While we often try our best to not live in the past, our biology often has other ideas. Adding to a growing body of evidence that links weight to cancer, researchers have found significantly higher risks for 17 different cancers among men who carried around extra pounds in their youth.
In two new studies, scientists out of the University of Gothenburg looked at the body mass index (BMI), independent of aerobic fitness level, of 1,489,115 men enlisted in then-mandatory military service in Sweden between 1968 and 2005. Some 84,621 were diagnosed with a form of cancer during the follow-up period.
They found that a high BMI at conscription was linked to a higher risk of lung, head and neck, brain, thyroid, esophageal, stomach, pancreatic, liver, colon, rectal, kidney, and bladder cancer, as well as malignant melanoma, leukemia, myeloma, and lymphoma (Hodgkin's and non-Hodgkin's).
“Overweight and obesity at a young age seems to increase the risk of developing cancer, and we see links between unhealthy weight and cancer in almost every organ,” said the studies’ first author Aron Onerup from the University of Gothenburg. “Given the alarming trend of obesity in childhood and adolescence, this study reinforces the need to deploy strong resources to reverse this trend."
Interestingly, several cancers were already more prevalent among men with a BMI of 20-22.4, which is within the ‘normal’ range (18.5-24.9). These were cancers of the head and neck, esophagus, stomach, pancreas, liver and kidney, plus malignant melanoma and non-Hodgkin's lymphoma.
“This suggests that the current definition of normal weight may be applicable primarily for older adults, while an optimal weight as a young adult is likely to be in a lower range,” said senior author Maria Åberg, professor of family medicine at the University of Gothenburg. “Our research group has drawn similar conclusions regarding BMI in early adulthood and later cardiovascular disease.”
While it’s been widely acknowledged that BMI does not tell the full picture of an individual’s weight or health status, the research turned up significant associations between cancers and these measurements.
High BMI at time of enrolment delivered a three- to four-times higher risk of abdominal cancers later in life, including cancer of the esophagus, stomach and kidney. Right now, youthful weight issues explain an estimated 15-25% of cases of these cancers in Sweden today.
In 30 years, the researchers expect a significant rise in cancer linked to weight. For example, they predict 32% of stomach cancer cases and 37% esophagal cancer cases will be tied to historical weight issues.
On top of that, the data analysis revealed that overweight or obese men were two- to three-times more likely to die within five years of receiving a diagnosis for skin cancer, Hodgkin's lymphoma and thyroid, bladder, and prostate cancer, and up to twice as likely to die from cancers of the head and neck, rectum and kidneys.
This mirrors the findings of a previous study published in the journal Nature Communications in June, which linked high BMI in more than 2.6 million Spanish adults to a greater risk of 18 different cancers.
Meanwhile, the Centers for Disease Control and Prevention (CDC) currently says weight plays a role in the prevalence of 13 different cancers. However, the CDC also points out that cancer is not a guaranteed outcome of obesity at any stage in life, and that the risk can be mitigated with better lifestyle choices or medical intervention.
It also highlights the importance of being vigilant with health check-ups and monitoring for early signs of disease.
The Swedish researchers also point out that the prevalence of obesity will most certainly put increasing pressure on healthcare systems as people age and become more susceptible to these cancers.
The research was published as two papers in the journals Obesity and Cancer Medicine.
Source: University of Gothenberg
