Daniel M. Keller, PhD
March 25, 2015
NICE, France — Higher consumption of green tea was associated with a lower risk for dementia or mild cognitive impairment (MCI), even after possible confounding factors were considered, a Japanese study shows. Black tea or coffee did not show the same effect.
Researchers led by Moeko Noguchi-Shinohara, MD, from Kanazawa University Graduate School of Medical Science in Japan, conducted a population-based, prospective study of residents of Nakajima older than age 60 years, starting with participants with normal cognitive function in 2007-2008 as evaluated by using the Mini-Mental State Examination (MMSE) and the Clinical Dementia Rating (CDR) scale.
The investigators reported these results here at AD/PD 2015: International Conference on Alzheimer’s and Parkinson’s Diseases.
Participants’ consumption of green tea, black tea, and coffee was assessed at baseline, at which point various blood tests were also performed, including determination of ApoE genotype.
Of the 723 starting participants, 490 completed a follow-up survey in 2011–2013. Participants were excluded from the final analysis if they had moved or died, had not completed the final questionnaire, or were lost to follow-up.
Participants were stratified according to how often they drank green tea: not at all, 1 to 6 days/week, or every day.
The groups did not differ by gender; ApoE ε4 status; hypertension, hyperlipidemia, or diabetes at baseline; or smoking status, alcohol use, or coffee consumption.
But there were some significant differences. Notably, non–green tea drinkers had slightly lower MMSE scores (higher is better) although still within the range of normal cognition. They also had fewer years of education and hobbies and less physical activity….