Table 3.

Studies on dementia risk factors.

Author	Year	Country	Study design	Outcome measure	Sample size	Setting/sampling tech	Study key findings
Chaaya et al. [29]	2018	Lebanon (Beirut, Shouf, and Aley)	Cross-sectional secondary analysis of Chahine et al. [21]	[1] 10/66 DRG, modified CERAD, animal naming tests modified 10-word list recall, GMS, CSI-D [2] Self-reported on HTN, DM, CVD, smoking, PA [3] 3 consecutive measurements of blood pressures	N = 502	Households Multi-stage cluster sampling	Age: OR 75–84 years = 4.00 (95% CI: 1.46, 10.95); OR 85+ years = 7.07 (1.84, 27.03) compared to age group 64-74 years Perceived insufficient income (vs. sufficient income): OR 3.90 (95% CI: 1.58, 9.60) No formal education (vs. formal education): OR 3.39 (95% CI: 1.71, 6.70) Uncontrolled hypertension (vs. no hypertension): OR 6.35 (95% CI: 1.60, 25.10)
Farrag et al. [17]	1998	Egypt (Assiut Governorate)	3-stage cross-sectional	MMSE Clinical diagnosis Lab investigation	2000	Household, systematic random of total elderly $\text{population\hspace{0.17em}}\underset{¯}{>}60$ years (N = 130,000)	Occupation and residence did not affect the prevalence or severity of dementia Age-specific dementia prevalence tends to double every 5 years after age 75 years and above
Ouanes et al. [24]	2014	Tunis	Cross-sectional	MoCA	77	Manouba nursing home All 116 residents (mean 72.6 years ± 10.3)	Prevalence of dementia did not differ significantly by gender, age, marital status, level of education, profession, current financial situation, or depending on the participation in the activities at the center
El Tallawy et al. [19]	2014	Egypt (Al-Quseir city)	Cross-sectional	MMSE, clinical exam, investigations	8,173 (≥50)	Household All persons (N = 33,285)	Prevalence of dementia significantly higher among illiterate than educated participants (3.6% vs. .79%)
Khedr et al. [20]	2015	Egypt	Cross-sectional	MES and MMSE Neuro exam of all positive cases—DSM-IV, Hachinski ischemic score	691	Household, multistage probability random sampling	CPRs were significantly higher in the following: Illiterate than literate participants (10.12 vs. 2.25 cases per 100 population, p < 0.001) Urban than rural areas (7.1 versus 3.27%, p = 0.03) Industrial than nonindustrial areas (13.23 vs. 1.99; p < 0.001)
Al-Khateeb et al. [30]	2014	Jordan	Case control	MMSE, Clock Drawing Test	102	Senior homes and Jordan University Hospital (52 dementia patients and 50 controls) >60 yrs	Risk for dementia: Educational level < 12 years—OR 3.29 (p = 0.026) Illiterate—OR 6.29 (p = 0.002) compared to education level more than 12 years No significant correlation between serum copper, lipid profile, and cognitive decline in elderly Jordanians Coffee intake has a protective effect against cognitive decline (6.25-fold lower risk)
Alaama et al. [31]	2016	Saudi Arabia (Jeddah)	Cross-sectional	MoCA, RUDAS	241	King Abdulaziz University Hospital volunteers 171 outpatients with DM, matched with 70 controls without DM Age 59.6 ± 9.2 years	Diabetics more likely to have cognitive impairment than nondiabetics (16% vs. 3%; p = 0.004). With MoCA, 85% of the cases and 78% of the controls had abnormal results (p = 0.194). Among diabetics, there was no statistically significant effect found for glycemic control or DM duration on either test
Haithem et al. [32]	2018	Tunisia	Case control		200 dementia patients and 300 controls	—	Association between dementia risk and all the studied polymorphisms except PON1-Q192R was found to be significant APOE e4 allele—OR 4.32 (p = 0.001) ACE I and PON1-L55M T alleles—OR 2.58 and 2.11 (p < 0.001 and p = 0.015) GTICC haplotype associated with 9-fold dementia risk (p < 0.001), whereas AADTT seems to reduce dementia risk by 80% (p = 0.003)
Albugami et al. [3]	2018	Saudi Arabia	Retrospective, cohort	No standardized diagnostic protocol	418	Medical records of patients have dementia at tertiary care hospital from 1995 to 2010 Mean age 78.8	Comorbidities: 27.44% of patients have more than 3 risk factor comorbidities High prevalence of mixed dementia could be related to high prevalence of CVD risk factors like hypertension, dyslipidemia, and diabetes mellitus among Saudis Stroke is reported in 15.03%
Shamieh et al. [34]	2018	Lebanon	Cross-sectional		591 individuals	—	Prevalence of APOE genotypes in Lebanon was similar to that seen in Asian populations APOE genotypes not associated with hypercholesterolemia A significant difference between APOE genotypes in AD cases versus controls and versus Lebanese general population was seen E4 allele was approximately threefold higher in Alzheimer's disease study patients when compared with the remaining individuals

MMSE: modified mini-mental state examination; CPR: crude prevalence rate; VaD: vascular dementia; MES: Memory and Executive Screening test; GDS: Geriatric Depression Scale; NINCDS-ADRDA: National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association; NINDSAIREN: National Institute of Neurological Disorders and Stroke (NINDS) and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences; SMQ: short-memory questionnaire; BCST: Brookdale Cognitive Screening Test; A-IQCODE 16: Arabic Version of 16-item Informant Questionnaire on Cognitive Decline for the older adults; DRG: Dementia Research Group; MoCA: Montreal Cognitive Assessment; GMS: Geriatric Mental State Interview; CERAD: Consortium to Establish a Registry of Alzheimer's Disease; NEUROEX: physical assessment and brief neurological examination; RUDAS: Rowland Universal Dementia Assessment Scale.