September: Exercise and Breast Cancer | News and Features

Findings were generally consistent across all types and stages of the disease, revealing Mendel’s randomized study and recommending researchers focus more on exercise as a way to prevent breast cancer. I urged you to

Mendelian randomization is a technique that uses genetic variants as a surrogate for a particular risk factor (in this case, lifetime physical activity level/sedentary behavior) in order to obtain genetic evidence supporting causality. .

Observational studies have shown that physical inactivity and sedentary behavior are associated with increased breast cancer risk, but proving that they cause breast cancer is another matter.

Therefore, the researchers used Mendelian randomization to assess whether lifelong physical activity and sedentary time are causally associated with breast cancer risk in general, and different tumor types in particular.

These included data from 130,957 women of European descent. 6,667 had tumors that had not yet developed (in situ). A comparison group of 54,452 women without breast cancer.

These women were participants in 76 studies under federal custody. Breast Cancer Society Consortium (BCAC), a forum for researchers interested in genetic risk for breast cancer.

Researchers then drew on previously published studies that used its vast repository. UK Biobank Using data on potential genetic explanations for overall predisposition to physical activity, vigorous physical activity, or sedentary time (as measured by wrist-worn activity trackers), study participants were tested for how physically active they were. Genetically predicts active or inactive.

The researchers then estimated the overall breast cancer risk depending on whether the woman had gone through menopause. By cancer type (positive for estrogen or progesterone, or HER-2, or positive/negative for all three hormones), stage (size and extent of tumor spread), and grade (degree of tumor cell abnormality) classified.

These case-control groups consisted of 23,999 perimenopausal women with invasive breast cancer and 17,686 women without. 45,839 postmenopausal breast cancer patients and 36,766 breast cancer patients.

Overall, there were 46,528 estrogen receptor-positive tumors and 11,246 controls. 34,891 progesterone receptor-positive tumors and 16,432 controls. 6,945 HER2-positive tumors and 33,214 controls. 1,974 triple positive cases. and 4,964 triple-negative cases.

There were also 42,223 invasive ductal/lobular carcinomas, 8,795 controls, and 3,510 ductal carcinomas in situ. 17,583 stage 1 cancers, 15,992 stage 2, and 4,553 stage 3-4 cancers. 34,647 moderately abnormal cell tumors and 16,432 highly abnormal cell tumors.

Analysis of the data showed that a higher genetically predicted overall level of physical activity was associated with a 41% lower risk of invasive breast cancer. This was not significantly related to menopausal status, tumor type, stage, or grade.

Similarly, the genetically predicted three or more days of vigorous physical activity per week was associated with a 38% lower risk of breast cancer compared to self-reported inactivity. These findings were consistent across most case groups.

Finally, longer genetically predicted sedentary hours were associated with a 104% higher risk of triple-negative breast cancer. These findings were consistent across hormone-negative tumor types.

The findings did not change after considering the production by a single gene of two or more apparently unrelated effects (pleiotropy), such as smoking and being overweight.

The researchers point to reasonable evidence that there are multiple causal pathways between physical activity and breast cancer risk, including overweight/obesity, metabolic disorders, sex hormones, and inflammation. states that there is a plausible biological explanation.

“The mechanisms linking sedentary time and cancer likely overlap, at least partially, with those underpinning the physical activity relationship,” the researchers suggest.

Their findings, they said, provide “strong evidence” that increasing overall physical activity and reducing sedentary time are likely to reduce the risk of breast cancer.

Associate Professor Brigid LynchDeputy Director, Division of Cancer Epidemiology Cancer Council VictoriaAustralia and lead author, explains:

“Given the high disease burden attributed to cancer, the most common cancer in women, there is a need for enhanced cancer control with an emphasis on physical activity and sedentary time as modifiable cancer risk factors. ”

Sarah LewisProfessor of Molecular Epidemiology Bristol College of Medicine: Population Health Sciences, MRC Integrated Epidemiology Unit “This study shows that increasing overall physical activity levels and reducing sedentary time can prevent future breast cancer risk,” said the co-authors.

“Further studies are underway to determine how physical activity affects cancer risk and to investigate the effects of physical activity on cancers at other sites.”

paper

‘Physical Activity, Sedentary Time, and Breast Cancer Risk: A Mendelian Randomized StudyBy Brigid M. Lynch et al.ofBritish Journal of Sports Medicine