The association of smoke exposure and tuberculosis in Saskatchewan

Abstract

This cross-sectional study observed the association of smoke exposure and tuberculosis-related outcomes in Saskatchewan by individuals who had been exposed to someone with infectious TB. This study is unique in that we were quantifying the amount of smoke exposure that increases susceptibility to TB infection and/or active TB. Subjects who were at least 18 years old were enrolled into the study because they were contacts to infectious tuberculosis. The study involved a detailed interview. This interview involved questions on demographics, hair treatment (specifically, hair dying), tobacco smoke exposure, co-morbidities/risk factors, and alcohol consumption. After the interview was conducted, a small 10mg sample of hair was collected from each individual. This was to ensure a more accurate level of smoke exposure was attained. In total, 104 individuals were recruited to participate in this study. Linear regression analysis was used to compare cigarette consumption and nicotine concentration. A quadratic term was added to the linear model and the result was that reported cigarette consumption per day (x) was significantly associated with nicotine concentration (y) where y=0.91+1.35x-0.25x2 (p=0.001). A Fisher’s exact test was conducted to see if there was a relationship between smoking and TB disease; there was no statistically significant association between TB disease and smoking (OR= 3.28, 95%CI 0.37-29.1, p = 0.24). Logistic regression analysis was used to see if there was a relationship between smoking and TB infection. Of the five predictor variables, none were statistically significant. Smokers had an association with higher odds of TB infection (OR=2.03, 95%CI 0.71-5.80, p=0.19). Canadian-born Aboriginals had an association with lower odds of TB infection (OR=0.52, 95%CI 0.18-1.46, p=0.21). The results from this study could provide insight into creating a larger, more complex study involving TB and smoking.