ABSTRACT
SETTING: Tijuana, Mexico. OBJECTIVE: To describe the association between salivary cotinine levels and interferon-gamma (IFN-γ) release assay results. DESIGN: We conducted a cross-sectional study among injection drug users. Salivary cotinine levels were measured using NicAlert, a semi-quantitative dipstick assay. QuantiFERON©-TB Gold In-Tube (QFT-GIT) was used to determine Mycobacterium tuberculosis infection. RESULTS: Among 234 participants, the prevalence of QFT-GIT positivity for NicAlert cotinine categories 0 (non-smoking), 1 (second-hand smoke exposure or low-level smoking) and 26 (regular smoking) were respectively 42.1%, 46.4% and 65.2% (Ptrend 0.012). We found increasing trends in QFT-GIT positivity (Ptrend 0.003) and IFN-γ concentrations (Spearman's r 0.200, P 0.002) across cotinine levels 0 to 6. In multivariable log-binomial regression models adjusted for education, cotinine levels were not associated with QFT-GIT positivity when included as smoking categories (1 and 26 vs. 0), but were independently associated with QFT-GIT positivity when included as an ordinal variable (prevalence ratio 1.09 per 1 cotinine level, 95%CI 1.021.16). CONCLUSION: Our findings suggest that a dose-response relationship exists between tobacco smoke exposure and M. tuberculosis infection. Longitudinal studies that use biochemical measures for smoking status are needed to confirm our findings.
Subject(s)
Cotinine/metabolism , Mycobacterium tuberculosis/isolation & purification , Saliva/metabolism , Smoking/metabolism , Tuberculosis/microbiology , Adult , Chi-Square Distribution , Cross-Sectional Studies , Dose-Response Relationship, Drug , Drug Users , Female , Humans , Interferon-gamma Release Tests , Male , Mexico/epidemiology , Middle Aged , Multivariate Analysis , Predictive Value of Tests , Prevalence , Reagent Strips , Risk Factors , Smoking/adverse effects , Smoking/epidemiology , Substance Abuse, Intravenous/epidemiology , Tuberculosis/diagnosis , Tuberculosis/epidemiologyABSTRACT
The authors report the impact of smoking upon health in Puerto Rico for the year 1983. Using a microcomputer spread-sheet program that calculates smoking-attributable disease impact, they estimated that 2,468 deaths were attributable to smoking. This represented 11.5% of all deaths on the island in 1983 and resulted in approximately 19,445 years of potential life lost (YPLL). It appears that cigarette smoking caused US+55.9 million in direct health care expenditures for Puerto Rico in 1983, an amount equal to 10% of the island's yearly expenditures on health. Calculations such as these demonstrate the enormous disease impact of smoking and may assist policy-makers in planning prevention and intervention activities, both in Puerto Rico and elsewhere in Latin America.