title: Do "Moderate" Drinkers Have Reduced Mortality Risk? A Systematic Review and Meta-Analysis of Alcohol Consumption and All-Cause Mortality.
abstract: OBJECTIVE
  Previous meta-analyses of cohort studies indicate a J-shaped relationship between alcohol consumption and allcause mortality, with reduced risk for low-volume drinkers. However, low-volume drinkers may appear healthy only because the "abstainers" with whom they are compared are biased toward ill health. The purpose of this study was to determine whether misclassifying former and occasional drinkers as abstainers and other potentially confounding study characteristics underlie observed positive health outcomes for lowvolume drinkers in prospective studies of all-cause mortality.
  
  
  METHODS
  A systematic review and meta-regression analysis of studies investigating alcohol use and mortality risk after controlling for quality-related study characteristics was conducted in a population of 3,998,626 individuals, among whom 367,103 deaths were recorded.
  
  
  RESULTS
  Without adjustment, meta-analysis of all 87 included studies replicated the classic J-shaped curve, with low-volume drinkers (1.3-24.9 g ethanol per day) having reduced mortality risk (RR = 0.86, 95% CI [0.83, 0.90]). Occasional drinkers (<1.3 g per day) had similar mortality risk (RR = 0.84, 95% CI [0.79, 0.89]), and former drinkers had elevated risk (RR = 1.22, 95% CI [1.14, 1.31]). After adjustment for abstainer biases and quality-related study characteristics, no significant reduction in mortality risk was observed for low-volume drinkers (RR = 0.97, 95% CI [0.88, 1.07]). Analyses of higher-quality bias-free studies also failed to find reduced mortality risk for low-volume alcohol drinkers. Risk estimates for occasional drinkers were similar to those for low- and medium-volume drinkers.
  
  
  CONCLUSIONS
  Estimates of mortality risk from alcohol are significantly altered by study design and characteristics. Meta-analyses adjusting for these factors find that low-volume alcohol consumption has no net mortality benefit compared with lifetime abstention or occasional drinking. These findings have implications for public policy, the formulation of low-risk drinking guidelines, and future research on alcohol and health.
authors.affiliation: Centre for Addictions Research of BC, University of Victoria, Victoria, British Columbia, Canada.|National Drug Research Institute, Curtin University, Perth, WA 6845, Australia.
authors.forename: Tim
authors.initials: T
authors.lastname: Stockwell
authors.affiliation: Centre for Addictions Research of BC, University of Victoria, Victoria, British Columbia, Canada.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Institute for Scientific Analysis, San Francisco, California.
authors.forename: Sapna
authors.initials: S
authors.lastname: Panwar
authors.affiliation: Centre for Addictions Research of BC, University of Victoria, Victoria, British Columbia, Canada.
authors.forename: Audra
authors.initials: A
authors.lastname: Roemer
authors.affiliation: Boston University Schools of Medicine and Public Health, Boston, Massachusetts.
authors.forename: Timothy
authors.initials: T
authors.lastname: Naimi
authors.affiliation: Institute for Scientific Analysis, San Francisco, California.|National Drug Research Institute, Curtin University, Perth, WA 6845, Australia.
authors.forename: Tanya
authors.initials: T
authors.lastname: Chikritzhs
mesh_terms: D064829:Alcohol Abstinence / Q000639:trends; D000428:Alcohol Drinking / Q000401:mortality* / Q000639:trends*; D000435:Alcoholic Intoxication / Q000175:diagnosis / Q000401:mortality; D000437:Alcoholism / Q000175:diagnosis / Q000401:mortality; D015982:Bias; D002423:Cause of Death / Q000639:trends; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality / Q000639:trends; D011446:Prospective Studies; D012307:Risk Factors