The researchers observed a so-called birth cohort effect in 14 types of cancer. This means that successive groups of people born within certain decades are progressively at risk of contracting the disease. This is likely due to the risk factors they were exposed to when they were younger. Mr. Dr. Shoji Ogino of Brigham and Women’s Hospital explained: “For example, people born in 1960 were more likely to develop cancer before the age of 50 than those born in 1950. We assume that this risk will continue to increase in future generations.”
An unhealthy lifestyle increases the risk of cancer
Based on their extensive research, the team suspects that the reason for this lies in the significant changes in diet, lifestyle, body weight, environmental pollution and the microbiome over the past few decades. They hypothesize that factors such as Western diet and lifestyle contribute to the early onset of cancer. The increase in the number of cancer diagnoses is partly due to preventive programs and early detection of cancer screening. However, an increase in many of the 14 cancers seems unlikely due to improved screening alone.
Potential risk factors for early-stage cancer include alcohol consumption, sleep deprivation, smoking, obesity, and high consumption of processed foods. While adults’ sleep duration has not changed drastically over decades, according to this study, children today are sleeping much less than they did decades ago. Risk factors such as highly processed foods, sugary drinks, obesity, type 2 diabetes, sedentary lifestyles, and alcohol consumption have increased dramatically since the 1950s. These affect the composition of the intestinal flora. Of the 14 types of cancer studied, eight have been linked to the digestive system. This leads researchers to suspect that changes in the gut microbiome have an impact on disease risk.
Which: DOI 10.1038/s41571-022-00672-8