Adolescent Lifestyle Factors and Adult Breast Density in U.S. Chinese Immigrant Women

Abstract

We examined recalled measures of adolescent diet, physical activity, and body size in relation to adult breast density in 201 U.S. Chinese immigrant women recruited in January 2002 to May 2003 from Philadelphia region screening programs. Mammographic images were classified into 1 of 4 categories ranging from “entirely fatty” to “extremely dense.” Questionnaires assessed diet and physical activity between ages 12–17, relative weight and height at age 10, and weight at age 18. To estimate odds ratios (ORs), we conducted logistic regression analyses using proportional odds models for polychotomous outcomes. Higher adult breast density was significantly associated with adolescent red meat intake (adjusted 3rd vs. 1st tertile OR = 3.0, 95% confidence interval (CI) 1.5–6.4, trend P = 0.003) but not with other adolescent factors. For the association of adult acculturation with breast density, adjustment for adolescent red meat intake attenuated the OR for the highest vs. lowest level of acculturation from 2.5 (95% CI 1.2–5.3) to 1.9 (95% CI 0.9–4.0). Greater adolescent red meat intake may have increased adult breast density and partly accounted for the strong association between acculturation and breast density in this sample of immigrant Chinese women. If confirmed by further study, dietary prevention efforts for breast cancer should be considered earlier in life.

ACKNOWLEDGMENTS

The authors are indebted to Ms. Yun Song for her crucial work in the collection and management of data for this study. The authors also thank Andrew Balshem and the Fox Chase Cancer Center Population Studies Facility for their assistance in data entry. Finally, for their generous assistance in participant recruitment, the authors are deeply grateful to Dr. Philip Siu, Dr. Catherine Piccoli, Kin Lam, and Lih-Yuh Chen of Thomas Jefferson University Hospital, and Nancy Liao and Viki Chen of the American Cancer Society. This work was supported by grants CRTG-01-018-01-CCE from the American Cancer Society and P30 CA006927 from the National Institutes of Health.

Notes

*Analyses including all women were adjusted for age and menopausal status. Stratified analyses were adjusted for age only.

**OR for 5-yr increment.

^†Due to missing data, N = 198 for length of U.S. residence and age at migration (n = 90 premenopausal, n = 108 postmenopausal); N = 197 for hormonal contraceptives (n = 88 premenopausal, n = 109 postmenopausal); N = 199 for estrogens (n = 89 premenopausal, n = 110 postmenopausal).

^‡No premenopausal women reported a first-degree relative with breast cancer.

*Odds ratios for higher vs. lower breast density estimated from polychotomous logistic regression, adjusted for age, menopausal status, BMI, family history of breast cancer, level of acculturation, combined variable representing number of live births and age at first live birth, and adult weekly frequency of dairy food intake.

^†OR for weight at age 18 yr is per 5 kg change; OR for adult height is per 0.1 m change.

*Odds ratios for higher vs. lower breast density estimated from polychotomous logistic regression, adjusted for age, BMI, level of acculturation, combined variable representing number of live births and age at first live birth, and adult weekly frequency of dairy food intake.

**P value for trend was estimated using an ordinal variable representing the scaled median value for each category.