REVIEW Alcohol Consumption and Risk of Stroke A Meta-analysis Kristi Reynolds, MPH L. Brian Lewis, MPH John David L. Nolen, MD, PhD, MSPH Gregory L. Kinney, MPH Bhavani Sathya, MPH Jiang He, MD, PhD S TROKE IS THE THIRD LEADING cause of death and a major cause of disability in the United States. 1,2 In 1999, 167 366 deaths in the United States resulted from stroke. 1 Approximately 30% of stroke survivors are permanently disabled and 20% re- quire institutionalized care. 1 Stroke is also a huge financial burden for patients, their families, and the health care system. The cost of stroke in the United States in 2002 is estimated to be $49.4 billion, which includes direct health expenditures and lost productivity resulting from morbid- ity and mortality. 1 Alcoholic beverages are consumed widely throughout the world, and an association between alcohol consump- tion and stroke could have considerable public health and clinical implications. Over the past 2 decades, many observa- tional epidemiologic studies 3-37 have examined the role of alcohol as both a risk factor and a potential protective fac- tor for stroke. Heavy alcohol consump- tion has been linked to an increased risk of total stroke, 23,32 ischemic stroke, 29,33 and hemorrhagic stroke. 3,7,33,35 However, stud- ies investigating the association between moderate alcohol consumption and stroke have reported conflicting results. Some studies have reported that mod- erate alcohol consumption is inversely related to risk of total stroke, 31 ischemic stroke, 27,31,37 and hemorrhagic stroke, 27,31 while others found that moderate alco- hol consumption is positively related to risk of stroke. 3,25 We performed a meta-analysis of epi- demiologic studies to examine the rela- tive risk of stroke at various levels of alcohol consumption. METHODS Study Selection A literature search of the MEDLINE da- tabase (from January 1966 through April 2002) using the Medical Subject Headings alcohol drinking, ethanol, cere- brovascular accident, cerebrovascular dis- orders, and intracranial embolism and thrombosis and the keyword stroke was performed. The search was restricted to Author Affiliations: Department of Epidemiology, Tu- lane University School of Public Health and Tropical Medicine, New Orleans, La. Corresponding Author and Reprints: Kristi Rey- nolds, MPH, Department of Epidemiology, Tulane Uni- versity Health Sciences Center, School of Public Health and Tropical Medicine, 1430 Tulane Ave SL18, New Orleans, LA 70112 (e-mail: kreynol1@tulane.edu). Context Observational studies suggest that heavy alcohol consumption may in- crease the risk of stroke while moderate consumption may decrease the risk. Objective To examine the association between alcohol consumption and relative risk of stroke. Data Sources Studies published in English-language journals were retrieved by search- ing MEDLINE (1966–April 2002) using Medical Subject Headings alcohol drinking, ethanol, cerebrovascular accident, cerebrovascular disorders, and intracranial embo- lism and thrombosis and the key word stroke; Dissertation Abstracts Online using the keywords stroke and alcohol; and bibliographies of retrieved articles. Study Selection From 122 relevant retrieved reports, 35 observational studies (co- hort or case control) in which total stroke, ischemic stroke, or hemorrhagic (intracerebral or total) stroke was an end point; the relative risk or relative odds and their variance (or data to calculate them) of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and abstainers served as the reference group. Data Extraction Information on study design, participant characteristics, level of alco- hol consumption, stroke outcome, control for potential confounding factors, and risk esti- mates was abstracted independently by 3 investigators using a standardized protocol. Data Synthesis A random-effects model and meta-regression analysis were used to pool data from individual studies. Compared with abstainers, consumption of more than 60 g of alcohol per day was associated with an increased relative risk of total stroke, 1.64 (95% confidence interval [CI], 1.39-1.93); ischemic stroke, 1.69 (95% CI, 1.34-2.15); and hemorrhagic stroke, 2.18 (95% CI, 1.48-3.20), while consump- tion of less than 12 g/d was associated with a reduced relative risk of total stroke, 0.83 (95%, CI, 0.75-0.91) and ischemic stroke, 0.80 (95% CI, 0.67-0.96), and con- sumption of 12 to 24 g/d was associated with a reduced relative risk of ischemic stroke, 0.72 (95%, CI, 0.57-0.91). The meta-regression analysis revealed a significant non- linear relationship between alcohol consumption and total and ischemic stroke and a linear relationship between alcohol consumption and hemorrhagic stroke. Conclusions These results indicate that heavy alcohol consumption increases the relative risk of stroke while light or moderate alcohol consumption may be protective against total and ischemic stroke. JAMA. 2003;289:579-588 www.jama.com ©2003 American Medical Association. All rights reserved. (Reprinted) JAMA, February 5, 2003—Vol 289, No. 5 579 Downloaded From: http://jama.jamanetwork.com/ on 02/25/2013