Abstract: BACKGROUND: A lot of attention has been paid to the relationship of blood pressure and dementia because epidemiological research has reported conflicting evidence. Observational data has shown that midlife hypertension is a risk factor for cognitive decline and dementia later in life, whereas there is evidence that low blood pressure is predictive in later life. The aim of the present study was to examine the association between dementia and blood pressure measured up to 27 years (mean 17.6 years) prior to ascertainment. METHODS: In Nord-Trondelag County, Norway, incident dementia data were collected during 1995-2011, and the diagnoses were validated by a panel of experts in the field. By using the subjects' personal identification numbers, the dementia data were linked to data from the Nord-Trondelag Health Study (the HUNT Study), a large, population-based health study performed in 1984-1986 (HUNT 1) and 1995-1997 (HUNT 2). A total of 24,638 participants of the HUNT Study were included in the present study, 579 of whom were diagnosed with Alzheimer disease, mixed Alzheimer/vascular dementia, or vascular dementia. Multiple logistic regression analyses were conducted to analyze the association between dementia and blood pressure data from HUNT 1 and HUNT 2. RESULTS: Over the age of 60 years, consistent inverse associations were observed between systolic blood pressure and all-cause dementia, mixed Alzheimer/vascular dementia, and Alzheimer disease, but not with vascular dementia, when adjusting for age, sex, education, and other relevant covariates. This was observed for systolic blood pressure in both HUNT 1 and HUNT 2, regardless of antihypertensive medication use. There was an adverse association between systolic blood pressure, pulse pressure, and Alzheimer disease in individuals treated with antihypertensive medication under the age of 60 years. CONCLUSIONS: Our data are in line with those in previous studies demonstrating an inverse association between dementia and systolic blood pressure in individuals over the age of 60 years. We cannot exclude a survival effect, however. Among middle-aged subjects (<60 years), elevated systolic blood pressure and pulse pressure were associated with eventual Alzheimer disease in individuals who reported using antihypertensive medication.

Abstract: BACKGROUND: Headache has not been established as a risk factor for dementia. The aim of this study was to determine whether any headache was associated with subsequent development of vascular dementia (VaD), Alzheimer's disease (AD) or other types of dementia. METHODS: This prospective population-based cohort study used baseline data from the Nord-Trondelag Health Study (HUNT 2) performed during 1995-1997 and, from the same Norwegian county, a register of cases diagnosed with dementia during 1997-2010. Participants aged >/=20 years who responded to headache questions in HUNT 2 were categorized (headache free; with any headache; with migraine; with non-migrainous headache). Hazard ratios (HRs) for later inclusion in the dementia register were estimated using Cox regression analysis. RESULTS: Of 51,383 participants providing headache data in HUNT 2, 378 appeared in the dementia register during the follow-up period. Compared to those who were headache free, participants with any headache had increased risk of VaD ( N = 63) (multivariate-adjusted HR = 2.3, 95% CI 1.4-3.8, P = 0.002) and of mixed dementia (VaD and AD ( N = 52)) (adjusted HR = 2.0, 95% CI 1.1-3.5, P = 0.018). There was no association between any headache and later development of AD ( N = 180). CONCLUSION: In this prospective population-based cohort study, any headache was a risk factor for development of VaD.