Environmental tobacco smoke exposure and heart disease: A systematic review

Table 7 Meta-analyses of heart disease¹ risk among never smokers in relation to four other indices of environmental tobacco smoke exposure

		Fixed-effect	Random-effects	Publication bias	Heterogeneity
Index of exposure	n2	Relative risk (95%CI)	Relative risk (95%CI)	P3	χ2	DF4	P5 value
Workplace	22	1.08 (0.99-1.19)	1.08 (0.99-1.19)	NS	20.12	21	NS
Childhood	7	1.12 (0.95-1.31)	1.12 (0.95-1.31)	< 0.1	4.77	6	NS
Total	33	1.21 (1.16-1.26)	1.23 (1.12-1.35)	NS	90.21	32	P < 0.001
Biomarker	9	1.11 (0.98-1.26)	1.15 (0.94-1.40)	NS	15.40	8	P < 0.1

¹Nearest equivalent to IHD as shown in Tables 1 and 6;

²n: Number of estimates in meta-analysis;

³Egger test P expressed as < 0.001, < 0.01, < 0.05, < 0.1 or NS (P ≥ 0.1);

⁴DF: Degrees of freedom;

⁵Expressed as < 0.001, < 0.01, < 0.05, < 0.1 or NS (P ≥ 0.1).