Objectives The aim of this study was investigate effects of heading and concussion on pituitary dysfunction in soccer players.

Methods 32 retired football players at the average age of 43.38 ± 5.49 (35 -59) who played professionally in Turkey Football League and 26 sedentary at the average age of 43.31 ± 6.38 (35 -59) were included in this study. The investigation of football background, head trauma, concussion and cardiometabolic disease of all the volunteers were conducted. After the basal blood specimens had been taken for hematologic and biochemical parameters, first the ACTH stimulation test and the other day, the glucagon stimulation test were carried out. For cardiometabolic parameters, BMI, Fat%, FFM, heart rate, SBP, DBP were measured and EKG, transthoracic echo and effort test were performed. The Student’s t-test was conducted in the comparison of the football players and the control group. The significance level was accepted as p < 0.05.

Results The growth hormone (GH) level of 3 football players (9.2%) was below 1 ng/dl which was accepted as the threshold value. It was identified that 5 out of 32 football players (16%) experienced a concussion during their football career. While the MET values were statistically significantly high in favour of retired football players, Hb, ACTH, fT4, prolactin and HR values were found out to be lower when compared to sedentary participants (p < 0.05). However, all values were within the reference ranges.

Discussion It has been claimed that the concussion rate was between 0.06/1000 - 0.6/1000 player hours in soccer. Our results were more than the results of other studies because of all soccer career were included of the players. It has been indicated that 23,5% pituitary dysfunction, 19% GH deficiency and 50% metabolic syndrome in retired American football players and 21, 9% GH deficiency in boxers and kickboxers. The fact that multiple head traumas are more frequent and severe in boxing, kickboxing and American football than soccer. In addition to the fact that football is a contact and combat sport, the number of head traumas resulted in concussion is low. In our study, it was found out that for a player the average number of heading per match was 8.81. However there was no significant relationship between the number of heading and the GH deficiency. It was indicated that the fact that the muscle mass of professional players is high and the fact that they use the right techniques minimise the effect of heading on the brain. Furthermore, some researchers indicated that concussions rather than heading of soccer players result in chronic brain injuries.

Conclusion According to these results, we can say that the heading in soccer does not cause pituitary dysfunction as in boxing and other combat sports. However, one should be alert in that the head traumas that cause loss of consciousness in retired soccer players may lead GH deficiency.

Acknowledgements This study was supported by Erciyes University Scientific Research Project Commission (TCD-2014-5459).