TABLE 4.
Characteristics of the included observational human studies on the DASH diet in relation to cognitive decline, dementia, and AD1
| Authors, year, study name | Study design | Population | Follow- up (y) | Exposure | Outcome | Results | Covariates |
|---|---|---|---|---|---|---|---|
| Blumenthal et al. (2017) (50), US | Cross-sectional | n = 160 (33% men) age: 65.4 sedentary adults aged ≥55 y with cognitive impairment and CVD risk factors | — | FFQ and 4-d food diary, A-MeDi and A-DASH score | Verbal memory (HVLT-R, ANT), visual memory (CFT), and executive function/processing speed (ST, DST, COWA, TMT, DSST, Ruff 2&7 Test) | Higher adherence to the DASH diet was associated with better verbal memory (β: 0.18; P = 0.018), but not with executive function/processing speed (P = 0.569) or visual memory (P = 0.248) | Age, education, sex, ethnicity, total caloric intake,, family history of dementia, and chronic use of anti-inflammatory medications |
| Shakersain et al. (2018) (79), Sweden SNAC-K | Longitudinal | n = 2223 (39% men) age: 69.5 y community residents from Kungsholmen ≥60 y | 6 | 98-item SFFQ, A-MeDi, A-DASH and MIND scores, dietary components | Global cognition (MMSE) | DASH score was not associated with cognitive decline (P = 0.568; PT3vs.T1 = 0.472), nor with risk of MMSE score ≤24 (P = 0.970; PT3vs.T1 = 0.746) | Total caloric intake, age, sex, education, civil status, physical activity, smoking, BMI, vitamin/mineral supplement intake, vascular disorders, diabetes, cancer, depression APOE ε4, and dietary components other than those included in each dietary index |
| Berendsen et al. (2017) (72), US Nurses’ Health Study | Longitudinal | n = 16,144 (0% men) age: 74.3 ywomen ≥70 y | 4.1 | 116-item SFFQ, DASH | Global cognition (TICS and composite score of TICS, EBMT, CF, and DST backward) and verbal memory (immediate and delayed recalls of EBMT and TICS 10-word list) | Higher long-term adherence to the DASH diet was associated with better average global cognition (P-trend = 0.009), verbal memory (P-trend = 0.002), and TICS (P-trend = 0.03), but was not significantly associated with change in global cognition (P-trend = 0.51), verbal memory (P-trend = 0.68), or TICS score (P-trend = 0.98) during follow-up | Age, education, physical activity, caloric intake, alcohol intake, smoking status, multivitamin use, BMI, and history of depression, high blood pressure, hypercholesterolemia, myocardial infarction, and diabetes mellitus |
| Haring et al. (2016) (52), US WHIMS | Longitudinal | n = 6425 (0% men) age: 65–79 y postmenopausal women | 9.11 | FFQ, A-MeDi score and DASH score | MCI (MMSE and battery of neuropsychological tests [animal category, BNT, word list memory task, copying and recalling 4 line drawings, TMT]) | Quintile of DASH score was significantly associated with lower risk of MCI (HRQ5vs.Q1: 0.72; 95% CI: 0.52, 1.02; P-trend = 0.04) | Age, race, education level, WHI hormone trial randomization assignment, baseline 3MS level, smoking status, physical activity, diabetes, hypertension, BMI, family income, depression, history of CVD, and total energy intake |
| Morris et al. (2015) (53), US Rush MAP | Longitudinal | n = 923 (± 24% men) age: 58–98 y people living in retirement communities or senior public housing units | 4.5 | 144-item SFFQ, A-MeDi, A-DASH, and MIND scores | AD (based on NINCDS-ADRDA criteria) | For the DASH diet only the highest tertile of adherence was significantly associated with lower risk of AD (HRT3vs.T1: 0.61; 95% CI: 0.38, 0.97; P-trend = 0.07) | Age, sex, education, Apolipoprotein E ( EAPOE) ε4, participation in cognitively stimulating activities, physical activity, total energy intake, and cardiovascular conditions |
| Tangney et al. (2014) (54), US MAP | Longitudinal | n = 826 (26% men) age: 81.5 y elderly living in Chicago retirement communities and subsidized housing, normal cognitive function | 4.1 | 144-item SFFQ, A-MeDi score, A-DASH score | Global cognition (composite score of 19 tests), episodic memory (logical memory, word list recall, word list recognition, EBS), semantic memory (verbal fluency from CERAD, BNT, 12-item reading test), working memory (DST forward and backward, DO), perceptual speed (SDMT, NC, SNS), and visuospatial ability (JLO, SPM) | Continuous DASH score was significantly associated with slower rate of decline in global cognition (β: 0.007; P = 0.03), episodic memory (β: 0.008; P = 0.04), and semantic memory (β: 0.009; P = 0.02). Tertile of DASH score was only significantly associated with a slower rate of change in global cognition (βT3vs.T1: 0.022; P = 0.04). DASH and MeDi scores were almost as predictive for rate of change of global cognition (standardized β: 2.33 and 2.0, respectively) | Total energy intake, age, sex, education, and cognitive activities |
| Wengreen et al. (2013) (69), US Cache County Study on Memory, Health and Aging | Longitudinal | n = 3580 (± 43% men) age ≥65 y mainly non-Hispanic white | 10.6 | 142-item FFQ, MeDi score, DASH score | Global cognition (3MS) | Higher quintile of DASH score was associated with better average cognition during follow-up (mean differenceQ5vs.Q1: 0.97; P-trend = 0.0001), but was not significantly associated with rate of change of cognitive function | Age, sex, education, BMI, frequency of moderate physical activity, multivitamin and mineral supplement use, history of drinking and smoking, and history of diabetes, heart attack, or stroke |
AD, Alzheimer's disease; A-MeDi, alternate Mediterranean diet; ANT, animal naming test; APOE ε4, apolipoprotein E; BNT, Boston Naming Test; CERAD, Consortium to Establish a Registry for Alzheimer's Disease; CF, category fluency; CFT, complex figure test; COWA, controlled oral word association test; CVD, cardiovascular disease; DASH, Dietary Approaches to Stop Hypertension; DO, digit ordering; DSST, digit symbol substitution test; DST, digit span test; EBMT, East Boston Memory Test; EBS, East Boston Story; HVLT-R, Hopkins Verbal Learning Test-Revised; JLO, judgement of line orientation; MAP, Memory And Aging Project; MCI, mild cognitive impairment; MIND, Mediterranean-DASH Intervention for Neurodegenerative Delay; MMSE, Mini-Mental State Examination; NC, number comparison; NINCDS-ADRDA, National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association; SDMT, Symbol Digit Modalities Test; SFFQ, semi-quantitative FFQ; SNAC-K, Swedish National Study on Aging and Care in Kungsholmen; SNS, Stroop Neuropsychological Screening; SPM, standard progressive matrices; ST, Stroop Test; TICS, Telephone Interview for Cognitive Status; TMT, trail making test; WHI, Women's Health Initiative; WHIMS, Women's Health Initiative Memory Study; 3MS, modified mini-mental state.