A researcher examining cancer rates among California Latinos and Asians who were born in and out of the U.S. reached conclusions that reveal two very different versions of the American dream.
For Latino males born in the U.S., rates of liver cancer are more than double those of their foreign-born counterparts. For Asians born in the U.S., rates of liver cancer fall by half or more.
“The diversion of patterns in these two ethnic groups is really interesting and raises questions we can study more in depth,” said Ellen Chang, a research scientist with the Cancer Prevention Institute of California who conducted the study.
The study, released last week, was published in the journal Cancer Epidemiology, Biomarkers and Prevention.
Overall, Chang said, the findings indicate that environment, behavior and lifestyle may trump genetics as predictors of liver cancer. Factors such as alcohol abuse, diabetes and Hepatitis C – a disease transmitted by needle use – can affect cancer rates, Chang said.
Both alcohol abuse and obesity are more common among U.S.-born Latino men than those born abroad, according to the California Health Interview Survey.
Many of the problems giving rise to liver cancer among Latino males, Chang said, can be addressed effectively. She said her study indicates that public health campaigns around substance abuse treatment, healthy eating and exercise could be effective if done in a culturally appropriate manner.
Chang and colleagues also found that U.S.-born Asians living in California have much lower rates of liver cancer than those who immigrated. For Japanese born in the U.S., the annual rate was less than five cases per 100,000 people, but nearly 15 per every 100,000 for those born overseas. For Filipino, Vietnamese and Koreans, the annual rate was nine cases per 100,000 for those born in the U.S. versus 20 for those born outside the country.
Chang said the reason is likely the overseas prevalence of Hepatitis B, a disease that wears heavily on the liver. In the U.S., she said a vaccine against the disease has been in common use since 1991.
In general, Chang said research has shown that immigrants coming to the U.S. encounter less risk of infectious diseases, but are more likely to get chronic conditions like diabetes or high blood pressure.
A recent study examining obesity among foreign and U.S.-born people found that Hispanic and black men born outside of the U.S. were less likely to be obese.
And in a similar vein, a study examining diabetes rates among Pima Indians living in Mexico and in the U.S. also suggested that lifestyle, not genetics, is a dominant force in the development of the disease.
That study found that the Pima Indians living in Mexico have one-fifth the chance of having diabetes compared to the American Pimas.
Researchers concluded that the key difference between the two groups was their level of physical activity, which was about three to seven times higher for the Pima living in Mexico:
The differences in physical activity between the Mexican populations and the U.S. Pima Indians are largely environmentally determined. The Mexican Pima mostly live in a subsistence economy on rancherias where they farm and grow most of their own food, plowing with the aid of oxen or mules and planting and harvesting their crops by hand. Both the men and women participate in these activities. ... In contrast, the U.S. Pima Indians, although traditionally farmers, now have a more typical rural U.S. lifestyle with very low levels of occupational physical activity.