title: Estimating average alcohol consumption in the population using multiple sources: the case of Spain.
abstract: BACKGROUND
  National estimates on per capita alcohol consumption are provided regularly by various sources and may have validity problems, so corrections are needed for monitoring and assessment purposes. Our objectives were to compare different alcohol availability estimates for Spain, to build the best estimate (actual consumption), characterize its time trend during 2001-2011, and quantify the extent to which other estimates (coverage) approximated actual consumption.
  
  
  METHODS
  Estimates were: alcohol availability from the Spanish Tax Agency (Tax Agency availability), World Health Organization (WHO availability) and other international agencies, self-reported purchases from the Spanish Food Consumption Panel, and self-reported consumption from population surveys. Analyses included calculating: between-agency discrepancy in availability, multisource availability (correcting Tax Agency availability by underestimation of wine and cider), actual consumption (adjusting multisource availability by unrecorded alcohol consumption/purchases and alcohol losses), and coverage of selected estimates. Sensitivity analyses were undertaken. Time trends were characterized by joinpoint regression.
  
  
  RESULTS
  Between-agency discrepancy in alcohol availability remained high in 2011, mainly because of wine and spirits, although some decrease was observed during the study period. The actual consumption was 9.5 l of pure alcohol/person-year in 2011, decreasing 2.3 % annually, mainly due to wine and spirits. 2011 coverage of WHO availability, Tax Agency availability, self-reported purchases, and self-reported consumption was 99.5, 99.5, 66.3, and 28.0 %, respectively, generally with downward trends (last three estimates, especially self-reported consumption). The multisource availability overestimated actual consumption by 12.3 %, mainly due to tourism imbalance.
  
  
  CONCLUSIONS
  Spanish estimates of per capita alcohol consumption show considerable weaknesses. Using uncorrected estimates, especially self-reported consumption, for monitoring or other purposes is misleading. To obtain conservative estimates of alcohol-attributable disease burden or heavy drinking prevalence, self-reported consumption should be shifted upwards by more than 85 % (91 % in 2011) of Tax Agency or WHO availability figures. The weaknesses identified can probably also be found worldwide, thus much empirical work remains to be done to improve estimates of per capita alcohol consumption.
authors.affiliation: National Epidemiology Center, Carlos III Health Institute, Avenida Monforte de Lemos 5, E-28029 Madrid, Spain ; Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Avenida Monforte de Lemos 5, E-28029 Madrid, Spain ; Department of Preventive Medicine and Public Health, Madrid Complutense University, Ciudad Universitaria s/n, E-28040 Madrid, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Sordo
authors.affiliation: National School of Public Health, Carlos III Health Institute, Avenida Monforte de Lemos 5, E-28029 Madrid, Spain.
authors.forename: Gregorio
authors.initials: G
authors.lastname: Barrio
authors.affiliation: National Epidemiology Center, Carlos III Health Institute, Avenida Monforte de Lemos 5, E-28029 Madrid, Spain ; Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Avenida Monforte de Lemos 5, E-28029 Madrid, Spain.
authors.forename: María J
authors.initials: MJ
authors.lastname: Bravo
authors.affiliation: Agència de Salut Pública de Barcelona, Pl. Lesseps, 1. E-08023 Barcelona, Spain.
authors.forename: Joan R
authors.initials: JR
authors.lastname: Villalbí
authors.affiliation: Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Avenida Monforte de Lemos 5, E-28029 Madrid, Spain ; Agència de Salut Pública de Barcelona, Pl. Lesseps, 1. E-08023 Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Espelt
authors.affiliation: Ministry of Health, Social Services and Equality, Paseo del Prado 18-20, E-28071 Madrid, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Neira
authors.affiliation: Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Avenida Monforte de Lemos 5, E-28029 Madrid, Spain ; Department of Preventive Medicine and Public Health, Madrid Complutense University, Ciudad Universitaria s/n, E-28040 Madrid, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Regidor
keywords: Alcohol; Availability; Consumption; Data sources; Population surveys; Purchases; Sales; Self-report; Underestimation