There are many upsides to growing old, but one of the downsides, unfortunately, is a higher risk of developing cancer. Increasing age is a key risk factor. And with more of us living longer worldwide, millions of older people will have to contend with the disease.
Now a new study adds weight to previous work warning of a grim trend in global health: cancer in people under the age of 50 is becoming more common.
In the study, researchers led by the University of Edinburgh in Scotland and Zhejiang University School of Medicine in Hangzhou, China, found that the number of under-50s being diagnosed with cancer worldwide rose by 79% between 1990 and 2019, from 1.82 million to 3.26 million. Cancer deaths in the same age group grew by 27%, and more than 1 million under-50s a year are now dying of cancer, the research published in BMJ Oncology reveals.
The study is not the first to show the trend. A review in 2022 of cancer registry records from 44 countries found that the incidence of early onset cancer was rising rapidly for 14 types of cancers, and this increase was happening across many middle- and high-income nations.
The new research adds meat to the bone. Examining data from 204 countries, it found a striking increase in the global incidence of early onset cancers. It also showed the highest incidence rates of cancer in the under-50s was in North America, Oceania and western Europe.
Researchers worldwide are only just starting their next task: working out why.
The authors of the 2022 review, led by Harvard University, said any uptick in testing or checks could not account for the rise in diagnoses. They suggested the rise was most likely due to an unhealthy mix of risk factors that could be working together, some which are known and others of which need to be investigated.
Many of these risks had established links to cancer such as obesity, inactivity, diabetes, alcohol, smoking, environmental pollution and western diets high in red meat and added sugars, not to mention shift work and lack of sleep. Experts have speculated that ultra-processed food may also be partly to blame.
The researchers behind the new study echoed those observations. Genetic factors are likely to have a role, they say. But diets high in red meat and salt and low in fruit and milk, as well as alcohol consumption and tobacco use, are the main risk factors underlying the most common cancers among under-50s, with physical inactivity, excess weight and high blood sugar other contributory factors.
As worrying as the increase in early onset cancers is, caution is required. Cancer in people under 50 is still uncommon. With breast cancer, the most common type in under-50s, there were 13.7 cases per 100,000 people in 2019. Nine in 10 of all cancers affect people over 50.
There were also limitations to the latest research, principally the variable quality of cancer registry data in different countries.
Until experts unlock definitive answers, there remains plenty that people young and old can do to reduce their risk of cancer. Not smoking, maintaining a balanced diet and a healthy weight, getting plenty of exercise and staying safe in the sun are among them.
