Does place of birth influence endogenous hormone levels in Asian-American women?

Abstract

In 1983 -87, we conducted a population-based case -control study of breast cancer in Asian women living in California and Hawaii, in which migration history (a composite of the subject's place of birth, usual residence in Asia (urban/rural), length of time living in the West, and grandparents' place of birth) was associated with a six-fold risk gradient that paralleled the historical differences in incidence rates between the US and Asian countries. This provided the opportunity to determine whether endogenous hormones vary with migration history in Asian-American women. Plasma obtained from 316 premenopausal and 177 naturally premenopausal study controls was measured for levels of estrone (E1), estradiol (E2), estrone sulphate (E1S), androstenedione (A), testosterone (T), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), progesterone (PROG) and sex hormone-binding globulin (SHBG). Levels of the oestrogens and sex hormone-binding globulin did not differ significantly between Asian-and Western-born women, although among premenopausal women, those least westernised had the lowest levels of E1, E2, and E1S. Androgen levels, particularly DHEA, were lower in women born in the West. Among premenopausal women, age-adjusted geometric mean levels of DHEA were 16.5 and 13.8 nmol l 71 in Asian-and Western-born women respectively; in postmenopausal women these values were 11.8 and 9.2 nmol l 71 , (P50.001) respectively. Among postmenopausal women, androgens tended to be highest among the least westernised women and declined as the degree of westernisation increased. Our findings suggest that aspects of hormone metabolism play a role in population differences in breast cancer incidence.

Phenotypic comparison of Caucasian and Asian women with polycystic ovary syndrome: a cross-sectional study

“…This suggests a role for a geographic and environmental influences, potentially through diet, on the phenotype of hirsutism. Although studies on the role of migration and endogenous hormone levels suggest that androgen levels are lower in Western-born women than their counterparts born in Asia or Pakistan (15,16), small trials of women with PCOS suggest that diet may influence sex hormonebinding globulin (SHBG) levels and androgen levels (17)(18)(19)(20). One trial of 28 overweight women with PCOS demonstrated that with energy restriction the participants experienced weight loss and increased SHBG levels accompanied by decreased testosterone levels (17).…”

Rural urban differences in breast cancer in India

“…Most of the etiological studies have used current area of residence as a definition for rural [10,11] and limited studies which have taken early years of life spent [12] or place of the birth [13,14] in rural areas as a definition for "rural." However, current residence is not a good marker for studying the effect of the rural environment on the risk of breast cancer, as exposures in early life may be more important in the development of breast cancer compared to current exposures.…”

Exploring the Underlying Hormonal Mechanisms of Prenatal Risk Factors for Breast Cancer: A Review and Commentary

“…Whereas androgens have been generally lower in pre-and postmenopausal Asian compared with Caucasian women (48), a recent study showed an inverse correlation with increasing westernization in Asian migrants to the West (67). Published data on androgen concentrations in the maternal and fetal circulation, however, are unavailable, although data 5 from a study of Chinese living in Shanghai and Caucasians in Boston on cord androstenedione and testosterone concentrations are forthcoming.…”