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

Our plain-English summary of Expiratory and inspiratory forced vital capacity and one-second forced volume in asymptomatic never-smokers in Norway, by A. Gulsvik, T. Tosteson, P. Bakke, et al (Clinical Physiology, 2001).

The study

• Authors: A. Gulsvik, T. Tosteson, P. Bakke, S. Humerfelt, S.T. Weiss, F.E. Speizer
• Journal: Clinical Physiology
• Published: 2001;21(6):648-60
• Cited by: 71 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

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.

In plain English

This cross-sectional survey set out to produce reference ('normal') values for breathing tests in healthy adults in Norway. Asbestos was not studied as a cause of disease: people ever exposed to asbestos or quartz at work were excluded. The authors tested 488 never-smokers without respiratory symptoms, aged 18 to 73, from Bergen and surrounding municipalities between April 1987 and August 1988. They measured how much air people could forcibly breathe out and in (FVC, FEV1, FIVC and FIV1). Forced breathing in was harder to do well: 74 of the 488 could not give three satisfactory FIV1 recordings. The average variation between a person's repeated tests was 63 ml for FVC and FEV1, 77 ml for FIVC and 252 ml for FIV1. Lung volumes adjusted for height changed only slightly before age 35 and then declined, and the decline ran in parallel in men and women. The fifth percentile of FEV1 as a percentage of FVC was 75 in both sexes overall, though in women it declined with age. The authors noted that the sample included only seven men over 65.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional population survey to develop reference (prediction) values for spirometry
• Who was studied: 488 asymptomatic never-smokers aged 18 to 73 (288 women and 192 men among those with acceptable FVC tests), drawn from a random population sample in Bergen and 11 surrounding municipalities, Hordaland county, south-western Norway. 540 people (81.4% of those invited) attended, and examinations ran from April 1987 to August 1988.
• Exposure: No asbestos exposure was studied. Subjects were selected because they had never been occupationally exposed to asbestos or quartz and had never smoked. The measurements were forced expiratory and inspiratory spirometry (FVC, FEV1, FIVC, FIV1).
• Main results:
  • Average within-subject variation (standard deviation of three recordings) was 63 ml for FVC and FEV1, 77 ml for FIVC and 252 ml for FIV1.
  • 74 of 488 subjects (44 women and 30 men) could not produce three satisfactory FIV1 recordings in eight attempts.
  • Height-standardized expiratory and inspiratory volumes showed only slight changes before age 35.
  • The height-standardized lung volumes decreased in parallel in men and women.
  • Mean difference between maximum FVC and maximum FIVC was 78 ml (SD 105 ml).
  • In the reference population as a whole, the fifth percentile of FEV1 as a percentage of FVC was 75 in both men and women. The fifth percentile of FIV1 as a percentage of FIVC was 73 in men and 63 in women.
  • The observed fifth percentile of FEV1 as a percentage of FVC declined with age in women but not in men.
  • Maximum FEV1 as a percentage of maximum FIV1 was 6% lower for men than for women.
• The authors' conclusion: The authors concluded that, in asymptomatic never-smokers on the south-western coast of Norway, expiratory and inspiratory lung volumes had a long plateau lasting until the fourth decade of life, followed by an accelerating decline with age. They provided prediction equations for ages 18 to 73.
• Limitations the authors state:
  • Very few older men were included, and the authors said this may explain a slight mismatch between the model and the data in the elderly.
  • Forced inspiration was measured immediately after forced expiration. The authors said testing inspiration separately might have given higher and more reproducible results.

Topics

Medical terms in this study, explained in our Lexicon: Spirometry, FEV1.

Related studies

• Vital capacity and one-second forced expiratory volume in Australian male asbestos cement workers — L.N. Balaam, S.F. McCullagh (1975)
• Diffusing capacity and forced vital capacity in 5,003 asbestos-exposed workers: relationships to interstitial fibrosis (ILO profusion score) and pleural thickening — A. Miller, R. Warshaw, et al. (2013)
• Auscultated forced expiratory time as a clinical and epidemiologic test of airway obstruction — D.G. Kern, S.R. Patel (1991)
• Prevalence of obstructive lung disease in a general population: relation to occupational title and exposure to some airborne agents — P.S. Bakke, V. Baste, et al. (1991)
• Lung cancer in never smokers: a review — J. Subramanian, R. Govindan (2007)
• Occupational exposure and regional variation of malignant mesothelioma in Norway, 1970-79 — G. Mowé, B. Gylseth (1986)

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