Prevalence and pattern of cognitive impairment in rural and urban populations from Northern Portugal

Abstract

BackgroundDespite worldwide recognition of the burden of dementia, no epidemiological data is yet available in Portugal. The objective of this study is to estimate the prevalence and describe the pattern of cognitive impairment with dementia or no dementia (CIND) in rural and urban populations from Northern Portugal.MethodsTwo random samples of residents aged 55 to 79 years in rural and urban communities were drawn from the health centres registries to be screened for cognitive impairment. The screening criteria for dementia were an abnormal Mini-Mental State Examination (MMSE) score or a Blessed Dementia Scale score. After excluding those who tested positive for dementia, cut-off points for CIND were set at 1 standard deviation below the mean of the MMSE according to educational level. All those who screened positive either for dementia or CIND were examined by a neurologist for establishing a definitive diagnosis.ResultsThe prevalence of cognitive impairment was higher in rural than in urban populations, 16.8% (95% CI: 14.3-19.8%) vs. 12.0% (95%CI: 9.3-15.4%), with a rural/urban prevalence ratio (PR) of 2.16 (95% CI: 1.04-4.50) in the eldest and 2.19 (95% CI: 1.01-4.76) in persons with vascular risk factors. The prevalence of dementia was 2.7% (95% CI: 1.9-3.8%) with a rural/urban PR = 2.1 and the prevalence of CIND was 12.3% (95% CI: 10.4-14.4%) and PR = 1.3. The prevalence of dementia increases exponentially with age and in those with cerebrovascular disease or other comorbid conditions while the prevalence of CIND, besides these factors, is also higher in persons with low levels of education or vascular risk factors. Alzheimer's and vascular disease were equally likely aetiologies of dementia (38.7%), the later more common in men PR(F:M = 0.3) as opposed to the former PR(F:M = 2.0). Vascular CIND, associated either with cerebrovascular disease or vascular risk factors was more frequent (39.7%) then depression (18.4%) or any other aetiology.ConclusionsThe prevalence of cognitive impairment is higher in rural compared with urban populations. This is shown in the synergy between age and rurality, with the rural/urban prevalence ratio increasing with age. In this relatively young population from Northern Portugal, cerebrovascular disease as well as vascular risk factors account for 48% of overall cognitive impairment.

Prevalence of cognitive impairment and related risk factors incommunity-dwelling elderly in Kayseri, Turkey

“…Although mean MMSE score was found to be 26.2 and the frequency of CImp was 26.1% in comparison of the distribution of CImp between certain age groups, the odds ratio of CImp after 75 years was higher than that between 60 and 64 years ( Table 2). CImp risk increases with age and it is more prevalent in females compared with males (1,19,20,25,(33)(34)(35). Our results confirm this finding from other studies, and although the rate of CImp in females is similar, prevalence of CImp in our study is higher than other studies in both sexes (males: 20.6%, females: 31.5%).…”

“…The wide range of CImp prevalence both in local and international studies may be related to the characteristics of study samples and local parameters, such as geographic location and socioeconomic status (25). Since the distribution of income in the general population is similar within our sample (Table 1), our results can be extended to the broader Turkish population.…”

Epidemiologia da Demência e da Doença de Alzheimer em Portugal: Estimativas da Prevalência e dos Encargos Financeiros com a Medicação

“…O valor obtido de prevalência de 5,91% é também superior à taxa de 2,7% sugerida no único estudo de base populacional efectuado em Portugal até à data. 27,28 Deve no entanto salientar-se que Nunes e colaboradores restringiram o seu estudo a uma faixa populacional entre os 55 e os 79 anos de idade, excluindo muito idosos e, de acordo com a nossa estimativa, é nos grupos etários acima dos 80 anos que se encontram mais de 64% das pessoas com demência.…”

Post-Stroke Cognitive Impairment – Phenomenology and Prognostic Factors

“…4,30 Low education level has also been announced as an independent predictor of post-stroke dementia. 3,27 The risk of dementia is significantly higher in patients with a history of cognitive deficit before stroke onset. 30,44,45 According to the Sydney Stroke Study 21 , cerebrovascular risk factors are not independent predictors of post-stroke cognitive impairment.…”

“…The frequency of vascular dementia doubles every 5.3 years, 26 and is twice as frequent in patients with a low level of education. 27 The incidence of post-stroke dementia is 6.7% in the age range 60-64 years and 26.5% in patients over 85 years of age 4,28,29 Data concerning genderrelated prevalence of post-stroke cognitive impairments are contradictory. 4,13,30 Regardless of the great variations in the incidence and epidemiology of post-stroke dementia, data from longitudinal studies confirm the higher risk of developing cognitive impairment after stroke.…”