The constructs of “vulnerable populations” and “vulnerability” have increasingly gained a foothold in the fields of Clinical Medicine, Genetics, Epidemiology and Public Health. Vulnerability, outside of the health context, is broadly defined as susceptibility to attack or to physical or emotional damage. In Public Health, vulnerable populations are typically conceptualized as culturally, economically, geographically or socially defined groups who experience health disparities in relation to a pre-defined dominant (e.g. less vulnerable or invulnerable) group. In Epidemiology, however, vulnerable populations are characterized as groups who experience “greater risk of risks.” This framing of vulnerability acknowledges that (a) health or illness is often a result of social risks that give rise to environmental exposures (or risks), and (b) these social and environmental risks compound one another to generate a higher and higher risk of being exposed to a causative agent, either at one point in time, or over the life course.
Why is this discourse important? We now have volumes of reports documenting health disparities in the US. For example, Blacks are much more likely to die of a heart attack, asthma, or lung cancer than their White counterparts. Exactly why these disparities exist remains a topic of much debate, and scientists from the bench to the bedside to the population are engaged in attempting to understand how “race gets under the skin.” Last month, the Center for Disease Control and Prevention (CDC) provided us with a profoundly disturbing illustration of the epidemiologic framework of vulnerability when it published an important study on the state of secondhand smoke (SHS) exposure in the US, in the February 3 2015 issue of the Morbidity and Mortality Weekly Report (MMWR). This work sheds new light on the question of how and why Blacks in the US are more likely to die of a heart attack, asthma, or lung cancer.
The so-called War on Tobacco has arguably been the greatest public health achievement of the last 50 years and, since its inception, it has been estimated to have saved over 1 billion lives globally. However, the benefits of anti-tobacco related legislative, regulatory, environmental and policy changes, as well as associated changes in social norms, may not have accrued equally across population subgroups. CDC investigators measured the 2 decade change in serum cotinine levels (a blood marker of SHS exposure) among adult and child non-smokers. What they found was both striking and disturbing. As expected, as a result of major public health efforts, the reduction in SHS exposure among non-smokers was ~50% over that time period. However, declines were much smaller among “vulnerable populations”, leading to much greater degrees of disparities in SHS. For example, while White non-Hispanics had a decline of SHS of 56.2%, Blacks experienced a decline of only 36.6%. While non-smokers with a college degree showed a decline of 66.5% in exposure to SHS, those with a high school degree or less declined by only 46.7%. While those who own a home declined in their SHS exposure by 58.5%, renters declined by only 46%. Lastly, while those > age 20 declined in their SHS exposure by 55.6%, children age 3-11 declined by only 37.4%. And when vulnerabilities were combined (e.g. race and age), we begin to see how the compounding effect of the “risk of risks” plays out: while White non-Hispanic children reduced SHS by 41.2%, Black children’s SHS exposure was reduced by only 19.8%. In fact, in 2012, among White non-Hispanic children, 37.2% had SHS exposure; among Black children, 67.9% (nearly double) had SHS exposure. In other words, in the US today, despite the multipronged and continual public health efforts against tobacco use and SHS, over 2/3 of Black children continue to be exposed to SHS.
While there are many questions and lessons for public health policy generated by this report, as a primary care physician and a public health professional, I have 5 takeaways for my practice:
- For my non-smoking patients, I will always inquire about 2nd hand smoke, especially among “vulnerable” patients, and I will spend as much time as needed to assist them in advocating for their rights and their health.
- I will add yet another battery to my engine to keep me encouraging and supporting my smoking patients to quit smoking---for themselves, their families and their communities
- We must promote policies that incentivize low-income smokers to quit smoking. One such program is the Medicaid Incentives to Quit Smoking (http://www.nobutts.org/miqs), an evidence-based initiative in California that provides $20 to Medicaid smokers who access the California Smokers’ Helpline.
- We must promote smoke-free policies in the workplace, in multi-unit housing and in vehicles.
- We must recognize that the high and intransigent rate of smoking in vulnerable communities is, in part, a reflection of unequal opportunities to fully engage in society, and of the high degrees of stress resulting from marginalization. No public health campaign can achieve complete health equity until the social conditions that lead to vulnerability are confronted.