California Teachers Study | Study Findings: Body Size

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BODY SIZE

Researchers pooled data from 159 prospective cohort studies, including the California Teachers Study, to study the relationship between adult height and risk of breast cancer. Their study found that adult height may be a risk factor for breast cancer in women, and suggested that there may be underlying genetic pathways that affect both a woman’s height and the pathogenesis (biological mechanisms that lead to disease) of breast cancer. Read more here.
By pooling data from 20 different cohort studies, researchers found that study participants who had a BMI > 25 during their early adulthood and a BMI > 30 when they joined their respective studies had a higher risk of developing multiple myeloma compared with participants who had a BMI between 18.5 and 25 at those same points in time. This study also found that participants who remained heavy throughout their adulthood had the highest risk of death from this cancer. Read more here.

Using data from six different cohorts, this 2022 study looked at the relationship between body size and risk of multiple myeloma. The research team found that larger body size was associated with an increased risk of multiple myeloma. Read more here.
Using data from six different cohort studies, including the California Teachers Study, researchers looked at the relationship between body size and risk of certain non-Hodgkin lymphoma (NHL) subtypes. In this study, adult height was associated with increased risk of most subtypes, including the more common NHL subtypes DLBCL, CLL/SLL, FL. Adult height was also associated with increased risk of two rare subtypes: MCL and MF/SS. Body mass index (BMI) was also associated with risk of NHL subtype DLBCL. Read more here.
Using data from the Epidemiology of Endometrial Cancer Consortium (E2C2), this study investigated whether BMI in young adulthood (age 18–21), BMI at study enrollment, and weight change over time were associated with risk of endometrial cancer. Results from this study suggest that young adulthood and adulthood obesity were both associated with risk of endometrial cancer, as was weight gain over time. Read more here.
A 2011 study found that CTS participants who were underweight (BMI ≤ 18.5) or obese (BMI ≥ 30) were at a higher risk of all-cause mortality. Obese participants also had an increased risk of death from cancer and from cardiovascular and respiratory diseases. Read more here.
A study of CTS participants found that abdominal adiposity (excessive fat around the stomach and abdomen) and weight gain – but not overall obesity – appeared to increase participants’ risk of ovarian cancer. Read more here.
A 2012 study found that associations between a CTS participant’s level of physical activity, whether they were overweight or obese, and their built environment (human-made surroundings and use of natural resources) varied by participants’ sociodemographic characteristics, such as their race/ethnicity and age. Read more here.
Being overweight or obese is strongly associated with increased risk of endometrial cancer. Two common genetic variations, FTO rs9939609 and MC4R rs17782313, have been linked to increased body weight and obesity; however, a 2011 study found that these variations themselves were not directly associated with endometrial cancer. Read more here.
In white adults, higher waist circumference was associated with higher mortality, even among adults with a BMI in the normal range. Read more here.
A 2014 study found class III obesity (BMI of 40-59 kg/m2) was associated with substantially higher risk of death compared to normal BMI (18.5-24.9 kg/m2), with the majority of deaths occurring from heart disease, cancer, and diabetes. Read more here.
A 2014 study found the relationship between body size (BMI and waist-to-hip ratio) and breast cancer patients’ risk of death varied across racial/ethnic groups. Using data from the California Breast Cancer Survivorship Consortium, researchers found that non-Latina white participants who were underweight (BMI <18.5) or morbidly obese (BMI ≥ 40) had an increased risk of dying from breast cancer. Among Latina participants, only the morbidly obese had a higher risk of death. This study did not find any association between BMI and breast cancer mortality among African American or Asian American study participants. Read more here.
Using pooled data from multiple prospective cohort studies, researchers found that higher BMI was associated with increased risk of mortality among Asian Americans aged 35 to 69 years. Read more here.
Using pooled data from 20 cohort studies, researchers found waist circumference and waist-to-hip ratio were associated with head and neck cancer, and that risk did not vary by smoking status. BMI was associated with risk of head and neck cancer among never smokers. Read more here.
A 2015 study found that having a higher waist-to-hip ratio and waist circumference was associated with increased risk of pancreatic cancer mortality, independent of BMI. The findings from this study suggest being obese or overweight during early adulthood may also influence pancreatic cancer mortality risk later in life. Read more here.
Genome-wide association studies have identified common gene variants that predispose individuals to a higher BMI, which is an independent risk factor for endometrial cancer. However, a 2015 study showed that possessing a large number of high BMI risk alleles in itself, independent of having a higher BMI, did not increase endometrial cancer risk. 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 2009 study found obesity and waist circumference were associated with a greater risk of asthma. Women with a waist circumference of greater than 88 cm were found to have greater prevalence of asthma, as well as more frequent and severe episodes of asthma, even if the women had a normal BMI. 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 2010 study found that being overweight and obese were associated with an increased risk of mortality in white adults. Overall, a BMI of 20.0 to 24.9 was found to have the lowest all-cause mortality. Read more here.
This 2018 study evaluated the relationship between prediagnostic body-mass-index (BMI), waist-to-hip-ratio (WHR), weight-gain during adulthood, and Amyotrophic Lateral Sclerosis (a progressive nervous system disease that is often known as Lou Gehrig's disease). Findings confirmed somewhat conflicting, underpowered evidence that adiposity is inversely associated with ALS and that the rate of weight gain during adulthood is strongly statistically correlated with ALS risk. Read more here.
A 2020 pooling project combined data from 17 different studies to examine whether changes in adult weight were associated with risk of developing premenopausal breast cancer. Findings from this study suggest that weight loss was not consistently associated with breast cancer risk, and weight increase from early adulthood to ages 45-54 was associated with a reduced risk of premenopausal breast cancer. Read more here.
Previous studies have demonstrated varied findings on the associations between anthropometric factors (body size) and risk of developing breast cancer by breast cancer receptor status. Using pooled data from 20 cohort studies, this analysis evaluated the relationship between body size—height, early adult BMI, and adult weight gain—and breast cancer risk by receptor subtype. Read more here.