New research says you can blame the troubling trend on a number of bad health habits new to the immigrants when they arrive here, including fatty diets and a lack of exercise.
High blood pressure is an important measure of health because it's linked to an increased risk of heart disease, kidney disease and stroke, says study author Mark S. Kaplan, an associate professor of community health at Portland State University in Oregon.
According to his research, recent arrivals from Asian countries who settled in Canada had lower rates of hypertension, or high blood pressure, than the general population. However, as time went on, their rates of high blood pressure equaled or even exceeded that of the general population.
Asians living in Canada for three years or less had hypertension rates of below 3 percent, compared to about 10 percent of the population aged 20 and older. After five years, more than 7 percent of the immigrants had hypertension; after 10 or more years, 13 percent had the condition.
The study also found people who were "psychologically distressed" or depressed had twice the risk of hypertension.
Researchers used length of residence as a measure of "acculturation" -- or Westernization. They controlled for age, sex, education, smoking, drinking and access to health care.
"We often think of changes from one generation to the next, but what we're finding is that in a shorter period of time, we're seeing changes in their health status," Kaplan says. "Asian immigrants arrive in fairly good health relative to the general population, but within 10 years begin to show the negative health effects of exposure to North American culture."
The study will be published in the June issue of the Journal of Epidemiology and Community Health.
Kallyane Sok, health program coordinator for the Philadelphia-based Southeast Asian Mutual Assistance Association Coalition, says the study results come as no surprise.
"We're seeing obesity, diabetes and high blood pressure in our communities like never before," Sok says. "People, especially the elderly, are dying from it."
The study included data from nearly 2,000 Asian immigrants who were part of the 1996-97 Canadian National Population Health Survey. Kaplan notes one weakness in the study is the high blood pressure was self-reported, rather than gleaned from actual blood pressure measurements.
So, what is it about American and Canadian culture that leads to high blood pressure? A diet of high fat and low fruits and vegetables is one factor, Kaplan says. Another is obesity, which is linked to hypertension.
Sok says many immigrants continue to eat traditional foods from their native country; she blames a sedentary lifestyle.
"Here, people drive a car everyday everywhere," she says. "Over there, they walk. Many people who came here are peasants or farmers. They used to get exercise running their farm and doing chores."
Rather than simply prescribe pills to lower blood pressure, Kaplan suggests education and social service programs should deal with the lifestyle changes immigrants face that contribute to potential health problems.
"I think the challenge for us as a society is how to reduce the harmful effects of the acculturation process, as well as preserve the positive effects," he says.
Research has shown assimilation can do some good. Immigrants, for example, tend to smoke less when they come to the United States, he says.