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Reproductive Health

  • Researchers pooled data from the CTS, 3 other cohort studies, and 14 case-control studies to examine the relationship between intrauterine devices (IUDs) and risk of endometrial cancer. Within these study populations, use of IUDs, older age (≥ 35 years) at first use, older age (≥ 45) at last use, longer duration (≥ 10 years), and recent use (within 1 year of study entry) were associated with a reduced risk of endometrial cancer.  Read more here.
     

  • A 2013 study found that CTS participants who were using estrogen-only therapy when they enrolled in the study (1995-1996) had a lower risk of pancreatic cancer than participants who had never used hormone therapy.  Read more here.

  • Researchers compiled data from the Epidemiology of Endometrial Cancer Consortium to study the relationship between age at last birth and risk of endometrial cancer. They found that within these studies, risk of endometrial cancer declined with increasing age at last birth.  Read more here.
     

  • Researchers combined data from the Los Angeles-Shanghai Bladder Cancer Study and the CTS to study the relationship between parity (having children) and bladder cancer risk. Parous women (women who had given birth to children) in these studies had at least 30% reduced risk of developing bladder cancer compared with nulliparous women (women who had never given birth).  Read more here.
     

  • Compared with CTS participants who had never been pregnant, parous CTS participants had a reduced risk for breast carcinoma in situ (CIS) and invasive breast cancer. The risk reduction grew with an increasing number of full-term pregnancies. The age at which participants had their first-full term pregnancy was also associated with breast cancer risk. Participants whose first full-term pregnancy occurred at age 35 or later had a 115% greater risk for breast CIS and a 27% greater risk for invasive breast cancer than participants whose first full-term pregnancy occurred before age 21.  Read more here. 
     

  • The parental age at which CTS participants were conceived (i.e. how old a CTS participant’s mother and father where when she was conceived) was associated with that participant’s risk of developing non-Hodgkin lymphoma.  Read more here. 
     

  • A 2008 study found that there was no statistically significant association between incomplete pregnancy (i.e. miscarriage or abortion) and the risk of breast cancer for California Teachers Study participants.  Read more here. 
     

  • A 2002 study found that CTS participants had a higher incidence rate of breast, ovarian, and endometrial cancer than comparable California women. These three cancers share several risk factors that may be more common among California female teachers, including low parity, short duration of breastfeeding, and use of postmenopausal hormones.  Read more here.
     

  • Among younger women (<45 years at baseline), later age at first menstruation (>or=14 years) was associated with an increased risk of thyroid cancer. Risk was also elevated in young women with longer menstrual cycles (>30 days) and whose last pregnancy had ended within five years of cohort enrollment. These results suggest that factors related to delayed puberty may play a role in papillary thyroid cancer risk.  Read more here.
     

  • Researchers found that menopausal hormonal therapy was not associated with risk of B-cell non-Hodgkin lymphoma among postmenopausal women. Bilateral oophorectomy and hysterectomy were associated with a greater risk of NHL among women who had not used menopausal hormonal therapy.  Read more here.
     

  • Women with a surgically confirmed endometriosis diagnosis were younger than those with a surgically confirmed adenomyosis diagnosis. Having a mother or sister with endometriosis and never having become pregnant were significantly associated with an increased risk of endometriosis. Having a higher number of children (parity), an early full-term pregnancy, early menarche (<or=10 years of age), obesity, and short menstrual cycles (<or=24 days in length) were significantly associated with an increased risk of adenomyosis.  Read more here.
     

  • Researchers investigated the effects of surgical menopause through bilateral oophorectomy (removal of both ovaries and fallopian tubes). Having the operation did not increase all-cause, cardiovascular, or cancer mortality.  Read more here.
     

  • A 2014 study suggested that lifelong high estrogen exposure is associated with a decreased risk in Parkinson’s disease, suggesting that estrogen exposure over a long period of time may be important to Parkinson’s disease reduction.  Read more here.
     

  • A 2014 study found that the association between SNP rs10235235 (locus CYP3A, chromosome 7q22.1) and breast cancer varied by age at menarche. The modest protective effect of rs10235235 only occurred in women with an older age at menarche (>or=15 years) and was not found for women with an age at menarche of <or=11 years, consistent with the well-documented association between later age at menarche and a reduction in breast cancer risk. This relationship between later menarche and reduced risk can likely be attributed to changes in hormone circulation patterns.  Read more here.
     

  • A 2014 study found 123 signals at 106 loci associated with age at menarche. These genomic loci include genes that have also been implicated with body mass index and various diseases, including rare disorders of puberty. Loci DLK1-WDR25, MKRN3-MAGEL2, and KCNK9 exhibited parent-of-origin specific associations (for example, a trait that is only influenced by father’s chromosome). Findings suggest that these variants intersect to play a role in coordinating the time of puberty.  Read more here.
     

  • Researchers examined risk factors of ovarian cancer along with specific ovarian cancer subtypes. Higher parity (number of pregnancies) was strongly associated with decreased risk of endometrioid and clear cell carcinoma. Younger age at menopause, never having had endometriosis, and tubal ligation were associated with decreased endometrioid and clear cell tumor risk. Family history of breast cancer only had modest variation among subtypes. Smoking was associated with an increased risk of mucinous but decreased risk of clear cell tumors.  Read more here.
     

  • Researchers found that for women with a history of preeclampsia, the T allele of IGF1R variant rs2016347 was associated with a lower risk of breast cancer. This effect was most noticeable for HR+ breast cancer and in women whose age at first birth was younger than 30 years.  Read more here.

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