Hormone levels in older women: a study of post-menopausal breast cancer patients and healthy population controls

202

(SHBG) and risk of breast cancer in post-menopausal women were investigated in a prospective study on the island of Guernsey. Sixty-one women who developed breast cancer an average of 7.8 years after blood collection were matched for age, year of blood collection and number of years post-menopausal with 179 control subjects. Women using exogenous hormones at the time of blood collection were excluded from the study. Women who subsequently developed breast cancer had a 29% higher geometric mean oestradiol concentration than control women (P = 0.004). The odds ratio for breast cancer in the top third compared with the lowest third of the oestradiol concentration distribution was 5.03 (95% confidence interval 2.02-12.49, Pfor trend < 0.001). Adjusting for testosterone and SHBG concentrations did not substantially alter the odds ratio for oestradiol. Although testosterone and SHBG concentrations were associated with breast cancer risk, the concentrations of these hormones were correlated with those of oestradiol; the associations were not statistically significant after adjusting for oestradiol concentration. These data provide evidence that serum oestradiol concentrations in post-menopausal women may have a substantial effect on breast cancer risk.

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confidence: 96%

A prospective study of endogenous serum hormone concentrations and breast cancer risk in post-menopausal women on the island of Guernsey

Thomas¹,

Key²,

Allen³

et al. 1997

202

“…In a review of 32 studies published up until 1987, we concluded that postmenopausal breast cancer cases are exposed to more endogenous oestrogen than controls (Key and Pike, 1988), and more recent studies have in general supported this conclusion. In two small case-control studies, Bernstein et al (1990a) and Zaridze et al (1992) reported higher oestradiol levels in cases than in controls among postmenopausal women. Two small prospective studies found similar oestradiol levels in women who subsequently developed breast cancer and control women (Garland et al, 1992;Helzlsouer et al, 1994), but a large prospective study of post-menopausal women found a significant increase in risk associated with increased serum concentrations of oestradiol, and particularly of free oestradiol (Toniolo et al, 1995).…”

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confidence: 99%

A prospective study of urinary oestrogen excretion and breast cancer risk

Key¹,

Wang²,

Brown³

et al. 1996

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Sinmary To test the hypothesis that high levels of endogenous oestrogens increase the risk for developing breast cancer, concentrations of oestrone, oestradiol and oestriol were measured in 24 h urine samples from 1000 women partipants in a prospective study of breast cancer on the island of Guersey. Sixty-nine subjects were diagnosed with breast cancer subsequent to urine collection. Among women who were premenopausal at the time of urine collection, cases excreted less oestrogen than controls; the odds ratios (95% Cl) for breast cancer in the middle and upper thirds of the distribution of oestrogen excretion, in comparison with the lower third (reference group, assigned odds ratio= 1.0), were 0.5(0.2-1.2) and 0.4(0.2-1.1) respectively for oestrone, 0.8(0.4-1.8) and 0.4(0.2-1.1) for oestradiol, 0.7(0.3-1.6) and 0.7(0.3-1.6) for oestriol and 0.9(0.4-2.0) and 0.5(0.2-1.3) for total oestrogens. Among women who were post-menopausal at the time of urine collection, the trend was in the opposite direction, with an increase in risk associated with increased oestrogen excretion; the odds ratios were 0.9(0.3-2.2) and 1.1(0.5-2.8) for oestrone, 0.8(0.3-2.3) and 1.9(0.8-4.6) for oestradioL 1.5(0.6-3.9) and 1.8(0.7-4.6) for oestriol and 0.9(0.4-2.6) and 1.9(0.7-4.7) for total oestrogens. The trends of increasing risk with increasig oestrogen excretion among post-menopausal women were statistically significant for oestradiol (P=0.022) and for total oestrogens (P=0.016). We conclude that high levels of endogenous oestrogens m post-menopausal women are associated with increased breast cancer risk, but that the relationship of oestrogens in premenopausal women with risk is unclear.

“…There was little difference in SHBG levels between the Japanese and the American women. These results for El and E2 could be an important part of the explanation why Japanese and American breast cancer rates continue to diverge further after the menopause.There is considerable evidence that oestrogens are involved in the aetiology of breast cancer and that increased blood levels of oestrogen in postmenopausal breast cancer patients are one marker of high risk (Key & Pike, 1988;Bernstein et al, 1990). The incidence rates for breast cancer in Japan are substantially lower than those in the USA and European countries (Muir et al, 1987), and some systematic pathological and clinical differences between breast cancer diagnosed in Japan and western countries have been reported (Wynder et al, 1963;Chabon et al, 1974).…”

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confidence: 99%

Serum oestrogen levels in postmenopausal women: comparison of American whites and Japanese in Japan

Shimizu

Ross²,

Bernstein³

et al. 1990

Self Cite

156

Summary Serum oestrone (El), oestradiol (E2) and sex hormone binding globulin (SHBG) levels were studied in postmenopausal Japanese women in Japan (n = 91) and postmenopausal American white women (n = 38). The Japanese women were deliberately chosen to be from a rural agricultural area in order to get samples which represent as closely as possible the traditional Japanese 'lifestyle' that gave rise to the low rates of breast cancer in Japan. El levels were 47%, and E2 levels 36%, greater in the American women; these differences were only reduced to 43% and 27% after adjustment for the lower weight of the Japanese. These results were all statistically highly significant. There was little difference in SHBG levels between the Japanese and the American women. These results for El and E2 could be an important part of the explanation why Japanese and American breast cancer rates continue to diverge further after the menopause.There is considerable evidence that oestrogens are involved in the aetiology of breast cancer and that increased blood levels of oestrogen in postmenopausal breast cancer patients are one marker of high risk (Key & Pike, 1988;Bernstein et al., 1990). The incidence rates for breast cancer in Japan are substantially lower than those in the USA and European countries (Muir et al., 1987), and some systematic pathological and clinical differences between breast cancer diagnosed in Japan and western countries have been reported (Wynder et al., 1963;Chabon et al., 1974). These observations suggest that there may be important differences in endocrine function among residents in these areas, but there are surprisingly few data on blood hormone levels in healthy populations from these countries. We report here a study comparing serum oestrogen and sex-hormone-binding globulin (SHBG) levels of post-menopausal Japanese women in Japan to those of white women in the USA. Subjects and methodsThe Japanese subjects were volunteers residing in rural areas of Miyagi, a prefecture in north-east Japan. These women were mainly from rice farming families. We first contacted them at a general medical screening clinic for the healthy elderly sponsored by their farmer's union, informing them of the purpose of our study and asking for their cooperation. The subjects in the USA were American non-Latino volunteers from a retirement community in Southern California, who had a blood sample drawn during a well-patient visit to a local health clinic. All women had to have intact ovaries, be postmenopausal, and be 60 to 70 years of age. Ninety-one women were sampled in Japan; 38 women were sampled in California. Women with any past or present endocrine disease, or who had used steroid hormones during the previous 12 months, or had more than 12 months total use of steroid hormones, were excluded.All subjects were asked to provide information on a series of factors related to breast cancer risk and, possibly, to hormonal status, including ages at menarche, menopause, and first full-term pregnancy, number of children, and present h...