Environmental tobacco smoke exposure and heart disease: A systematic review

Table 8 Other indices of environmental tobacco smoke exposure - dose response results among never smokers

Study No.	Author1	Sex	Exposure grouping	Relative risk by grouping (95%CI)2	Significance3
Workplace exposure
22	Kawachi et al[48]	F	No, occasional, regular	1.00, 1.49, 1.92
26	He et al[52]	F	0-5, 6-10, 11-20, 21+ cigs/d	1.00, 0.87, 2.95, 3.56	+
		F	0-5, 6-15, 16+ year	1.00, 3.08, 1.56
		F	0, 1-2, 3, 4+ smokers	1.00, 1.16, 5.06, 4.11	+
		F	0, 1-2, 3-4, 5+ h/d	1.00, 0.62, 4.03, 21.32	+
		F	0, 1-2000, 2001-4000, 4000+, cigs/d × year × smokers × h	1.00, 1.00, 2.05, 9.23	+
28	Rosenlund et al[54]	M + F	0, 1-31, 32+ yr	1.00, 1.04, 1.30
		M + F	0, 1-68, 69+ h-year (= h/d × year)	1.00, 0.99, 1.48
39	Wen et al[64]	F	0, < 10, 10-24, > 24 yr	1.00, 0.86, 0.96, 0.934
40	Eisner et al[65]	M + F	Per 10 yr exposure	1.04
Childhood exposure
18	Muscat et al[44]		Exposure to mother, father, other relatives
		M	None, 1-17, > 17 yr	1.0, 0.9, 0.7
		F	None, 1-17, > 17 yr	1.0, 0.6, 0.8
39	Wen et al[64]	F	In early life from family members5
			0, < 20, 20+, year	1.00, 1.21, 1.364	+
Total exposure
3	Lee et al[31]		Home, work, travel, leisure combined index
		M	Score: 0-1, 2-4, 5-12	1.00, 0.43, 0.43
		F	Score: 0-1, 2-4, 5-12	1.00, 0.59, 0.81
5	Svendsen et al[33]		Spousal and/or workplace exposure
		M	Neither, spouse, work, both	1.0, 1.2, 1.0, 1.7
9	Jackson[37]		Exposure at home and/or work6
		M	No, yes	1.00, 1.14 (0.76-1.70)
		F	No, yes	1.00, 1.56 (0.76-3.20)
12	Dobson et al[40]		Exposure at home and/or work
		M	No, yes	1.00, 1.09 (0.72-1.63)
		F	No, yes	1.00, 2.24 (1.28-3.91)	+
19	Tunstall-Pedoe et al[45]		Exposure to tobacco smoke from someone else in the previous three days
		M + F	None, little, some, a lot, (self-classified)	1.00, 1.2, 1.5, 1.6	+
22	Kawachi et al[48]		Exposure at home and/or work
		F	None, occasional, regular	1.00, 1.58, 1.91	+
26	He et al[117]		ETS exposure from spouse and/or work
		F	Neither, spouse, work, both	1.00, 2.07, 2.53, 4.18	+
27	Iribarren et al[53]		Exposure at home, in small spaces, in large indoor areas
		M	0, 1-9, 10-39, 40+ total h/wk	1.00, 0.90, 1.08, 1.13	+
		F	0, 1-9, 10-39, 40+ total h/wk	1.00, 0.86, 1.07, 1.17	+
28	Rosenlund et al[54]		Exposure from spouse and/or work
		M + F	0, > 16, 7-16, 1-6, < 1, year ago	1.00, 0.92, 1.11, 1.30, 1.39
		M + F	0, 1-12, 13-23, 24-34, 35+, year	1.00, 0.72, 0.97, 1.54, 1.48	+
		M + F	0, 1-17, 18-41, 42-89, 90+, h-year, (= year × h/d)	1.00, 0.70, 1.22, 1.27, 1.55	+
29	Pitsavos et al[55]		Exposure at home and/or work
		M	None, occasional, regular	1.00, 1.25, 1.47	+
		F	None, occasional, regular	1.00, 1.29, 1.56	+
31	Chen et al[56]		Exposure to tobacco smoke from someone else in the previous three days
		M + F	None, a little, some, a lot	1.00, 1.30, 1.50, 1.80	+
			Exposure to other people’s tobacco smoke
		M + F	0, > 0-2, 3-5, ≥ 6 h/d	1.00, 1.20, 1.60, 1.70
37	Stranges et al[62]		Cumulative lifetime ETS exposure at home, work and in public settings
		M	Tertile: 1, 2, 3	1.00, 0.93, 1.40
		F	Tertile: 1, 2, 3	1.00, 0.50, 0.67
38	Teo et al[63]		Exposure from family, friends, co-workers
		M + F	< 1, 1-7, 8-14, 15-21, 22+ h/wk	1.00, 1.32, 1.52, 1.73, 1.49	+
43	He et al[67]		Exposed at home and/or work
		F	0, 1-9, 10-19, 20+, cigs/d	1.00, 1.41, 1.85, 1.77	+
			0, 1-20, 21-40, 41+, min/d	1.00, 1.46, 1.78, 1.86	+
52	He et al[76]		Exposed at home and/or work7
		M + F	None Low Moderate High	1.00, 1.74, 2.25, 3.79	+
54	Iversen et al[78]		Time spent in a smoke-filled rooms
		M	0, 1-6, > 6, h/d	1.00, 1.00, 0.80
		F	0, 1-6, > 6, h/d	1.00, 0.70, 0.70
58	Shiue[82]		Exposed at home, work, other people’s home
		M + F	0, 1, 2+ of these places	1.00, 1.37, 2.64	+
Biomarker
19	Tunstall-Pedoe et al[45]		Serum cotinine (ng/mL)
		M + F	0, > 0-1.05, 1.06-3.97, 3.98-17.49	1.00, 1.00, 1.30, 1.20
31	Chen et al[56]		Serum cotinine (ng/mL)
		M + F	0, > 0-1.05, 1.06-3.97, 3.98-17.49	1.00, 0.70, 1.00, 1.10
33	Whincup et al[58]		Serum cotinine (ng/mL)
		M	≤ 0.7, 0.8-1.4, 1.5-2.7, 2.8-14.0	1.00, 1.54, 1.89, 1.67	+
36	Hedblad et al[61]		Blood carboxyhaemoglobin (%)
		M	0.13-0.49, 0.50-0.57, 0.58-0.66, 0.67-5.47 (quartiles)	1.00, 1.26, 1.77, 3.71	+
48	Hamer et al[72]		Salivary cotinine (ng/mL)
		M + F	≤ 0.05, 0.06-0.70, 0.71-14.99	1.00, 1.33, 2.00	+
			Per unit increase in log cotinine	1.60 (1.11-2.31)
49	Jefferis et al[73]		Serum cotinine (ng/mL)
		M + F	≤ 0.05, 0.06-0.19, 0.20-0.70, 0.71-15	1.00, 0.91, 0.99, 0.94
			Per doubling of cotinine	1.00 (0.86-1.16)
56	Rostron[80]		Serum cotinine (ng/mL)
		M + F	< 0.1, 0.1- < 1, 1- < 15	1.00, 0.97, 1.41
57	Batty et al[81]		Salivary cotinine (ng/mL)
		M	≤ 0.3, 0.4-1.2, 1.3-15.0	1.00, 0.41, 0.62
		F	≤ 0.3, 0.4-1.2, 1.3-15.0	1.00, 0.99, 1.70

¹First author;

²Relative risks presented are adjusted for covariates if adjusted data are available. When two groups only are being compared (or results for log cotinine are given), the relative risk and 95%CI limits for the exposed group (per unit increase) are shown; when more than two exposure groups are being compared, only the set of relative risks is shown;

³Significant (P < 0.05) positive (or negative) differences or trends are indicated by + (or -). ? indicates not known whether significant or not. Blank entries indicate non-significance. The trend test includes the unexposed group;

⁴Results for CVD. Not available for CVD - Stroke;

⁵For study 39 the results for any childhood exposure (yes/no) shown in Table 4 relate to CVD minus stroke but the results by years exposed shown here relate to CVD as a whole;

⁶The data shown here for study 9 come from the publication describing study 24;

⁷The index of exposure was a combination of exposure at home (four categories of pack-years) and exposure at work (four categories of pack-years × h/d). M: Male; F: Female; CVD: Cardiovascular disease.