The aim of this study is to analyse urinary neurotrophin levels in healthy children. Urine samples will be collected at 3 different times of day (morning, noon, and evening) at urge sensation from all age groups of children who gained bladder control, i.e. from 3-18 years of age. Urinary levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) normalised to urinary creatinine will be analysed. Age and daytime related variations will be reported for both boys and girls. These results will contribute to understanding the role of neurotrophins in the physiology of lower urinary tract and pathophysiology of idiopathic and secondary hyperactive bladder in children.

Inclusion Criteria:

• 3-18 years of age
• a unremarkable clinical examination
• a normal voiding pattern
• a minimum of 3 micturitions per day
• informed oral and written consent from the child and both parents/legal guardian

Exclusion Criteria:

• history of urinary tract infection
• diseases of central or peripheral nerve system
• anomalies of lumbosacral region
• chronic diseases
• operative procedures or anomalies of urinary or genital tract
• lower urinary tract symptoms
• constipation
• hypercalcuria
• urolithiasis, depression, eating disorders or cardio-metabolic diseases
• prior use of anticholinergic treatment

We will include a group of healthy children recruited from a primary care clinic.