Statistical Analyses Descriptive statistics included means Carfilzomib order and CI for continuous variables and percentages for categorical variables. We compared demographic characteristics and prevalence of lifetime panic disorder, major depression, PTSD, and alcohol use disorders according to lifetime ST use status (users vs. nonusers) across each tribe. Logistic regression analyses examined the strength of the association between the individual psychiatric disorders and the odds of lifetime ST use by fitting three separate models adjusted for age, sex, education, marital status, employment status, and smoking status. We then estimated each psychiatric disorder��s association with ST after adjusting for demographic variables, smoking status, and the two remaining psychiatric disorder diagnoses.

We constructed a final model to estimate the association between the individual psychiatric disorders and ST after adjusting for demographics, smoking status, comorbid psychiatric conditions, and lifetime alcohol use disorder diagnosis. Results were reported using OR and 95% CI. Next, regression analyses examined the association of psychiatric comorbidity and the odds of ST in the two tribes. We estimated the lifetime ST use OR for groups defined as having 0, 1, 2, and 3 or more psychiatric disorders, after adjusting for demographic factors. Participants with no psychiatric disorders were the reference group for all comparisons. In addition, we fit a similarly adjusted logistic model to allow a test for trend in the odds of lifetime ST with the increasing number of comorbid psychiatric diagnoses.

All statistical tests were two-sided adjusted Wald tests. We conducted analyses with Stata 10 for Windows (Stata Corporation, College Station, TX) using ��svy�� commands to accommodate the weights for complex sampling and survey nonresponse. Results Sample Description Three-hundred ten participants (10%) were excluded from analyses due to incomplete data on ST history or lifetime psychiatric disorders. Excluded and included participants had similar sociodemographic characteristics, with the exception of age. Excluded participants were, on average, 2.2 years older than included participants (p < .01). The analytic sample included 1,506 Northern Plains participants and 1,268 Southwest participants. Table 1 presents participant characteristics by tribal region and lifetime ST use status.

The prevalence of lifetime ST use was similar in the Northern Plains and Southwest tribes (31% vs. 30%). ST users in the Northern Plains were younger than nonusers (p < .01). Conversely, in the Southwest, users were older than nonusers (p < .01). In both tribes, a lower proportion of ST users were female (p < Batimastat .01) than nonusers. ST users from both the Northern Plains and Southwest tribes were more likely to be married or living with their partner (p NP = .02, p SW < .