Table 4

Smoking and lung function of small airways (FEF50 and FEF25–75%) in working-age adults with newly diagnosed asthma, the Finnish Environment and Asthma Study 1997–2000

SmokingPre-bronchodilator effect estimatePost-bronchodilator effect estimate
FEF50 (L/s)FEF25–75% (L/s)FEF50 (L/s)FEF25–75% (L/s)
β95% CIβ95% CIβ95% CIβ95% CI
All*n=470†n=469‡n=386§n=386¶
 NeverReferenceReferenceReferenceReference
 Quit >1 year ago−0.120−0.406 to 0.166−0.025−0.269 to 0.220−0.248−0.604 to 0.109−0.101−0.400 to 0.198
 Quit <1 year ago−0.5360 −0.980 to − 0.091 −0.406 −0.791 to − 0.021 −0.498−1.040 to 0.045−0.463−0.927 to 0.001
 Occasional0.113−0.347 to 0.5730.188−0.204 to 0.580−0.200−0.761 to 0.3620.070−0.413 to 0.553
 Regular−0.476 −0.750 to − 0.202 −0.372 −0.607 to − 0.137 −0.557 −0.877 to − 0.236 −0.394 −0.663 to − 0.124
Men**n=164†n=165‡n=135§n=136¶
 NeverReferenceReferenceReferenceReference
 Quit >1 year ago0.142−0.398 to 0.6830.118−0.344 to 0.579−0.074−0.834 to 0.6850.061−0.559 to 0.681
 Quit <1 year ago−0.596−1.393 to 0.202−0.624−1.305 to 0.058−0.198−1.269 to 0.872−0.432−1.305 to 0.442
 Occasional−0.158−1.163 to 0.847−0.118−0.976 to 0.740−0.283−1.538 to 0.9730.170−0.912 to 1.253
 Regular−0.284−0.849 to 0.281−0.279−0.760 to 0.201−0.377−1.124 to 0.370−0.217−0.822 to 0.389
Women**n=306†n=304‡n=251§n=250¶
 NeverReferenceReferenceReferenceReference
 Quit >1 year ago−0.267−0.616 to 0.082−0.115−0.412 to 0.182−0.335−0.720 to 0.051−0.180−0.513 to 0.152
 Quit <1 year ago−0.462−0.999 to 0.075−0.236−0.705 to 0.233−0.730 −1.328 to − 0.132 −0.457−0.994 to 0.080
 Occasional0.273−0.233 to 0.7790.352−0.077 to 0.781−0.196−0.774 to 0.381−0.037−0.535 to 0.461
 Regular−0.489 −0.802 to − 0.177 −0.368 −0.635 to − 0.101 −0.598 −0.923 to − 0.272 −0.436 −0.719 to − 0.154

  • *Adjusted for sex, age, height, education, past 12 months secondhand smoking (SHS), lifetime cumulative SHS and mould odour.

  • †Pre-bronchodilator FEF50 is available for 473 participants (165 men and 308 women), of whom smoking status is missing for 3 (1 man and 2 women).

  • ‡Pre-bronchodilator FEF25–75% is available for 472 participants (166 men and 306 women), of whom smoking status is missing for 3 (1 man and 2 women).

  • §Post-bronchodilator FEF50 is available for 388 participants (136 men and 252 women), of whom smoking status is missing for 2 (1 man and 1 woman).

  • ¶Post-bronchodilator FEF25–75% is available for 388 participants (137 men and 251 women), of whom smoking status is missing for 2 (1 man and 1 woman).

  • **Adjusted for age, height, education, past 12 months SHS, lifetime cumulative SHS and mould odour.