Epidemiology

Estimated incidence is 3.0 to 5.5 cases per 100,000 people per year, and prevalence estimates range from 0.02% to almost 9%.

In a survey of a rural Bavarian population, NPH prevalence was reported to be 0.4% in people >65 years of age; however, the diagnostic criteria used in this study were not clear.[2] A Norwegian study reported a lower prevalence (0.02%) and an incidence of 5.5 per 100,000 per year; however, the authors noted that these values should be regarded as minimum estimates, and that the prevalence increased with increasing age.[3] In an elderly Japanese rural community-dwelling population, an NPH prevalence estimate of 2.9% among residents has been reported.[4]

A study in patients in the north of Spain estimated a crude incidence rate of NPH for the 10-year period was 3.25 per 100,000 people per year.[5] Another Spanish study estimated the annual incidence rate of NPH at 4.43 per 100,000 people, with the incidence highest in patients aged between 70 to 80 years.[6]

A Swedish study demonstrated a prevalence of 0.2% in patients aged 70-79 years, and 5.9% in those aged 80 years and older.[7] A 2019 study of 1000 randomly selected participants in Jämtland, Sweden, found a prevalence of 2.1% in those aged 65-79 years, and 8.9% in those aged 80 years and older.[8] Between 1996 and 1998, surgery for NPH was undertaken in 1.6 per 100,000 adults in Sweden.[9] As only a minority of patients with NPH are suitable for surgery (partly due to the unwillingness of older adults to undergo cranial surgery, and partly because of associated vascular risk factors), the prevalence of the condition in this population was likely to be many times higher. The condition is estimated to be about five times more common than idiopathic Parkinson's disease.

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