Purpose

Alcohol use by trial participants is summarized in a set of variables that are available for researchers in the DHQ Alcohol dataset. These same variables are also included in the Diet History Questionnaire Dataset with over 900 other diet variables.

Population

Approximately 5400 intervention arm participants were selected for interview. Participants were required to be living and in contact with the PLCO trial (as of 2004) and have at least five years of follow-up (i.e., entered the trial prior to September 1999). As the University of Alabama began enrollment in 1998, participants from this center were not included.

Selected participants were contacted via telephone in 2005 and 2006. Of the 5400 queried, about 5000 consented to the interview process. Of these, 4100 had colonoscopy at baseline and are therefore the focus of surveillance colonoscopy analyses. Participants with baseline adenoma or without repeat (T3/T5) screen were intentionally oversampled. Sampling weights are provided in the data.

Data Collected

The Diet History Questionnaire (DHQ) asked participants to answer current and historical alcohol consumption of beer, wine and liquor. The current alcohol frequency/amount was collected for beer (Q8), wine (Q9) and liquor/mixed drinks (Q10) as a standard component of the DHQ. Historical data on the frequency/amount of alcohol consumption was collected for the following age groupings: 18-24, 25-39 40-54, 55+ (Q156). Data from their responses was cleaned to address inconsistencies.

Population

The DHQ covers nearly 119,000 participants and was completed a median time of 3 years after randomization. It was introduced 5yrs into the trial and was administered at different times for participants in the intervention arm vs. participants in the control arm. See https://cdas.cancer.gov/learn/plco/early-qx/dhq/ for more details on the DHQ.

Drinking Status and Lifetime Data Available

Drinking status at the DHQ was calculated to identify current/former/never using both the current and historical data. Lifetime alcohol consumption (mped_alc_bev_lifetime_dhq), which represents the average MPEDs of alcohol (drinks/day) from age 18 to DHQ completion, was derived for more than 110,000 participants.