Thursday, September 11, 2014

Why African Americans are under Much Higher Risk of Pancreatic Cancer than Whites?

Incidence Rate among African Americans

When NFL Hall of Famer Gene Upshaw died of pancreatic cancer in 2008, it was the first time that many Americans had heard of the disease. Like many patients with this deadly cancer, the 63‐year‐old Upshaw died a short period after his diagnosis, shocking many football fans. The news of his death also put a spotlight on a disease that, although rare, but deadly, disproportionately affects African Americans.  

Pancreatic cancer is diagnosed in African Americans more often than in other racial/ethnic groups in the United States. And African Americans are more likely than other groups to die from the disease. The reasons for these disparities are not clear. Some researchers have noted, however, that certain risk factors are more common among African Americans than among other groups. Known risk factors for pancreatic cancer include tobacco use, long‐standing diabetes, obesity, inflammation of the pancreas, a family history of pancreatic cancer, and certain hereditary conditions.

According to a report by the Sol Goldman Pancreatic Cancer Center, the incidence rate of pancreatic cancer among Blacks is 50% to 90% higher than other racial groups. It also concludes that Blacks are less likely to receive surgery.

Smoking Effect on Increased Risk

Cigarette smoking is considered a significant risk of cancer of the pancreas. In fact some studies show that smoking causes about 25% of all cases of pancreatic cancer. Smoking is more common among African Americans versus other races. Although Blacks do quit smoking at the same rate as Whites, a higher ratio of Blacks still continue to smoke. These facts would tend to be a legitimate reason why Blacks do experience a higher degree of risk of pancreatic cancer.

Obesity, Pancreatitis and Type 2 Diabetes Risk Factors

Obesity is a high risk factor for pancreatic cancer. That is likely because obesity is also a risk factor of diabetes, which in-turn is a significant pancreatic cancer risk factor. According to the Department of Human Services Office of Minority Health, 31% of Black men and 39% of Black women over the age of 18 are obese or significantly overweight. Those numbers compare to 26% of White men and 23% of White women.

Type 2 Diabetes and Pancreatitis is also more common among African Americans than Whites. Over 80% of people that have Type 2 Diabetes are overweight. According to the Sol Goldman Pancreatic Center, Type 2 Diabetes doubles the risk of cancer of the pancreas. These facts would also serve to support reasons why Blacks experience a higher occurrence of pancreatic cancer.

Possible Income Disparity

According to the US Census Bureau, African Americans account for about 25% of Americans at the poverty level. Poverty and low income could be associated with increased risk. Individuals who earn lower incomes tend to smoke more which doubles the risk of pancreatic cancer. Those at poverty levels are also less likely to receive proper nutrition or quality healthcare.

It is interesting however that even though there is a greater number of Hispanics and Native Americans at the poverty level versus Whites, the incidence rates of pancreatic cancer among Hispanics and Native Americans are significantly less versus the White population.

Latest Research

To better understand the causes and risk factors for pancreatic cancer, researchers led by Jiemin Ma, Ph.D., now affiliated with Brigham and Women's Hospital in Boston examined long-term disease trends in pancreatic cancer death rates in the United States between 1970 and 2009. They found in white men, pancreatic cancer death rates decreased by 0.7% per year from 1970 to 1995, then reversed, increasing by 0.4% per year through 2009 (the latest year for which data was available). Among white women, rates increased slightly from 1970 to 1984, stabilized until the late 1990-s, then increased by 0.5% per year through 2009. In contrast, death rates among African Americans increased between 1970 and the late 1980-s (women) or early 1990-s (men), after which they began to decrease. However, death rates continued to be substantially higher in blacks than in whites in both men and women.

The authors say the difference in mortality trends between blacks and whites are not fully explained by differences in patterns of smoking, widely recognized as the main contributor to decreases in pancreatic cancer death rates. Smoking prevalence has decreased in both blacks and whites since 1965. The authors surmise that other factors may have modified the impacts of smoking on pancreatic cancer, and say further studies on the mechanisms by which smoking causes pancreatic cancer are warranted.
While obesity has been linked with a 20% increased death risk from pancreatic cancer, the lack of an increase in pancreas cancer mortality rates in blacks, among whom obesity is more prevalent, would make obesity alone an unlikely culprit. In addition, improvements in diagnostic techniques may have contributed to increasing incidence and mortality rates among whites by identifying pancreatic cancers that previously went un-diagnosed. But a lack of reliable long-term data makes it difficult to evaluate the potential influence of other suspected risk factors, like meat and vegetable intake. The authors say the decreasing mortality trend in African Americans over the past 10 to 15 years is particularly interesting, as the factors that are likely contributing to recent increases in pancreatic cancer deaths in whites (e.g.: obesity, diabetes, and improved diagnosis) have also increased in African Americans.

"This study underscores the need for urgent action on several fronts," said Ahmedin Jemal, DVM PhD, senior author of the paper. "We need to invest more into pancreatic cancer research to understand why this disease is rising or falling in different races. In the meantime, we have to address modifiable risk factors such as obesity and smoking to reduce the future burden of pancreatic cancer in all populations."

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