Table 3.

Mediation by smoking status of the association of dichotomized depressive symptoms with lung cancer incidence (n=42,906; 1009 cases).

	Model 1: Sociodemographics		Model 2: Model 1 + other factors
	HR	(95% CI)	HR	(95% CI)
Natural direct effect	1.26	(1.08–1.48)**	1.24	(1.06–1.45)**
Natural indirect effect	1.13	(1.11–1.16)****	1.12	(1.10–1.14)****
Total effect	1.43	(1.23–1.68)****	1.39	(1.19–1.63)****
Proportion mediated	39%		38%

^**p≤ .01

^****p≤ .0001.

M1: adjusted for age (continuous); 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 + 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)