UNIFAI, Instituto de Ciências Biomêdicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal.
BMC Neurol. 2010 Jun 11;10:42. doi: 10.1186/1471-2377-10-42.
Despite 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.
Two 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.
The 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.
The 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.
尽管痴呆症的负担在全球范围内得到了认可，但葡萄牙仍缺乏相关的流行病学数据。本研究的目的是评估葡萄牙北部农村和城市人群中痴呆症或无痴呆症（CIND）的患病率，并描述其认知障碍模式。
从农村和城市社区的卫生中心登记处抽取了年龄在 55 至 79 岁之间的两个随机样本，对其进行认知障碍筛查。痴呆症的筛查标准是简易精神状态检查（MMSE）异常或Blessed 痴呆量表评分异常。在排除那些对痴呆症检测呈阳性的人群后，根据教育水平，将 CIND 的截断值设定为 MMSE 平均值减去 1 个标准差。所有筛查出痴呆症或 CIND 阳性的人都由神经科医生进行检查，以确定明确的诊断。
农村人群的认知障碍患病率高于城市人群，分别为 16.8%（95%CI：14.3-19.8%）和 12.0%（95%CI：9.3-15.4%），农村/城市的患病率比值（PR）在年龄最大的人群中为 2.16（95%CI：1.04-4.50），在有血管危险因素的人群中为 2.19（95%CI：1.01-4.76）。痴呆症的患病率为 2.7%（95%CI：1.9-3.8%），农村/城市 PR = 2.1，CIND 的患病率为 12.3%（95%CI：10.4-14.4%），PR = 1.3。痴呆症的患病率随年龄呈指数增长，且在有脑血管疾病或其他合并症的人群中更高，而 CIND 的患病率除了这些因素外，在受教育程度较低或有血管危险因素的人群中也更高。阿尔茨海默病和血管性疾病是痴呆症的同等病因（38.7%），后者在男性中更为常见（PR（F：M）= 0.3），而前者的 PR（F：M）= 2.0。与脑血管疾病或血管危险因素相关的血管性 CIND 更为常见（39.7%），而抑郁（18.4%）或任何其他病因则较少见。
与城市人群相比，农村人群的认知障碍患病率更高。这在年龄和农村地区之间的协同作用中得到了体现，农村/城市的患病率比值随年龄增长而增加。在葡萄牙北部这个相对年轻的人群中，脑血管疾病以及血管危险因素占总体认知障碍的 48%。
