Introduction
Materials and methods
Search strategy and inclusion criteria
Study selection
Data extraction
Statistical methods
Results
First author, publication year, country | Study name or description | Study period | Number of participants, sex, age, number of sudden cardiac deaths | Type of Smoking, subgroup | Comparison | Relative risk (95% confidence interval) | Adjustment for confounders |
---|---|---|---|---|---|---|---|
Wannamethee G et al., 1995, United Kingdom | British Regional Heart Study | 1978–1980 —NA, 8 years follow-up | 7735 men, age 40–59 years: 117 sudden cardiac deaths | Smoking status | Never Former Current | 1.0 1.4 (0.8–2.9) 2.3 (1.2–4.0) | Age |
Jouven X et al., 1999, France | Paris Prospective Study 1 | 1967–1972–1994, 23 years follow-up | 7746 men, age 43-52 years: 118 sudden deaths | Smoking | Per 10.5 g/d | 1.79 (1.31–2.40) | Age, BMI, DM, heart rate, SBP, cholesterol, TG, parental MI, parental sudden death |
Wennberg P et al., 2007, Sweden | Vasterbotten Intervention Program and the Northern Sweden MONICA study | 1986, 1990, 1994, 1999–1985–1999, ~ 4 years follow-up | Nested case–control study: 93 sudden cardiac deaths 1798 controls | Tobacco use | Never used tobacco | 1.00 | Age, sex, BMI, leisure-time physical activity, education + cholesterol |
Never smoker/former snuff | 0.71 (0.36–1.43) | ||||||
Never smoker/current snuff | 0.90 (0.52–1.56) | ||||||
Former smoker/never snuff | 1.22 (0.85–1.74) | ||||||
Former smoker/former snuff | 1.39 (0.88–2.18) | ||||||
Former smoker/current snuff | 1.38 (0.89–2.14) | ||||||
Current smoker/no current snuff | 2.78 (2.05-3.78) | ||||||
Current smoker/current snuff | 2.33 (1.40–3.88) | ||||||
Never used tobacco | 1.00 | ||||||
Never smoker/former snuff | 0.66 (0.32–1.34) | ||||||
Never smoker/current snuff | 0.82 (0.46–1.43) | ||||||
Former smoker/never snuff | 1.18 (0.82–1.70) | ||||||
Former smoker/former snuff | 1.34 (0.84–2.12) | ||||||
Former smoker/current snuff | 1.25 (0.80–1.96) | ||||||
Current smoker/no current snuff | 2.60 (1.91–3.54) | ||||||
Current smoker/current snuff | 2.14 (1.28–3.60) | ||||||
Laukkanen JA et al., 2010, Finland | Kuopio Ischemic Heart Disease Risk Factor Cohort | 1984–1989 –2005, 17 years follow-up | 2368 men, age 42–60 years: 146 sudden cardiac deaths | Cigarette smoking | Per 10 pack-years | 1.27 (1.19–1.36) | Age, alcohol, hs-CRP, LDL cholesterol, HDL cholesterol, WHR, maximal heart rate during exercise |
Sandhu RK et al., 2012, USA | Nurses’ Health Study | 1980–2010, 30 years follow-up | 101,018 women, age 34–59 years: 351 sudden cardiac deaths | Smoking status | Never | 1.00 | Age, DM, hypertension, hypercholesterolemia, BMI, alcohol, physical activity, menopausal status, postmenopausal hormone use, aspirin, multivitamin use, vitamin E, FH—MI |
Former | 1.40 (1.10–1.79) | ||||||
Current | 2.44 (1.80–3.31) | ||||||
Cigarettes per day | Current, 1–14 cig/d | 1.84 (1.16–2.92) | |||||
Current, 15–24 | 2.62 (1.74–3.94) | ||||||
Current, ≥ 25 | 3.30 (2.04–5.33) | ||||||
Duration of smoking | Never | 1.00 | |||||
<12 years | 1.35 (0.92–1.98) | ||||||
13-< 24 | 1.02 (0.69–1.52) | ||||||
25-< 35 | 1.48 (1.05–2.08) | ||||||
≥35 | 2.22 (1.71–2.90) | ||||||
Smoking cessation, no CHD at time of SCD | Current | 1.00 | |||||
<5 years | 0.47 (0.24–0.92) | ||||||
5-< 10 | 0.63 (0.35–1.14) | ||||||
10-< 15 | 0.43 (0.21–0.87) | ||||||
15-< 20 | 0.52 (0.28–0.98) | ||||||
≥20 | 0.45 (0.30–0.68) | ||||||
Never | 0.41 (0.29–0.58) | ||||||
Smoking cessation, CHD at time of SCD | Current | 1.00 | |||||
<5 years | 2.14 (0.91–5.03) | ||||||
5 < 10 | 1.25 (0.49–3.19) | ||||||
10-< 15 | 1.61 (0.65–3.99) | ||||||
15-< 20 | 0.53 (0.17–1.64) | ||||||
≥20 | 0.59 (0.26–1.35) | ||||||
Never | 0.51 (0.24–1.10) | ||||||
Bertoia ML et al., 2012, USA | Women’s Health Initiative | 1993–1998–2009, 10.8 years follow-up | 161,808 women, age 50–79 years: 418 sudden cardiac deaths | Smoking status | Never, former Current | 2.26 (1.66–3.09) | Age, race, total family income, resting pulse, BMI, WHR, CHD (excluding MI), MI, heart failure, atrial fibrillation, diabetes mellitus, carotid artery disease, hypertension |
Ohira T et al., 2012, Japan | Circulatory Risk in Communities Study | 1975–2005, ~ 3.5 years follow-up | 26,870: nested case–control study: 239 sudden cardiac deaths 717 controls | Smoking | Never, former Current | 1.55 (1.08–2.24) | Hypertension, diabetes, hyperlipidemia, excess ethanol intake, BMI, heart rate, atrial fibrillation, SVPC/VPC, major ST-T abnormalities, minor ST-T abnormalities, prolonged PQ duration, wide QRS, left high amplitude R wave, abnormal Q wave |
Lahtinen AM et al., 2012, Finland | FINRISK 1992 | 1992–2008, ~ 16 years follow-up | 5345 men and women, mean age 44.3 years: 129 sudden cardiac deaths | Smoking status | Never | 1.00 | Age, sex, geographic region, HDL/TC ratio, SBP, BMI, diabetes, physical activity, prevalent CHD, QT-prolonging drug, digoxin |
Former | 1.21 (0.79–1.84) | ||||||
Current | 2.70 (1.85–3.94) | ||||||
Lahtinen AM et al., 2012, Finland | FINRISK 1997 | 1997–2008, ~ 11 years follow-up | 7672 men and women, mean age 48.4 years: 178 sudden cardiac deaths | Smoking status | Never | 1.00 | Age, sex, geographic region, HDL/TC ratio, SBP, BMI, diabetes, physical activity, prevalent CHD, QT-prolonging drug, digoxin |
Former | 1.28 (0.86–1.90) | ||||||
Current | 2.78 (1.89–4.09) | ||||||
Lahtinen AM et al., 2012, Finland | FINRISK 2002 | 2002–2008, ~ 6 years follow-up | 8212 men and women, mean age 48.0 years: 75 sudden cardiac deaths | Smoking status | Never | 1.00 | Age, sex, geographic region, HDL/TC ratio, SBP, BMI, diabetes, physical activity, prevalent CHD, QT-prolonging drug, digoxin |
Former | 1.08 (0.56–2.09) | ||||||
Current | 5.48 (3.04–9.86) | ||||||
Lahtinen AM et al., 2012, Finland | Health 2000 | 2000–2008, ~ 8 years follow-up | 6400 men and women, mean age 53.0 years: 112 sudden cardiac deaths | Smoking status | Never | 1.00 | Age, sex, geographic region, HDL/TC ratio, SBP, BMI, diabetes, physical activity, prevalent CHD, QT-prolonging drug, digoxin |
Former | 2.36 (1.38–4.02) | ||||||
Current | 4.83 (2.84–8.22) | ||||||
Karppi J et al., 2013, Finland | Kuopio Ischemic Heart Disease Risk Factor Cohort | 1984–1989 –2008, 15.9 years follow-up | 1031 men, age 46–65 years: 59 sudden cardiac deaths | Smoking | Never, former | 1.00 | Age, SBP, diabetes, waist circumference, alcohol, education, prevalent CHD, CHF, MI, hypertension, serum beta-carotene, LDL cholesterol, triglycerides, hs-CRP |
Current | 2.04 (1.20–3.48) | ||||||
Deo R et al., 2016, USA | Atherosclerosis Risk in Communities Study (ARIC) | 1989-1990 - 1992-1993 - NA, 14.2 years follow-up | 13,677 men and women, mean age 54 years and 4207 men and women, mean age 72 years: 345 sudden cardiac deaths | Smoking status | Never/former | 1.00 | Age, sex, race, SBP, antihypertensive medication use, DM, potassium quadratic potassium term, albumin, HDL cholesterol, eGFR, QT interval |
Current | 2.41 (1.77–3.30) |
Subgroup and sensitivity analyses and study quality
Current Smoking | Former smoking | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
n
| RR (95% CI) | I
2
(%) |
P
h
1
|
P
h
2
|
n
| RR (95% CI) | I
2
(%) |
P
h
1
|
P
h
2
| |
All studies | 7 | 3.06 (2.46–3.82) | 40.5 | 0.12 | 7 | 1.38 (1.20–1.60) | 0 | 0.55 | ||
Follow-up | ||||||||||
< 10 years | 3 | 3.97 (2.37–6.64) | 58.6 | 0.09 | 0.10 | 3 | 1.58 (0.99–2.53) | 43.8 | 0.17 | 0.37 |
≥ 10 years | 4 | 2.67 (2.21–3.22) | 0 | 0.85 | 4 | 1.34 (1.14–1.57) | 0 | 0.94 | ||
Sex
| ||||||||||
Men | 1 | 2.30 (1.20–4.00) | 0.20 | 1 | 1.40 (0.80–2.90) | 0.91 | ||||
Women | 1 | 2.44 (1.80–3.31) | 1 | 1.40 (1.10–1.79) | ||||||
Men and women | 5 | 3.44 (2.62–4.51) | 40.2 | 0.15 | 5 | 1.38 (1.12–1.71) | 18.9 | 0.30 | ||
Geographic location
| ||||||||||
Europe | 6 | 3.26 (2.54–4.20) | 37.2 | 0.16 | 0.35 | 6 | 1.38 (1.15–1.64) | 0 | 0.42 | 0.91 |
America | 1 | 2.44 (1.80–3.31) | 1 | 1.40 (1.10–1.79) | ||||||
Asia | 0 | 0 | ||||||||
Number of cases
| ||||||||||
< 100 | 2 | 4.10 (2.40–7.01) | 45.8 | 0.18 | 0.15 | 2 | 1.30 (0.99–1.71) | 0 | 0.55 | 0.86 |
100-< 150 | 3 | 3.10 (2.05–4.67) | 51.4 | 0.13 | 3 | 1.56 (1.03–2.38) | 47.1 | 0.15 | ||
≥150 | 2 | 2.57 (2.02–3.26) | 0 | 0.60 | 2 | 1.37 (1.11–1.68) | 0 | 0.71 | ||
Study quality | ||||||||||
0–3 stars | 0 | 0.18 | 0 | 0.90 | ||||||
4–6 stars | 2 | 2.41 (1.84–3.16) | 0 | 0.86 | 2 | 1.40 (1.11–1.76) | 0 | 0.99 | ||
7–9 stars | 5 | 3.44 (2.62–4.51) | 40.2 | 0.15 | 5 | 1.38 (1.12–1.71) | 18.9 | 0.30 | ||
Adjustment for confounding factors
| ||||||||||
Age | ||||||||||
Yes | 7 | 3.06 (2.46–3.82) | 40.5 | 0.12 | NC | 7 | 1.38 (1.20–1.60) | 0 | 0.55 | NC |
No | 0 | 0 | ||||||||
Family history of CHD
| ||||||||||
Yes | 1 | 2.44 (1.80–3.31) | 0.35 | 1 | 1.40 (1.10–1.79) | 0.91 | ||||
No | 6 | 3.26 (2.54–4.20) | 37.2 | 0.16 | 6 | 1.38 (1.15-1.64) | 0 | 0.42 | ||
Alcohol
| ||||||||||
Yes | 1 | 2.44 (1.80–3.31) | 0.35 | 1 | 1.40 (1.10–1.79) | 0.91 | ||||
No | 6 | 3.26 (2.54–4.20) | 37.2 | 0.16 | 6 | 1.38 (1.15–1.64) | 0 | 0.42 | ||
BMI
| ||||||||||
Yes | 6 | 3.18 (2.49–4.05) | 46.6 | 0.10 | 0.46 | 6 | 1.38 (1.19–1.60) | 0 | 0.42 | 0.97 |
No | 1 | 2.30 (1.20–4.00) | 1 | 1.40 (0.80–2.90) | ||||||
Diabetes
| ||||||||||
Yes | 5 | 3.22 (2.42–4.28) | 57.1 | 0.05 | 0.62 | 5 | 1.40 (1.14–1.70) | 18.6 | 0.30 | 0.88 |
No | 2 | 2.76 (1.85–4.10) | 0 | 0.43 | 2 | 1.36 (1.04–1.78) | 0 | 0.92 | ||
Hypertension
| ||||||||||
Yes | 1 | 2.44 (1.80–3.31) | 0.35 | 1 | 1.40 (1.10–1.79) | 0.91 | ||||
No | 6 | 3.26 (2.54–4.20) | 37.2 | 0.16 | 6 | 1.38 (1.15–1.64) | 0 | 0.42 | ||
Blood cholesterol
| ||||||||||
Yes | 5 | 3.22 (2.42–4.28) | 57.1 | 0.05 | 0.63 | 5 | 1.40 (1.14–1.70) | 18.6 | 0.30 | 0.88 |
No | 2 | 2.76 (1.85–4.10) | 0 | 0.43 | 2 | 1.36 (1.04–1.78) | 0 | 0.92 | ||
Prevalent coronary heart disease
| ||||||||||
Yes | 4 | 3.55 (2.52–5.00) | 54.9 | 0.08 | 0.24 | 4 | 1.40 (1.03–1.91)1 | 38.9 | 0.18 | 0.98 |
No | 3 | 2.55 (2.01–3.25) | 0 | 0.66 | 3 | 1.38 (1.15–1.66) | 0 | 0.98 | ||
QT prolonging drug use
| ||||||||||
Yes | 4 | 3.55 (2.52–5.00) | 54.9 | 0.08 | 0.24 | 4 | 1.40 (1.03–1.91) | 38.9 | 0.18 | 0.98 |
No | 3 | 2.55 (2.01–3.25) | 0 | 0.66 | 3 | 1.38 (1.15–1.66) | 0 | 0.98 | ||
Digoxin
| ||||||||||
Yes | 4 | 3.55 (2.52–5.00) | 54.9 | 0.08 | 0.24 | 4 | 1.40 (1.03–1.91) | 38.9 | 0.18 | 0.98 |
No | 3 | 2.55 (2.01–3.25) | 0 | 0.66 | 3 | 1.38 (1.15–1.66) | 0 | 0.98 | ||
Physical activity
| ||||||||||
Yes | 6 | 3.18 (2.49–4.05) | 46.6 | 0.10 | 0.46 | 6 | 1.38 (1.19–1.60) | 0 | 0.42 | 0.97 |
No | 1 | 2.30 (1.20-4.00) | 1 | 1.40 (0.80–2.90) |
Ever smoking | |||||
---|---|---|---|---|---|
n
| RR (95% CI) | I
2
(%) |
P
h
1
|
P
h
2
| |
All studies | 7 | 2.01 (1.70–2.38) | 54.1 | 0.04 | |
Follow-up | |||||
< 10 years | 3 | 2.57 (1.80–3.68) | 54.8 | 0.11 | 0.04 |
≥10 years | 4 | 1.78 (1.58–2.01) | 0 | 0.86 | |
Sex
| |||||
Men | 1 | 1.82 (1.18–2.83) | 0.47 | ||
Women | 1 | 1.74 (1.44–2.10) | |||
Men and women | 5 | 2.15 (1.69–2.72) | 64.3 | 0.02 | |
Geographic location
| |||||
Europe | 6 | 2.09 (1.70–2.57) | 56.3 | 0.04 | 0.49 |
America | 1 | 1.74 (1.44-2.10) | |||
Asia | 0 | ||||
Number of cases
| |||||
< 100 | 2 | 2.03 (1.29–3.21) | 69.5 | 0.07 | 0.68 |
100-< 150 | 3 | 2.26 (1.54–3.32) | 70.7 | 0.03 | |
≥ 150 | 2 | 1.79 (1.53–2.09) | 0 | 0.58 | |
Study quality
| |||||
0–3 stars | 0 | 0.41 | |||
4–6 stars | 2 | 1.75 (1.47–2.08) | 0 | 0.85 | |
7–9 stars | 5 | 2.15 (1.69–2.72) | 64.3 | 0.02 | |
Age
| |||||
Yes | 7 | 2.01 (1.70–2.38) | 54.1 | 0.04 | NC |
No | 0 | ||||
Family history of CHD
| |||||
Yes | 1 | 1.74 (1.44–2.10) | 0.49 | ||
No | 6 | 2.09 (1.70–2.57) | 56.3 | 0.04 | |
Alcohol
| |||||
Yes | 1 | 1.74 (1.44–2.10) | 0.49 | ||
No | 6 | 2.09 (1.70–2.57) | 56.3 | 0.04 | |
BMI
| |||||
Yes | 6 | 2.04 (1.69–2.46) | 61.6 | 0.02 | 0.74 |
No | 1 | 1.82 (1.18–2.83) | |||
Diabetes
| |||||
Yes | 5 | 2.15 (1.72–2.68) | 65.0 | 0.02 | 0.35 |
No | 2 | 1.70 (1.36–2.13) | 0 | 0.72 | |
Hypertension
| |||||
Yes | 1 | 1.74 (1.44–2.10) | 0.49 | ||
No | 6 | 2.09 (1.70–2.57) | 56.3 | 0.04 | |
Blood cholesterol
| |||||
Yes | 5 | 2.15 (1.72–2.68) | 65.0 | 0.02 | 0.35 |
No | 2 | 1.70 (1.36–2.13) | 0 | 0.72 | |
Prevalent coronary heart disease
| |||||
Yes | 4 | 2.32 (1.77–3.03) | 61.8 | 0.05 | 0.14 |
No | 3 | 1.72 (1.49–1.99) | 0 | 0.93 | |
QT prolonging drug use
| |||||
Yes | 4 | 2.32 (1.77–3.03) | 61.8 | 0.05 | 0.14 |
No | 3 | 1.72 (1.49–1.99) | 0 | 0.93 | |
Digoxin
| |||||
Yes | 4 | 2.32 (1.77–3.03) | 61.8 | 0.05 | 0.14 |
No | 3 | 1.72 (1.49–1.99) | 0 | 0.93 | |
Physical activity
| |||||
Yes | 6 | 2.04 (1.69–2.46) | 61.6 | 0.02 | 0.74 |
No | 1 | 1.82 (1.18–2.83) |