Aim. To investigate the impact of fibroblast growth factor 21 (FGF-21) on the severity of androgen deficiency in young and middle-aged men with type 2 diabetes mellitus.
Materials and methods. The study comprised 100 men with type 2 diabetes mellitus, cardiovascular multi-morbidity, obesity and androgen deficiency (study group) and 20 healthy men aged 35-50 years. The study group was further divided into two subgroups. Patients of the subgroup 1 received the standard treatment for type 2 diabetes and cardiovascular disease. Patients of the subgroup two were treated with conventional therapy concurrently with testosterone undecanoate. The baseline examination included the following parameters: glycated hemoglobin, total testosterone, prolactin, thyroid stimulating hormone and blood FGF-21. At nine months after the treatment, the blood levels of glycated hemoglobin, FGF21 and testosterone were re-examined. The evaluation of the severity of androgen deficiency was carried out using the ICEF-5 questionnaire and the Aging Males’ Symptoms scale (AMS).
Results. In the study group, the mean FGF-21 level was 2.7 times higher, and the total testosterone level was 2-2.5 times lower than in the control group (p<0.05). A negative correlation was found between the blood levels of FGF-21 and total testosterone (r=-0.41, p<0.05). At nine months post treatment, the subgroup with testosterone undecanoate administered as add-on therapy showed a further decrease in FGF-21 levels and improved androgen deficiency symptoms.
Discussion. FGF-21 is one of the markers for type 2 diabetes, cardiovascular multi-morbidity, obesity and androgen deficiency. Given the association of FGF-21 with androgen deficiency, it can be assumed that FGF-21 plays a role in premature aging. Treatment of androgen deficiency as add-on therapy to the standard treatment of this category of patients improves their prognosis and the quality of life.
Conclusion. Young and middle-aged men with type 2 diabetes should undergo regular screening for androgen deficiency with the purpose of its early diagnosis and timely treatment. The detection of elevated levels of FGF-21 in young and middle-aged men with type 2 diabetes mellitus and cardiovascular multi-morbidity may indicate premature aging and requires preventive measures.

Keywords: fibroblast growth factor 21, diabetes mellitus type 2, androgen deficiency, premature aging, cardiovascular diseases, obesity