Behavioral associations with waterpipe tobacco smoking dependence among US young adults.

BACKGROUND AND AIMS Waterpipe tobacco smoking (WTS) is increasingly prevalent in the United States, especially among young adults. We aimed to (1) adapt items from established dependence measures into a WTS dependence scale for US young adults (the US Waterpipe Dependence Scale), (2) determine the factor structure of the items and (3) assess associations between scale values and behavioral use characteristics known to be linked to dependence. DESIGN Cross-sectional survey. SETTING United States. PARTICIPANTS A total of 436 past-year waterpipe tobacco users ages 18-30 years selected at random from a national probability-based panel. MEASUREMENTS Participants responded to six tobacco dependence items adapted for WTS in US populations. Behavioral use characteristics included factors such as frequency of use and age of initiation. FINDINGS Principal components analysis yielded an unambiguous one-factor solution. Approximately half (52.9%) of past-year waterpipe tobacco users received a score of 0, indicating that none of the six WTS dependence items were endorsed. Approximately one-quarter (25.4%) endorsed one dependence item and 22.7% endorsed two or more items. Higher WTS dependence scores were associated significantly with all five behavioral use characteristics. For example, compared with those who endorsed no dependence items, those who endorsed two or more had an adjusted odds ratio (AOR) of 3.90 [95% confidence interval (CI) = 1.56-9.78] for having had earlier age of initiation and an AOR of 32.75 (95% CI = 9.76-109.86) for more frequent WTS sessions. CONCLUSIONS Scores on a six-item waterpipe tobacco smoking dependence scale (the US Waterpipe Dependence Scale) correlate with measures that would be expected to be related to dependence, such as amount used and age of initiation.