Table 4.

Association between baseline smoking variables and incident PD in the CHS according to several outcome definitions

Baseline smoking characteristics	Definition 1 (≥1 data source)		Linear trend	Definition 2 (≥2 data sources)		Linear trend	Self-report only		Linear trend
	OR	95% CI	p value	OR	95% CI	p value	OR	95% CI	p value
Smoking status			0.04			0.17			0.17
Never	1.00	reference		1.00	reference		1.00	reference
Former	0.84	0.59–1.19		0.82	0.48–1.40		0.94	0.57–1.55
Current	0.50	0.26–0.95		0.49	0.17–1.41		0.45	0.17–1.12
Total pack-years			0.03			0.12			0.22
Never smoker	1.00	reference		1.00	reference		1.00	reference
1st quartile (0–13)	0.82	0.57–1.50		1.01	0.49–2.11		1.06	0.54–2.07
2nd quartile (14–27)	0.95	0.58–1.56		0.87	0.39–1.93		0.95	0.47–1.95
3rd quartile (28–49)	0.72	0.42–1.23		0.86	0.40–1.84		0.84	0.41–1.73
4th quartile (≥50)	0.53	0.29–0.96		0.44	0.16–1.14		0.57	0.25–1.32
Years since quitting			0.33			0.38			0.34
Never smoker	1.00	reference		1.00	reference		1.00	reference
30	1.01	0.61–1.68		0.93	0.43–2.01		1.21	0.59–2.42
20–29	0.92	0.54–1.58		1.03	0.47–2.22		1.02	0.47–2.14
10–19	0.76	0.43–1.34		0.83	0.36–1.91		0.97	0.46–2.05
<10	0.67	0.36–1.25		0.54	0.19–1.57		0.69	0.29–1.68
Current smoker	0.50	0.26–0.95		0.49	0.17–1.41		0.45	0.18–1.18

Adjusted for age, sex and African American race; pack-years: quartiles of total pack-years determined among non-PD smokers.