Effects of Lifestyle on Prevalence of Colorectal Cancer Author: Dr Christa Maria Joel Module: Effects of Lifestyle on Health Supervisor: Ms Jane Tobias, Mr Daniel Boakye University of the West of Scotland

1. EFFECTS OF LIFESTYLE ON PREVALENCE OF COLORECTAL CANCER
Master of Public Health
Module: Effects of Lifestyle on Health
Banner ID: B00495281

2. CONTENTS
1. INTRODUCTION TO COLORECTAL CANCER.
2. EPIDEMIOLOGY OF COLORECTAL CANCER
3. ASSOCIATION OF DIET WITH COLORECTAL CANCER
4. ASSOCIATION OF OBESITY AND PHYSICAL INACTIVITY WITH
COLORECTAL CANCER
5. ASSOCIATION OF LIFESTYLE HABITS WITH COLORECTAL CANCER
6. GLOBAL NATIONAL AND LOCAL POLICIES
7. PREVENTIVE STRATEGIES
8. CONCLUSION

3. 1. Introduction to Colorectal Cancer:
The 21st
century is an era with improved living standards, increased life expectancy
and accessibility to healthcare. Despite these advantages, there has been an increase
in cancer-related mortality by 40% over the past 40 years. However, this is estimated to
increase to 60% and 13 million people are predicted to die from cancer within the next
two decades (Kuipers, Rosch, Bretthauer, 2013). Cancer, a non- communicable
disease, is the first or second prominent cause of death in most countries worldwide
(WHO,2020).
Colorectal cancer (CRC) is the third predominant cancer which is slow in onset,
gradually progressive cancer and is characterised by a tumour forming on the lining of
the large intestine or rectum (American Cancer Society, 2016). Its prevalence has
been gradually increasing in developing countries that adopted a westernised lifestyle
(Bray et al., 2018). CRC was rare in 1950 but now accounts for 10% of cancer-
related mortality in developed nations. In 2012, around 1.4 million people were
diagnosed with CRC (Ferlay et al., 2015).The probability of suffering from colorectal
cancer in a person’s lifespan is 4 to 5% (Marmol et al., 2017). It is associated with
significant risk drivers such as male gender, ageing populations, family history of
CRC, unhealthy diets (Chan et al., 2011), obesity, sedentary lifestyles (Rawla, Sunkara,
Barsouk, 2019) and usage of habit-forming substances (Limsui et al., 2010: Bagnardi et
al., 2015).
Many policies and frameworks proposed at the global, national, and local levels prevent
and manage colorectal cancer. For example, some developed countries promote
campaigns to educate the public about how behavioural risk factors contribute to CRC
and successfully prevent the disease (Arnold et al., 2017). In addition, there are
primary, secondary, and tertiary preventive interventions that help to tackle CRC.
Recent advances and research in preventive medicine have enabled people above 50
years to undergo compulsory screening and take precautionary measures even
at the first sign of a risk factor (WHO, 2021). Following these strategies has improved

4. the five-year survival rate over the past few years and is now more than 65% in most
affluent nations (Siegel et al., 2017). However, nations with low survival rates, including
several developed countries, require more stringent policies to battle CRC.
Furthermore, youngsters are at elevated risk of developing CRC due to most of the
predominant risk factors from early childhood (Rahib et al., 2021). But the age for
screening starts from the age of 50 years onwards (WHO, 2021). Therefore, this is one
of the biggest challenges in preventing CRC from adolescence. However, some
countries like the US have lowered the age for screening (USPSTF, 2021).
Therefore, this report on colorectal cancer focuses on the recent trends in prevalence,
associated risk factors, and global, national, local policies through a critical analysis of
current literature. This review will conclude by addressing appropriate preventive
interventions to prevent this disease in future generations.
2. Epidemiology of Colorectal Cancer:
CRC accounts for 11% of all cancers. It is more common in men in 10 out of 191
countries globally, frequently seen in those above 50 years old (Rawla, Sunkara,
Barsouk, 2019).
The prevalence of CRC is measured in age-standardised incidence rate (ASRi). For
both genders combined, the ASRi is 19.7; in males, it is 23.6, and in females, it is
16.3 (Ferlay et al., 2019). However, the prevalence of the disease varies
geographically. The highest age-standardised incidence rate for CRC is seen in
Australia, New Zealand, followed by Europe, North America, and Japan, which is
around 40 per 100,000 for both genders combined. The lowest incidence is seen in
Western Africa, followed by Asia, Latin America, and the Caribbean Islands (Ferlay et
al., 2015).
ASRi is 50% higher in men than in women (Brenner, Chen, 2018). Hungary has the
most increased occurrence of CRC for the male population, whereas Norway has the

5. highest number of cases for females. The most diagnosed cancer in males in Japan,
Saudi Arabia, UAE, South Korea, Oman, Bahrain, Yemen, Kuwait, Qatar, and Slovakia
is CRC. In contrast, Africa and Southeast Asia have the lowest rates for CRC in both
genders (Bray et al., 2018). These geographical and gender variations are associated
with the population’s socioeconomic status, disparities in access to screening and
unhealthy behaviours (Rohani-Rasaf et al., 2013).
There is a direct relation between ASRi and the human development index (HDI). High
HDI nations will have a high prevalence of CRC. In high HDI (human development
index) countries, the ASRi is 30.1 per 100,000 and 8.4 in low HDI nations (Bray et al.,
2018). Demographic changes alone will contribute to the higher prevalence of CRC and
is expected to witness more than 2.4 million cases in 2035 (Ferlay et al., 2015).
When discussing the disease in terms of mortality, CRC is the second most deadly
cancer globally (Bray et al, 2018) and has increased to 896,000 between 1990 and
2017 (GBD, 2019). Hungary has the highest CRC age-standardised mortality rate
(Ferlay et al., 2019). Mortality depends upon the HDI of the country. Therefore, the
country with high HDI will have a higher mortality rate (Bray et al., 2018). There are
around 42,886 cases, and 16571 deaths were reported due to CRC in the United
Kingdom (Cancer Research UK, 2020). In Scotland, about 3800 cases of CRC
were estimated, and 1743 deaths were recorded (Public Health Scotland, 2020).
Overall, the prevalence and mortality rates seem to stabilise or decline in a few
developed countries due to successful interventions (Brenner et al., 2016).
3. Association of diet with colorectal cancer:
Diet is a significant factor as it can have adverse effects and defensive action against
CRC. Red and processed meats, part of the western diet, are commonly known to
elevate CRC risk (Zhao et al., 2017) and have shown a relative risk of 1.22 (Chan et al.,
2011). Red meat is declared ‘probably carcinogenic’ and processed meat is termed
‘carcinogenic’ (Bouvard et al., 2015). Red meat contains excessive amounts of fats,

6. omega six and helps form certain carcinogens such as N-nitroso compounds (Bastide,
Pierre, Corpet, 2011). In the UK, around 1 in 5 CRC cases are associated with eating
red and processed meats. Therefore, it is advised to limit the consumption of red meat
to 500 grams per week and limit eating processed meat which can drastically reduce
the risk of CRC (Public Health England, 2016). Vitamin D deficiency also reduces the
survival rate of a CRC patient, and therefore the patient should be provided with a
Vitamin D rich diet (Maalmi et al., 2017). In addition, different cooking modes can
contribute to the formation of CRC, such as cooking at high temperatures, curing, and
smoking meat (Kim, Coelho, Blachier, 2013).
In contrast, a prudent diet containing calcium, fibre-rich foods such as fruits, vegetables
and whole grains, Vitamin D protects against CRC (Mehta et al., 2017). Fiber-rich food
is essential because it promotes good bowel movements and decreases exposure
to potential carcinogens (Song, Garrett, Chan, 2015). A 10% regular intake of fiber,
300mg calcium and 200ml milk will reduce CRC risk (Dahm et al., 2010). Unfortunately,
in the UK, people consume less than 23 grams of fiber a day which has been linked
to about 12% of CRC cases (Public Health England, 2016).
4. Association of Obesity and Physical Inactivity with colorectal cancer:
Physical inactivity and obesity are primarily seen in developed nations (Hales et al.,
2017). Active individuals have a 25% less risk of developing CRC. In contrast, people
who lead a sedentary lifestyle have a 50% elevated risk of developing CRC. After a
well-established diagnosis of CRC, it is recommended to walk for 5 hours a week as
walking reduces mortality by 35% (Schmid, Leitzmann, 2014).
Physical inactivity leads to obesity which can cause inflammation in the intestines and
cause the release of carcinogens (Rawla, Sunkara, Barsouk, 2019). A study
demonstrated that a 5 kg weight increment is correlated to 3% elevated risk of
CRC (Karahalios et al., 2016). Therefore, daily physical activity for 30 minutes will
reduce the risk of CRC considerably (Arem et al., 2014).

7. To assess the risk of CRC, specific parameters such as waist circumference and body
mass index (BMI) are used (Robsahm et al., 2013). The risk of CRC increases by 2-3%
with each unit increase of BMI (World Cancer Research Fund, 2011). Obesity beginning
from childhood has become an epidemic and are the predominant risk factors for CRC
occurrence at a very young age (Exarchakou et al., 2019). Therefore, it is necessary to
raise awareness about the necessity of physical activity and the adverse effects of
obesity in young families.
5. Association of lifestyle habits with colorectal cancer:
5.1 Smoking:
Smoking is a leading preventable cause of CRC, although the prevalence has declined
globally by 10% from 1980 to 2013. This reduction in occurrence is seen in developed
nations with firm tobacco smoking policies. However, there is still an increase in
smoking prevalence in low- and middle-income countries with no stringent smoking
cessation guidelines (The Tobacco Atlas, 2021). The components in smoking cause
molecular abnormalities in the colon and rectum and promote carcinogenesis (Limsui et
al., 2010). The relative risk of smoking in CRC is 1.18 (Botteri et al., 2008).
Thus, current and former smokers have a higher risk of CRC and have a poor prognosis
than nonsmokers. On the other hand, smoking cessation is associated with increased
life expectancy in a person with CRC (Ordonez-Mena et al., 2018).
5.2 Alcohol consumption:
Alcohol intake and its metabolism can have catastrophic molecular consequences that
lead to CRC development by forming harmful byproducts and genetic, immunological
and cell changes (Shukla, Lim, 2013). Moderate to heavy alcohol consumption is
another risk factor for CRC development (Bagnardi et al., 2015). The relative risk is 1.21

8. for moderate drinking (2 to 3 drinks per day) and 1.52 for heavy drinking (more
than four drinks per day). People who consume two to three alcoholic servings a day
have a 20% elevated risk of developing CRC, and individuals who drink more than
three servings a day have an elevated CRC risk of 40%. (Fedirko et al., 2011).
6. Global, National and Local Policies:
6.1 Global Policies:
The approach to tackling colorectal cancer by WHO has four pillars: prevention,
screening, management, and palliative care and has consolidated different screening
and prevention policies for different countries across the globe, known as the national
cancer control programme. This programme is implemented to increase awareness of
the risk factors, promote screening and management and discusses the need for
affordable diagnostics, treatment and referral to higher centres (WHO, 2021). If
screening were done routinely in individuals aged 50 years and above and in people
with family history, 60% of colon cancer deaths could be prevented yearly worldwide
(Global Colon Cancer Association, 2021).
Various screening methods are available globally to diagnose CRC, such as
colonoscopy, faecal occult blood test (CDC, 2021), sigmoidoscopy, faecal
immunochemical test, stool DNA or Cologuard, double-contrast barium enema (Global
Colon Cancer Association, 2021).
6.2 National policies:
When it comes to the policies in the United Kingdom, Public Health England (PHE) has
put forward specific recommendations. The health organisation recommends people
participate in the active prevention and screening process. Over 54% of CRC cases in
the UK are associated with unhealthy habits. PHE has advised the public to avoid the

9. consumption of red and processed meats and add more fibre to the diet (Public Health
England, 2016).
In addition, individuals above the age of 60 years who have risk factors or have
a significant family history can undergo screening methods such as colonoscopy
and faecal immunochemical testing (FIT), which is available in the form of a home
kit (NHS, 2019).
NICE guidelines have put forward suggestions to fight CRC. Along with the compulsory
screening, the individuals are referred to a higher specialist, get information support
and good counselling, and adequate palliative care if required (NICE Guidelines, 2020).
6.3 Local policies:
In Scotland, Bowel Cancer Framework inculcates the three essential elements for
CRC- lifestyle interventions, chemoprevention and population screening and
surveillance. When discussing lifestyle interventions, the public is educated about the
adverse effects of certain unhealthy habits such as eating more red meat and less fiber,
smoking, alcohol consumption, and physical inactivity. Therefore, the public is advised
to add more fibre to the diet and less red and processed meat (Scottish Government,
2004).
The second element is chemoprevention which is the use of nonsteroidal anti-
inflammatory drugs (NSAIDs) to prevent the occurrence of CRC. Certain studies have
suggested that intake of NSAIDs have a defensive role against CRC (Rothwell et al.,
2010).
The third element is active surveillance and screening. According to the Scottish Bowel
Screening Programme, individuals in the age group between 50 and 74 years are
advised to undergo screening every two years. They are provided with a faecal
immunochemical test (FIT) home kit (Public Health Scotland, 2021). In addition, the

10. Scottish Government launched a programme in 2012 called Detect Cancer Early
Programme to improve the life expectancy of the Scottish people. The programme is
centred around specific objectives:
 Enhancing treatment in primary care.
 Active surveillance and data collection within NHS Scotland to determine
the prevalence of CRC in the populations.
 Promoting referral to higher specialists for better management.
 Launching campaigns to raise awareness among the public about the
disease and its risk factors.
 Encouraging active participation in screening for cancer (Scottish
Government, 2018)
7. Preventive Strategies:
7.1 Primary prevention- Lifestyle modifications:
This form of prevention has high priority. It has more benefits in preventing CRC at an
early stage and preventing some chronic diseases like Diabetes and cardiovascular
diseases in the long term. Studies have shown that more fish, fibre-rich diets such as
vegetables, fruits, and whole grains, diet enhanced with essential minerals and
vitamins, adequate exercise regularly are beneficial in reducing CRC risk. In addition,
less red and processed meats, alcohol, and smoking are expected to reduce CRC risk
(Baena, Salinas, 2015). Aspirin is used as primary prevention in individuals between 50
and 59 years and can take the medication for at least ten years to prevent CRC risk
(Bibbins-Dominigo, 2016).
7.2 Secondary prevention- Screening methods:
According to the World Health Organisation, people in the age group between 50 and
75 years should undergo compulsory screening. There are various cost-effective
screening methods such as faecal occult blood testing, faecal immunochemical test

11. home kits, sigmoidoscopy and colonoscopy (WHO, 2021). Recently there has been a
surge in CRC cases in the young adult population, so countries like the USA have
decreased the recommended screening age from 50 to 45 years (USPSTF, 2021).
7.3 Tertiary prevention- Medications and surgery:
Chemoprevention is the use of drugs to prevent CRC. Certain studies suggest that
aspirin is an excellent medication to reduce CRC risk (Li et al., 2015). In addition,
studies are being undertaken to observe the benefits of Vitamin D in CRC survival rates.
A randomised phase 2 trial reported an improvement in the survival of metastatic CRC
after Vitamin D supplementation (Maalmi et al., 2017). In this prevention, minimally
invasive surgery with neoadjuvant radiotherapy is another treatment provided in most
cases (Babaei et al., 2016).
7.4 Family or community support:
Motivation and encouragement are necessary to battle CRC. The patient’s family,
caregivers and community can support them during screening and physical activity and
help them follow a healthy diet (Breitkopf et al., 2014). However, caregivers face
challenges such as financial and job stress, disturbed domestic environments and
routines and their own mental and physical health issues such as depression and
generalised anxiety disorder (Mosher, Bakas, Champion, 2013). But this can be solved
by providing the caregivers with appropriate counselling, psychoeducation, and
sufficient skills training on how to care for these patients (Northouse et al., 2010).
8. Conclusion:
Colorectal cancer is one of the deadliest cancers, and its prevalence is likely to increase
in the future if the proper preventive interventions are not followed in the right manner.
The occurrence of CRC is exacerbated by behavioural risk factors such as poor diet,
physical inactivity, smoking and alcohol and other unfavourable trends like advancing

12. age and population growth. Multiple policies at the global, national and local levels have
helped reduce the prevalence of CRC by suggesting appropriate screening methods
and management. Several health campaigns in different countries across the globe
have educated the public about the need for primary prevention in the form of lifestyle
modifications which have already reduced the prevalence of CRC and other common
chronic diseases in the long run in some developed countries. In addition, secondary
prevention in the form of various cost-effective screening tests such as FIT and
colonoscopy help in reducing the primary burden of CRC. Furthermore, tertiary
prevention with medications and surgery has played a massive part in reducing
CRC. Along with the above interventions, community support is the biggest strength for
a CRC patient, mentally and physically. These strategies hold great promise in
improving quality of life, preventing CRC, and paving the way for a better future.
References:
1. American Cancer Society (2016). What is colorectal cancer? Available at:
https://www.cancer.org/cancer/colon-rectal-cancer/about/what-is-colorectal-
cancer.html (Accessed on 25/10/2021).
2. Arem, H., Moore, S.C., Park, Y., Ballard-Barbash, R., Hollenbeck, A., Leitzmann,
M., Matthews, C.E. (2014). Physical activity and cancer-specific mortality in the
NIH-AARP Diet and Health Study cohort. International journal of cancer, 135(2),
pp.423–431. DOI:10.1002/ijc.28659. (Accessed on 15/11/2021).
3. Arnold, M., Sierra, M.S., Laversanne, M., Soeriomataram, I., Jemal, A., Bray, F.
(2017). Global patterns and trends in colorectal cancer incidence and mortality.
Gut, 66(4), pp.683-691. DOI: 10.1136/gutjnl-2015-310912. (Accessed on
20/10/2021).
4. Babaei, M., Balavarca, Y., Jansen, L., Gondos, A., Lemmens, V., Sjövall, A.,
Johannesen, T. B., Moreau, M., Gabriel, L., Gonçalves, A. F., Bento, M. J., Van
De Velde, T., Kempfer, L. R., Becker, N., Ulrich, A., Ulrich, C. M., Schrotz-King,
P., Brenner, H. (2016). Minimally invasive colorectal cancer surgery in
Europe. Medicine (United States), 95(22),

13. e3812. https://doi.org/10.1097/MD.0000000000003812. (Accessed on
14/11/2021)
5. Baena, K., Salinas, P., (2015). Diet and colorectal cancer. Maturitas, 80, pp.258-
264. DOI: 10.1016/j.maturitas.2014.12.017. (Accessed on 26/10/2021).
6. Bagnardi, V., Rota, M., Botteri, E., Tramacere, I., Islami, F., Fedirko, V., Scotti,
L., Jenab, M., Turati, F., Pasquali, E., Pelucchi, C., Galeone, C., Bellocco, R.,
Negri, E., Corrao, G., Boffetta, P., La Vecchia, C. (2015). Alcohol consumption
and site-specific cancer risk: a comprehensive dose-response meta-analysis.
British Journal of cancer, 112(3), pp.580-593. DOI: 10.1038/bjc.2014.579.
(Accessed on 26/10/2021).
7. Bastide, N.M., Pierre, F.H.F., Corpet, D.E. (2011). Heme iron from meat and risk
of colorectal cancer: a meta-analysis and a review of the mechanisms involved.
Cancer prevention research (Philadelphia, Pa.), 4(2), pp.177-184. Doi:
10.1158/1940-6207.CAPR-10-0113. (Accessed on 7/11/2021).
8. Bibbins-Domingo, K. (2016). Aspirin use for the primary prevention of
cardiovascular disease and colorectal cancer: U.S. Preventive Services Task
Force Recommendation Statement. Annals of Internal Medicine. Available at:
https://doi.org/10.7326/M16-0577. (Accessed on 13/11/2021).
9. Botteri, E., Iodice, S., Bagnardi, V., Raimondi, S., Lowenfels, A.B., Maisonneuve,
P. (2008). Smoking and colorectal cancer: a meta-analysis. JAMA, 300(23),
pp.2765-2778. DOI: 10.1001/jama.2008.839. (Accessed on).
10.Bouvard, V., Loomis, D., Guyton, K.Z., Grosse, Y., Ghissassi, F.E., Benbrahim-
Talla, L., Guha, N., Mattock, H., Straif, K., International agency for research on
cancer monograph working group (2015). Carcinogenicity of consumption of red
and processed meat. The Lancet, Oncology, 16(16), pp.1599-1600. Doi:
10.1016/s1470-2045(15)00444-1. (Accessed on 6/11/2021).
11.Bray, F., Ferlay, J., Soerjomataram, I., Siegel, R.L., Torre, L.A., Jemal, A. (2018).
Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality
worldwide for 36 cancers in 185 countries. CA: a cancer journal for clinicians,
68(6), pp.394-424. DOI: 10.3322/caac.21492. (Accessed on 20/10/2021).

14. 12.Breitkopf, C.R., Asiedu, G.B., Egginton, J., Sinicrope, P., Opyichal, S.M., Howell,
L.A., Patten, C., Braidman, L. (2014). An investigation of the colorectal cancer
experience and receptivity to family-based cancer prevention programs. Support
care cancer, 22, pp.2517-2525. DOI: 10.1007/s00520-014-2245-9 (Accessed on
27/10/2021).
13.Brenner, H., Chen, C. (2018). The colorectal cancer epidemic: challenges and
opportunities for primary, secondary and tertiary prevention. British Journal of
cancer, 119, pp.785-792. Doi: https://doi.org/10.1038/s41416-018-0264-x
(Accessed on 7/11/2021).
14.Brenner, H., Schrotz-King, P., Holleczek, B., Katalinic, A., Hoffmeister, M. (2016).
Declining bowel cancer incidence and mortality in Germany- an analysis of time
trends in the first ten years after the introduction of screening colonoscopy.
Deutsches Arzteblatt International, 113(7), pp.101-106. Doi:
10.3238/arztebl.2016.0101. (Accessed on 8/11/2021).
15.Cancer research UK (2020). Bowel Cancer statistics. Available from:
https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-
by-cancer-type/bowel-cancer#heading-Six (Accessed on 11/11/2021)
16.Centers for Disease Control and Prevention (CDC) (2021). Colorectal Cancer
Screening Tests. Available at:
https://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (Accessed
on 12/11/2021).
17.Chan, D.S., Lau, R., Aune, D., Vieira, R., Greenwood, D.C., Kampman, E., Norat,
T. (2011). Red and processed meat and colorectal cancer incidence: meta-
analysis of prospective studies. PloS one, 6(6), e20456. DOI:
10.1371/journal.pone.0020456. (Accessed on 26/10/2021).
18.Dahm, C.C., Keogh, R.H., Spencer, E.A., Greenwood, D.C., Key, T.J., Fentiman,
I.S., Shipley, M.J., Brunner, E.J., Cade, J.E., Burley, V.J., Mishra, G., Stephen,
A.M., Kuh, D., White, I.R., Luben, R., Lentjes, M.A., Khaw, K.T., Rodwell,
Bingham, S.A. (2010). Dietary fiber and colorectal cancer risk: a nested case-
control study using food diaries. Journal of the National Cancer Institute, 102(9),
pp.614-26. DOI: 10.1093/jnci/djq092. (Accessed on 16/11/2021).

15. 19.Exarchakou, A., Donaldson, L.J., Girardi, F., Coleman, M.P. (2019). Colorectal
cancer incidence among young adults in England: trends by anatomical subsite
and deprivation. PLoS One, 14(12): e0225547. Doi:
10.1371/journal.pone.0225547. (Accessed on 9/11/2021).
20.Fedirko, V., Tramacere, I., Bagnardi, V., Rota, M., Scotti, L., Islami, F., Negri, E.,
Straif, K., Romieu, I., La Vecchia, C., Boffetta, P., Jenab, M. (2011). Alcohol
drinking and colorectal cancer risk: an overall and dose-response meta-analysis
of published studies. Annals of Oncology, 22(9), pp.1958-1972. DOI:
10.1093/annonc.mdq653. (Accessed on 26/10/2021).
21.Ferlay, J., Soerjomataram, I., Dikshit, R., Eser, S., Mathers, C., Rebelo, M.,
Parkin, D.M., Forman, D., Bray, F. (2015). Cancer incidence and mortality
worldwide: sources, methods and major patterns in GLOBOCON 2012.
International Journal of Cancer, 136: E359-E386. DOI:10.1002/ijc.29210
(Accessed on 25/10/2021).
22.Ferlay, J., Colombet, M., Soerjomataram, I., Mathers, C., Parkin, D.M., Pineros,
M., Znaor, A., Bray, F. (2019). Estimating the global cancer incidence and
mortality in 2018: GLOBOCAN sources and methods. International Journal of
cancer, 144(8), pp.1941-1953. Doi: 10.1002/ijc.31937. (Accessed on 6/11/2021).
23.Global Burden of Disease (GBD) 2017 (2019). The global, regional, and national
burden of colorectal cancer and its attributable risk factors in 195 countries and
territories, 1990-2017: a systematic analysis for the Global Burden of Disease
study 2017. The Lancet: Gastroenterology and Hepatology, 4(12), pp.913-933.
Doi: 10.1016/s2468-1253(19)30345-0. (Accessed on 6/11/2021).
24. Global Colon Cancer Association (2021). Cancer screening. Available at:
https://www.globalcca.org/cancer-screening (Accessed on 12/11/2021).
25.Hales, C.M., Carroll, M.D., Fryar, C.D., Ogden, C.L. (2017). Prevalence of
obesity among adults and youth: United States, 2015-2016. NCHS Data Brief,
pp.1-8. Available at: https://www.cdc.gov/nchs/data/databriefs/db288.pdf .
(Accessed on).

16. 26.International Agency for research on cancer, WHO (2020). Colorectal cancer.
Available at: https://gco.iarc.fr/today/data/factsheets/cancers/10_8_9-
Colorectum-fact-sheet.pdf (Accessed on 20/10/2021).
27.Karahalios, A., Simpson, J.A., Baglietto, L., MacInnis, R.J., Hodge, A.M., Giles,
G.G., English, D.R. (2016). Change in weight and waist circumference and risk of
colorectal cancer: results from the Melbourne Collaborative Cohort Study. BMC
Cancer, 16(1), pp.1-7. DOI: 10.1186/s12885-016-2144-1. (Accessed on
26/10/2021).
28.Kim, E., Coelho, D., Blachier, F. (2013). Review of the association between meat
consumption and risk of colorectal cancer. Nutrition Research, 33(12), pp.983-
994. DOI: 10.1016/j.nutres.2013.07.018. (Accessed on 5/11/2021).
29.Kuipers, E.J., Grady, W.M., Lieberman, D., Seufferlein, T., Sung, J.J., Boelens,
P.G., van de Velde, C.J.H., Watanabe, T. (2015). Colorectal cancer. Nature
Review Disease Primer, 1, 15065. DOI:10.1038/nrdp.2015.65 (Accessed on
25/10/2021).
30.Kuipers, E.J., Rosch, T., Bretthauer, M. (2013). Colorectal cancer screening-
optimizing current strategies and new directions. Nature Reviews- Clinical
Oncology, 10(3), pp.130-142. Doi: 10.1038/nrclinonc.2013.12. (Accessed on
7/11/2021).
31.Li, P., Wu, H., Zhang, H., Shi, Y., Xu, J., Ye, Y., Xia, D., yang, J., Cai, J., Wu, Y.
(2015). Aspirin use after diagnosis but not prediagnosis improves established
colorectal cancer survival: a meta-analysis. BMJ-Gut, 64:1419-1425. Available
at: https://gut.bmj.com/content/64/9/1419 (Accessed on 13/11/2021).
32.Limsui, D., Vierkant, R.A., Tillmans, L.S., Wang, A.H., Weisenberger, D.J., Laird,
P.W., Lynch, C.F., Anderson, K.E., French, A.J., Haile, R.W., Harnack, L.J.,
Potter, J.D., Slager, S.L., Smyrk, T.C., Thibodeau, S.N., Cerhan, J.R., Limburg,
P.J. (2010). Cigarette smoking and colorectal cancer risk by molecularly defined
subtypes. Journal of National Cancer Institute, 102(14), pp.1012-1022. DOI:
10.1093/jnci/djq201. (Accessed on 26/10/2021).
33.Maalmi, H., Walter, V., Jansen, L., Chang-Claude, J., Owen, R.W., Ulrich, A.,
Schottker, B., Hoffmeister, M., Brenner, H. (2017). Relationship of very low

17. serum 25-hydroxyvitamin D3 levels with long term survival in a large cohort of
colorectal cancer patients from Germany. European Journal of epidemiology,
32(11), pp.961-971. Doi: https://doi.org/10.1007/s10654-017-0298-z (Accessed
on 11/11/2021).
34.Marmol, I., Sanchez-de-Diego, C., Dieste, A.P., Cerrada, E., Yoldi, M.J.R.
(2017). Colorectal carcinoma: a general overview and future perspectives in
colorectal cancer. International Journal of Molecular Sciences, 18(1): 197. PMID:
28106826. (Accessed on 5/11/2021).
35.Mehta, R.S., Nishihara, R., Cao, Y., Song, M., Mima, K., Qian, Z.R., Nowak, J.A.,
Kosumi, K., Hamada, T., Masugi, Y., Bullman, S., Drew, D.A., Kostic, A.D., Fung,
T.T., Garrett, W., Huttenhower, C., Wu, K., Meyerhardt, J.A., Zhang, X., Willett,
W.C., Giovannucci, E.L., Fuchs, C.S., Chan, A.T., Ogino, S. (2017). Association
of dietary patterns with risk of colorectal cancer subtypes classified by
Fusobacterium nucleatum in tumor tissue. JAMA Oncology, 3(7), pp.921-927.
Doi: 10.1001/jamaoncol.2016.6374. (Accessed on 8/11/2021).
36.Mosher, C.E., Bakas, T., Champion, V.L. (2013). Physical health, mental health,
and life changes among family caregivers of patients with lung cancer. Oncology
Nursing forum, 40(1), pp.53-61. Doi: 10.1188/13.ONF.53-61. (Accessed on
13/11/2021)
37.National Health Services (NHS) (2019). Diagnosis- bowel cancer. Available at:
https://www.nhs.uk/conditions/bowel-cancer/diagnosis/ (Accessed on
12/11/2021).
38.National Institute of Health and Care Excellence (2020). Colorectal Cancer
Recommendations. Available at:
https://www.nice.org.uk/guidance/ng151/chapter/Recommendations (Accessed
on 27/10/2021).
39.Northouse, L.L., Katapodi, M., Song, L., Zhang, L., Mood, D.W. (2010).
Interventions with family caregivers of cancer patients: meta-analysis of
randomized trials. CA: cancer journal for clinicians, 60(5), pp.317-339. Doi:
10.3322/caac.20081. (Accessed on 13/11/2021).

18. 40.Ordonez-Mena, J.M., Walter, V., Schootker, B., Jenab, M., O’Doherty, M.G., Kee,
F., Bueno-de-Mesquita, B., Peeters, P., Stricker, B.H., Ruiter, R., Hofman, A.,
Soderberg, S., Jousilahti, P., Kuulasmaa, K., Freedman, N.D., Wilsgaard, T.,
Wolk, A., Nilsson, L.M., Tionneland, A., Quiros, J.R., Consortium on health and
ageing: network of cohorts in Europe and the United States (CHANCES) (2018).
Impact of prediagnostic smoking and smoking cessation on colorectal cancer
prognosis: a meta-analysis of individual patient data from cohorts within the
CHANCES consortium. Annals of Oncology, 29(2), pp.472-483. DOI:
10.1093/annonc/mdx761. (Accessed on 26/10/2021).
41.Public Health England (2016). Health matters: improving the prevention and
diagnosis of bowel cancer. Available at:
https://www.gov.uk/government/publications/health-matters-preventing-bowel-
cancer/health-matters-improving-the-prevention-and-detection-of-bowel-cancer
(Accessed on 11/11/2021).
42.Public health Scotland (2020). Cancer statistics. Colorectal cancer. Available
from: https://www.isdscotland.org/Health-Topics/Cancer/Cancer-
Statistics/Colorectal/#summary (Accessed on 11/11/2021)
43. Public Health Scotland (2021). Bowel screening. Available at:
www.healthscotland.scot/health-topics/screening/bowel-screening (Accessed on
13/11/2021).
44.Rahib, L., Wehner, M.R., Matrisian, L.M., Nead, K.T. (2021). Estimated projection
of US Cancer Incidence and death to 2040. JAMA Network, 4(4), e3214708.
DOI: 10.1001/jamanetworkopen.2021.4708. (Accessed on 16/11/2021).
45.Rawla, P., Sunkara, T., Barsouk, A. (2019). Epidemiology of colorectal cancer:
incidence, mortality, survival and risk factors. Przeglad gastroenterologiczny,
14(2), pp.89-103. DOI: 10.5114/pg.2018.81072. (Accessed on 25/10/2021)
46.Robsahm, T.E., Aagnes, B., Hjartaker, A., Langseth, H., Bray, F.I., Larsen, I.K.
(2013). Body mass index, physical activity, and colorectal cancer by anatomical
subsites: a systematic review and meta-analysis of cohort studies. European
journal of Cancer prevention, 22(6), pp.492-505. DOI:
10.1097/CEJ.0b013e328360f434. (Accessed on 27/10/2021).

19. 47.Rohani-Rasaf, M., Abdollahi, M., Jazayeri, S., Kalantari, N., Asadi-Lari, M.
(2013). Correlation of cancer incidence with diet, smoking and socio- economic
position across 22 districts of Tehran in 2008. Asian Pacific Journal of Cancer
Prevention, 14(3), pp.1669-1676. DOI: 10.7314/apjcp.2013.14.3.1669.(Accessed
on 15/11/2021).
48.Rothwell, P.M., Wilson, M., Elwin, C.E., Norrving, B., Algra, A., Warlow, C.P.,
Meade, T.W. (2010). Long term effect of aspirin on colorectal cancer incidence
and mortality: 20-year follow up- of five randomized trials. Lancet, 376(9754),
pp.1741-1750. DOI: 10.1016/S0140-6736(10)61543-7. (Accessed on
16/11/2021).
49.Schmid, D., Leitzmann, M.F. (2014). Association between physical activity and
mortality among breast cancer and colorectal cancer survivors: a systematic
review and meta-analysis. Annals of Oncology, 25(7), pp.1293-1311. Doi:
10.1093/annonc/mdu012. (Accessed on 9/11/2021).
50.Scottish Government (2004). Bowel Cancer Framework for Scotland. Available
at: https://www.gov.scot/publications/bowel-cancer-framework-scotland/pages/2/
(Accessed on 27/10/2021).
51.Scottish Government (2018). Detect cancer early. Available at:
https://www.webarchive.org.uk/wayback/archive/20180514160429/http://www.go
v.scot/Topics/Health/Services/Cancer/Detect-Cancer-Early (Accessed on
13/11/2021).
52.Shukla, S.D., Lim, R.W. (2013). Epigenetic effects of ethanol on the liver and
gastrointestinal system. Alcohol Research, 35(1), pp.47-55. PMID: 24313164.
(Accessed on 12/11/2021)
53.Siegel, R.L., Miller, K.D., Fedewa, S.A., Ahnen, D.J., Meester, R.G.S., Barzi, A.,
Jemal, A. (2017). Colorectal cancer statistics, 2017. CA: a cancer journal for
clinicians, 67(3), pp.177-193. Doi: 10.3322/caac.21395. (Accessed on
5/11/2021).

20. 54.Song, M., Garrett, W.S., Chan, A.T. (2015). Nutrients, foods, and colorectal
cancer prevention. Gastroenterology, 148(6), pp.1244-1260. DOI:
10.1053/j.gastro.2014.12.035. (Accessed on 26/10/2021).
55.The Tobacco Atlas (2021). Prevalence. Available at:
https://tobaccoatlas.org/topic/prevalence/ (Accessed on 12/11/2021).
56.US Preventive Services Task Force (USPSTF) (2021). Final recommendation
statement: Colorectal cancer screening. Available from
https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal
-cancer-screening. (Accessed on 16/11/2021).
57.World Cancer Research Fund (2011). Continuous Update Project Report. Food,
Nutrition, Physical Activity, and the Prevention of Colorectal Cancer. Available at:
http://www.dietandcancerreport.org/cancer_resource_center/downloads/cu/Color
ectal-Cancer-2011-Report.pdf. (Accessed on 10/11/2021).
58.Word Health Organisation (2020). Cancer. Available at:
https://www.who.int/news-room/fact-sheets/detail/cancer . (Accessed on
25/10/2021).
59. World Health Organization (2021). Policy. Cancer- Noncommunicable diseases.
Available at: https://www.euro.who.int/en/health-topics/noncommunicable-
diseases/cancer/policy. (Accessed on 27/10/2021).
60.Zhao, Z., Feng, Q., Yin, Z., Shuang, J., Bai, B., Yu, P., Guo, M., Zhao, Q. (2017).
Red and processed meat consumption and colorectal cancer risk: a systematic
review and meta-analysis. Oncotarget, 8(47), pp.83306-83314. DOI:
10.18632/onoctarget.20667 (Accessed on 27/10/2021).