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

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.

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.

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.

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.

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.