(Author)
Abstract
Colon is the part of the large intestine and its cancer is one of the important problems of modern society. Several factors can result in the development of colonic cancer. These factors may include non-modifiable types of risk factors as for example growing age, gender, race or ethnicity, and hereditary factors, and modifiable types of risk factors as for example obesity, poor diets, tobacco use, alcohol intake, reduced physical activity and sedentary life. Sedentary behavior is an important risk factor for modern life. It can result in obesity, insulin problems, and diabetes, which are found to be involved in the development of colon cancer. Sedentary behavior is more involved in distal colon and rectal cancers as compared to the proximal colon cancer. Changes in lifestyle factors can help in the prevention of colonic cancer as a result of sedentary behavior. Moreover, vitamin D can also help in preventing cancer development from sedentary behavior. Further investigations are required in finding the mechanisms behind the development of cancer from sedentary behavior, and its prevention and treatment.
Introduction
Colon is the part of the large intestine that takes water from food before its excretion from the body. Its cancer is an important problem of the modern society. Colon cancer is the cancer of colon and rectal cancer is the cancer of the last several inches portion of the colon. Collectively, both of them are also known as colorectal cancer. Colon cancer usually starts with polyps that are small, harmless clumps of cells. Doctors recommend regular screening tests to help prevent colon cancer by recognizing these polyps. There are several factors that can increase or decrease the chances of colon cancer. These factors include non-modifiable types of risk factors as for example growing age, gender, race or ethnicity, and hereditary factors, and modifiable types of risk factors as for example obesity, poor diets, tobacco use, alcohol intake, reduced physical activity and sedentary life (Giovannucci et al., 2010).
Research has shown that inactive person, who has sedentary behavior, has more chances of developing colon cancer as compared to active person. Sedentary behavior can be represented by the long-hours of sitting and other such tasks requiring very low energy expenditure, i.e. less than 1.5 metabolic equivalents. Some researchers consider sedentary behavior different from low levels of physical activity. National Health and Nutrition Examination Survey have reported that American adult spends over 50% of their waking time, i.e. about 7.7 hours in sedentary tasks. Moreover, this percentage elevates by over 60%, i.e. equal to or over 8 hours in adults above 60 years of age or more (Boyle, Fritschi, Heyworth & Bull, 2011).
Researchers have reported that prolonged sedentary work increases the chances of developing rectal cancer and distal colon cancer, whereas sedentary work is not related to proximal colon cancer. People with sedentary work are found to have 2 times more chances of developing distal colon cancer as compared to people who are doing a job with light activity. In the same way, people who experienced 10 or more years of sedentary work had 2 times more chances of developing distal colon cancer and nearly 1.5 times more chances of developing rectal cancer as compared to people who have done very little or no sedentary work. Further work showed that people with 9 hours or more than 9 hours of sitting per day have about 25% more chances of developing colon cancer as compared to the people who spend less than 3 hours in sitting per day. Researchers have also found that Chinese-American with sitting habit of 5 to 9 hours have 2.4 times more chances of developing colorectal cancer as compared to Chinese-Americans with sitting habit of less than 5 hours. Moreover, Chinese-Americans with 10 hours or more than 10 hours of sitting habit have 3.9 times more chances of colorectal cancer (Boyle, Fritschi, Heyworth & Bull, 2011).
Occupations having less movement or walking options can increase the chances of colon cancer and rectal cancer in people. Researchers have reported that people with mainly sitting related occupation have 67% more chances of colon cancer and 41% more chances of developing rectal cancer as compared to those who walk regularly. In another study, it has been found that people with habit of spending more than 2 hours per day watching television have two times more chances of developing colorectal cancer than people who have the habit of spending 1.14 hours per day watching television (Boyle, Fritschi, Heyworth & Bull, 2011).
Pathophysiology of colonic cancer and sedentary life
Several mechanisms have been proposed that are thought to be involved in increasing the risk of colorectal cancer as a result of sedentary work and sedentary behavior. Researchers have reported that blood glucose levels are increased during sedentary behavior and insulin sensitivity is decreased that is independent of physical activity. Both elevated levels of blood glucose and decreased sensitivity to insulin can increase the chances of colorectal cancer. Sedentary behavior can also increase the chances of developing diabetes and can also result in weight gain leading to obesity that are also involved in the development of colorectal cancer. Among other mechanisms of development of colorectal cancer as a result of sedentary behavior are elevated levels of proinflammatory factors, reduced levels of anti-inflammatory factors, and reduced levels of vitamin D. It has been suggested that reduced levels of local contractile activity as a result of sitting can also result in unique gene expressions that are involved in disease etiology (Boyle, Fritschi, Heyworth & Bull, 2011). Regarding diet-induced adiposity and insulin resistance as a result of sitting, it has been proposed that these are caused by decreased regulation of skeletal muscle lipoprotein lipase that has an important role in lipid metabolism (Lynch, 2010).
Factors responsible for colon cancer as a result of sedentary life
Researchers are of opinion that lifestyle factors have more important role in the development of distal colon cancer as compared to the development of proximal colon cancer. Working area with more work in sitting is also responsible for sedentary behavior. Obesity and an elevated body mass index are also found to be important factors in the development of colon cancer as a result of sedentary behavior. Vitamin D is found to have a strongly positive effect on distal colon and rectal cancers as compared to proximal colon cancers (Boyle, Fritschi, Heyworth & Bull, 2011).
Prevention of colonic cancer as a result of sedentary behavior
One of the most important strategies in decreasing the chances of colonic cancer as a result of sedentary behavior is to encourage physical activity and to decrease the long times spent in sitting. Risks of developing proximal colon cancer are significantly reduced in people who are habitual of doing heavy or very heavy tasks in their jobs. Use of vitamin D can also help in reducing the chances of cancer. Introduction of non-sitting breaks into long sitting hours of working can also help in preventing the increased chances of colon cancer as a result of sedentary behavior.
Studies are showing that it is very difficult to remove sedentary work from modern life. However, some countries such as Canada, Australia, and the United Kingdom are working on the recommendations for sedentary behavior for people of different ages.
Conclusion and future directions
Researchers have reported that people with sedentary work have more chances of developing colorectal cancer even if they have a good level of physical activity. Further research can help in differentiating the physical activity and sedentary work. Literature is showing the more significant relation of meat consumption, vegetable and fruit intake, and calcium ingestion with distal colon cancer as compared to the proximal colon cancer. However, literature is showing inconsistent results in relation of physical activity with distal and proximal colon cancer. Further investigations are required in order to find the mechanism behind the more chances of developing distal colon and rectal cancers as compared to the proximal colon cancer due to sedentary behavior (Boyle, Fritschi, Heyworth & Bull, 2011). Understanding the exact mechanisms behind the development of cancer from sedentary behavior could help in the prevention and treatment of colon cancer.
References
Boyle, T., Fritschi, L., Heyworth, J., & Bull, F. (2011). Long-term sedentary work and the risk of subsite-specific colorectal cancer. American journal of epidemiology, 173(10), 1183-1191.
Giovannucci, E., Harlan, D. M., Archer, M. C., Bergenstal, R. M., Gapstur, S. M., Habel, L. A., . . . Yee, D. (2010). Diabetes and cancer: a consensus report. [Consensus Development Conference Research Support, Non-U.S. Gov't]. Diabetes Care, 33(7), 1674-1685. doi: 10.2337/dc10-0666
Lynch, B. M. (2010). Sedentary behavior and cancer: a systematic review of the literature and proposed biological mechanisms. Cancer Epidemiology Biomarkers & Prevention, 1055-9965.
