Why are more Gen Z and millennials getting cancer? – Firstpost

When you think of cancer, you normally associate it with older people. One has always believed that things like bad genes and even worse habits, like smoking, were combining to cause cancer.

However, this perception is slowly changing. On this World Cancer Day, which is observed each year on February 4, data reveals that cancer is no longer just a disease of the old. Oncologists have observed a disturbing trend — cancers are increasingly being diagnosed in younger adults, particularly those in their late 20s to early 40s — namely Gen Z and millennials.

But what’s behind this trend? Here are a few answers.

Growing burden of cancer in Gen Z and millennials

Before we deep dive into what could be the cause of the rise in
cancer among Gen Z and millennials, let’s take a better look at the data available.

A major study found that the
global incidence of early onset cancer has risen by 79 per cent between 1990 and 2019. The same study also showed that deaths caused by cancer had risen by 28 per cent.

A study published by The Lancet in 2024 showed that the incidence of 17 cancers in the United States has risen steadily among young men and women, particularly among those born after 1990. The steepest rises were seen in cancers of the small intestine and pancreas, says study coauthor Hyuna Sung, a cancer epidemiologist at the American Cancer Society in Atlanta.

Sung added that people born after the 1980s are four times more likely to be diagnosed with rectal cancer than those born in the ’50s. The study adds that the global incidence of early onset cancers is expected to rise by 31 per cent by 2030.

Millennials and Gen Zers will carry disproportionate cancer risks with them as they age, “potentially slowing decades of progress against cancer,” Sung says.

The numbers in India also paint a similar picture. The Indian Council of Medical Research noted that one in nine Indians is likely to have cancer in a lifetime. Even an Apollo Hospitals study found that people in India are getting cancer at relatively lower ages compared to Western countries.

Factors contributing to rise in cancer among the young

Many doctors across the world confirm the data with what they are seeing on a daily basis. For instance, oncologist Alok Khorana told ScienceNews that he is seeing more otherwise healthy young people being diagnosed with cancer.

“It’s a question we’re all asking,” he told ScienceNews. “Why are we seeing more and more younger people in our clinics, and why are they … presenting [cancers] at more advanced stages?”

Medical experts also note it’s likely not a single factor but the interaction of several that contribute to an increased cancer risk in this age group, such as rising rates of obesity and metabolic syndrome, as well as environmental exposures.

Diet

One of the main reasons why the young are being diagnosed with different types of cancer is their diet. Scientists have found that certain diets, including those rich in
ultra-processed foods, are associated with a higher risk of cancer, regardless of a person’s BMI.

Some epidemiological evidence points to
obesity being a key risk factor for early onset cancers. An analysis of 21 cancers in 25- to 49-year-olds between 2000 and 2012 found global increases in colon, rectal, pancreatic, and kidney cancers may be partly explained by increases in excess body weight. However, the link isn’t clear-cut.

A study by the Colon Cancer Foundation involving more than 4.7 million people showed that those with a high body mass index (BMI) in early life are at greater risk of colorectal cancer in adulthood: 39 per cent higher in men and 19 per cent higher in women compared to those who had a healthy BMI in childhood.

Lack of sleep and increased stress

It’s a known fact that Gen Z and millennials
sleep worse than their previous generations. Survey after survey reveals that millennials and Gen Z get an average of 30-45 minutes less sleep than baby boomers, mostly owing to night-time exposure to their devices — namely, their mobile phone. This artificial light disrupts the release of melatonin, an antioxidant hormone that regulates the cell cycle.

Research has linked chronic circadian misalignment to higher risks of breast, colorectal, lung, liver, and pancreatic cancers, all increasingly diagnosed in younger populations. Moreover, in 2007, the International Agency for Research on Cancer declared that shift work, which disturbs circadian rhythms, is a probable human carcinogen.

Besides lack of sleep, millennials and Gen Z also struggle with higher stress levels. Experts have noted that stress levels are highest among millennials, with cortisol leading to insulin resistance and hypertension, along with weakening of the immune system.

According to studies, chronic stress leads to an inflammation spike, which then hinders your body’s defences from eliminating abnormal cells, and doctors believe that it can even “awaken” dormant tumour cells. Research says those with higher stress levels are twice as likely to die from cancer as those who manage stress better.

Alcohol consumption

Alcohol has long been considered a carcinogen, on the same level as tobacco. This is because the body converts ethanol into acetaldehyde, a compound that damages DNA.

While data suggests that millennials are drinking less frequently, they engage in more binge drinking, which carries significant risks. Experts have warned that binge drinking drives early-onset breast cancer. Health experts have even warned that festival binge drinking can be connected to oral cancer.

And if that wasn’t enough, a study by Environmental Science & Technology found that many beers contain perfluoroalkyl substances (PFAS). These chemicals, also known as “forever chemicals”, are linked to higher rates of testicular and kidney cancer.

Maternal medication

The rising case of cancers in the young isn’t just linked to
lifestyle and behavioural choices, though. As per a report in the Washington Post, medicines used by women during their pregnancy could also be a cause of early onset cancer in their children.

Caitlin Murphy, a professor and cancer epidemiologist at the University of Chicago, carried out a study to investigate whether maternal medication had any link to cancer. Through tests and studies, she found that children whose mothers had taken bendectin, an anti-nausea drug, during pregnancy were 3.6 times more likely to develop colon cancer as adults, when all other factors were taken into consideration.

Moreover, children of women who took hydroxyprogesterone caproate, to prevent miscarriage had more than double the overall lifetime cancer risk. In this group, about 65 per cent of cancers occurred before the age of 50.

Microplastics and cancer risks

Many health experts also point to the exposure to
microplastics and ‘forever chemicals’ that have become more commonly used over the last few decades. They permeate our everyday life — in the air we breathe, the food we eat, and even the products we use.

Frank Frizelle, a colorectal surgeon at the University of Otago in New Zealand, noted that evidence that microplastics cause early onset cancers is “weak but increasing”. Global plastic production increased from around 120 million metric tonnes in 1990 to over 460 million tonnes in 2023, which coincides with the rising incidence of early onset cancer.

Steps to reduce cancer risk

So, what can Gen Z and millennials do to reduce their risk of developing cancers? There are certain steps one can take, such as indulge in a healthy lifestyle, eat a balanced diet, exercise and limit alcohol, smoking and screen exposure. Apart from that, getting vaccinated against HPV can help reduce the risks of cervical and throat cancers, and there is some evidence that the hepatitis B vaccines help prevent liver cancer.

Doctors also note that people should be made aware of the signs of cancer and opt for cancer screenings.

However, millennials and Gen Z can take hope from the fact that scientists are making tremendous strides in reducing overall cancer mortality.

With inputs from agencies