Asian women who immigrate to the U.S. may be more likely to develop breast cancer than Asian American women, according to a new study.
The finding contradicts research in previous decades, which revealed that U.S. women had higher breast cancer rates than their counterparts abroad.
The study, published in the journal “Preventing Chronic Disease,” found that Asian women who moved and spent more than half of their lives in the U.S. were three times more likely to develop breast cancer than Asian women born in the country.
Still, those who moved and spent less than half of their lives in the U.S. were 2.46 times more likely to have the condition.
Researchers collected data from 570 Asian American women living in the San Francisco Bay Area between March 2013 and Oct. 2014.
Of this sample size, 132 had breast cancer, while the rest without the condition were matched to the cases by age and country of origin.
Specific factors contributing to the increased risk among Asian immigrants remain unclear, but researchers speculate that it has to do with “effects of globalization and economic development.”
These include increased screening, lower parity, delayed childbirth, decreased breastfeeding and sedentary lifestyles, all of which contribute to the development of breast cancer.
Interestingly, a study published in 2017 also showed that the breast cancer incidence among Asian Americans in California has been on the rise since 1988.
Of the seven ethnicities studied from that year to 2013 — Chinese, Japanese, Korean, Filipino, Vietnamese, South Asians (Asian Indians and Pakistanis) and Southeast Asians (Cambodians, Hmong, Laotians and Thai) — the largest increase occurred among Koreans, South Asians and Southeast Asians.
Further research is necessary to corroborate the new findings. Researchers recommend larger samples in broader areas, as well as cross-national studies that examine breast cancer risk in the country of origin and upon immigration to the U.S.