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Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
“ Cigarette Smoking, Systolic Blood Pressure, and Cardiovascular Diseases in the Asia-Pacific
Region. ”
Nakamura K, Barzi F, Lam TH, Huxley R, Feigin VL, Ueshima H, Woo J, Gu D, Ohkubo T, Lawes CMM, Suh
I, Woodward M
for Asia Pacific Cohort Studies Collaboration.
Stroke (published on 2008 Mar 6)
Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
Background and Purpose
• Smoking and increased levels of blood pressure (BP) substantially increase the risk of cardiovascular diseases (CVD).
• If these two risk factors have a synergistic impact on cardiovascular events, lowering BP and quitting smoking will contribute more to reducing CVD than would be expected from ignoring their interaction.
Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
Methods• A total of 41 cohorts involving 563,144 participants (82% Asians;
35% female) were included in the analysis with a mean age of 47 years.
• Hazards ratios (HRs) and 95% confidence intervals (CIs) for an increase in systolic blood pressure (SBP) were estimated by smoking status (non-smokers and current smokers), using Cox proportional hazards regression models.
Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
Results• There was a log-linear relationship between SBP and all subtypes of
CVD.
• The HRs relating SBP to both CHD and ischemic stroke were broadly similar irrespective of smoking status.
• The HRs relating SBP to hemorrhagic stroke (intracerebral hemorrhage) were greater in current smokers than in non-smokers.
Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
110 120 130 140 150 160
0.7
1.0
2.0
3.0
5.0
8.0
12.0A. Coronary heart disease
Haz
ard
ratio
110 120 130 140 150 160
0.7
1.0
2.0
3.0
5.0
8.0
12.0C. Hemorrhagic stroke
110 120 130 140 150 160
0.7
1.0
2.0
3.0
5.0
8.0
12.0B. Ischemic stroke
110 120 130 140 150 160
0.7
1.0
2.0
3.0
5.0
8.0
12.0D. Other strokes
Haz
ard
ratio
Usual SBP (mmHg) Usual SBP (mmHg)
Usual SBP (mmHg)Usual SBP (mmHg)
Continuous line Non-smokers
Dashed line Current smokers
Stroke
Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
HR (95%CI) associated with a 10 mmHg increase in SBP
1 1.2 1.5 2 2.5
Men
Women
Asia
ANZ
<65 years
65+ years
Overall
0.12
0.16
0.97
0.53
0.97
0.26
0.14
p value for interaction
CHD
Men
Women
Asia
ANZ
<65 years
65+ years
Overall
0.20
0.08
0.91
0.42
0.28
0.84
0.53
Ischemic stroke
Men
Women
Asia
ANZ
<65 years
65+ years
Overall
0.01
0.19
0.05
0.30
0.78
0.008
0.003
Hem. stroke
Continuous line Non-smokers
Dashed line Current smokers
Stroke
Copyright © 2008 Society for Heart Attack Prevention and Eradication. All Rights Reserved.
Conclusions• Smoking exacerbated the impact of SBP on the risk of hemorrhagic
stroke.
• Although quitting smoking and lowering BP are both crucial for prevention of CVD, combining the two could be expected to have extra beneficial effect on preventing hemorrhagic stroke.
