Surging Surgeons: How Lifestyle Choices Fuel the Bowel Cancer Surge Among Under-50s

Bowel cancer among individuals under 50 is escalating rapidly in numerous nations, with studies indicating that lifestyle choices are likely a significant contributor. Sarah Allinson, a professor in biomedical and life sciences in the UK, reports.

Nearly two million individuals receive a bowel cancer diagnosis annually. Also referred to as colorectal cancer, it ranks as the third most prevalent cancer globally.

Although most bowel cancer diagnoses occur in those over 50, recent years have witnessed a concerning uptick in the number of young individuals diagnosed with this ailment.

A 2019 study revealed that among seven high-income nations with historically elevated bowel cancer rates, the incidence in those over 50 had started to stabilize or even decrease. This decline was credited to the effectiveness of standard screening initiatives that detect precancerous lesions before they can evolve into cancer.

However, the same research noted that the condition is becoming increasingly prevalent among those under 50 in every country examined. For instance, in Norway, the likelihood of developing rectal cancer (a variant of bowel cancer) at a young age was fivefold higher for individuals born in 1990 compared to those born in 1920.

A more recent, expansive study that examined bowel cancer rates in 50 different nations indicated that similar trends are occurring globally. An increase in bowel cancer diagnoses was found in countries within Europe, Latin America, the Caribbean, and Asia – with many observing the most significant rises in the under-50 demographic.

Although researchers are not fully certain what is driving this increase specifically among younger individuals, it may relate to our progressively unhealthy lifestyles.

Preventable factors

For decades, it has been understood that the likelihood of developing bowel cancer is deeply affected by an individual’s lifestyle and surroundings.

For instance, a pivotal study from 1968 demonstrated that bowel cancer rates were markedly higher in ethnically Japanese citizens residing in the US compared to the population in Japan, which had comparatively low disease prevalence at the time. This phenomenon, supported by various subsequent studies, strongly suggests that a Westernized lifestyle promotes bowel cancer.

In the intervening years, we have gained a clearer understanding of the elements that drive this effect. Reduced physical activity, a low-fiber and high-fat diet or one rich in red or processed meats, being overweight or obese, excessive alcohol consumption, and smoking are all associated with a significantly elevated risk of developing bowel cancer.

The influence of these lifestyle choices on the total number of bowel cancer instances is considerable. Cancer Research UK estimates that more than half of bowel cancer cases in the UK can be attributed to preventable factors.

In contrast, Japan, where rapid economic growth has led to the adoption of a more Westernized diet, now reports some of the highest bowel cancer rates worldwide.

Our increasingly inactive lifestyles, along with the heightened intake of high-calorie, nutritionally deficient foods, likely plays a crucial role in the generational variations in bowel cancer rates that we are witnessing. Diets became more prevalent in the US and certain European regions during the 1970s, spreading to other countries as a consequence of economic development.

We are currently facing a global obesity epidemic, with estimates suggesting that 2.2 billion people are overweight and 890 million of these individuals are classified as obese.

Alarmingly, while obesity rates are rising across all age groups, children and adolescents are particularly affected. Obesity is now ten times more prevalent among children aged five to 14 years old compared to the mid-1970s.

This is significant, as many metabolic changes linked with obesity—such as abnormal hormone levels and a persistent state of inflammation—are believed to facilitate cancer progression. Furthermore, obesity correlates with type 2 diabetes, which has been connected to a heightened risk of developing bowel cancer. Moreover, type 2 diabetes is increasingly common in younger populations.

Our dietary habits also significantly affect the health of our gut microbiome—the community of trillions of bacteria and microbes residing within us. Evidence indicates that a Western-style diet may promote a condition known as dysbiosis. This condition disrupts the balance of gut bacteria, allowing harmful microbes to proliferate while hindering the growth of beneficial ones.

It is becoming increasingly evident that the makeup of our microbiome can substantially influence our susceptibility to developing bowel cancer. One study even indicated that the impacts of gut dysbiosis on bowel cancer rates may be more pronounced in younger patients than in older individuals.

Regrettably, bowel cancer in those under 50 is frequently diagnosed at an advance stage. This is partly due to screening programs being focused on individuals over 50. Nonetheless, a survey by Bowel Cancer UK also pointed to a lack of awareness about the disease among younger individuals and their healthcare providers as a contributing factor.

Early detection is crucial for a more favorable prognosis, so it is vital to recognize the symptoms. Abdominal discomfort, blood in stools, altered bowel habits, or unexplained weight loss can all indicate bowel cancer. Many of these symptoms can arise without the presence of cancer, but it’s essential to have them evaluated to rule out cancer.

To mitigate the risk of developing bowel cancer at any age, the message is decidedly clear. Maintain a nutritious diet, restrict your consumption of highly processed foods and alcohol, refrain from smoking, and engage in regular physical activity.

This article is republished from The Conversation under a Creative Commons licence.

Sarah Allinson is a professor in the department of biomedical and life sciences, Lancaster University, UK.