neoplasms. According to the WHO, cancer constitutes the second‐leading cause of death on a global scale – one out of six death events occurring globally is attributed to cancer. Epidemiological data show that males are mostly affected by lung, prostate, colorectal, stomach, and liver cancers, whereas females are more susceptible to breast, colorectal, lung, cervix, and stomach malignancies.
In addition to the health burden of the disease, cancer incurs a significant economic burden, over 1.5 trillion US dollars in 2020. Given that 30–50% of cancer incidence may be preventable, it is obvious that we should urgently employ preventive strategies to constrain cancer incidence. Raising public awareness regarding the risk factors associated with cancer development and providing people with sufficient information and resources to enhance compliance with healthy lifestyle behaviors stand at the forefront of cancer prevention. The major risk factors for cancer onset include consumption of tobacco products, excessive alcohol intake, unhealthy body weight, physical inactivity, and certain infections and occupational/environmental chemical exposures.
Key Point
The major risk factors for cancer onset include use of tobacco products, excessive alcohol intake, unhealthy body weight, physical inactivity, and certain infections and occupational/environmental chemical exposures.
Tobacco use accounts for approximately six million deaths on an annual basis. At least 50 of the chemicals contained in tobacco have a well‐established causal effect on cancer development. Tobacco smoking causes malignancies in lung, esophagus, larynx, mouth, throat, kidney, bladder, pancreas, stomach, and cervix. Second‐hand smoking can also cause lung cancer. Additionally, smokeless tobacco products, such as oral or chewing tobacco, have been shown to cause oral, esophageal, and pancreatic neoplasms. Interestingly, the majority of smokers globally (i.e., 80% of 1 billion) live in regions of low or middle income.
Other lifestyle‐related factors associated with cancer onset include unhealthy dietary habits, being physically inactive, and obesity. Obesity has been linked to esophageal, colorectal, breast, endometrial, and kidney malignancies. Excess alcohol intake increases the risk of malignancies developed in the oral cavity, pharynx, larynx, esophagus, liver, colorectum, and breast.
There is a dose–response relationship between alcohol intake and cancer development, and the risk of several cancer types is further exacerbated when increased alcohol consumption is combined with smoking. Alcohol use accounted for about 6% of all cancers and 4% of all cancer deaths in the United States in 2020.
Infection‐related factors, exposure to carcinogens derived from occupational environment or environmental pollution, and ultraviolet and ionized radiation can also increase the risk for developing cancer. Infectious agents such as helicobacter pylori, human papilloma virus (HPV), hepatitis B and C, and Epstein–Barr virus accounted for 20% of cancer cases in 2020, and their prevalence was substantially greater in developing countries. Air, water, and soil contamination with carcinogens plays a role in the total burden of the disease. Contamination of foods with carcinogenic chemicals, such as aflatoxins and dioxins, is another means by which humans are exposed to carcinogens. Exposure to occupational carcinogens mainly affects specific population groups whose working environment incurs exposure to carcinogenic chemicals, such as asbestos. Exposure to ionized and ultraviolet radiation can also aggravate the risk of developing certain types of neoplasms. There is a dose–response relationship between the extent to radiation exposure and risk of carcinogenesis, and a greater risk of cancer onset when the exposure occurs at a young age.
More than 80% of US health‐care costs are spent in the treatment of preventable chronic diseases and conditions, such as T2DM, obesity, osteoporosis, heart disease, hypertension, stroke, and many types of cancer. Preventing even a small fraction of chronic disease cases could significantly improve people's health and alleviate the pressure on health‐care systems around the world.
Key Point
Preventing even a small fraction of chronic disease cases could significantly improve people’s health and alleviate the pressure on health-care systems around the world.
Take‐Home Messages
NCDs, also known as chronic diseases, usually have a long duration, and they are the result of a combination of genetic, physiological, environmental, and behavioral factors.
There are four types of NCDs: CVDs (e.g., heart attacks and stroke), cancers, CRDs (e.g., chronic obstructive pulmonary disease and asthma), and diabetes.
The genetic predisposition of a disease explains only part of the disease risk, while lifestyle factors such as unhealthy diet, physical inactivity, excessive stress, and environmental factors (e.g., access to health‐care systems) are also key contributors.
The “globesity” phenomenon has an important contribution to the global incidence of most major NCDs.
The human body has been programmed to preserve energy, and this has deleterious effects when people are found in an obesogenic environment.
Exposure to an obesogenic environment affects the onset of T2DM, irrespective of existing genetic factors.
It has been estimated that up to 50% of cancer incidence is preventable.
Self‐Assessment Questions
1 List the types of NCDs.
2 Which are the main adverse effects of obesity?
3 Why is the prevalence of obesity rising in modern societies?
4 Genome‐wide association studies:assess how genes can be modified to combat chronic diseasesexamine similarities in the entire DNA sequence of different people, as regards specific SNPs, and the presence of a certain abnormality across this populationinvestigate interactions between diet and genesinvestigate how people with a certain genetic background respond to different dietary manipulations (e.g., increased saturated fat intake)none of the above
5 Which of the following are modifiable risk factors for obesity?dietgenesagesexphysical activitystressall of the above
6 T1DM is characterized by:defects in liver glucose productioninefficient use of insulin from the bodydefective production of insulininability of glucose transportation in the adipose tissuea and bnone of the above
7 What is T2DM, and how is lifestyle linked to its development?
8 Which of the following are possible consequences of diabetes?cardiovascular diseaseretinopathykidney failurenerve damageamputation of lower limbsall of the above
9 Which of the following are CVDs?strokecancerheart failurediabetesischemic heart diseaseasthma
10 Which are the main contributors to CVDs?
11 Which are the major risk factors for cancer onset?
12 Excess alcohol intake increases the risk of malignancies developed in:the lungsthe oral cavitythe brainthe larynxthe liver
Bibliography
1 American Diabetes Association. (2020). Classification and diagnosis of diabetes: standards of medical care in diabetes–2020. Diabetes Care
