Food, beverage, and macronutrient intakes in postmenopausal Caucasian and Chinese-Canadian women.

International differences in breast cancer rates and diet, and studies in migrants, suggest that diet may be a modifiable risk factor for breast cancer. The goal of this cross-sectional study was to examine the dietary intakes of women from populations considered to be at different risks for breast cancer. We collected four 24-h food recalls in 3 groups of postmenopausal Canadian women: Caucasians (n = 392), Chinese women born in the West or who migrated to the West before age 21 (n = 156), and recent Chinese migrants (n = 383). Compared to Caucasians, recent Chinese migrants had lower energy and fat intakes and higher protein and carbohydrate intakes. Recent Chinese migrants consumed higher amounts of grains, vegetables, fish, and soy and lower amounts of alcohol, meat, dairy products, and sweets than Caucasians. Western-born Chinese and early Chinese migrants had intakes intermediate between the other 2 groups. The differences in intake between the ethnic groups suggest foods and nutrients that may contribute to the differences in risk of breast cancer between women in Canada and China. Future work will examine whether these dietary differences are associated with biological markers of breast cancer risk.

Risk factors for breast cancer in postmenopausal Caucasian and Chinese-Canadian women.

INTRODUCTION: Striking differences exist between countries in the incidence of breast cancer. The causes of these differences are unknown, but because incidence rates change in migrants, they are thought to be due to lifestyle rather than genetic differences. The goal of this cross-sectional study was to examine breast cancer risk factors in populations with different risks for breast cancer. METHODS: We compared breast cancer risk factors among three groups of postmenopausal Canadian women at substantially different risk of developing breast cancer - Caucasians (N = 413), Chinese women born in the West or who migrated to the West before age 21 (N = 216), and recent Chinese migrants (N = 421). Information on risk factors and dietary acculturation were collected by telephone interviews using questionnaires, and anthropometric measurements were taken at a home visit. RESULTS: Compared to Caucasians, recent Chinese migrants weighed on average 14 kg less, were 6 cm shorter, had menarche a year later, were more often parous, less often had a family history of breast cancer or a benign breast biopsy, a higher Chinese dietary score, and a lower Western dietary score. For most of these variables, Western born Chinese and early Chinese migrants had values intermediate between those of Caucasians and recent Chinese migrants. We estimated five-year absolute risks for breast cancer using the Gail Model and found that risk estimates in Caucasians would be reduced by only 11% if they had the risk factor profile of recent Chinese migrants for the risk factors in the Gail Model. CONCLUSIONS: Our results suggest that in addition to the risk factors in the Gail Model, there likely are other factors that also contribute to the large difference in breast cancer risk between Canada and China.