L. Sandvik et al., LONG-TERM EFFECTS OF SMOKING ON PHYSICAL-FITNESS AND LUNG-FUNCTION - A LONGITUDINAL-STUDY OF 1393 MIDDLE-AGED NORWEGIAN MEN FOR 7 YEARS, BMJ. British medical journal, 311(7007), 1995, pp. 715-718
Objective-To study association between smoking habits and long term de
cline in physical fitness and lung function in middle aged men who rem
ained healthy. Design-Baseline and follow up measurements performed du
ring 1972-5 and 1980-2 respectively. Setting-National University Hospi
tal of Oslo, Norway. Subjects-1393 men aged 40-59 at baseline who were
all healthy at baseline and at follow up. Main outcome measures-Force
d expiratory volume in one second and physical fitness (defined as tot
al work done during a symptom limited bicycle ergometer test divided b
y body weight. Results-Initial fitness was substantially lower among 3
47 persistent smokers than among 791 persistent non-smokers (1349 J/kg
v 1618 J/kg), as was initial forced expiratory volume (3341 ml v 3638
ml). Mean (95% confidence interval) decline in fitness over 7.2 years
was 217 (185 to 249) J/kg among smokers compared with 86 (59 to 113)
J/kg among non-smokers (P<0.001). Corresponding declines in forced exp
iratory volume were 271 (226 to 316) ml in smokers and 116 (85 to 147)
ml in non-smokers (P<0.001). Differences between smokers and non-smok
ers remained practically unchanged after adjustment for age and level
of physical activity. Changes in fitness and forced expiratory volume
among 199 men who had stopped smoking mimicked the findings for persis
tent non-smokers, and 56 men who started smoking presented findings cl
ose to those of persistent smokers. Conclusion-Decline in physical fit
ness and lung function among healthy middle aged men was considerably
greater among smokers than among nonsmokers and could not be explained
by differences in age and physical activity.