Monthly variations in self-reports of alcohol consumption

Objective: This study examines monthly variation in reports of recent alcoh ol consumption behavior. Method: Telephone survey data collected by the Behavioral Risk Factor Surve illance System were used to measure self-reports of drinking and heavy epis odic drinking in the 30 days before the interview. The sample (N = 57,758) comprised cases collected in six states in 5 selected years. Monthly variab ility in self-reported alcohol consumption was evaluated by logistic regres sion analysis, using "deviation from means coding" for the month of intervi ew, with background variables and year of interview controlled and state-le vel clustering adjusted. Results: Adults were significantly more likely to report past 30-day alcoho l consumption when interviewed during the month of January and less likely to report consumption when interviewed during March. Respondents were also more likely to report heavy episodic drinking during tile month of July. De spite large differences in alcohol consumption between male and female part icipants, these seasonal patterns were essentially the same for bath gender s. Conclusions: The findings suggest that assessments of alcohol consumption t hat do not consider seasonal variation may be biased. In order to minimize this bias, it is recommended that researchers avoid collecting data only du ring these particular times of the year or extend the data collection inter val and control for seasonal variability.