Two main types of studies of alcohol consumption and total mortality/morbidity are distinguished, namely: individual level studies and aggregate level studies.
Alcohol consumption is usually characterized in terms of volume or average volume of consumption. More recently, patterns of drinking, especially heavy drinking occasions, have been introduced. On the individual level, the definition of mortality is trivial (death) and morbidity is either defined by hospitalization or by subjective definitions. On the aggregate level, mortality is defined either in death rates or in years of life lost, and morbidity as hospitalization rates or years of life lost to disability. Disability Adjusted Life Years (DALYs) combine mortality and morbidity into a summary measure of health.
Individual level studies clearly should be given preference in assessing the relationship between alcohol and outcomes, as long as the assessment of alcohol consumption is state-of-the-art and the sample includes all relevant drinking patterns, plus if there is adequate control for confounding and adequate statistical analysis.