Long-Term Smoking Behavior Patterns Predicting Self-Reported Chronic Bronchitis

Figures & data

Table 1 Incident chronic bronchitis in 1981 by smoking status in 1975–1981 with number of subjects in each category, proportion of subjects affected, odds ratios (OR) and confidence intervals (95% CI) among Finnish twin cohort individuals without chronic bronchitis in 1975 ¹

Smoking status^75 − 81	n	% with incident chronic bronchitis	OR^2	95% CI
Constant never smokers	9,499	1.04	1.00	Reference group
Constant former smokers	2,439	1.26	1.26	0.82, 1.92
Quitters	1,808	0.99	1.27	0.76, 2.13
Initiators	325	0.91	1.44	0.45, 4.59
Recurrent smokers	531	1.85	2.54**	1.31, 4.93
Constant daily light smokers^3	97	0.00	—	—
Constant daily moderate smokers	2,253	2.04	2.73***	1.89, 3.94
Constant daily heavy smokers	840	7.39	10.04***	7.03, 14.35
Increasers	717	5.16	8.10***	5.42, 12.10
Decreasers	484	3.01	3.78***	2.16, 6.62
Occasional/non-daily smokers	534	0.37	0.46	0.11, 1.88
Others	347	1.14	1.19	0.44, 3.25

¹Total n = 20,208.

²Adjusted for age and sex.

³Omitted from the logistic regression analysis.

** p < 0.01, *** p < 0.001.

Figure 1 Odds Ratios (OR) and proportional sizes (bars) of those smoking subgroups with statistically significant relative risks for incident chronic bronchitis in 1981 (n = 14,602; total n = 20,208). Data points (joined by a line) represent OR with 95% confidence intervals in each smoking subgroup.

Figure 2 Odds Ratios (OR) of chronic bronchitis in different smoking groups based on random-effects model analysis carried out for longitudinal data. Data points represent OR with 95% confidence intervals in each smoking category. Continuous line represents the result of the trend test.