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Biomedical subjects

S Humerfelt

Publications and source records attributed to S Humerfelt.

At least 19 recordsLinked to original sources
PubMed2001

Standardized submaximal exercise testing in never smokers: a normative study.

In a population survey on the south-western coast of Norway, 373 never smokers aged 18-73 years (230 women) without respiratory symptoms performed a standardized, progressive, incremental submaximal bicycle exercise test. All individuals were able to do an exercise involving oxygen uptake of 1.0 l min(-1), 80% of the subjects reached 1.5 l min(-1) and 50% of the subjects reached 2.0 l min(-1). The respiratory frequency (RF), ventilation (VE) and heart rate (HR) for a given oxygen uptake were all higher in women than in men. Significant predictors of failure to reach oxygen uptake of 1.5 and 2.0 l min(-1) were sex, age, body height and weight. Prediction equations are given for respiratory frequency, heart rate and ventilation for an oxygen uptake of 1.0 l min(-1) in women and 1.5 l min(-1) in men; and body height is a strong predictor for all dependent variables. A multiple linear regression analysis in women showed that age was a significant predictor of respiratory frequency (P<0.05), ventilation (P<0.001) and heart rate (P<0.001), while in men age was a significant predictor only of ventilation (P<0.001) during the bicycle exercise protocol.

Adolescent↗
PubMed2001

Expiratory and inspiratory forced vital capacity and one-second forced volume in asymptomatic never-smokers in Norway.

The objectives of this study were to examine within and between individual variation detected during forced expiratory (FE) and forced inspiratory (FI) manoeuvers in a general population and to investigate the dependence of these variables on age, body size, and gender. A random sample of asymptomatic never smokers who had never been exposed occupationally to quartz or asbestos and who were living on the south-western coast of Norway were examined by spirometry; 81% of the individuals invited to attend did so. Of the 488 subjects between 18 and 73 years of age, 98% contributed three acceptable recordings for forced expiratory vital capacity (FVC) and one-second forced expiratory volume (FEV1), 94% contributed three acceptable recordings for forced inspiratory vital capacity (FIVC) and 85% contributed three acceptable recordings for one-second forced inspiratory volume (FIV(1)). The within-subject variation increased with body height and was considerably larger for FIV(1) than for FVC, FEV(1) or FIVC. A four-parameter model of pulmonary function measurement divided by height squared, including a gender term and a linear and quadratic term of age, fit the median of the observed values well. The residuals had a close-to-normal distribution, and the fifth-percentile values were estimated as the lower limit of normal. The peak value of dynamic lung volumes was observed into the middle of the fourth decade of life, and the decline thereafter did not differ greatly between the genders or among the different indices. The forced inspiratory volumes are the first reported in any reference population.

Adolescent↗
PubMed1998

Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) variability in asymptomatic never-smoking men.

We examined the effects from subjects, technicians and spirometers on within-session variability in successful recordings of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in 4989 asymptomatic never-smoking men. All eligible men aged 30-46 years living in western Norway (n = 45,380) were invited to a cross-sectional community survey. Information on respiratory symptoms, smoking habits and occupational exposures was obtained from a self-administered questionnaire. Three successful FEV1 and FVC recordings were obtained in 26,368 attendants using three dry-wedge bellow spirometers operated by 10 different technicians. Within-subject standard deviation (SD) from three recordings of FEV1 and FVC was on average 102 and 106 ml, respectively, and increased with height (14 and 17 ml, respectively, per 10 cm) and body mass index (BMI) (11 and 14 ml, respectively, per 5 kg m-2). Between-subject SD of the mean of three FEV1 and FVC recordings was 591 and 754 ml, respectively, and increased in groups of increasing height (43 and 40 ml, respectively, per 10 cm). Small, but significant, differences were observed between technicians in within-subject SD and in levels of FEV1 and FVC. Homogeneity of between-subject variability, necessary for linear regression analysis, was obtained using FEV1 and FVC divided by height squared. In conclusion, within-subject variability in three successful spirometric recordings was small, but dependent on height and BMI of the subjects as well as technician performance. The observed heterogeneity in between-subject variation in FEV1 and FVC levels disappeared when each variable was divided by height squared. Novel multiple linear regression equations for FEV1/height2 and FVC/height2 were developed to be used in evaluating the effects from occupational airborne exposures in Nordic men aged 30-46 years.

Adult↗
PubMed1998

Association of years of occupational quartz exposure with spirometric airflow limitation in Norwegian men aged 30-46 years.

BACKGROUND: The association between occupational quartz exposure and ventilatory function was investigated in men in a general population after adjusting for other potential determinants of outcome. METHODS: All eligible men aged 30-46 years living in western Norway (n = 45,380) were invited to a cross sectional community survey. This included a self administered questionnaire (with respiratory symptoms, smoking habits and occupational exposures), spirometric recordings (using dry wedge below spirometers), and a chest radiograph (65% attendance). Measurements of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were obtained in 91% (n = 26,803) of those who participated, 26,106 of whom performed successful spirometric tests and had normal chest radiographs and remained for further analysis. Age, body mass index, and technician standardised residuals ((observed minus predicted value)/residual standard error) of maximum FEV1/height2 and FVC/height2 were used as outcome variables for adjusted lung function levels, respectively. RESULTS: Occupational quartz exposure was reported by 13% (n = 3445) of those who participated in the survey, with a mean duration of seven years. Among those exposed to quartz, significant inverse linear relationships were observed between years of exposure and FEV1 level and the ratio of FEV1/FVC, independent of host characteristics. Multiple linear regression analyses showed that the difference in FEV1 associated with each year of quartz exposure was -4.3 ml (95% CI -1.1 to -7.5 ml; p = 0.01) compared with -6.9 ml (95% CI -4.7 to -9.1 ml; p < 0.01) from smoking 20 cigarettes/day for one year after adjusting for age, atopy, asthma, wheezing, marital status, and other occupational exposures. CONCLUSION: In men aged 30-46 years with occupational quartz exposure and normal chest radiographs the duration of occupational quartz exposure was an independent predictor for spirometric airflow limitation.

Adult↗
PubMed1998

Effectiveness of postal smoking cessation advice: a randomized controlled trial in young men with reduced FEV1 and asbestos exposure.

There have been few community-based randomized, controlled intervention trials for cessation in high-risk smokers. In such a trial we evaluated the effects of postal smoking cessation advice in smokers with asbestos exposure and/or reduced forced expiratory volume in one second (FEV1). All men aged 30-45 yrs (n=22,392) living in 34 municipalities in western Norway were invited to a cross-sectional community survey. Information on smoking habits and occupational asbestos exposure were obtained from self-administered questionnaires and measurements of FEV1 were performed with dry-wedge bellow spirometers. Among 16,393 participants we identified a group of 2,610 smokers with previous occupational asbestos exposure and/or adjusted FEV1 in the lowest quartile. A random half (n=1,300) received a mailed personal letter from a respiratory physician with a person-specific health advice to quit smoking and a pamphlet on smoking cessation. The remaining smokers (n=1,310) acted as controls and did not receive any information. Twelve months after the intervention, information on smoking habits was re-examined using a postal questionnaire. Among the respondents (n=2,282), smoking cessation was reported altogether by 13.7% in the intervention group versus 9.9% in the control group (p<0.01). The 1 yr sustained quit rate (no smoking at all during the last year) was 5.6 versus 35% (p<0.05), respectively. Measurements of carbon monoxide in expired air (with < or = 10 parts per million) confirmed self-reported nonsmoking in samples of the two groups. In a community this simple postal smoking cessation advice from a respiratory physician based on person-specific risk factors improved the 1 yr sustained success rate by 60% in identified high-risk smokers.

Adult↗
PubMed1995

Predictors of spirometric test failure: a comparison of the 1983 and 1993 acceptability criteria from the European Community for Coal and Steel.

OBJECTIVES: To identify, in this general population study, predictors of spirometric test failure on the 1983 and 1993 acceptability criteria from the European Community for Coal and Steel (ECCS). METHODS: All men aged 30-46 years living in western Norway (n = 45,380) were invited to join a cross sectional community survey. Respiratory symptoms, smoking habits, and marital status were found from self administered questionnaires, and measurements of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were performed with dry wedge bellow spirometers. RESULTS: Altogether 29,611 subjects (65%) participated in this survey. Spirometric recordings were obtained in 26,803 of these (91%) of whom 1.6% failed the 1983 criterion (< or = 300 ml between the two highest FVC values) and 9.5% failed the 1993 criteria (< or = 5% or 100 ml between the two highest FEV1 and the two highest FVC values). Spirometric failures on both criteria were more prevalent in never smokers, single men, and subjects with respiratory symptoms than in ever smokers, married, and asymptomatic subjects. Failure of the 1993 criteria increased with age and declining height. Morning cough and phlegm, breathlessness uphill, attacks of breathlessness, and wheezing were related to failure of the 1993 criteria after adjustment for demographic variables and smoking, whereas only breathlessness uphill was related to failure of the 1983 criterion. CONCLUSIONS: In men aged 30-46 years, spirometric test failures on both the 1983 and 1993 ECCS acceptability criteria occurred more often in never smokers than in smokers and ex-smokers after adjustment for other covariables. Spirometric test failure with the 1993 criteria also varied with height and most respiratory symptoms. The higher failure rates found in non-smokers, in shorter, and in single men could be due to late compression of the airways, smaller lung volumes, and poor general health, respectively.

Adult↗
PubMed1993

Decline in FEV1 and airflow limitation related to occupational exposures in men of an urban community.

The purpose of this survey was to evaluate the effects of smoking and occupational exposures on the decline in forced expiratory volume in one second (FEV1), and the presence of airflow limitation (FEV1 x100/forced vital capacity (FVC) being < 65) at follow-up. A random sample of 1,933 men aged 22-54 years in Bergen, Norway, were invited into the survey. Smoking habits and measurements of FEV1 were recorded at the initial survey in 1965-1970 (n = 1,591) and at follow-up in 1988-1990 (n = 951). Past or present self-reported occupational exposures to eleven airborne agents (dusts, gases, vapours and fumes) and measurements of FVC were recorded at follow-up only. The decline in FEV1 was associated (p < 0.001) with age, body height and smoking. Smoking cessation reduced the decline to the level of lifetime nonsmokers. Accelerated decline in FEV1 was observed in subjects exposed to sulphur dioxide gas and to metal fumes. The adjusted decline in FEV1 increased progressively in subjects exposed to increasing numbers of occupational agents (test for trend: p < 0.01). Airflow limitation was observed in 9.5% at follow-up, and increased with age and cigarette consumption. In this community follow-up survey in men, smoking and occupational exposures to sulphur dioxide gas, metal fumes and the numbers of specific agents were found to be important predictors for accelerated decline in FEV1.

Adult↗
PubMed1992

Single breath transfer factor for carbon monoxide in an asymptomatic population of never smokers.

BACKGROUND: Data on reference values of transfer factor variables in general populations of asymptomatic never smokers are limited. The aim of this study was to examine the relation between test variables and age, height, haemoglobin concentration and carboxyhaemoglobin concentration. METHODS: Measurements of single breath transfer factor for carbon monoxide (TLCO) were obtained for a randomly selected sample of never smokers in north western Europe who were 18-73 years old and had no respiratory symptoms or disorders. Two recordings of TLCO with a ratio of inspiratory vital capacity to forced vital capacity of greater than 0.09 were obtained by standardised techniques for 304 subjects. RESULTS: The measurement errors expressed as a percentage of the common mean value of TLCO, volume adjusted TLCO (KCO), and alveolar volume (VA) were 4.5%, 4.2%, and 2.4% respectively. Multiple linear regressions showed sex specific effects of height and age on TLCO, and, in addition, of haemoglobin and carboxyhaemoglobin concentrations on KCO. VA was associated with height but not with age. The 5th and 95th centiles for TLCO and KCO in men and women were between 78% and 82% and between 120% and 127%, respectively, of predicted values when age and height were taken into account. CONCLUSION: Reference equations and normal values for transfer test variables in a large healthy population of never smokers are described in relation to age, height, and haemoglobin concentrations. To our knowledge, this is the first report of an association between carboxyhaemoglobin concentrations and KCO in a population of never smoking men and women.

Adolescent↗