Home  >  For Participants  >  Study Findings  >  Medications


  • A 2017 study found that CTS participants who took three or more tablets of low-dose aspirin per week had a reduced risk of breast cancer. This reduced risk was particularly evident in women with the hormone receptor-positive/HER2-negative subtype of breast cancer. Previous studies have also found that regular-dose aspirin is associated with a reduced risk of breast cancer, but this CTS report this is the first study to suggest that the reduction in risk also occurs with low-dose aspirin use. Read more here.

  • Using data from the CTS and two other cohort studies, researchers examined whether prior oral contraceptive use decreased ovarian cancer risk. This 2016 study found that oral contraceptives had a protective effect against ovarian cancer for decades after menopause. Parity (having children) also provided a protective effect in these cohorts but this protection waned in older women, particularly those aged 75 or older.  Read more here.

  • A 2014 study found that CTS participants who exclusively used estrogen therapy (ET) were less likely to die from lung cancer than CTS participants who had never used estrogen therapy.  Read more here.

  • A 2011 study found that among women in the California Teachers Study, menopausal hormone therapy (HT) was associated with a reduced risk of mortality – but only among younger users. The reduced risk was not apparent for postmenopausal women.  Read more here.

  • Abdominal adiposity (excessive fat around the stomach and abdomen) and weight gain of 40 or more pounds increased ovarian cancer risk among CTS participants who had never used hormone therapy. Within this study, overall obesity did not appear to be associated with increased ovarian cancer risk.  Read more here.

  • Within the CTS, long-term (≥5 years) use of antihypertensive medication was associated with a small increased risk of invasive breast cancer. This increased risk appeared to be confined to estrogen-receptor-positive (ER +) breast cancer and younger women.  Read more here.

  • Although NSAIDs were found to have no association with breast cancer risk, long term (>= 5 years) daily aspirin use was associated with an increased risk of ER/PR-negative breast cancer. Long term daily ibuprofen use was furthermore associated with an increased risk of breast cancer.  Read more here

  • Researchers found a higher rate of surgically diagnosed fibroids in African-American women than non-Latina white woman. The rate was also higher among premenopausal women, women who used postmenopausal therapy, and women who were overweight, drank alcohol or had a family history of fibroids. However, smoking and diabetes were found to be associated with a decreased risk of fibroids.  Read more here.

  • A 2010 study found that CTS participants who used menopausal hormone therapy at the time of the baseline questionnaire had a lower risk of invasive colon cancer. Estimated risk was lower among participants who used menopausal hormone therapy between 5 and 15 years.  Read more here.

  • A 2010 study suggested that declines in breast cancer are largely attributable to the decrease in hormone therapy use. Breast cancer incidence in the California Teachers Study decreased sharply (30.6% from 2003 to 2005) among women who stopped taking hormone therapy, but remained generally consistent in the population who had never taken hormone therapy.  Read more here.

  • A 2012 study investigated genetic variations in sex steroid metabolism and their effect on the relationship between hormone therapy and risk of endometrial cancer. Allele variations in CYP11A1, a gene involved in sex steroid metabolism, may alter the risk of estrogen therapy use on risk of postmenopausal endometrial cancer; however, further research is required.  Read more here.

  • Women with prior history of hypertensive disorders of pregnancy (HDP) were found to have an increased risk of stroke over long term, particularly after 60 years of age, although this risk was reduced overall in women with aspirin use. The same effect was not observed with statins use.  Read more here.

  • A 2018 study suggested that daily aspirin use was associated with a 10% lower risk of developing ovarian cancer.  Read more here.

Biomedical Research Center, Cubicle 2016.04

1218 S. Fifth Ave.

Monrovia, California 91016


(800) 568-9471


Copyright 2020 California Teachers Study