Increased levels of insulin-like growth factor I and younger age at peak height velocity appear to be associated with gynecomastia in pubertal boys, according to recent study findings published in The Journal of Clinical Endocrinology & Metabolism.
Changes in ratio of estrogen to testosterone do not appear to be related to the condition, according to researchers.
Mikkel Grunnet Mieritz, MD, of the University of Copenhagen in Denmark, and colleagues evaluated 106 healthy boys aged 5 to 16 years to determine the rate of physiologic gynecomastia and possible etiologic factors. Participants were evaluated every 6 months during an 8-year follow-up period.
Immunoassays were used to examine blood samples for follicle-stimulating hormone (FSH), luteinizing hormone, testosterone, estradiol, sex hormone-binding globulin, inhibin B, anti-Müllerian hormone, IGF-I and IGF-binding protein 3. At each visit, participants were evaluated for auxologic parameters, pubertal development and the presence of gynecomastia.
During follow-up, 49% of participants exhibited gynecomastia, which developed in most participants during pubertal stages G3 and G4.
Of the participants who developed the condition, 27% experienced intermittent gynecomastia; six had two to three examinations without gynecomastia lasting a median of 2.1 years, and the others had one intermittent examination without the condition.
Different growth patterns were found between the groups with and without gynecomastia (P = .017) with peak height velocity occurring at a younger age in the gynecomastia group (P = .027).
Participants with gynecomastia had higher levels of IGF-I (P < .0005), estradiol (P = .013), free-testosterone (P < .001) and FSH (P = .03) during the pubertal transition compared with participants without gynecomastia. No significant differences were found for serum LH or estradiol-to-testosterone ratio.
“In conclusion, our study confirmed that physiological gynecomastia is a frequent condition appearing in mid-puberty and in most cases transient — lasting less than 1 year,” the researchers wrote. – by Amber Cox
The researchers report no relevant financial disclosures.