A new diagnosis of asthma or COPD is linked to smoking cessation - the Tromsø study

Patients with COPD have had a lower tendency to quit smoking compared to patients with coronary heart disease (CHD). We wanted to investigate if this is still true in a Norwegian population.

Our data came from the fifth and sixth Tromsø surveys, which took place in 2001-2002 and 2007-2008. The predictors of smoking cessation were evaluated in a cohort of 4,497 participants who had stated their smoking status in both surveys.

Of the 4,497 subjects in the cohort, 1,150 (25.6%) reported daily smoking in Tromsø 5. In Tromsø 6, 428 had quit (37.2%). A new diagnosis of obstructive lung disease (asthma or COPD) and CHD were both associated with increased quitting rates, 50.6% (P=0.01) and 52.1% (P=0.02), respectively. In multivariable logistic regression analysis with smoking cessation as outcome, the odds ratios (ORs) of a new diagnosis of obstructive lung disease and of CHD were 1.7 (1.1-2.7) and 1.7 (1.0-2.9), respectively. Male sex had an OR of 1.4 (1.1-1.8) compared to women in the multivariable model, whereas the ORs of an educational length of 13-16 years and ≥17 years compared to shorter education were 1.6 (1.1-2.2) and 2.5 (1.5-4.1), respectively.

The general trend of smoking cessation in the population was confirmed. Increased rates of smoking cessation were associated with a new diagnosis of heart or lung disease, and obstructive lung disease was just as strongly linked to smoking cessation as was CHD. This should encourage the pursuit of early diagnosis of COPD.