Country | Condition | Smokeless tobacco status | Cigarette smoking status* | Number of study estimates (estimate numbers†) | Relative risk (95% CI) | Measures of heterogeneity |
Sweden | Ischaemic heart disease | Current | Never | n=3 (15, 17, 37) | 1.04 (0.93 to 1.16) | p=0.494 I2=0.0% |
Current | Any | n=4 (15, 17, 18, 37) | 0.99 (0.85 to 1.16) | p=0.345 I2=9.7% | ||
Former | Never | n=5 (1, 16, 22, 23, 28) | 0.85 (0.66 to 1.08) | p=0.609 I2=0.0% | ||
Stroke | Current | Never | n=1 (39) | 1.04 (0.92 to 1.17) | – | |
Current | Any | n=2 (19, 39) | 1.04 (0.93 to 1.17) | p=0.914 I2=0.0% | ||
Former | Never | n=2 (24, 29) | 0.91 (0.50 to 1.64) | p=0.131 I2=56.2% | ||
Other circulatory disease | ||||||
Heart failure | Current | Any | n=2 (34, 35) | 1.43 (0.91 to 2.24) | p=0.190 I2=41.9% | |
Former | Never | n=1 (36) | 0.99 (0.44 to 2.22) | – | ||
Hypertension | Current | Never | n=1 (25) | 1.43 (1.12 to 1.83) | – | |
Former | Never | n=1 (26) | 0.85 (0.40 to 1.79) | – | ||
All circulatory disease | Ever | Never | n=1 (27) | 1.15 (0.97 to 1.37) | – | |
Among users with previous myocardial infarction (‘quitters’ vs ‘continuers’) | ||||||
Cardiovascular events | Current | Any | n=1 (38) | 0.38 (0.11 to 1.32) | – | |
US | Ischaemic heart disease | Current | Never | n=3 (6, 9, 40) | 1.17 (1.09 to 1.27) | p=0.292 I2=18.7% |
Current/ever | Never | n=5 (2, 3, 6, 9, 40) | 1.18 (1.06 to 1.31) | p=0.167 I2=38.2% | ||
Former | Never | n=2 (12, 42) | 0.80 (0.61 to 1.05) | p=0.220 I2=33.7% | ||
Stroke | Current | Never | n=3 (7, 10, 41) | 1.28 (1.01 to 1.62) | p=0.028 I2=72.0% | |
Current/ever | Never | n=5 (4, 5, 7, 10, 41) | 1.25 (1.00 to 1.55) | p=0.066 I2=54.6% | ||
Former | Never | n=2 (13, 43) | 1.25 (0.93 to 1.69) | p=0.766 I2=0.0% | ||
Other circulatory disease | ||||||
Circulatory disease excluding ischaemic heart disease and stroke | Current | Never | n=2 (8, 11) | 1.06 (0.93 to 1.20) | p=0.902 I2=0.0% | |
All circulatory disease | ||||||
Ischaemic heart disease and stroke | Current | Never | n=1 (30) | 1.14 (0.55 to 2.39) | – | |
Former | Never | n=1 (31) | 1.25 (0.77 to 2.03) | – | ||
Ischaemic heart disease and stroke | Current | Non-current (adjusted) | n=1 (32) | 1.31 (1.06 to 1.61) | – | |
Former | Non-current (adjusted) | n=1 (33) | 0.90 (0.73 to 1.11) | – | ||
Among former cigarette smokers (‘switchers’) | ||||||
Ischaemic heart disease | Current | Former | n=1 (20) | 1.13 (1.00 to 1.29) | – | |
Stroke | Current | Former | n=1 (21) | 1.24 (1.01 to 1.53) | – |
*Meta-analyses of studies with any smoking status include all study estimates for that condition and smokeless tobacco use status regardless of cigarette smoking status in individual studies. Meta-analyses of studies with non-current smoking status include estimates from studies that excluded current but not former smokers.
†Study estimate numbers are from table 3.