Research has found that breast cancer incidence among women under 40 has risen in recent years, while rates in women older than 50 have either fallen or remained steady. Now, a new study has found increasing cancer cases across the board in people under 50.
Researchers at Brigham and Women’s Hospital recently examined the worldwide incidence of early onset cancers, including those of the breast, colon, esophagus, liver, and pancreas. Findings published in Nature Reviews Clinical Oncology show that these numbers are on the increase and have been since 1990. The team says this may be linked to our environment in childhood.
Dr. Shuji Ogino, professor and physician-scientist at Brigham’s Department of Pathology, says, “From our data, we observed something called the birth cohort effect. This effect shows that each successive group of people born at a later time (e.g., decade-later) have a higher risk of developing cancer later in life, likely due to risk factors they were exposed to at a young age. We found that this risk is increasing with each generation. For instance, people born in 1960 experienced higher cancer risk before they turn 50 than people born in 1950 and we predict that this risk level will continue to climb in successive generations.”
To examine these differences in risk level, the team looked at global figures on 14 types of cancer that had an increased incidence in younger people between 2000 and 2012. They then searched for other studies focused on possible risk factors, as well as research on the differences in tumors found before age 50 and those found after.
In so doing, the team found that stark differences in early life exposure have appeared over the past few decades. That includes changes in diet, lifestyle, weight, environmental characteristics, and microbiome. This led them to theorize that the western diet and lifestyle could be playing a role in people developing cancers at a younger age. However, they did note that part of the increase is due to better screening that catches cancers earlier.
There is one change they believe may play an outsized role, though.
Dr. Tomotaka Ugai, lead author from the Department of Pathology, explains, “Among the 14 cancer types on the rise that we studied, eight were related to the digestive system. The food we eat feeds the microorganisms in our gut. Diet directly affects microbiome composition and eventually these changes can influence disease risk and outcomes.”
The team says that since the 1950s, we’ve consumed more highly processed foods and sugary beverages, and there are higher rates of sedentary behavior, obesity, type 2 diabetes, and alcohol consumption. They believe these play a role in the altered microbiome, while many are risk factors in their own right. Other possible risk factors include smoking and sleep deprivation, with children getting far less sleep than they used to.
Going forward, the team says it’s important to analyze data from more low- and middle-income countries, which was limited in this study. They also believe it may be key to have long-term studies beginning when participants are children, with the permission of their parents, so that their health data can be monitored for decades to come.
To read more on the study, click here.Whizzco