An Asian American born in Connecticut in 2009 could expect to liveย 89.1 years. An African American, on the other hand, couldย expect to live 77.8 years. It’s seldom surprising toย see large discrepanciesย when comparing life expectancies inย developed and developing nations, considering the vast differences in availableย health care. But how do we explain such a wide variance between two populations or ethnic groups living in the same region?
The complicated ย relationship between population, ethnicity and ‘race’–and how it impacts our health –involves a complex equation ofย factors,ย includingย medicine,ย economics, psychology, anthropology, sociology andย geography. But it also seems clear that there are so-called race-related genetic factors in play .
Cultures and health behaviors
At this point in the history of medicine, there are a handful of behaviors withย well-established impacts onย our health. Among this is tobacco smoking,ย which has been linked unequivocallyย to lung cancer and chronic obstructive pulmonary disease (COPD). It’s also associated withย cardiovascular and cerebrovascular conditions (leading to high blood pressure, atherosclerosis, heart disease, and strokes), and a host of non-pulmonary cancers. Yet different ethnic groups react differently to prolonged exposure.
Consider that theย rate of smoking among Native Americans is higher than for any other group in North America, at 26.1 percent, according toย American Lung Association. At the other end of the smoking spectrum areย Asian Americans, at 9.6 percent, andย Hispanics atย 12.1 percent. In the middle areย African Americans, 18.3 percent, andย Caucasians,ย 19.4 percent.
Based on smoking rates alone, you’d expect Asians and Latinos to have lower lung cancer rates, and they do. However, you’d also expect Native Americans to have higher lung cancer rates. Yet their lung cancer rates are only slightly worse thanย those of Latinos. Strikingly, the ethnic group with the highest lung cancer rate is African Americans,ย according to the Center for Disease Control (CDC).
A similar phenomenon is seen inย alcohol use. According to the National Institute of Alcohol Abuse and Alcoholism (NIAAA), the most common drinkers are white males, 74.27 percent, while Asian-American women were the least common, at 36.11 percent. In terms of “daily heavy drinking,” the highest rates were recorded among Hispanic males, at 40.48 percent, while Asian American men had the lowest rate, at 18.84 percent. Alcohol abuse relates to liver disease, nutritional disorders, and various cancers, but as with smoking the disease rates among ethnic groups do not correlate precisely with consumption.
Black men (25.81 percent)ย and women (19.02 percent), for example, reported lower rates of daily heavy drinking, when compared to white men and women. Yet, African Americans have a higher risk of developing alcohol-related liver disease, according to the National Institutes of Health.
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Health genetics
With majorย killers like heart disease and stroke,ย there are a multitude of genetic factors, making forย complex relationships between genetics and disease.ย For example, despite having a relatively high risk of developing cardiovascular disease, Latinos have aย lower risk of actually dying from the disease. Thus, studies are constantly underway to examine genetic risk factors and markers. African Americans have a notoriously high rate of high blood pressure compared with other ethnic groups, and for decades there has been a debate regarding whether genetic factors or environmental factors are more important.
What about discrimination?
A potentially troubling possibility emerged from a University of Florida studyย published in December 2016ย in theย journal PLOS ONE. By interviewing 157 African American subjects in creative ways, researchers were able to show a relationship between the feeling of discrimination and high blood pressure. The study pointed toย eight genetic variants of five genesย previously known to be associated with cardiovascular disease. The cause ofย high blood pressure isย complex, given that it’s related both to physical phenomena such as factors controlling how tightly blood vessels squeeze, as well as psychological factors, since blood pressure rises in nearly everyone when they become anxious or stressed.
Putting all of these factors into a coherent picture of how diseases are generated appears to be a daunting task. Year by year, month by month, the science community is inundated with new data, especiallyย from genomic studies. Various new instruments are in use too, and yet, when the goal is to assess anything related toย ethnicity or race, the task grows progressively more difficult.
A version of this article originally appeared on the GLP on Feb. 16, 2017.ย
David Warmflash is an astrobiologist, physician and science writer. BIO. Follow him on Twitter @CosmicEvolution
