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

Table 5 Ischaemic heart disease 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		28	23	2.01 (1.84-2.21)	< 0.001
19	Sex	Combined	10	10	1.94 (1.71-2.21)
		Males	7	7	1.86 (1.53-2.26)
		Females	11	11	2.23 (1.86-2.69)	NS
20	Region	N. America	9	8	2.23 (1.92-2.58)
		Europe	17	14	1.90 (1.67-2.15)
		Japan	2	1	2.15 (1.73-2.69)	NS
21	Study population	National	9	8	2.10 (1.92-2.30)
		Regional	12	9	1.85 (1.56-2.19)
		Other	7	6	2.18 (1.77-2.69)	NS
22	Year of start of baseline	< 1988	5	5	1.89 (1.56-2.27)
		1988+	23	18	2.04 (1.83-2.28)	NS
23	Number of cases	< 1000	12	11	1.97 (1.58-2.45)
		1000+	16	12	2.04 (1.83-2.27)	NS
24	Exclusive cigarettes	No	26	22	2.00 (1.82-2.21)
		Yes	2	1	2.15 (1.73-2.69)	NS
25, 26	Lowest age considered	< 30	5	4	2.45 (1.77-3.39)
		30-44	11	9	1.81 (1.61-2.05)
		45+	9	7	2.06 (1.76-2.42)	NS trend without missing NS
		Missing	3	3	2.09 (1.16-3.78)
27	Yr of follow-up	< 10	2	2	2.52 (1.07-5.90)
		10-< 20	13	10	2.04 (1.77-2.35)
		20-< 30	10	8	1.99 (1.78-2.23)
		30+	3	3	1.68 (1.23-2.29)	NS trend NS
28	Endpoint	Died	13	10	2.23 (1.94-2.57)
		Diagnosed	15	13	1.83 (1.62-2.05)	< 0.05
29	Number of adjustment factors	None	6	5	2.11 (1.78-2.50)
		Age only	5	4	1.64 (1.39-1.93)
		More	17	14	2.10 (1.88-2.35)	< 0.05
30	Disease definition standard	No	13	12	1.83 (1.59-2.10)
		Yes	15	11	2.17 (1.93-2.45)	< 0.1