Serum IGF-1 is higher in patients with idiopathic normal pressure hydrocephalus than in the population.

Background: Hypopituitarism has been reported in patients with idiopathic normal pressure hydrocephalus (iNPH), which could enhance characteristic symptoms like impaired wakefulness, gait, body balance, and subcortical cognitive deterioration.
Purpose: To compare basal serum levels of pituitary and sex hormones and serum insulin-like growth factor-1 (S-IGF-1) in patients with iNPH and an age-matched control population, and to correlate the preoperative hormone levels with symptoms and signs pre-operatively and three months after surgery.
Methods: A cross-sectional case control design was used. Patients diagnosed with iNPH, n=108 (65 men and 43 women, mean age 72.3 years), were consecutively included during 2006-2011 at Sahlgrenska University Hospital, Gothenburg, Sweden. S-TSH, S-free T4, S-FSH, S-LH, S-prolactin, plasma ACTH, S-testosterone, S-oestradiol and S-IGF-1 were examined. Symptoms and signs were scored using the iNPH scale score. Population controls, n=146, were recruited from the WHO MONICA project, Gothenburg in 2008.
Results: Men and women with iNPH had higher S-IGF-1 than controls (p<0.001). Women with iNPH had lower S-TSH (p=0.016) than controls, but the frequency of levothyroxine substitution was similar. Among men, a higher level of S-IGF-1 was associated with milder symptoms, while higher levels of S-FSH and S-LH were associated with more severe symptoms.
Conclusions: Patients with iNPH did not have lower levels of pituitary or sex hormones but presented with higher levels of S-IGF-1, compared with healthy, age-matched controls. Higher S-IGF-1 in men was related to milder mental and physical symptoms and signs.
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