Asians low cancer rate
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Breast Cancer Rates On The Rise Among Asian Americans
Japanese-American Women May Be Hardest Hit
Article date: 2002/08/01
Breast cancer rates among Asian Americans have traditionally been lower than those of other Americans, but that may be changing.
The rates of breast cancer among some women of Asian-American descent, particularly Japanese Americans, may be approaching those of white women, according to new research.
University of Southern California researchers examined the trends in Los Angeles County and reported their results in the International Journal of Cancer (Vol. 99: 747-750).
Traditionally Lower Rates Of Breast Cancer Among Asians
Asian women have some of the lowest breast cancer rates of any group in the world, while the rates are highest in countries such as the US.
Much of this has been linked to differences in lifestyle factors such as diet, exercise, body weight, and choosing to have children later in life (or not at all).
Ethnicity and national origin are among the strongest known predictors of breast cancer risk, the authors said. These factors are thought to affect a woman's risk even more than those associated with menstrual periods and childbearing.
But breast cancer rates have risen sharply in recent years in some Asian countries such as Japan, where women have adopted more "Westernized" lifestyles. In fact, breast cancer is expected to soon become the most common cancer among women in Japan, the authors said.
It has also been known for some time that the risk of breast cancer increases among generations of Asians who migrate to the US. But experts say this risk is still low compared to other groups such as whites and African Americans.
Rates Often Difficult To Measure
Nationwide, cancer rates among Asian-American populations have been difficult to measure. This is because they represent a smaller fraction of the population than do whites or African Americans. They may not be accurately represented for other reasons as well. They may be misclassified, or they may not use Western-style doctors.
When cancer rates are recorded, all Asian Americans are usually lumped together in a single category, even though groups from different countries often have different genetic and environmental backgrounds.
Study: Breast Cancer Trends Are Disturbing
For this study, Dennis Deapen, DrPh, and colleagues looked at cancer rates in Los Angeles County — the most highly populated and one of the most ethnically diverse counties in the US. They examined cancer trends among different ethnic groups from 1993 to 1997.
Over this five-year period, breast cancer rates among Asian Americans older than 50 increased by slightly more than 6% per year. In contrast, the increase among whites averaged only 1.5% per year, and was even lower among African Americans.
The researchers also looked at the numbers among different Asian-American groups. The highest increases were among Japanese Americans, who were the earliest to settle in large numbers in the Los Angeles area.
By 1997, these rates were higher than those seen for blacks, and were approaching those of white women.
If this trend has continued (there is a lag time of a few years needed to collect results), the rate among Japanese Americans may now be higher than among any other group, said the authors.
The rates for Filipino women were almost as high as those for Japanese Americans. Women of Chinese and Korean descent had rates about half those of Japanese and Filipino women.
The study authors pointed out that in general, these groups migrated to the US later, which may mean that the rates can be expected to rise in the future, as they too adopt more Westernized lifestyles.
Awareness Needed Among These Populations
Both doctors and the Asian-American women they care for need to be mindful that they may be at greater risk than once thought, the authors noted.
"These data demonstrate the need for increasing awareness among Asian women and their health care providers of breast cancer as a significant health hazard," said the authors.
"It is possible that many physicians are unaware that the well-known low breast cancer risk among these women in past decades is no longer true and that breast cancer screening is as important as among white and African-American women," they concluded.