Current Research Projects

This study will explore the role of dermal melanin in the uptake of tobacco smoke chemicals from clothing, in human subjects.  Melanin is the pigment that gives color to our skin, hair and eyes.  Many different drugs, including nicotine, bind to melanin. Although African-Americans start smoking later than whites and smoke fewer cigarettes per day, they are more likely to die of smoking-related disease than whites.  More African-American smokers want to quit, more attempt to quit and fewer succeed in quitting smoking, compared to whites and Hispanics.  National surveys also consistently show that African-American children have higher urinary cotinine levels than non-Hispanic white or Mexican-American children.  Understanding whether these disparities are due strictly to racism and lack of access to healthcare or whether there are biological factors that also contribute is essential to reducing and eliminating the disparities. 

60 people will participate in this study: 30 with low-melanin, light colored skin and 30 with high-melanin, dark colored skin.  Everyone will wear clothing that has been exposed to cigarette smoke (pants and long-sleeved shirt) for three hours.  We will collect blood samples for 6 hours to track how fast nicotine moves through their skin and we will collect urine samples for 10 days to measure how much nicotine they take in and how long it stays in their skin.  We will test the samples for nicotine, NNK (a tobacco carcinogen) and their metabolites and compare them to skin color and melanin content.  This is the first study to test both skin color and skin uptake of smoke chemicals. 

If people with more melanin in their skin absorb less nicotine uptake and we see the metabolites in the urine for a shorter period of time, then melanin is probably protective and the health disparities are caused by other factors.  If people with more melanin absorb less nicotine, and we see the metabolites for a longer time or they absorb more nicotine and we see the metabolites or longer, then melanin may be part of the cause of the health disparities.  No matter what we find, this study will improve our understanding of the health effects of tobacco in people with darker skin.  

There is growing evidence that toxic thirdhand smoke (THS) persists in indoor environments long after smoking ends. THS is expensive to remediate, lowers the value of real estate and used cars, and contains numerous chemicals known to cause cancer and harm reproductive health. Research from laboratory and field studies has demonstrated that chemicals in THS sorb (reversibly bind) to surfaces during smoking and become embedded in materials. THS can then desorb (emit) from the materials after smoking has stopped. To develop effective remediation approaches, the role of various household materials in the storage and release of THS must be understood. Prior research investigated the short-term sorption (e.g., hours) and desorption of THS using different materials in test chambers or model rooms. Although an important first step, these studies did not test realistically long exposure periods, patterns, or amounts (e.g., months) that may lead to different outcomes under real-world conditions. This proposal aims to quantify the sorption capacities of common household materials that are suspected major reservoirs of THS (carpet, drywall, cushioned furniture) the effectiveness of common remediation methods, and the long-term persistence of THS in remediated materials. 

In this proposal, samples of THS-contaminated household materials of carpet, drywall, and cushioned furniture (e.g., couches) will be collected from participants’ homes. First THS in these household materials will be characterized in detail, in particular the depth to which THS penetrates the different items. Remediation experiments will then determine the effectiveness of commonly used clean methods that attempt to remove THS: painting drywall, shampooing carpet, and shampooing cushioned furniture. THS measurements over time after remediation will determine the effectiveness of each method. Results will guide advice on how to best remediate THS by cleaning or replacing items in contaminated homes and will also help inform occupants what they can expect in terms of the longevity of the existing contamination. Knowledge of how much THS accumulates in these materials and which materials release the most THS will be crucial for THS remediation, prevention, and education about THS risks. This proposal collaborates with three THS Consortium Cores and three subsidiary projects.