Study identifies main drivers behind alarming rise of cancer among millennials

Millennials, born between 1981 and 1995, are the first generation with a higher risk of developing tumours than their parents. Between 1990 and 2019, cases of early-onset cancer among people under 50 rose by 79% globally, with mortality increasing by 28%. 

Roughly 80% of cancers are “sporadic”, meaning they stem not from inherited mutations but from external, lifestyle-related factors that gradually damage DNA. These include diet, pollution, physical activity, sleep, stress, and exposure to harmful substances. Dietary patterns appear to be one of the primary drivers of this “new epidemic,” as highlighted by The Independent.

Lifestyle, rather than genetics, plays the dominant role. Lifestyles across generations have shifted dramatically, and the consequences are becoming increasingly clear. Childhood obesity surged in the 1980s, and by 2022, more than 390 million children and adolescents aged 5 to 19 were overweight, including 160 million who were obese, according to the WHO.

Childhood obesity is linked to insulin resistance, chronic inflammation, and hormonal changes that elevate the risk of colorectal, breast, and endometrial cancers. Importantly, its effects persist into adulthood. 

A meta-analysis of more than 4.7 million people cited by the Colon Cancer Foundation found that individuals with a high childhood BMI had a 39% higher risk of colorectal cancer in men and 19% higher risk in women compared to those with a healthy BMI.

Diet-related changes have also reshaped gut microbiota. Diets rich in ultra-processed foods decrease bacterial diversity and increase strains that produce pro-inflammatory metabolites. This fuels gastrointestinal conditions such as irritable bowel syndrome and SIBO, which appear widespread among millennials.

Other lifestyle choices affecting overall health

Alcohol is another major factor, with millennial socializing often centered on food and drink. Although it was once thought that moderate wine intake could “protect” you, current scientific consensus states 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 category as tobacco, because the body converts ethanol into DNA-damaging acetaldehyde. 

Drinking patterns differ by generation: baby boomers drink more regularly, while millennials drink less frequently but binge more often, raising significant health risks. The Spanish Ministry of Health’s 2024 EDADES survey confirms these generational differences.

Compounding the issue, research published in Environmental Science & Technology found that many beers contain perfluoroalkyl substances (PFAS), or “forever chemicals”, which are linked to higher rates of testicular and kidney cancers.

Sleep deprivation also plays a role. Millennials and Gen Z sleep 30–45 minutes less per night than baby boomers, largely because of evening exposure to screens and social media. Artificial light disrupts melatonin, an antioxidant hormone essential for regulating the cell cycle. Chronic sleep loss impairs DNA repair and diminishes melatonin’s protective effects against cancer, contributing to oxidative DNA damage and increased cell proliferation. Disrupted circadian rhythms further interfere with genes responsible for DNA repair, allowing mutations to accumulate.

Millennials are also a highly stressed generation, likely experiencing the highest cortisol levels. Prolonged elevation of this “stress hormone” promotes insulin resistance, hypertension, and suppressed immune function.

Research shows that chronic stress increases inflammation, weakens the body’s ability to eliminate abnormal cells, and can even “awaken” dormant tumour cells. Studies indicate that people with higher stress levels are up to twice as likely to die from cancer as those who manage stress more effectively.

By Nazrin Sadigova