High BMI in Late Teens is Linked with Higher Risk of Certain Types of Cancer, Cancer Mortality Later

A person’s weight can influence their risk of a variety of cancers, including that of the breast, thyroid, pancreas, colon and rectum, ovaries, and stomach. Two new studies find this risk may even be present based on your weight as a teen.

Research recently published in the journals Obesity and Cancer Medicine investigated how BMI and fitness levels in youth impacted cancer risk and cancer mortality risk in men. Using 35-plus years of health data from conscripts in the Swedish military, a team from the University of Gothenburg learned that cardiorespiratory fitness and BMI when these men joined the military were each linked with the risk of mortality from a variety of cancers in different parts of the body.

Being overweight or obese at 18 was also linked with a higher risk of developing 17 different types of cancers in the first place. The researchers say their findings suggest the importance of public health efforts to promote fitness and a healthy weight in teens.

Aron Onerup, the studies’ first author and postdoc at Sahlgrenska Academy at the University of Gothenburg, and St. Jude Children’s Research Hospital, says, “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. Given the alarming trend of obesity in childhood and adolescence, this study reinforces the need to deploy strong resources to reverse this trend.”

The studies involved data from men who were conscripted into the Swedish military between 1968 and 2005. For the cancer mortality study, their cardiorespiratory fitness was rated as low, moderate, or high based on a cycle ergometer test, and their BMIs were categorized as underweight, normal weight, overweight, or obese. In this study, more than 84,000 cancer cases were studied among just under 1.5 million conscripts.

The team found that the men who were overweight or obese when they joined the military were two to three times more likely to die within five years of being diagnosed with Hodgkin’s lymphoma and skin, thyroid, bladder, and prostate cancer, and there was also at least a 1.4 times higher risk of death with head and neck, rectum, and kidney cancers.

Higher fitness levels, meanwhile, were linked with a protective effect against dying from non-Hodgkin lymphoma, and skin, lung, head and neck, pancreatic, stomach, liver, rectum, and bladder cancers.

The other study, meanwhile, showed that being overweight or obese at 18 was also linked with a higher risk of developing 17 different cancers later, including both types of lymphoma studied, melanoma, leukemia, myeloma, and lung, head and neck, brain, thyroid, esophageal, stomach, pancreatic, liver, colon, rectal, kidney, and bladder cancers. The risk was especially pronounced with the abdominal cancers.

Based on their findings and the current rates of excess weight in Swedish teens, the researchers say the proportion of cancer cases linked to weight in youth is expected to increase within the next 30 years, with 37% of esophageal cancer cases related to this, along with 32% of stomach cancers.

This may be a similar concern in the United States, with 2017-2018 National Health and Nutrition Examination Survey data showing that about 1 in 6 American children and teens was overweight at that time, along with nearly 1 in 5 being obese.

The researchers say their findings should inspire “rapid action to stem the obesity epidemic and to prepare the health care system for steep increases in cancer cases.”