The objective was to determine the complete modern vascular risk factor (VRF) profile of idiopathic normal pressure hydrocephalus (INPH) using a large sample of representative INPH-patients and population-based controls, in order to confirm the impact of vascular disease on INPH pathophysiology.
All shunted INPH-patients in Sweden 2008-2010 were compared to age- and gender-matched population-based controls. Inclusion criteria: 60-85 years and mini mental state estimation ³23. The ten most important modern VRFs as well as cerebrovascular and peripheral vascular disease were prospectively assessed through blood samples, by-protocol clinical examinations and standardized questionnaires. Investigated VRFs: hypertension, hyperlipidemia, diabetes, obesity, psychosocial factors, smoking, diet, alcohol intake, cardiac disease and, physical activity.
After exclusion, 176 INPH-patients and 368 controls participated. Using multivariable logistic regression, hyperlipidemia (OR: 2.380, 95%CI: 1.434-3.950), diabetes (OR: 2.169, 95%CI: 1.195-3.938), obesity (OR: 5.428, 95%CI: 2.502-11.772) and, psychosocial factors (OR: 5.343, 95%CI: 3.219-8.868) were independently associated with INPH. Hypertension, physical inactivity, cerebrovascular and peripheral vascular disease were overrepresented in INPH, although not independently. The protective factors: moderate alcohol intake and physical activity were overrepresented among the controls. The population attributable risk percentage was 24%.
Our findings confirm that INPH-patients have a more dangerous VRF-profile and lack the protective factors present in the population. Almost one quarter of INPH could be explained by VRF, suggesting that INPH possibly may be a subgroup of vascular dementia. Targeted interventions against modifiable VRF are likely to have beneficial effects in INPH.