Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline.
Our objective was to determine whether the consumption of green tea, coffee, or black tea influences the incidence of dementia and mild cognitive impairment (MCI) in older people. We conducted a population-based prospective study with Japanese residents aged >60 years from Nakajima, Japan (the Nakajima Project). Participants received an evaluation of cognitive function and blood tests. The consumption of green tea, coffee, and black tea was also evaluated at baseline. Of 723 participants with normal cognitive function at a baseline survey (2007-2008), 490 completed the follow up survey in 2011-2013. The incidence of dementia during the follow-up period (mean ± SD: 4.9 ± 0.9 years) was 5.3%, and that of MCI was 13.1%. The multiple-adjusted odds ratio for the incidence of overall cognitive decline (dementia or MCI) was 0.32 (95% CI: 0.16-0.64) among individuals who consumed green tea every day and 0.47 (95% CI: 0.25-0.86) among those who consumed green tea 1-6 days per week compared with individuals who did not consume green tea at all. The multiple-adjusted odds ratio for the incidence of dementia was 0.26 (95% CI: 0.06-1.06) among individuals who consumed green tea every day compared with those who did not consume green tea at all. No association was found between coffee or black tea consumption and the incidence of dementia or MCI. Our results indicate that green tea consumption is significantly associated with reduced risk of cognitive decline, even after adjustment for possible confounding factors.
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Moeko
M
Noguchi-Shinohara
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Sohshi
S
Yuki
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Chiaki
C
Dohmoto
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Yoshihisa
Y
Ikeda
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Miharu
M
Samuraki
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Kazuo
K
Iwasa
Department of Physical Therapy, Division of Health Sciences, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Masami
M
Yokogawa
Bishoen Geriatric Health Services Facility, Suzu, Japan.
Kimiko
K
Asai
Department of Neurology, Ioh Hospital, National Hospital Organization, Kanazawa, Japan.
Kiyonobu
K
Komai
Department of Environmental and Preventive Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Hiroyuki
H
Nakamura
Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan.
Masahito
M
Yamada
D000368:Aged; D000369:Aged, 80 and over; D003069:Coffee; D060825:Cognitive Dysfunction / Q000453:epidemiology* / Q000517:prevention & control; D003704:Dementia / Q000453:epidemiology* / Q000517:prevention & control; D004326:Drinking; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D013662:Tea
D003069:Coffee; D013662:Tea