http://www.sltrib.com/news/ci_
Study: Cancer rate among American Indians goes undercounted
By Lisa Rosetta
The Salt Lake Tribune
Article Last Updated:09/19/2008 02:30:38 PM MDT
The cancer burden of American Indians has long been underestimated, according to new research. The incidence rate - or how quickly a disease is spreading in a group - is estimated by dividing the number of new cancer cases by the population.
The numbers plugged into that formula for American Indians have not been accurate, said Charles Wiggins, director of the New Mexico Tumor Registry in Albuquerque. His work was featured in Cancer last month.
“Historically, we believe many [American Indian] cases were undercounted in central cancer registries,” he said. “This has been documented in every registry where we’ve looked.”
Part of the problem, he said, is cancer registries have relied on medical records, many of which are inaccurate, for information about race.
The artificially low number of American Indian cancer cases reported by the central cancer registries have been coupled with higher population numbers from the U.S. Census Bureau - where race is self-identified. That combination has lowered the estimated rates.
American Indians’ rates for most kinds of cancer are typically lower than the general population, Wiggins said. But they are not a homogenous group; their cancer rates can differ as much as fivefold by geographic region.
In the Southwest, which includes the Navajo Nation, American Indian rates for stomach, gallbladder, kidney and liver cancer were higher than non-Hispanic whites. American Indians there get stomach and liver cancer, for example, at nearly three times the rate of the general population.
Wiggins said the difference may be due to the higher prevalence of Helicobacter pylori (H. pylori), a bacteria linked to stomach cancer and ulcers, and chronic hepatitis B and C, which may increase risk for liver cancer.
The Cancer studies also found that while cancer rates were declining significantly for most non-Hispanic whites, declines among American Indians were generally smaller and not statistically significant.
“That is one of the things that is the saddest,” Wiggins said. American Indians “are probably not accessing health care that say, the majority of the population in the U.S. is.”
Wiggins is now working on a report of cancer incidence on the Navajo Nation. lrosetta@sltrib.com