Extra Pounds in Youth Could Raise a Man's Odds for Fatal Prostate Cancer Decades Later
When young men pack on excess weight during their teens and 20s, they may inadvertently drive up their risk for prostate cancer later on.
The concern stems from new research that examined several decades' worth of weight fluctuations and prostate cancer rates among nearly 260,000 men in Sweden.
The men ranged in age from 17 to 60. Researchers initially observed that overall, participants who put on roughly 1 pound or more per year across their life span had a 10% higher risk for developing aggressive prostate cancer as older adults.
A similar weight pattern was linked to a 29% greater risk of fatal prostate cancer.
But digging deeper, researchers found that most of the men grew heavier between the ages of 17 and 29. And ultimately most of the weight-associated increase in cancer risk was pegged to weight gains in that age bracket.
“We were surprised [by] the rapid weight gain in young adulthood, and that the risk of prostate cancer later in life was strongly associated with this rapid weight gain,” said lead author Marisa da Silva, a postdoctoral fellow at the Lund University Cancer Center in Sweden.
She stressed that the findings are not definitive proof that youthful weight gains caused prostate cancer risk to rise, only that the two are linked.
Even the possibility of a weight-driven risk factor is important, da Silva pointed out, because none of the other factors that are known to drive up prostate cancer risk -- including getting older, genetic predisposition and/or a family history of the disease -- are issues that patients at high risk can do anything about.
Prostate cancer is the world's second most common cancer, researchers pointed out.
The research was part of the ongoing “Obesity and Disease Development Sweden” study (ODDS). Participants enrolled between 1964 and 2014 and their health was monitored through 2019. On average, they were tracked for more than four decades.
During that time, more than 23,000 men were diagnosed with prostate cancer, at an average age of 70. Of those, almost 4,800 died of the disease.
Average weight gain varied by age group, with the greatest gains -- about 1.6 pounds per year -- seen among 17- to 29-year-olds. Men between 30 and 44 gained three-quarters of a pound per year, and 45- to 60-year-olds, a half-pound.
Beyond linking most of the increased risk to the youngest group's weight gains, researchers noted that 17- to 29-year-olds who gained just over 2 pounds a year faced a 13% increased risk for developing aggressive prostate cancer, and a 27% higher risk of dying as a result.
Da Silva noted that other research has suggested that weight gain can affect a particular growth hormone known to drive prostate cancer development.
Still, she said it remains an open question whether the new study uncovered an increased risk specifically due to gaining weight while young, or whether the increased risk is linked to gaining weight period.
Either way, it begs the question as to whether losing weight later in life might reduce any increased risk brought about by prior weight gain.
The study was not designed to answer this, da Silva said, noting that prior studies of bariatric surgery patients indicate that cancer risk drops after weight loss.
Connie Diekman is a St. Louis-based dietitian and food and nutrition consultant, and former president of the Academy of Nutrition and Dietetics. She reviewed the study findings.
Diekman said it's important to distinguish between youthful weight gains due to fat accumulation and those more readily attributed to muscle.
“Boys tend to grow the most from 16 to 25, so during that time frame there is muscle mass development,” she said.
Still, Diekman acknowledged that adding excess fat during these growth years likely brings more hormone release. "This might be the connection to disease risk," she said.
Diekman noted that youth is when people develop eating habits that become the foundation for the future.
"If food choices promote more body fat development, this lays the groundwork for an increased potential for many diseases,” she said, which could mean that prostate cancer risk is really a broad reflection of poor choices made by many young men with respect to nutrition and exercise. These bad habits often last a lifetime.
“At the same time,” Diekman said, “if a young man is looking to gain weight by building muscle mass, and he finds a good balance of the best food choices with a good workout routine, I'm not sure we know that body weight is a health issue.”
Researchers are slated to discuss their findings at a meeting of the European Congress on Obesity in Dublin, from Wednesday through Saturday. Studies presented at meetings are typically considered preliminary until published in a peer-reviewed journal.
There's more about prostate cancer risk at the U.S. Centers for Disease Control and Prevention.
SOURCES: Marisa da Silva, PhD, postdoctoral fellow, Department of Translational Medicine, Lund University Cancer Center, Lund, Sweden; Connie Diekman, RD, MEd, LD, food and nutrition consultant, St. Louis, and former president, Academy of Nutrition and Dietetics; presentation, European Congress on Obesity meeting, Dublin, Ireland, May 17-20, 2023