But in the past 40 years, there hasn't been any real change in age of menarche, which remains at just over 12 years.

但是在过去的40年间，初潮发生的年龄段并没有实质性的改变，还是在12岁左右。

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Indeed, two teams found that several other genes linked to height also predict age at menarche.

而事实上，两个小组发现，其他几个和身高有关的基因也能预测初潮的年龄。

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Smoking in male and age of menarche in female influenced BMD.

男性吸烟、女性初潮年龄对骨密度有一定的影响。

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Epidemiologic studies over the past 40 years have identified numerous risk factors for breast cancer, including: older age, an early age at menarche, a late age at first full-term birth, not having children, a family history of breast cancer in a first-degree relative, greater height, higher circulating estrogen levels, postmenopausal hormone use, breast density, history of breast biopsies, obesity (for postmenopausal breast cancer), and exposure to ionizing radiation.

FORBES: After 40 Years Of Research, What Do We Know About Preventing Breast Cancer?