Urinary Cotinine and Cotinine + Trans-3'-Hydroxycotinine (TNE-2) Cut-points for Distinguishing Tobacco Use from Nonuse in the United States: PATH Study (2013-2014).

BACKGROUND: Determine the overall, sex-, and racially/ethnically-appropriate population-level cotinine and total nicotine equivalents (TNE-2, the molar sum of the two major nicotine metabolites) cut-points to distinguish tobacco users from nonusers across multiple definitions of use (e.g., exclusive vs. polytobacco, and daily vs. non-daily). METHODS: Using Wave 1 (2013-2014) of the U.S. Population Assessment of Tobacco and Health (PATH) Study, we conducted weighted Receiver Operating Characteristic (ROC) analysis to determine the optimal urinary cotinine and TNE-2 cut-points, stratified by sex and race/ethnicity. RESULTS: For past 30-day exclusive cigarette users, the cotinine cut-point that distinguished them from nonusers was 40.5 ng/mL, with considerable variation by sex (male: 22.2 ng/mL; female: 43.1 ng/mL) and between racial/ethnic groups (non-Hispanic other: 5.2 ng/mL; non-Hispanic black: 297.0 ng/mL). A similar, but attenuated, pattern emerged when assessing polytobacco cigarette users (overall cut-point = 39.1 ng/mL, range = 5.5 ng/mL-80.4 ng/mL) and any tobacco users (overall cut-point = 39.1 ng/mL, range = 4.8 ng/mL-40.0 ng/mL). Using TNE-2, which is less impacted by racial differences in nicotine metabolism, produced a comparable pattern of results although reduced the range magnitude. CONCLUSIONS: Because of similar frequency of cigarette use among polytobacco users, overall cut-points for exclusive cigarette use were not substantially different from cut-points that included polytobacco cigarette use or any tobacco use. Results revealed important differences in sex and race/ethnicity appropriate cut-points when evaluating tobacco use status and established novel urinary TNE-2 cut-points. IMPACT: These cut-points may be used for biochemical verification of self-reported tobacco use in epidemiologic studies and clinical trials.

Chronic Obstructive Pulmonary Disease Prevalence and Associated Factors in a Setting of Well-Controlled HIV, A Cross-Sectional Study.

In Sub-Saharan Africa, COPD remains prevalent but its association with HIV is not well characterized especially in rural settings. We assessed for COPD prevalence, associated factors and lung function profile among HIV-infected individuals attending ART clinics in rural Nakaseke district of Uganda. We enrolled HIV-positive participants from four HIV treatment centers in rural Uganda. Participants underwent spirometry testing following standard guidelines. We defined COPD as a post-bronchodilator FEV1/FVC ratio less than the fifth percentile of the NHANES III African-American reference. We assessed for factors associated with COPD and lung function profiles using multivariable logistic and linear regression analyses. We analyzed data from 722 HIV-positive participants (mean age 48.0 years, 59.7% women). Over 90% of participants were on ART for a median duration of 4 years (IQR 2-7 years), with a median viral load of 0 copies/mL (IQR 0-0 copies/mL), current and baseline CD4 + T cell count of 478 cells/mm3 (IQR 346-663 cells/mm3) and 335 cells/mm3 (IQR 187-523 cells/mm3) respectively. The prevalence of COPD was 6.22%. COPD was associated with worse respiratory symptoms and health status. History of pulmonary tuberculosis was strongly associated with COPD (adjusted OR = 4.92, 95% CI 1.71 to 14.15, p = 0.003) and reduced lung function. Use of ART, CD4+T cell count and viral load were not associated with COPD or reduced lung function. In conclusion, we report a COPD prevalence of 6.22% in HIV-infected individuals in rural Uganda. Pulmonary tuberculosis remains the strongest predictor of COPD risk and reduced lung function in well-controlled HIV.