Sexual minority compared to heterosexual women had higher levels of nicotine exposure.
Sexual minority compared to heterosexual women had higher levels of TSNAs.
Sexual identity differences varied by tobacco subgroup examined.
Sexual minority women are consistently at increased risk for tobacco use compared to heterosexual women. Neither biomarkers of nicotine exposure nor biomarkers of tobacco toxicant exposure have been examined by sexual identity.
This study used interview and biomarker data from women in the biomarker core sample of Wave 1 of the Population Assessment of Tobacco and Health (PATH) study (2013–2014; n = 4930). We examined associations of sexual identity with nicotine exposure (measured with urinary cotinine and TNE-2) and with tobacco-specific nitrosamines (measured with urinary NNAL). Multivariable regression modeling was used to examine these associations among the full biomarker core sample, among past 30-day tobacco users, and among exclusive established cigarette users before and after controlling for tobacco use quantity and intensity.
In the full biomarker sample of women, prior to adjusting for tobacco use quantity and intensity, bisexual women had significantly higher cotinine, TNE-2, and NNAL levels compared to heterosexual women. Among exclusive established cigarette users, gay/lesbian women had significantly higher NNAL compared to heterosexual women prior to adjusting for tobacco quantity and intensity. No differences by sexual identity were found after adjusting for tobacco use quantity and intensity.
This is the first study to demonstrate differences in biological markers of tobacco exposure by sexual identity among women in the U.S. This has important public health implications as greater exposure to both nicotine and to tobacco-specific nitrosamines are strongly linked to cancer risk.
Tobacco use remains the leading cause of preventable death in the U.S., accounting for 480,000 deaths including cancer, cardiovascular diseases, diabetes, and pulmonary illnesses [ ]. The health burden of tobacco use is largely driven by the complex mixture of over 7000 chemical compounds found in tobacco smoke, including multiple toxicants and carcinogens [ ]. Examining population-level exposure to toxicants and carcinogens from tobacco, and understanding whether vulnerable populations differ in their exposure, can provide a clearer picture of the distribution of the public health burden of tobacco use [ , ]. This is particularly important to understand among women, who experience unique challenges related to tobacco use. Women are disproportionately affected by the health consequences of smoking [ ], have a history of being targeted in tobacco marketing [ ], and often face greater smoking-related stigma [ , ].
The most potent carcinogens associated with tobacco use include tobacco-specific nitrosamines (TSNAs) [ ]. TSNAs are found in tobacco and tobacco smoke [ , ] and are highly specific to tobacco exposure, making these compounds excellent indicators of health risks stemming from tobacco use [ , , ]. Nicotine derived nitrosamine ketone 4-(metylnitrosamino)-1-(3-pyridyl)-1-butanon, or NNK, is the most understood and commonly studied TSNA in epidemiologic research. The primary metabolite of NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, or NNAL, provides utility as a biomarker of tobacco exposure as well as a direct marker of cancer risk [ , ]. Nicotine exposure is also critical to examine, as it is the addictive component in tobacco that contributes to tobacco use disorder. While nicotine itself is not considered carcinogenic, nicotine exposure is dose-dependently associated with tobacco use disorder severity, [ , ] the quantity of tobacco used, and lung cancer risk [ ]. Further, evidence suggests nicotine may facilitate endogenous formation of TSNAs, induce DNA damage, and serve as a tumor promoter, underscoring the importance of examining nicotine exposure as it relates to cancer prevention and care [ ].
Extant research has demonstrated a significantly greater prevalence of tobacco use among sexual minorities compared to heterosexual individuals [ ]. Sexual identity differences in tobacco use prevalence are most consistently found among women [ , , ], and recent studies have found fewer or no differences in tobacco use by sexual identity among men [ , ]. In particular, bisexual women are consistently at greatest risk for tobacco use compared to heterosexual women [ , , , ], and compared to gay/lesbian women using self-report survey data [ ]. Bisexual and gay/lesbian women are also less likely to report receiving preventative care related to cancer and other tobacco-related health consequences including cancer screenings [ ]. While evidence has clearly linked nicotine and toxicant exposure from tobacco to cancer and other tobacco-related health risks, neither biomarkers of nicotine nor tobacco toxicant exposure have been examined by sexual identity. Thus, it is not known if sexual identity differences in self-reported tobacco use prevalence among women translate into differences in biologically measured exposure to nicotine and tobacco toxicants. Biomarker data may provide an important connection to understanding the unique health risks of sexual minority women and reducing health disparities for sexual minority women.
Examining biological measures of nicotine exposure and tobacco-related toxicant exposure has important implications for understanding cancer and other health risks for sexual minority populations and can complement tobacco use data collected in surveys. Given previous research, we expect the survey data and biologically measured data to be highly correlated [ ]. However, differences due to the type of tobacco product used, topography of tobacco use, and differences due to stress levels, as well as other factors, could result in differences between tobacco use survey findings and biomarker findings. In this study we had two research questions:
- 1 Does nicotine exposure and tobacco toxicant exposure differ by sexual identity among adult women in the U.S.?
- 2 Are any sexual identity differences in nicotine and tobacco toxicant exposure accounted for by self-reported differences in tobacco use?