Abby Parent

Background: Inflammation and oxidative stress are key mechanisms in the pathogenesis of diseases caused by exposure to toxicants and carcinogens in cigarette smoke. Psychosocial stress can also contribute to physiological inflammation, potentially impacting inter-individual susceptibility to smoking-induced diseases. We investigated the relationship between proxy indicators of psychosocial stress (sociodemographics, education, income, marital status, etc.) and inflammatory biomarkers (C-reactive protein [CRP], oral cell mitochondrial DNA [mtDNA]) in smoking individuals. 

Methods: Analyses were conducted using available questionnaires and biomarker data on African American (AA n=78) and White (WH n=74) participants from a prior study investigating tobacco carcinogen exposures and metabolism in lung cancer risk from smoking. 

Results: Univariate analysis exploring the relationship between biomarkers and important predictors showed that biological sex (male), age, and BMI (kg/m2 ) was associated with levels of CRP (p=0.04, p=0.04, p<0.01, respectively). CRP levels and mtDNA content were not associated with smoking dose predictors such as cigarettes per day (CPD), nicotine intake (TNE), and years of smoking. Given the highly skewed distribution of the data, natural log mtDNA and CRP was used for regression analyses. When adjusting for important predictors (biological sex, age, and BMI [kg/m2 ]), CRP levels were associated with current employment status. Those who were currently employed part-time had about 0.3 times higher CRP levels compared to others (p=0.03). There was no apparent relationship between other potential psychosocial stressors and CRP. Our results showed that levels of mtDNA content were significantly associated with race (p<0.01), and this difference remained significant even after adjusting for age, sex, CPD, and TNE (p<0.01). Marital status was also associated with mtDNA content; separated individuals had 0.5 times higher levels of mtDNA when compared to other groups (married, never married, divorced, and widowed), (p=0.05). After adjusting for age, sex, CPD, and TNE, separated individuals still had higher mtDNA content compared to other marital statuses (p=0.05). 

Conclusion: Our results indicate that potential psychosocial stressors could contribute to the observed levels of CRP and mtDNA content in this cohort. The complex interaction between biological, behavioral, and psychosocial factors and their mechanistic contribution to the observed tobacco-associated health disparities should be further investigated.

Abby Parent¹, Aleksandra Alcheva^2,3, Christopher Ruszczak^2,5, Crina Cotoc^4,5, Samantha Case², Irina Stepanov^2,3. University of Minnesota – ¹School of Nursing; ²Masonic Cancer Center; ³Division of Environmental Health Sciences; ⁴Medical School; ⁵School of Public Health