females over 17 years of age. Nevertheless, lung volumes show the anticipated increase as a logarithmic function of stature. Furthermore, statistically fitted curves show only minor inter-survey differences in volumes for a given standing height. We thus conclude that the deterioration in other aspects of health-related fitness has not yet influenced the growth and development of respiratory function within this Inuit population.
Psychophysiology Laboratory, State Research Institute of Physiology, Siberian Branch, Russian Academy of Medical Sciences, 4 Timakov Street, 630117, Novosibirsk, Russia.
The aim of the present work was to identify possible associations between individual balances in the activity of the positive and negative reinforcement motivation systems using a method based on emotional modulation of the startle reaction (EMSR) by motivationally significant emotionally positive and negative contextual visual stimuli and measures of cardiovascular system activity. Studies were performed using healthy males (mean age 30.29 +/- 9.8 years) with normal and first-episode excessive increases in arterial blood pressure (systolic blood pressure to greater than 140 mmHg, diastolic to greater than 90 mmHg). Cluster analysis of EMSR data identified groups of individuals with different activity profiles for the positive and negative reinforcement systems. Groups of subjects with changes in the balance of activity towards a lower level of positive reinforcement system activity (smaller startle reflexes to positive contextual stimuli) or a higher level of negative reinforcement system activity (larger startle reactions to threatening contextual stimuli) showed significantly greater baseline SBP and DBP. The possible mechanisms of the modulatory influences of the balance of system activities on autonomic vascular regulatory processes are discussed.
The purpose of this study was to compare the maximal oxygen uptake (VO2max) in 18-19-year-old Norwegian men from 1980 to 1985 and 2002. In addition, we investigated the relationship between VO2max and education and smoking habits in the sample from 2002. From 1980 to 1985, VO2max was predicted using the Astrand-Rhyming bicycle test for 183 610 eighteen-year-old Norwegian men (91% of the male Norwegian population in this age group). In 2002, the same test was performed on a representative sample of the same age population (N=1028). VO2max (mL x kg(-1)x min(-1)), decreased by 8%, body weight increased by 7% and body mass index (BMI) increased by 6% over the approximately 20-year period (P
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 test of single-breath diffusing capacity for carbon monoxide (DLCO) has been widely used in population surveys. However, little is known about the effect of meeting or failing to meet the criteria for acceptability of this test. The American Thoracic Society (ATS) recommends a breathholding time of 9 to 11 s, two measurements within +/- 10% or 3 ml CO(STPD)/min/mm Hg of the average DLCO, and an inspiratory vital capacity (IVC) of at least 90% of the largest previously measured forced vital capacity (FVC) as criteria for this test. The objective of the present study was to examine the extent to which these criteria were met in a community study. To do this, a random sample of 3,740 persons, aged 15 to 70 yr, of the general population of the city of Bergen and 11 surrounding municipalities on the southwest coast of Norway were enrolled in a two-phase cross-sectional study. In the second phase, a stratified sample (n = 1,512) of the respondents to the postal questionnaire used for recruitment for the study (n = 3,370) were invited to a clinical and respiratory physiologic examination that included the DLCO test. The attendance rate was 84% (1,275 of 1,512). In the examination, all subjects were able to maintain a breathholding time of 9 to 11 s, and 98% had two DLCO values within +/- 10% or 3 ml CO(STPD)/min/mm Hg of the average DLCO. The criterion of an IVC of at least 90% of FVC in the two tests was met by 68% of the subjects. Younger age was an independent predictor of failure to meet the required criteria. Thus, only two-thirds of the participants fulfilled all of the ATS criteria for the DLCO test, the main reason for failure being an IVC of less than 90% FVC. This should not necessarily lead to the exclusion from further analysis of those failing to meet this criterion.
Are symptoms of obstructive sleep apnoea syndrome related to bronchitic symptoms or lung function impairment? Report from the Obstructive Lung Disease in Northern Sweden Study.
To investigate whether the high prevalence of symptoms related to obstructive sleep apnoea syndrome (OSAS) in a bronchitic cohort is correlated with the bronchitic symptoms or lung function impairment we examined two cohorts with bronchitic symptoms (n = 357 and 82) and a reference group who had reported no respiratory symptoms in a previous survey in 1986 (n = 140). The study was a part of the Obstructive Lung Disease in Northern Sweden Study and included clinical examination and lung function tests. Although lung function measured as FEV1 percentage predicted was correlated with bronchitic symptoms we found that bronchitic symptoms and body mass index but not lung function impairment were correlated with symptoms related to obstructive sleep apnoea. According to our findings it was the various bronchitic symptoms such as longstanding cough, wheezing, sputum production and chronic productive cough that were correlated with OSAS symptoms. This might be due to increased upper airway swelling or increased upper airway resistance, and lung function impairment does not seem to be responsible for the high prevalence of symptoms related to obstructive sleep apnoea in this bronchitic cohort.
Doppler indices of left ventricular diastolic filling are associated with various cardiac and extracardiac factors. Afterload is one of the extracardiac factors influencing left ventricular diastolic filling. The distensibility of the great arteries is one of the components of afterload. In this study, the relation between Doppler indices of left ventricular filling and the distensibility of the common carotid arteries was investigated. We studied 237 subjects at 50 years of age with Doppler echocardiography and ultrasound examination of the common carotid arteries. The following Doppler indices of left ventricular filling were studied: peak early diastolic velocity E-wave, peak atrial diastolic velocity A-wave and early to atrial peak velocity ratio, E/A. Carotid arterial characteristics were: distensibility coefficient, carotid arterial diameter change in systole and fractional change in the carotid arterial diameter. The relation between Doppler indices of left ventricular filling and carotid arterial characteristics was assessed by univariate and multivariate regression analysis. There was a significant univariate, positive association between E/A ratio and carotid arterial distensibility (r = 0.27, P
AIMS: An increased risk for Type 2 diabetes in male and female smokers has been associated with insulin resistance. However, this might also be the result of an adverse effect on the beta-cell. The aim of the present study was to examine the association between smoking and beta-cell function. METHODS: A community-based, cross-sectional observation study. In 1994, a randomized age-stratified sample of men and women aged > or = 40 years in the city of Skara, Sweden, were invited to a survey of cardiovascular risk factors. In all, 1,109 subjects participated (80%). After the exclusion of subjects with known hypertension or diabetes mellitus, 874 subjects remained to explore. Samples were drawn after an overnight fast. Lifestyle (smoking, physical activity, alcohol consumption) was assessed using a questionnaire. Insulin resistance and insulin secretion were estimated using the homeostasis model assessment (HOMA). RESULTS: Cigarette smoking men (n = 101) had a lower HOMA beta-cell value (58.1), than never-smokers (n = 158, beta-cell value 90.1, P
To examine the impact of smoking cessation on body weight compared with normal long-term weight development.
Of 1970 adults (20-69 years) in a rural town in Denmark invited to take part in the study in 1998-2000, 1374 (70%) participated. After 9 years, 1121 participated in the follow-up study. Weight changes were compared using multivariable regression models.
The mean baseline weight of never-smokers was 76.4 kg (SD 16.0). The adjusted weight of smokers and ex-smokers differed by -4.2 kg (95% CI: -5.9, -2.6), and -0.7 kg (95% CI: -2.5, 1.1), respectively. The adjusted weight gain rate (kg/year) of never-smokers, smokers, and ex-smokers was 0.213, 0.127, and 0.105, respectively. The absolute post cessation weight gain (PCWG) was 5.0 kg (SD 7.0), and the adjusted PCWG was 2.8 kg (95% CI: 1.7, 3.9) compared with never-smokers, and 3.5 kg (95% CI: 2.3, 4.8) compared with smokers. The follow-up weight did not differ between quitters and never-smokers (0.1 kg; 95% CI: -2.4, 2.6).
Smokers weigh less than never-smokers. By quitting, they gain weight and end up weighing the same as comparable never-smokers. Weight gain rates differ by smoking status. Consequently, PCWG depends on the length of follow-up. Our graphical model indicates that smoking cessation results in a return to normal weight development.
