If you're reading this, there's a good chance you're a millennial (someone born between 1981 and 1995). If so, you've probably noticed more and more cases of friends or people you know with diseases that you would normally see in older adults—high blood pressure, type 2 diabetes, or perhaps even cancer.

Millennials are the first generation at greater risk of developing tumors than their parents. Between 1990 and 2019, cases of early-onset cancer among people under 50 increased by 79% worldwide, and deaths increased by 28%.

Why Is This Happening?

The truth is that around 80% of cancers are "sporadic." This means they are not caused by genes passed down from parents, but by external factors that damage DNA over time. This includes:

• What we eat and breathe

• Our level of physical activity

• How much do we rest

• Our stress levels

• Exposure to harmful substances

In other words, the things that make the biggest difference are the lifestyle factors that surround us every day, not the genetics we inherit. And we know that our parents' and grandparents' lifestyles were very different from our own.

Diet's Effect on the Body

One of the main factors behind this "new epidemic" is diet. Childhood obesity began to increase rapidly in the 1980s. In 2022, more than 390 million children and teens aged 5 to 19 were overweight—160 million of these were obese, according to the World Health Organization (WHO).

This condition is not just about how people look. It's associated with:

• Insulin resistance (when the body doesn't respond well to insulin)

• Low-grade chronic inflammation (long-lasting swelling in the body)

• Hormonal changes that increase the risk of developing colorectal, breast, or endometrial cancer

Most importantly, the effects of childhood obesity don't disappear with age. According to the Colon Cancer Foundation, a large analysis 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% higher in men

• 19% higher in women (compared to those who had a healthy BMI in childhood)

Changes in diet have also changed our gut microbiota (the bacteria living in our intestines). Diets rich in ultra-processed foods reduce bacterial diversity and increase the proportion of strains that produce pro-inflammatory metabolites (substances that cause inflammation).

This contributes to gastrointestinal diseases like irritable bowel syndrome or SIBO. These problems seem to be very common among millennials—ask a group of 30-somethings which of them has gastrointestinal problems and you'll find few hands are left unraised.

Alcohol's Invisible Effects

The second major cause is alcohol. Millennial gatherings often revolve around a table full of food and drink. For years, people thought that a glass of wine could "protect" you in some way. But today we know that there is no safe level of alcohol consumption.

The International Agency for Research on Cancer classifies alcohol as a Group 1 carcinogen—the same level as tobacco. This is because the body converts ethanol (alcohol) into acetaldehyde, a compound that damages DNA.

Furthermore, drinking patterns differ between generations. While baby boomers (those born between 1946 and 1964) drink more on a daily basis, millennials tend to drink less frequently but engage in more binge drinking (drinking a lot at once), which carries significant risks. This is confirmed by the Spanish Ministry of Health's 2024 EDADES survey.

And, as if that weren't enough, a recent 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.

Not Enough Sleep

We sleep less and worse than previous generations. Recent surveys show that millennials and Generation Z get an average of 30–45 minutes less sleep per night than baby boomers. This is largely due to nighttime exposure to screens and social media. This artificial light disrupts the release of melatonin, an antioxidant hormone that regulates the cell cycle.

Chronic lack of sleep:

• Impairs DNA repair

• Reduces melatonin's protective effects against cancer

• Is linked to a reduced ability to fight oxidative DNA damage

• Increases cell proliferation (cells multiplying)

Furthermore, disrupted circadian rhythms (body clock) interfere with the expression of genes that are key to repairing DNA. This means mutations accumulate over time, increasing the risk of tumor-forming processes.

The Weight of Stress

Millennials are probably the generation with the highest cortisol levels. Cortisol is the "stress hormone." When this hormone remains elevated for a long time, it:

• Promotes insulin resistance

• Causes high blood pressure

• Weakens the immune system

Research reveals that chronic stress:

• Increases inflammation

• Hinders the body's defenses from eliminating abnormal cells

• Can even "awaken" dormant tumor cells

In fact, studies in the general population have found that people with higher stress levels are up to twice as likely to die from cancer as those who manage stress better.

The Risks of Self-Medicating

Lastly, younger generations also use medication on their own more than previous generations. This poses new short and long-term risks.

Frequent use of paracetamol (acetaminophen) is linked to increased liver damage and a possible increase in liver cancer.

Oral contraceptives (birth control pills), used for very long periods due to delayed motherhood, slightly increase the risk of breast and cervical cancer. However, they do protect against ovarian and endometrial cancer.

In addition, prolonged use of antacids and antibiotics has been linked to an increased risk of digestive cancer through indirect mechanisms such as carcinogenic compounds or intestinal dysbiosis (an imbalance in the gut bacteria).

What Does the Future Hold for Millennials?

The predictions are worrying. It's expected that cancer cases could rise from around 20 million in 2022 to nearly 35 million in 2050—an overall increase of almost 77%. The trend is particularly marked in digestive and gynecological tumors, which are becoming more common in young adults.

Can We Do Anything About It?

We are the generation of immediacy, anxiety, and quick-fix pills. But all is not lost. We can take control of many of the factors that make us ill, starting today. Adopting healthier habits can reduce risks and improve our quality of life in a future that is not as distant as we might like to believe. Medome is a good start to fighting back.