Serum oestrogen levels in postmenopausal women: comparison of American whites and Japanese in Japan
1990

Comparison of Estrogen Levels in Postmenopausal Women from Japan and America

Sample size: 129 publication Evidence: high

Author Information

Author(s): H. Shimizu, R.K. Ross, L. Bernstein, M.C. Pike, B.E. Henderson

Primary Institution: Gifu University School of Medicine; University of Southern California

Hypothesis

Are serum estrogen levels different in postmenopausal Japanese women compared to American white women?

Conclusion

Postmenopausal Japanese women have significantly lower serum estrogen levels than American white women.

Supporting Evidence

  • American women had 47% higher oestrone levels than Japanese women.
  • American women had 36% higher oestradiol levels than Japanese women.
  • After adjusting for weight, American women still had significantly higher estrogen levels.

Takeaway

This study found that older Japanese women have less estrogen in their blood than American women, which might help explain why they have lower breast cancer rates.

Methodology

The study compared serum estrogen and SHBG levels in postmenopausal Japanese and American women, adjusting for weight and other factors.

Potential Biases

Potential bias in sample selection as Japanese women were chosen from a rural agricultural area.

Limitations

The study may not represent urban Japanese women and was limited to specific rural areas.

Participant Demographics

Postmenopausal women aged 60 to 70, with 91 Japanese and 38 American participants.

Statistical Information

P-Value

p<0.0001

Confidence Interval

(78.0, 88.4) for Japanese oestrone, (109.5, 136.5) for American oestrone

Statistical Significance

p<0.0001

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