LOWERED CIRCANNUAL URINARY MELATONIN CONCENTRATIONS IN EPISODIC CLUSTER HEADACHE

The circannual secretion of melatonin in 14 Swedish and is Italian pat ients suffering from episodic cluster headache was compared with 14 Sw edish and 15 Italian healthy controls matched for sex and age. Overnig ht samples of urine were collected once a month from 8 to 14 months an d kept at -20-degrees-C until analysed with RIA. The melatonin concent rations in nocturnal urine were permanently low in cluster headache an d there was no consistent change of the melatonin concentration in rel ation to cluster periods occurring during the study. There was no defi nitive circannual or infraannual rhythmicity of melatonin in patients or controls. Multiple analysis of variance with repeated measurements showed a significant effect of disease (p < 0.05), but not of time. Se x, geographical location, age, and smoking also had significant effect s (p < 0.001) on the melatonin concentrations. Lower melatonin levels in cluster headache patients than in controls may in part be related t o a larger number of smokers in the patient group. The relation betwee n tobacco use and melatonin should be further studied.