title: Midlife vascular risk factors and their association with dementia deaths: results from a Norwegian prospective study followed up for 35 years.
abstract: There is growing evidence that midlife risk factors for vascular disease also are risk factors for dementia, but there is still need for long-term observational studies to address this. Our objective was to investigate the association of midlife vascular disease risk factors with dementia death. Participants were included in The Norwegian Counties Study (NCS) in the period 1974-78, aged 35-50 years at baseline. Information from NCS was linked with the Cause of Death Registry through the year 2009 using the unique personal identification number. The study included 48,793 participants, 1.5 million person years and 486 dementia deaths (187 Alzheimer's; 299 non-Alzheimer's dementia). Cox regression for cause-specific hazards was used. Dementia death was associated with increased total cholesterol levels (>7.80 vs. <5.20 mmol/l: HR=2.01, 95% confidence interval 1.37-2.93); diabetes (HR=2.43, 95% CI 1.40-4.32) and low body mass index (<20 kg/m(2) vs. 20-25 kg/m(2): HR=1.76, 95% CI 1.15-2.68) in midlife. The associations remained after adjustment for other vascular risk factors and educational level. Smoking status or blood pressure in midlife was not significantly associated with risk of dementia death, although the results indicate a possible increased risk in heavy smokers. People suffering from high cholesterol levels, diabetes or underweight in midlife are at increased risk of dying from or with dementia later in life. Our findings add to previous results suggesting that intervention in midlife may be important. To better understand the mechanisms involved in the associations between midlife underweight, diabetes, and elevated cholesterol level and late-life dementia death, these links need to be further investigated.
authors.affiliation: Norwegian Institute of Public Health, Marcus Thranes gt 6, 0473 Oslo, Norway. heine@fhi.no
authors.forename: Bjørn Heine
authors.initials: BH
authors.lastname: Strand
authors.forename: Ellen Melbye
authors.initials: EM
authors.lastname: Langballe
authors.forename: Vidar
authors.initials: V
authors.lastname: Hjellvik
authors.forename: Marte
authors.initials: M
authors.lastname: Handal
authors.forename: Oyvind
authors.initials: O
authors.lastname: Næss
authors.forename: Gunn Peggy
authors.initials: GP
authors.lastname: Knudsen
authors.forename: Helga
authors.initials: H
authors.lastname: Refsum
authors.forename: Kristian
authors.initials: K
authors.lastname: Tambs
authors.forename: Per
authors.initials: P
authors.lastname: Nafstad
authors.forename: Henrik
authors.initials: H
authors.lastname: Schirmer
authors.forename: Astrid Liv Mina
authors.initials: AL
authors.lastname: Bergem
authors.forename: Randi
authors.initials: R
authors.lastname: Selmer
authors.forename: Knut
authors.initials: K
authors.lastname: Engedal
authors.forename: Per
authors.initials: P
authors.lastname: Magnus
authors.forename: Espen
authors.initials: E
authors.lastname: Bjertness
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D002423:Cause of Death; D002784:Cholesterol / Q000097:blood; D016001:Confidence Intervals; D003704:Dementia / Q000401:mortality*; D005260:Female; D006801:Humans; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009664:Norway / Q000453:epidemiology; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014652:Vascular Diseases / Q000453:epidemiology* / Q000401:mortality / Q000523:psychology*
chemical_list: D002784:Cholesterol