Evidence relating cigarettes, cigars and pipes to cardiovascular disease and stroke: Meta-analysis of recent data from three regions

Table 6 Stroke and current vs never cigarette smoking – results from random effects meta-analyses

Full output table	Factor	Level	No. of RRs	No. of Studies	RR (95%CI)	Test of heterogeneity by level (NS = P ≥ 0.1) and trend if relevant, P value
	All		37	31	1.62 (1.48-1.77)	< 0.001
35	Sex	Combined	17	17	1.65 (1.52-1.50)
		Males	9	9	1.48 (1.21-1.80)
		Females	11	11	1.66 (1.39-1.99)	NS
36	Region	N. America	14	12	1.64 (1.48-1.83)
		Europe	19	16	1.71 (1.51-1.94)
		Japan	4	3	1.18 (1.04-1.34)	< 0.001
37	Study population	National	13	11	1.76 (1.47-2.11)
		Regional	19	15	1.55 (1.36-1.78)
		Other	5	5	1.51 (1.39-1.65)	N.S.
38	Yr of start of baseline	< 1988	8	8	1.43 (1.23-1.67)
		1988+	29	23	1.68 (1.52-1.85)	< 0.1
39	Number of cases	< 1000	18	16	1.66 (1.44-1.91)
		1000+	19	15	1.59 (1.41-1.78)	NS
40	Exclusive cigarettes	No	32	27	1.67 (1.52-1.84)
		Yes	5	4	1.31 (1.19-1.45)	< 0.001
41, 42	Lowest age considered	< 36	8	6	1.59 (1.19-2.14)
		30-44	16	13	1.48 (1.35-1.62)
		45+	11	10	1.89 (1.68-2.12)	< 0.01 trend without missing < 0.01
		Missing	2	2	1.87 (1.54-2.28)
43	Yr of follow-up	< 10	3	3	2.13 (1.80-2.53)
		10-< 20	22	17	1.69 (1.52-1.89)
		20-< 30	7	6	1.43 (1.29-1.60)
		30+	5	5	1.44 (1.10-1.89)	< 0.001 trend < 0.001
44	Endpoint	Died	16	13	1.60 (1.41-1.81)
		Diagnosed	21	18	1.63 (1.46-1.83)	NS
45	Number of adjustment factors	None	7	7	1.32 (1.08-1.62)
		Age only	4	3	1.70 (1.31-2.20)
		More	26	21	1.69 (1.53-1.88)	< 0.1
46	Disease definition standard	No	20	18	1.68 (1.51-1.88)
		Yes	17	13	1.55 (1.36-1.77)	NS