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Weight gain in a person’s early 20s may influence their prostate cancer risk, new findings suggest. Image credit: Jasmin Merdan/Getty Images.
  • Weight gain in a man’s young adult years is strongly associated with an increased risk of aggressive or fatal prostate cancer, according to a new Swedish study.
  • For young men with obesity, there are several known changes in the body that may explain the link to worse prostate cancer outcomes later on.
  • The study highlights the importance of maintaining a healthy weight across adulthood for men to help prevent the development of prostate cancer, as well as other serious diseases.

A study from Sweden finds that men who gain weight as young adults are more likely to develop aggressive or fatal prostate cancer later on.

According to the study, men who gained on average 1 kilogram each year from the ages of 17 to 29 increased their risk of developing aggressive prostate cancer by 13% and fatal prostate cancer by 27%.

The study was conducted by researchers from Lund University in Malmö, Sweden, and the authors presented their findings at the European Congress on Obesity (ECO) 2023 in Dublin, Ireland.

While weight gain was associated with prostate cancer across adulthood, its incidence was driven more directly by weight gain in young adults.

For men gaining about 1.1 pounds (0.5 kilograms) over the course of their adult lives, the risk of aggressive cancer was increased by 10%, and the risk of fatal cancer rose by 29%.

Researchers tracked health data for 258,477 men who had taken part in the Obesity and Disease Development Sweden (ODDS) study between 1963–2014. Each had been prostate-cancer-free at the start of the ODDS study, and was weighed at least three times between the ages of 17 and 60 years.

For the new study, participants were followed up for an average of 43 years, until 2019, at which time cases of prostate cancer and deaths among the group were recorded.

Of the entire study cohort, 23,348 participants had been diagnosed with prostate cancer at an average age of 70 years, and 4,790 had died from prostate cancer.

Following skin cancer, prostate cancer is the most common type of cancer in men. It is estimated that 288,300 American men will be diagnosed in 2023 with the disease, or about one out of every nine men.

Black men are at higher risk of developing prostate cancer than their white counterparts. The reasons are not fully understood, with theories ranging from disparities in healthcare access and socioeconomic status to the manner in which darker skin synthesizes vitamin D.

In the U.S., just two or three out of every 100 men will die from prostate cancer, with the most common factor being one’s age at diagnosis. The older someone is when they are told they have the disease, the more likely they are to die of it.

Dr. David Shusterman, medical director of urology at NY Urology, not involved in the recent study, told Medical News Today, however, that “not all prostate cancers are aggressive or fatal. In fact, many prostate cancers grow very slowly and may not cause any symptoms or health problems.”

In the U.S., many men are regularly screened for prostate cancer, resulting in frequent early detection when the disease is more treatable. It may be for this reason that in the U.S. the 5-year survival rate after a diagnosis of prostate cancer is 97%, with the 10-year survival rate being 98%.

Prostate cancer screening involves prostate-specific antigen (PSA) testing as a part of one’s checkup bloodwork. For some years, PSA testing was on the decline due to an abundance of false positives that resulted in unnecessary treatment. During those years, however, prostate cancer rates spiked, and PSA tests are now returning to greater regular use.

The new study, however, cites a concerning, strong link between weight gain and aggressive or fatal cancers.

Urologist Dr. Adam Ramin, not involved in the study, had some words of caution regarding the research: “You have to keep in mind that this is a study that was done in the Scandinavian countries. And in those countries, the way prostate cancer is diagnosed is different than in other countries.“

“Generally, people are not getting screened for prostate cancer [in those regions],” he claimed. As a result, said Dr. Ramin, “you end up finding the more aggressive cancers because those are patients who end up with some sort of symptom that requires further evaluation.”

“The research is important,” Dr. Shusterman said, “because it highlights the potential long-term health consequences of weight gain during a specific age range.”

“We know that obesity [at any time in adulthood] can increase [the likelihood of prostate cancer] by about 50%,” noted Dr. Ramin, but the young adult years may be especially critical.

Dr. Ramin cited a “whole slew” of chemical changes that can occur in young adult men.

“We know that obesity in this age group,” he explained, “is associated with higher levels of a particular growth factor called the insulin-like growth factor, or IGF. We know that IGF has been identified as a possible cause for prostate cancer.”

In addition, he said, fatty tissues at this age produce leptin, another substance that has been associated with prostate cancer.

Finally, pointed out Dr. Ramin, “[w]hat happens is as a person becomes more obese — especially in men, and especially in this age group — they develop more belly fat than fat in other areas in the body.“

“This belly fat tends to convert testosterone into other hormones, and it’s possible that there may be a hormonal connection to prostate cancer as well.”

– Dr. Adam Ramin

The takeaway from this study, said Dr. Ramin, is that “the earlier a person loses weight, the less likely it is that it’s going to cause prostate cancer. But what the sweet spot is [in age] and how many years, that’s very hard to tell. And I’m sure it would be different from person to person.”

“Overall,” concluded Dr. Shusterman, “this research highlights the importance of maintaining a healthy weight throughout life, as doing so could prevent having adverse health issues later in life.”