Blackouts increase with age, social class and the frequency of intoxication.

Of 2,076 Finnish males, 35% reported at interview as having one or more blackouts during the previous 12 months. Age-adjusted mean frequencies of blackouts showed an almost linear increase with the frequency of intoxication. Because of the skewness of the drinking variables, logarithmic transformations were used in multiple regression analysis. This indicated that the frequency of blackouts was significantly associated with age, social class and the frequency of intoxicating drinking, but not with marital status or the frequency of non-intoxicating drinking. Together, the regressors accounted for 21% of the total variance of blackouts.