California Teachers Study

A 2002 study found several associations between vitamin supplement use and various demographic, dietary, and health-related factors. Supplement users were more likely to be older, Caucasian, and leaner (BMI <30). They were also more likely to use cancer screening tests, eat fruits and vegetables, exercise, and were less likely to be current smokers compared with non-vitamin users.  Read more here.
 

Phytoestrogens are plant compounds sharing a similar molecular structure with estrogen. Researchers examined the validity of food-frequency questionnaires (FFQ) in quantifying phytoestrogen consumption by administering 24-dietary recalls, a pre- and post- study FFQ, and then comparing it to participants’ 24-hour urine samples. They found FFQs to be accurate in detecting isoflavones, a class of phytoestrogens, in non-Asian populations.  Read more here.
 

A 2007 study found that drinking 8 oz. or more of coffee or tea per day was associated with a modestly decreased risk of renal cancer.  Read more here.
 

A 2007 assessment found that a food-frequency questionnaire (FFQ) used in the CTS was valid and reproducible. Nutrient data had a reproducibility range of 0.60 to 0.87, and validity correlations were reasonably high (range: 0.55-0.85), with a few exceptions.  Read more here.
 

A 2008 study found no association between intake of fat and protein and increased risk of renal cancer. This includes their sub-types: red meat, processed meat, poultry, and seafood.  Read more here.
 

A 2012 study concerning intake of carotenoids α-Carotene, β-carotene, and lutein/zeaxanthin revealed that increased consumption of these pigments was associated with a lower risk of ER-negative breast cancer, though not ER-positive breast cancer. It is unclear whether the carotenoids themselves lend to the effect or if other components in the same food sources do.  Read more here.
 

Cadmium (Cd) is a toxic metal, and Urinary Cd 9 (U-cd) concentration has been considered a sign of long term exposure. Comparison of urine samples with environmental data collected about CTS participants regarding their diet, surroundings, and habits, revealed that a single measurement of U-Cd in a 24-hour sample did not accurately reflect medium to long-term effect on the body.  Read more here.
 

A 2013 study found no association between total fruit and vegetable intake and risk of overall breast cancer. However, increased vegetable consumption was correlated with lower risk of ER-negative breast cancer.  Read more here.
 

Researchers examined the relationship between 4 different diet indexes (Alternate Mediterranean Diet, Alternative Eating Index 2010, Dietary Approaches to Stop Hypertension, and Paleolithic index) and breast cancer risk. Diet quality indexes that emphasized intake of whole grains, vegetables, fruits, legumes, and nuts and seeds and de-emphasize red and processed meats and sugar-sweetened beverages were modestly associated with a lower risk of postmenopausal breast cancer. None of the diets evaluated were associated with a lower risk of premenopausal breast cancer, and the PALEO score had no association with cancer risk regardless of menopausal status.  Read more here.
 

In this 2019 study, consumption of sugar sweetened beverages (SSBs) was not associated with colorectal cancer risk. However, the biological effects of high SSB consumption make it important to continue to evaluate whether SSBs are associated with CRC. Read more here.
 

A 2020 study evaluated the relationship between sugar sweetened beverage (SSB) consumption (consumption of caloric soft drinks, sweetened bottled waters or teas, and fruit drinks) and risk of cardiovascular disease. Consuming more than 1 serving per day of SSB was associated with cardiovascular disease, revascularization, and stroke. Read more here.
 

Researchers analyzed the association between rice intake, which is a source of dietary arsenic, and risk of breast, lung, pancreatic, bladder, and kidney cancer. Rice intake did not appear to be associated with cancer risk for participants in the California Teachers Study. Read more here.
 

Using data from 21 different cohort studies, including the California Teachers Study, researchers evaluated the association between dairy product and calcium intake and risk of incident invasive breast cancer overall and by subtypes defined by ER status. This study did not find a clear association between consumption of specific dairy foods, calcium intake, and risk of breast cancer overall. This study did find that higher yogurt and cottage/ricotta cheese intakes were inversely associated with the risk of ER-negative breast cancer. Read more here.
 

This 2021 study evaluated the relationship between intake of sugar-sweetened beverages (SSB) and risk of mortality. Among California Teachers Study participants, consuming more than 7 servings a week of caloric soft drinks was associated with higher risk of all-cause and cancer-specific mortality. Read more here.