B. Cross-sectional studies.
| First Author, Publication Year, [Reference No.] | Study | Subjects | Exposure Assessment | Outcome Assessment | Adjustment for Potential Confounders | Main Findings | Quality Assessment | |||
|---|---|---|---|---|---|---|---|---|---|---|
| STROBE Score | Study Quality | |||||||||
| Xu H, 2018 [13] | CLAS, China, 2011–2012. | 1003 of randomly selected 4411 residents from 20 target communities in the eastern, mid, and western parts of China, aged ≥60. | Unclear (reviewed type of tea consumed with frequency of tea consumption). |
aMCI diagnostic criteria reported by Petersen with MMSE, MoCA, ADL, GDS, HIS, and MRI scans. | Education. | Green tea consumption | MCI OR (95% CI) | p | 11 | Low |
| All male | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.657 (0.46–0.93) | 0.019 | ||||||||
| 55–69 years male | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.376 (0.20–0.70) | 0.002 | ||||||||
| 70–79 years male | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.802 (0.64–1.79) | 0.802 | ||||||||
| ≥80 years male | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.652 (0.28–1.51) | 0.318 | ||||||||
| All female | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.82 (0.58–1.16) | 0.261 | ||||||||
| 55–69 years female | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 1.06 (0.62–1.80) | 0.840 | ||||||||
| 70–79 years female | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.96 (0.56–1.65) | 0.890 | ||||||||
| ≥80 years female | ||||||||||
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.43 (0.18–1.03) | 0.057 | ||||||||
| Lee CY, 2017 [14] | A nationwide, population-based, door-to-door, in-person survey in Taiwan, 2011–2013. | 7964 of 28,600 residents across Taiwan, aged ≥65. | Interview using a structured questionnaire, conducted by well-trained field interviewers according to an operational manual. | All-cause dementia: the core clinical criteria recommended by NIA-AA. | Age, gender, education, BMI, dietary habits, habitual exercises, and co-morbidities, including hypertension, diabetes, and cerebrovascular diseases. | Green tea consumption | All-cause dementia OR (95% CI) | p | 18 | Low |
| Non-consumption | 1 | - | ||||||||
| Consumption | 0.51 (0.34-0.75) | 0.00 | ||||||||
| Kitamura K, 2016 [15] | PROST, Japan, 2008–2014. | 1143 of 2161 patient registry of Sado General Hospital, aged ≥40, not undergoing kidney dialysis. | Self-administered questionnaire of frequency. | Cognitive impairment: MMSE score <24 (MMSE cutoff score of 23/24). | Age, BMI, history of stroke and myocardial infarction, walking time, alcohol, and fruit consumption. | Green tea consumption | Cognitive impairment OR (95% CI) | p | 19 | Low |
| 0 = none, 1 = 1–6 times/wk, 2 = 7 times/wk | 0.83 (0.70–0.98) | 0.032 | ||||||||
| Shen W, 2015 [16] | ZPHS, China, 2014. | 9375 of randomly selected 1500 residents from each of 7 sites in Zhejian province, aged ≥60. | Self-reported frequency/type/volume/preferred concentration in interview by trained researchers. | Cognitive impairment (CCM): MMSE score <18 for illiteracy, <21 for 0–6 years educated, <25 for >6 year educated Cognitive impairment (worldwide): MMSE score <24. |
Age, gender, ethnicity, education, marital status, BMI, WHR, SBP, DBP, income, having children, diabetes/CHD/AD/PD, family diabetes/CHD/AD/PD history, smoking, alcohol drinking, activity, vegetable intake, fruit intake, red meat intake, bean intake, milk intake, supplement use, depression, ADL (all analyses), tea types, tea concentration (Tea consumption volume), tea consumption volume, tea concentration (Tea types), tea consumption volume, and tea types (Tea concentration). | Tea types | Cognitive impairment (CCM) OR (95% CI) | p | 19 | Low |
| Non-consumption | 1 | - | ||||||||
| Green tea | 1.04 (0.72, 1.51) | Not shown | ||||||||
| Kuriyama S, 2006 [17] | Tsurugaya Project, Japan, 2002. | 1103 of 2730 residents of Tsurugaya, aged ≥70, with information on tea consumption, cognitive function, body weight, height, blood glucose, blood pressure, depressive symptoms. | Self-administered semi-quantitative questionnaire. | Cognitive impairment: MMSE score <26. | Age, gender, green tea/black or oolong tea consumption, coffee consumption, diabetes mellitus, hypertension, history of stroke, depressive symptoms, education, visiting friends, energy intake, VC/VE supplementation, and fish intake. | Green tea consumption | Cognitive impairment OR (95% CI) | p for trend | 19 | Low |
| ≤3 cups/w | 1 | 0.0006 | ||||||||
| 4–6 cups/w or 1 cup/d | 0.62 (0.33, 1.19) | |||||||||
| ≥2 cups/d | 0.46 (0.30, 0.72) | |||||||||
STROBE, strengthening the reporting of observational studies in epidemiology statement; AgeCoDe, study on ageing, cognition and dementia in primary care patients; AgeQualiDe, study on needs, health service use, costs, and health-related quality of life in a large sample of oldest-old primary care patients; FU-1, follow-up-1; AD, Alzheimer’s disease; SIDAM, structured interview for the diagnosis of dementias of the Alzheimer type and multi-infarct dementia and dementias of other etiology; BMI, body mass index; APOE ε4, apolipoprotein E ε4; CCI, Charlson comorbidity index; HR, hazard ratio; CI, confidence interval; FFQ, food frequency questionnaire; LTCI, long-term care insurance; MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination; DSM-III-R, Diagnostic and Statistical Manual of Mental Disorders 3rd edition, revised; OR, odds ratio; CLAS, China longitudinal aging study; MoCA, Montreal cognitive assessment; ADL, activities of daily living scale; GDS, global deterioration scale; HIS, Hachinski ischemia scale; MRI, magnetic resonance imaging; aMCI, amnestic mild cognitive impairment; NIA-AA, National Institute on Aging-Alzheimer’s Association workgroups; ZPHS, Zhejiang Major Public Health Surveillance Program; CCM, Chinese cut-off of MMSE; WHR, waist-to-hip ratio; SBP, systolic blood pressure; DBP, diastolic blood pressure; CHD, coronary heart disease; PD, Parkinson’s disease; VC, vitamin C; VD, vitamin D.