California Teachers Study

Using data from 19 studies participating in the Premenopausal Breast Cancer Collaborative Group (PBCCG), this publication examined how leisure-time physical activity, like participating in sports or other recreational physical activity, affects risk of premenopausal breast cancer. The findings from this project suggest that leisure-time physical activity is associated with a reduced risk of premenopausal breast cancer.  Read more here.
 

This 2022 publication used data from the Breast Cancer Association Consortium (BCAC) to study the relationship between physical activity and risk of developing breast cancer. The researchers used Mendelian randomization (MR), which is a research method designed to reduce confounding. The results from this study suggest that overall physical activity, vigorous physical activity, and less sedentary time (time spent sitting or inactive) may lower the risk of breast cancer. Read more here.
 

Windows of susceptibility refer to a developmental period when the body may be more vulnerable to certain exposures. This study focused on the window of susceptibility from first period (menarche) to first pregnancy and investigated how physical activity during that period affects future risk of breast cancer. Findings from this study suggest that physical activity during this window of susceptibility was associated with a lower risk of breast cancer. Read more here.
 

A 2015 study pooled data from the California Breast Cancer Survivorship Consortium and found that women in these studies with high levels of recent recreational physical activity had a statistically significant decreased risk of death from causes other than breast cancer, and particularly from cardiovascular diseases. The benefits of recreational physical activity on survival appeared to remain consistent across different races and ethnicities.  Read more here.
 

Among California Teachers Study participants, strenuous recreational physical activity (more than 3 hours per week per year) at study enrollment was associated with decreased endometrial cancer risk, but only among overweight/obese women (BMI ≥25 kg). Participants who participated in three or more hours of strenuous recreational physical activity at baseline had an approximately 25% lower risk of endometrial cancer than women who did less than a half hour a week per year of strenuous activity.  Read more here.
 

A 2013 study found that CTS participants whose long-term physical activity averaged at least 5.5 MET hours per week had a non-significant 23% lower risk of papillary thyroid cancer risk than inactive women. For participants with a BMI <25, long-term recreational moderate and strenuous physical activity was associated with reduced risk of papillary thyroid cancer.  Read more here.
 

A 2009 study found that taller CTS participants had a higher risk of B-cell Non-Hodgkin lymphoma and B-cell chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Participants taller than 1.70 meters (approximately 5 ft. 7 in.) had a 50% greater risk for B-cell NHL than women who were 1.61 to 1.65 meters (approximately 5 ft. 3 in. to 5 ft. 5 in.).  Read more here.
 

Lifetime recreational physical activity reduced colon cancer risk among postmenopausal CTS participants who had never used hormone therapy.  Read more here.
 

For women diagnosed with breast cancer, medium to high levels of physical activity (defined as moderate or strenuous activity for >or=3 hours/week/year) were associated with a lower risk of breast cancer related mortality. This effect was confined to women with a BMI ≥25.  Read more here.
 

A 2017 study evaluated the relationship between leisure-time physical activity and risk of stroke. Researchers found that participating in leisure-time physical activity (LTPA) at AHA recommendations (moderate intensity for more than 50 minutes/week; strenuous intensity for more than 75 minutes/week) decreased the risk of ischemic stroke for participants who met these requirements at both baseline questioning (1995-1996) and ten-year follow up (2005-2006).  Read more here.