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| Author(s): |
Leandro Fórnias Machado de Rezende
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) |
| Defense date: | 2019-02-05 |
| Examining board members: |
Jose Eluf Neto;
Maria Paula Curado;
Alicia Matijasevich Manitto;
Victor Wunsch Filho
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| Advisor: | Jose Eluf Neto |
| Abstract | |
Cancer is the second leading cause of death in Brazil and worldwide. This scenario has an aggravating effect due to expected population aging and growth and the increasing prevalence of cancer causes. To understand the role of physical activity in reducing the risk of cancer is of high interest in epidemiological literature. The objectives of this study were: (i) to evaluate the association between physical activity and risk of cancer in the population; (ii) to estimate the potential contribution of physical activity for cancer prevention and control in Brazil. Five manuscripts composed this thesis. The first presented a review of the literature on the consistency of epidemiological evidence between physical activity and 22 types of cancer. The results showed that physical activity in adults was associated with a lower risk of seven types of cancer. However, only breast post-menopausal and colon cancers were supported by convincing evidence. Evidence for the other types of cancer presented hints of bias and heterogeneity in the literature. The second manuscript examined the association between physical activity during the adolescence and risk of colorectal adenomas, a precursor of colorectal cancer. Physical activity during the adolescence was associated with lower the risk of colorectal cancer, independent of physical activity during adulthood. Women with high physical activity during adolescence presented lower risk of adenomas later in life compared to those with lower physical activity. The third manuscript investigated the influence of type and intensity of physical activity with cancer biomarkers of inflammatory and insulin response. High physical activity was associated with favorable concentration of cancer biomarkers. Associations were stronger for combined aerobic and resistance training. There were no additional benefits of engaging in vigorous physical activity over moderate activities. The fourth and fifth manuscripts evaluated, respectively, the preventability of cancer by increasing physical activity in Brazil; and the magnitude of this preventability vis-à-vis the reduction of other lifestyle risk factors. About 10 thousand cancer cases per year (12% of postmenopausal cancers and 19% of colon cancers) could be avoided by increasing population-wide physical activity in Brazil. However, smoking is still the major cause of cancer in Brazil, followed by overweight/obesity and alcohol consumption. The reduction of all lifestyle risk factors (smoking, overweight/obesity, alcohol consumption, lack of physical activity and unhealthy diet) could potentially avoid up to 27% of all cancer cases and 34% of all cancer deaths in Brazil. In conclusion, physical activity, from childhood to adulthood, may reduce the risk of some types of cancer. Biological mechanisms corroborate these associations and indicate more favorable outcomes for combined aerobic and resistance training. Our findings on preventability of cancer by increasing population-wide physical activity may be useful for cancer prevention strategies in Brazil (AU) | |
| FAPESP's process: | 14/25614-4 - Physical inactivity and cancer: from evaluation of etiological evidence to public health impact |
| Grantee: | Leandro Fórnias Machado de Rezende |
| Support Opportunities: | Scholarships in Brazil - Doctorate |