Continuous use of muscle-building supplements (MBS) may possibly be linked to the alarming increase of testicular germ cell cancer (TGCC) in young men for the past 30 years, based on a study from researchers at Yale University.
In their study published in the British Journal of Cancer, scientists found that men who had regularly consumed MBS with androstenedione or creatine were more likely to be diagnosed with TGCC than those who did not.
This first analytic epidemiological study to examine the relationship between MBS and TGCC risk used a population-based case-control sampling of 356 men with TGCC and 513 men without TGCC. All subjects were from Massachusetts and Connecticut.
The subjects were interviewed regarding their MBS consumption, especially the use of the supplements at least once a week for a minimum of four weeks, along with other potential factors for TGCC, such as drinking, smoking, exercise habits, family history and prior injury in the testicular area.
Based on the results, almost 20 percent of the subjects with TGCC had used MBS before.
The researchers also discovered that men who had consumed MBS were at a 65 percent higher risk of developing TGCC. The risks of being diagnosed with TGCC were greater for men who were 25 years old or younger when they started taking the MBS; for men who used multiple types of MBS; and for men who took them for three years or longer.
"The observed relationship was strong," said Tongzhang Zheng, lead researcher while at Yale University before joining Brown University's School of Public Health. "If you used at an earlier age, you had a higher risk. If you used them longer, you had a higher risk. If you used multiple types, you had a higher risk."
Data from the U.S.-based Surveillance Epidemiology and End Results program demonstrated that TGCC cases per 100,000 men who were between 15 and 39 years old almost doubled from 3.7 in 1975 to 5.9 in 2011.
The scientists added that further research is necessary to establish a fundamental link between MBS and TGCC.
TGCC is the most common type of the disease to affect men between 15 and 49 years old, according to the National Health Service (NHS), although it accounts for only 1 percent of cancers in men overall. The preferred treatment for most men with the initial stage of TGCC is active surveillance. Active surveillance consists of periodic history and physical examinations, radiographic imaging and tumor marker analysis. Around 85 to 95 percent of these testicular germ cell cancer cases will require no further treatment.
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