Serum α-linolenic and other ω-3 fatty acids, and risk of disabling dementia: Community-based nested case-control study.
It has been hypothesized that ω-3 polyunsaturated fatty acids have anti-atherosclerotic and neuronal protective functions and may benefit prevention of dementia, but the epidemiological evidence, especially for α-linolenic acid, is quite limited. The aim of this study was to examine whether serum ω-3 polyunsaturated fatty acids are associated with risk of dementia.



We performed an intracohort case-control study nested in a community-based cohort, the Circulatory Risk in Communities Study, involving 7586 Japanese individuals aged 40-74 years at the baseline period of 1984-1994. Omega-3 polyunsaturated fatty acid constituents (α-linolenic, eicosapentaenoic, and docosahexaenoic acids) in serum total lipid were measured in 315 cases of incident disabling dementia in the above-mentioned cohort between 1999 and 2004, and in 630 controls whose age, sex, area, and baseline year were matched with the cases.



As we had postulated, serum α-linolenic acid was inversely associated with risk of disabling dementia: the multivariate odds ratios (95% confidence intervals) were 0.57 (0.39-0.85), 0.51 (0.34-0.76), and 0.61 (0.41-0.90) for persons with the second, third, and highest quartiles of serum α-linolenic acid, respectively, as compared with the lowest quartile (P for trend = 0.01). Associations of other ω-3 fatty acids with disabling dementia were not statistically significant.



Serum α-linolenic acid was inversely associated with risk of disabling dementia. Although the causality needs to be confirmed by randomized control trials, we identified serum α-linolenic acid as a biomarker that predicts future dementia.
Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan; Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan. Electronic address: yamagishi.kazumas.ge@u.tsukuba.ac.jp.
Kazumasa
K
Yamagishi
Department of Public Health, Juntendo University, Tokyo, Japan.
Ai
A
Ikeda
Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan; Health Services and Systems Research, Duke-National University of Singapore Graduate Medical School, Singapore, Singapore.
Choy-Lye
CL
Chei
Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
Hiroyuki
H
Noda
Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan; Department of Public Health, Dokkyo Medical University, Mibu, Japan.
Mitsumasa
M
Umesawa
Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
Renzhe
R
Cui
Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan.
Isao
I
Muraki
Department of Epidemiology, Fukushima Medical University, Fukushima, Japan.
Tetsuya
T
Ohira
Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
Hironori
H
Imano
Department of Public Health Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
Tomoko
T
Sankai
Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan.
Takeo
T
Okada
Department of Public Health, Juntendo University, Tokyo, Japan.
Takeshi
T
Tanigawa
Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan; Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita, Japan; Research Team for Social Participation and Community Health, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
Akihiko
A
Kitamura
Osaka Center for Cancer and Cardiovascular Disease Prevention, Osaka, Japan.
Masahiko
M
Kiyama
Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
Hiroyasu
H
Iso
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D003704:Dementia / Q000097:blood* / Q000175:diagnosis*; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D017962:alpha-Linolenic Acid / Q000097:blood*
D015415:Biomarkers; D015525:Fatty Acids, Omega-3; D017962:alpha-Linolenic Acid
Cognitive dysfunction; Docosahexaenoic acid (DHA); Eicosapentaenoic acid (EPA); Follow-up study; α-Linolenic acid (ALA); ω-3 (n-3) Polyunsaturated fatty acids