Estimating the risk for conversion from mild cognitive impairment to Alzheimer's disease in an elderly Arab community.

BACKGROUND: Vascular risk factors and lack of formal education may increase the risk of Alzheimer's disease (AD). OBJECTIVE: To determine the contribution of vascular risk factors and education to the risk of mild cognitive impairment (MCI) and AD and to estimate the risk for conversion from MCI to AD. METHODS: This door-to-door survey was performed by an Arab-speaking team in Wadi Ara villages in Israel. All consenting residents aged ≥ 65 years were interviewed for medical history and underwent neurological and cognitive examinations. Individuals were cognitively classified as normal (CN), MCI, AD, vascular dementia, or unclassifiable. MCI patients were re-examined at least one year later to determine conversion to AD. The contributions of age, gender, school years, and vascular risk factors to the probability of conversion were estimated using logistic regression models. RESULTS: Of the 906 participants, 297 (33%) had MCI and 95 (10%) had AD. Older age (p = 0.0008), female gender (p = 0.023), low schooling (p < 0.0001), and hypertension (p = 0.0002) significantly accounted for risk of MCI versus CN, and diabetes was borderline (p = 0.051). The risk of AD versus CN was significantly associated with age (p < 0.0001), female gender (p < 0.0001), low schooling (p = 0.004) and hypertension (p = 0.049). Of the 231 subjects with MCI that were re-examined, 65 converted to AD. CONCLUSIONS: In this population, age, female gender, lack of formal education, and hypertension are risk factors for both AD and MCI. Conversion risk from MCI to AD could be estimated as a function of age, time interval between examinations, and hypertension.

Prayer at midlife is associated with reduced risk of cognitive decline in Arabic women.

Midlife habits may be important for the later development of Alzheimer's disease (AD). We estimated the contribution of midlife prayer to the development of cognitive decline. In a door-to-door survey, residents aged ≥65 years were systematically evaluated in Arabic including medical history, neurological, cognitive examination, and a midlife leisure-activities questionnaire. Praying was assessed by the number of monthly praying hours at midlife. Stepwise logistic regression models were used to evaluate the effect of prayer on the odds of mild cognitive impairment (MCI) and AD versus cognitively normal individuals. Of 935 individuals that were approached, 778 [normal controls (n=448), AD (n=92) and MCI (n=238)] were evaluated. A higher proportion of cognitively normal individuals engaged in prayer at midlife [(87%) versus MCI (71%) or AD (69%) (p<0.0001)]. Since 94% of males engaged in prayer, the effect on cognitive decline could not be assessed in men. Among women, stepwise logistic regression adjusted for age and education, showed that prayer was significantly associated with reduced risk of MCI (p=0.027, OR=0.55, 95% CI 0.33-0.94), but not AD. Among individuals endorsing prayer activity, the amount of prayer was not associated with MCI or AD in either gender. Praying at midlife is associated with lower risk of mild cognitive impairment in women.

High prevalence of mild cognitive impairment and Alzheimer's disease in arabic villages in northern Israel: impact of gender and education.

The prevalence of mild cognitive impairment (MCI) and Alzheimer's disease (AD) have not been well been studied in Arab populations. In a door-to-door study of all residents aged ≥ 65 years in Wadi-Ara, an Arab community in northern Israel, we estimated the prevalence of AD, MCI, and the risk of conversion to AD. Subjects were classified as cognitively normal, MCI, AD, or other based on neurological and cognitive examination (in Arabic). MCI subjects were re-examined (interval ≥ 1 year) to determine conversion to AD and contributions of age, gender, and education to the probability of conversion. Of the 944 participants (96.6% of those approached; 49.4% men), 92 (9.8%) had AD. An unusually high prevalence of MCI (n = 303, 32.1%) was observed. Since the majority of women (77.2%) had no schooling, we estimated the effect of gender on the risk of AD and MCI among subjects without schooling and of school years among men. Among subjects with no schooling (n = 452), age (p = 0.02) and female gender (p < 0.0001) were significant predictors of AD, whereas risk of MCI increased only with age (p = 0.0001). Among men (n = 318), age increased the risk (p < 0.0001), school years reduced the risk of AD (p = 0.039) and similarly for MCI [age (p = 0.0001); school years (p = 0.0007)]. Age (p = 0.013), but not gender or school years, was a significant predictor of conversion from MCI to AD (annual rate 5.7%). The prevalence of MCI and AD are unusually high in Wadi Ara, while the rate of conversion from MCI to AD is low. Yet unidentified genetic factors might underlie this observation.

Mild cognitive impairment is associated with mild parkinsonian signs in a door-to-door study.

Mild cognitive impairment (MCI) and healthy aging have been shown to be associated with mild parkinsonian signs (MPS). We performed a door-to-door observational and follow-up study amongst consenting residents of Wadi Ara Arab villages in northern Israel aged ≥65 years (n=687) to examine whether MPS represent a risk factor for MCI and/or conversion from MCI to Alzheimer's disease (AD). In Phase 1, 223 cognitively normal (CN) and 173 MCI subjects were assessed by interview for medical history, neurological examination, motor part of the Unified Parkinson Disease Rating Scale (mUPDRS) (divided into item-clusters: axial, limb bradykinesia, tremor and rigidity) and cognitive tests. MCI subjects (n=111) were re-evaluated in Phase 2 for conversion to AD at least one year after initial assessment. MCI subjects had a higher frequency of axial dysfunction (8.7% vs. 1.3%) and limb bradykinesia (10.4% vs. 1.3%) than CN subjects (p<0.001, both). Stepwise logistic regression analysis estimating the probability of MCI vs. CN revealed higher mUPDRS (OR =1.19, 95% CI, 1.05 to 1.35, p=0.006) and higher limb bradykinesia scores (OR=1.75, 95% CI, 1.2 to 2.56, p=0.003) and not age as explanatory variables. Presence of MPS did not predict conversion to AD after adjustment for age and time-interval. These results suggest that axial and bradykinetic parkinsonian signs represent risk factors for MCI but MPS may not predict conversion from MCI to AD.

Essential tremor might be less frequent than Parkinson's disease in North Israel Arab villages.

Essential tremor (ET) is much more prevalent than Parkinson's disease (PD) in Western countries. We estimated ET and PD prevalence in Wadi Ara Arabic villages in Northern Israel. In this door-to-door survey, all consenting residents aged >or=65 years were systematically examined by an Arabic speaking team. No prescreening questionnaires were used. A random sample of 900 subjects [437 males, mean age (SD) = 72.6 years (6.6)] of the 2,163 eligible residents were evaluated. Sixteen subjects had an action, intentional tremor. Tremor prevalence was estimated as 1.78% (95% CI 1.1-2.87). Nine of these had another likely cause of tremor. Only 7 patients were diagnosed as ET [prevalence 0.78% (95% CI 0.38-1.6)]. PD was diagnosed in 13 subjects. PD prevalence was 1.44% (95% CI 0.84-2.45). ET is unusually uncommon in this population and possibly even less frequent than PD. The PD prevalence in Wadi Ara is similar to that reported in Western countries.

Education effects on cognitive function in a healthy aged Arab population.

BACKGROUND: The Mini-mental State Examination (MMSE) has not been validated in Arabic speaking populations. The Brookdale Cognitive Screening Test (BCST) has been developed for use in low schooling populations. We investigated the influence of gender, education and occupation in a cognitively normal community sample which was assessed using an Arabic translation of the MMSE and the BCST. METHODS: Cognitively normal subjects (n=266, 59.4% males, mean age (SD): 72.4 (5.5) years) from an Arab community in northern Israel (Wadi Ara) were evaluated. Education was categorized into levels: 1=0-4 years, 2=5-8 years, 3=9-12 years. Effects of gender, education and occupation on MMSE and BCST were analyzed by ANOVA, taking age as a covariate. RESULTS: The mean MMSE score of males [26.3 (4.1)] was higher than that of females [23.6 (4.2) points]. Two-way ANOVA showed a significant interaction between gender and education on MMSE (p=0.0017) and BCST scores (p=0.0002). The effect of gender on MMSE and BCST was significant in education level 1 (p<0.0001, both tests) and level 2 (p<0.05, both tests). For education level 1, MMSE and BCST scores were higher for males, while both scores were higher for females in education level 2. The effect of occupation was not significant for both genders. CONCLUSION: Education and gender influence performance when using the Arabic translation of the MMSE and BCST in cognitively normal elderly. Cognitively normal females with 0-4 years of education scored lower than males. These results should be taken into consideration in the daily use of these instruments in Arabic.

Essential tremor prevalence is low in Arabic villages in Israel: door-to-door neurological examinations.

OBJECTIVE: To estimate the prevalence of essential tremor (ET) in Arabic villages of Wadi Ara. BACKGROUND: The prevalence ET which is higher than Parkinson's disease in North America and Europe, differs according to study population and methodology. Since hospital record based epidemiology carries referral bias and might provide low estimates of ET prevalence, we carried a population based survey. METHODS: This door-to-door survey comprised the Arabic villages of Wadi Ara in Northern Israel. Consecutive residents who agreed to participate in the study and were older than 64 years at prevalence day, underwent neurological examination. Medical and family history, medication and response to medication were recorded. RESULTS: Of the 444 subjects that were approached, 428 agreed to participate in the study (refusal rate 3.6%). Four were excluded owing to severe systemic disease. The study population consisted of 424 subjects (54% men, mean age 74+/-7 years). A clearly oscillatory action tremor of moderate amplitude was observed in 8 patients (age 75+/-7 years). Six patients had another possible cause of tremor. The prevalence of ET was calculated as 1.89% (95% CI 1.76-2.0) when all tremor cases were accepted as possible ET and 0.47% (95 CI 0.43-0.52) when patients with other causes of tremor were excluded. CONCLUSIONS: The prevalence of ET in Arabic villages of Wadi Ara is low.

Association between amantadine and the onset of dementia in Parkinson's disease.

The objective of this study is to compare the occurrence of dementia among Parkinson's disease (PD) patients treated with amantadine (AM group) with those never exposed to it (NoAM group). PD dementia shares neuroanatomical and biochemical similarities with Alzheimer's disease (AD). Memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist has been shown to be beneficial in AD. Memantine is a dimethyl derivative of amantadine, which also possesses NMDA receptor blocking properties. We hypothesized that amantadine could have a beneficial effect on the occurrence of PD dementia. PD patients attending the Movement Disorders Clinics in Hillel Yaffe, Asaf Harofe Medical Centers (Israel) and Pisa (Italy) were included. Taking the onset of dementia as the endpoint, survival curves for AM and NoAM patients were estimated by the Kaplan-Meier method. The study population consisted of 593 patients (age, 69.5 +/- 9.9 years; PD duration, 9.2 +/- 6.0 years; 263 patients (44%) amantadine treated). The endpoint of dementia was reached by 116 patients (20%). PD duration until dementia was significantly longer for AM patients (9.1 +/- 5.7 years) than for NoAM patients (5.9 +/- 4.6 years, P = 0.006). The duration of amantadine exposure positively correlated with PD duration until dementia (P = 0.0001). Survival analysis, taking dementia onset as endpoint, showed slower mental decline in AM patients (Log rank P = 0.0049, Wilcoxon P = 0.0024). Mini-Mental State Examination scores were significantly higher for AM patients than for the NoAM group (P = 0.01). Age of PD onset also significantly influenced the duration of PD until dementia. Amantadine use may delay the onset of dementia in PD patients and may attenuate its severity.