Table 2.

Association of level of depressive symptoms with lung cancer incidence (N=42,913; 1009 cases).

	Person-years	Model 1: Sociodemographics		Model 2: Model 1 + smoking		Model 3: Model 1 + other factors		Model 4: All covariates
	(cases)	HR	(95% CI)	HR	(95% CI)	HR	(95% CI)	HR	(95% CI)
Depressive symptoms levels
	763,399 (1,009)
Low or none	224,328 (274)	1.00	(ref.)	1.00	(ref.)	1.00	(ref.)	1.00	(ref.)
Moderate	272,950 (323)	1.06	(0.90–1.24)	1.00	(0.85–1.18)	1.03	(0.88–1.22)	0.99	(0.84–1.16)
High	149,317 (212)	1.30	(1.08–1.56)**	1.13	(0.94–1.36)	1.25	(1.04–1.49)*	1.11	(0.92–1.33)
Severe	116,804 (200)	1.62	(1.34–1.95)****	1.30	(1.08–1.57)**	1.52	(1.26–1.83)****	1.25	(1.04–1.51)*
p-trend		≤.0001		0.003		≤.0001		0.01

^*p≤ .05

^**p≤ .01

^****p≤ .0001.

M1: stratified by age in 1992 (continuous) and calendar time (continuous); further adjusted for exposure to second-hand smoking during childhood (yes, no [reference]); parents’ occupations when participant was 16 years old (both parents dead [reference], farmer, blue collar, white collar); familial history of lung cancer (yes, no [reference]); and husband’s education (participant unmarried [reference], less than high school, high school graduate, college graduate, graduate school)

M2: M1 + average cigarette packs per day per year smoked (not a current smoker [reference], 1–10 packs/year, 11–30 packs/year, 30 or more packs/year)

M3: M1 + diet quality (AHEI score; continuous); physical activity (less than 150min/week of moderate-to-vigorous physical activity [reference], 150min/week or more of moderate-to-vigorous physical activity); years of shiftwork (never [reference], 1–14 years, 15–29 years, 30 years or more)

M4: all covariates mentioned above.