California Teachers Study

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.
 

This 2019 study examined whether hypertension and regular use of specific anti-hypertensive medications was associated with the risk of age-related macular degeneration (AMD). Results suggested increased risks of AMD among women who were treated for hypertension at study baseline. Among a subset of participants for whom specific medication information was available, the researchers estimated a 45% increased risk of AMD among women receiving diuretics as monotherapy compared to women with medications more potent than diuretics. Read more here.
 

Previous research has shown that using postmenopausal hormone therapy increases the risk of having a stroke. This project evaluated whether physical activity levels that meet the American Health Association’s recommendations for leisure time physical activity—more than 150 min/week of moderate activity or more than 75 min/week of strenuous activity—reduced the risk of stroke among hormone therapy users. This study found that CTS participants who used hormone therapy and met the AHA’s recommendations for leisure time physical activity did not have an elevated risk of stroke. Read more here.
 

Researchers evaluated whether use of regular aspirin and/or other non-steroidal anti-inflammatory drugs (NSAIDs) was associated with the development of age-related macular degeneration (AMD) among California Teachers Study participants. The researchers did not find an association between the frequency or duration of aspirin or ibuprofen use and AMD. Among participants for whom more specific information on medication use was available, findings suggested a possible decrease in risk of intermediate- or late-stage AMD for participants who reported regular use of low-dose aspirin or specific COX-2 inhibitors. Read more here.