Fighting genetics as destiny in health

It’s long been known that heart disease, hypertension and diabetes are among the raft of medical conditions that affect the country’s African-American population at higher rates than the general population.

But African-Americans aren’t the only ethnic group for which a predisposition to specific health problems seems to exist. And this is true probably because of a complex interplay of genetics, family history and, even, culture.

Nevertheless, doctors stress that even given such ethnicity-based predispositions, people have the individual power to take measures — involving diet, exercise and regular medical screenings — that can help to blunt the effect of what ethnicity and genetics may have stacked against them.

According to the American Heart Association, heart disease is the No. 1 killer, and stroke the fourth-leading cause of death, among all Americans, but the risk of both is even higher among African-Americans.

High blood pressure, obesity and diabetes all are risk factors for heart disease and stroke. According to the heart association, the prevalence of hypertension among African-Americans is the highest in the world, African-Americans are “disproportionately affected” by obesity, and African-Americans are almost twice as likely as non-Hispanic whites to have diabetes.

Also, African-Americans have a risk of first-ever stroke almost twice that of whites, the association reports. Although incidence rates of strokes decreased for white people from the 1990s to 2005, it didn’t for African-Americans.

Dr. Paul Kalekas, chairman of Touro University Nevada College of Osteopathic Medicine’s primary care department, says also that kidney disease is more prevalent among African-Americans than in the population at large.

But people of other ethnic backgrounds may carry their own sets of health risks. For instance, in a reversal of overall rankings, people of Asian descent tend to get more cancer than heart disease, Kalekas says, and while the No. 1 cause of death among Americans as a group is heart disease, the top cause of death among Native American and native Alaskan people is cancer.

Dr. Mulugeta Kassahun, a Urology Specialists of Nevada urologist specializing in urologic oncology, says people’s ethnicity can factor in both the type of cancer they may be predisposed to and the chances of successful treatment once a cancer is diagnosed.

In general, Kassahun says, when you talk about cancer, you will have different kinds of cancer in one group versus another. For example, Kassahun says, black men are more than one-and-a-half times more likely than white men to have prostate cancer, and the death rate from prostate cancer for black men is about two-and-a-half times what it is for white men.

What’s behind such ethnicity-based trends? Is it ethnic background alone, or genetics or family history, or, even, cultural or demographic differences that vary from group to group?

“It’s probably all of the above,” Kalekas says.

Dr. Thomas Hunt, a Las Vegas family practice physician and associate professor of family and community medicine at the University of Nevada School of Medicine, agrees that the answer probably lies somewhere in the interplay of genetics and environmental factors.

“I always look at it this way: Are we dealing with genetics or are we dealing with environment, or are we dealing with both?” Hunt says. “And it seems that when you’re looking at conditions that seem to occur most frequently in one population versus another, usually it comes down to one or the other or to the both of those.”

Although an ethnicity-based predisposition to particular conditions may exist, it may take something else — such as something in someone’s lifestyle or diet — to serve as a tipping point. For instance, the American Heart Association notes that there is research suggesting that African-American people “may carry a gene that makes them more salt-sensitive, increasing the risk of high blood pressure.”

Then, add to that lifestyle factors — eating a diet rich in salty foods, for example — and what had been a predisposition toward hypertension evolves into diagnosed hypertension. Meanwhile, conversely, adopting a low-salt diet and regular exercise could have “a big impact” in keeping blood pressure in check.

In a similar vein, Hunt notes that the traditional diet eaten by Native American people was, from a health standpoint, a good one. Now, he says, “what we’re seeing is this epidemic of obesity and diabetes and things like that because of the introduction of a different diet.”

But teasing out the reasons for what appear to be ethnicity-based predispositions to disease can be difficult. For example, Kassahun says it’s still unclear why African-American men are at comparatively higher risk of prostate cancer.

“There is no specific reason,” he says. “Some people say that it may be a genetic difference (between African-American men and men from other groups), but we still have not found exactly what it is — the chemical that makes up the difference, or what kind of abnormality in the genetic makeup that can cause cancer to black people more than to white people.”

The connection also can be complicated when accounting for disparities in health care delivery from demographic to demographic.

“If, for instance, you have less access to a health care provider or you have less access to preventive medical screenings, cancers are found later than they tend to be and are less successfully treated,” Hunt says. “And that could have nothing to do with anything other than (availability of) resources.”

Access to care is particularly vital when treating chronic conditions that could be managed or conditions that, if detected early, might be treated successfully.

For example, prostate cancer tends to be a slow-growing cancer.

“In general, if you catch it early, it’s a curable cancer,” Kassahun says.

But avoiding or lacking access to preventive screenings, or seeing a doctor only after symptoms have appeared, likely will leave fewer effective treatment options.

Dietary habits, meanwhile, can also help push a predisposition into an active disease.

“I think a lot of people follow an awful lot of (dietary) eccentricities passed down to them,” Kalekas says. “They could be cultural, but don’t have to be.”

“The other thing is, it depends on resources and where you live,” Hunt says. There has, for example, been research about the availability of fresh fruit in particular neighborhoods, and “if you live in a place where you have to take a bus several miles to go to a store to get fresh fruit and it’s more expensive than, say, fast food that’s right down the street, now you’re going to see more obesity.”

But, even with all of this, doctors say the most important takeaway for patients is that having a potential predisposition to a medical condition — whether it’s a predisposition based on ethnic heritage, genetics or family history — doesn’t doom them to developing disease.

“We always say in medicine that genetics points the gun, but your lifestyle pulls the trigger,” Kalekas says. “I constantly tell my patients, ‘I understand you have a genetic predisposition (to a disease). There’s nothing we can do about that. That’s kind of the hand you’re dealt.’

“But what we can do is deal with whatever we can deal with, and all of these other preventive aspects are not hard to do and don’t cost much. In fact, you’ll save money if you do it correctly.”

Contact reporter John Przybys at jprzybys@reviewjournal.com or 702-383-0280.