Cerebrovascular disease incidence in central Spain (NEDICES): A population-based prospective study

Health impact assessment of port-sourced air pollution in Barcelona

INTRODUCTION

Air pollution is a major health risk factor. Ports might be an understudied source of air pollution.

METHODS

We conducted a spatial health impact assessment (HIA) of port-sourced air pollution for Barcelona for 2017 at the neighbourhood level. Total NO2 and PM10 and port-sourced NO2, PM10 and PM2.5 concentrations were available through the ADMS-Urban model. Population data, mortality and morbidity data, and risk estimates were obtained. We followed standard HIA methodologies and calculated relative risks and impact fractions for 1.35 million adults living in 73 neighbourhoods.

RESULTS

The city-wide mean total NO2 and PM10 concentrations were 37.88 μg/m3 (range: 19.61-52.17 μg/m3) and 21.68 μg/m3 (range: 17.33-26.69 μg/m3), respectively, of which 7% (range: 2-36%) and 1% (range: 0-7%) were port-sourced, respectively. The mean port-sourced PM2.5 concentration was 0.19 μg/m3 (range: 0.06-1.38 μg/m3). We estimated that 1,123 (PI: 0-3,060) and 1,230 (95% CI: 0-2,566) premature deaths were attributable to total NO2 and PM10, respectively, of which 8.1% (91; PI: 0-264) and 1.1% (13; 95% CI 0-29) were attributable to port-sourced NO2 and PM10, respectively. 20 (95% CI: 15-26) premature deaths were attributable to port-sourced PM2.5. Additionally, a considerable morbidity burden and losses in life expectancy were attributable to port-sourced air pollution. Neighbourhoods closest to the port in the south-east were most adversely affected, gradually decreasing towards the north-west.

CONCLUSIONS

The port is an understudied air pollution source in Barcelona with strong health impacts. Cities need local insight into health risk factors, their sources, attributable burdens and distributions for defining targeted policies.

Reported head trauma and odds of acute ischemic stroke or transient ischemic attack: A population-based study (NEDICES)

BACKGROUND

Six previous observational studies have found a higher risk for stroke among traumatic head injury survivors. However, these studies have used record linkage systems, which could lead to underestimating stroke numbers. This study aims to reexamine the relationship between head trauma and the risk of ischemic stroke/transient ischemic attack (TIA) in an older population using data from the Neurological Disorders in Central Spain (NEDICES) study, a population-based study that includes rigorous clinical examinations for patients with suspected neurological diseases.

METHODS

We asked participants if they had ever experienced head trauma that was severe enough to warrant a consult with a physician, leading, among others, to visiting the emergency room, hospitalization, or resulting in loss of consciousness. The history of head trauma was evaluated in 196 (5.7%) acute ischemic stroke/TIA cases and 3256 controls in the NEDICES study.

RESULTS

Among the final sample of 3452 participants, 354 (10.3%) subjects had a history of head trauma. Twenty-nine (14.8%) of 196 acute ischemic stroke/TIA cases vs. 325 (10.0%) of 3256 controls reported a history of head trauma (p = 0.039). In a regression analysis that adjusted for several variables (age in years, sex, educational level, ever smoker, ever drinker, diabetes mellitus, arterial hypertension, and heart disease), the odds ratio was 1.54 (95% CI = 1.02-2.35, p = 0.042).

CONCLUSIONS

The reported head injury was associated with a 54% higher probability of acute ischemic stroke/TIA. More research is needed to confirm these findings, especially using population-based longitudinal studies.

Neurological Disorders in Central Spain, Second Survey: Feasibility Pilot Observational Study

Background

The Neurological Disorders in Central Spain, second survey (NEDICES-2) is a population-based, closed-cohort study that will include over 8000 subjects aged ≥55 years. It will also include a biobank.

Objective

The objective of this study was to evaluate all major aspects of the NEDICES-2 (methods, database, screening instruments, and questionnaires, as well as interexpert rating of the neurological diagnoses) in each one of the planned areas (all of them in central Spain) and to test the possibility of obtaining biological samples from each participant.

Methods

A selection of patients and participants of the planned NEDICES-2 underwent face-to-face interviews including a comprehensive questionnaire on demographics, current medications, medical conditions, and lifestyle habits. Biological samples (blood, saliva, urine, and hair) were also obtained. Furthermore, every participant was examined by a neurologist.

Results

In this pilot study, 567 study participants were enrolled (196 from hospitals and 371 from primary care physician lists). Of these 567, 310 completed all study procedures (questionnaires and the neurological evaluation). The study was time-consuming for several primary care physicians. Hence, a few primary care physicians from some areas refused to participate, which led to a reconfiguration of study areas. In addition, the central biobank needed to be supplemented by the biobanks of local Spanish National Health System hospitals.

Conclusions

Population-based epidemiological surveys, such as the NEDICES-2, require a pilot study to evaluate the feasibility of all aspects of a future field study (population selection, methods and instruments to be used, neurological diagnosis agreement, and data collection).

Health impacts related to urban and transport planning: A burden of disease assessment

INTRODUCTION

Until now, estimates of the Global Burden of Disease (GBD) have mainly been produced on national or regional levels. These general estimates, however, are less useful for city governments who have to take decisions on local scales. To address this gap, we focused on the city-level burden of disease (BD) due to exposures affected by urban and transport planning. We conducted a BD assessment using the Urban and Transport Planning Health Impact Assessment (UTOPHIA) tool to estimate annual preventable morbidity and disability-adjusted life-years (DALYs) under compliance with international exposure recommendations for physical activity (PA), exposure to air pollution, noise, heat, and access to green spaces in Barcelona, Spain.

METHODS

Exposure estimates and morbidity data were available for 1,357,361 Barcelona residents ≥20years (2012). We compared recommended with current exposure levels to estimate the associated BD. We quantified associations between exposures and morbidities and calculated population attributable fractions to estimate the number of attributable cases. We calculated DALYs using GBD Study 2015 background DALY estimates for Spain, which were scaled to Barcelona considering differences in population size, age and sex structures. We also estimated annual health costs that could be avoided under compliance with exposure recommendations.

RESULTS

Not complying with recommended levels for PA, air pollution, noise, heat and access to green spaces was estimated to generate a large morbidity burden and resulted in 52,001 DALYs (95% CI: 42,866-61,136) in Barcelona each year (13% of all annual DALYs). From this BD 36% (i.e. 18,951 DALYs) was due to traffic noise with sleep disturbance and annoyance contributing largely (i.e. 10,548 DALYs). Non-compliance was estimated to result in direct health costs of 20.10 million € (95% CI: 15.36-24.83) annually.

CONCLUSIONS

Non-compliance of international exposure recommendations was estimated to result in a considerable BD and in substantial economic expenditure each year in Barcelona. Our findings suggest that (1) the reduction of motor traffic together with the promotion of active transport and (2) the provision of green infrastructure would result in a considerable BD avoided and substantial savings to the public health care system, as these measures can provide mitigation of noise, air pollution and heat as well as opportunities for PA promotion.

Performance on Specific Cognitive Domains and Cause of Death: A Prospective Population-Based Study in Non-Demented Older Adults (NEDICES)

Evidence regarding the relationship between performance on specific cognitive domains and cause of death is scarce. We assessed whether specific cognitive domains predicted mortality and the presence of any association with specific causes of death in a population-dwelling sample of non-demented older adults. In this population-based, prospective study (NEDICES), 2,390 non-demented subjects ≥65 years completed a brief neuropsychological battery. Cox's proportional hazards models, adjusted by sociodemographic and comorbidity factors, global cognitive performance, educational level, and premorbid intelligence were used to assess the risk of death. Participants were followed for a median of 9.2 years (range 0.01-10.7), after which the death certificates of those who died were examined. 880 (36.8%) of 2,390 participants died over a median follow-up of 5.5 years (range 0.01-10.5). Using adjusted Cox regression models, we found that hazard ratios for mortality in participants within the lowest tertiles (worse performance) were 1.31 (speed of cognitive processing, p = 0.03); 1.22 (semantic fluency, p = 0.04), 1.32 (delayed free recall, p = 0.003), and 1.23 (delayed logical memory, p = 0.03). Poor performance on delayed recall and speed of cognitive processing tests were associated with dementia and cerebrovascular disease mortality, respectively. Further, poor performance on semantic fluency was associated with decreased cancer mortality. In this study of community dwelling non-demented older adults, worse neuropsychological performance was associated with increased risk of mortality. Performance on specific cognitive domains were related to different causes of death. Of particular note there appears to be an inverse association between poor semantic fluency and cancer mortality.

Education and risk of incident dementia during the premotor and motor phases of essential tremor (NEDICES)

Individuals with late-onset essential tremor (ET) (e.g., older adults) seem to have an increased prevalence of mild cognitive impairment and dementia, and a higher risk of incident dementia. It is well-known that education has a protective role against dementia in individuals without a pre-existing neurologic disorder, but evidence regarding the maintenance of this effect during the premotor and motor phases of ET is unknown. Our aim was to determine the influence of education on the risk of dementia in a population-based cohort of ET patients and controls. In a prospective study (Neurological Disorders in Central Spain), participants ≥65 years old were evaluated twice: at baseline (1994-1995) and at follow-up (1997-1998). There were 3 groups: premotor (i.e., participants first diagnosed with incident ET at follow-up), prevalent ET (i.e., participants diagnosed with ET at baseline and at follow-up), and controls. Participants were stratified into lower education (≤primary studies) versus higher education (≥secondary studies) categories. Dementia risk was estimated using Cox proportional-hazards models (higher education control group = reference category). Among the participants, 3878 had a mean duration of follow-up of 3.2 years. Eight (16.7%) of 48 lower education premotor ET patients developed incident dementia versus 1 (3.3%) of 30 higher education premotor ET patients, 9 (7.1%) of 126 lower education prevalent ET patients, 7 (8.8%) of 80 higher education prevalent ET patients, and 92 (4.9%) of 1892 lower education controls (P < 0.001). In comparison to the higher education controls, the adjusted hazard ratios for incident dementia were 5.84 (lower education premotor ET, P < 0.001); 1.36 (higher education premotor ET, P = 0.76); 2.13 (lower education prevalent ET, P = 0.04); 2.79 (higher education prevalent ET, P = 0.01); and 1.66 (lower education controls, P = 0.01). Our results suggest that a higher educational attainment may ameliorate the risk of incident dementia during the premotor phase of ET, but not in the motor phase.

Symptomatic Atherosclerotic Disease and Decreased Risk of Cancer-Specific Mortality: A Prospective, Population-Based Study (NEDICES)

The few studies that have assessed the association between symptomatic atherosclerotic disease and risk of cancer have had conflicting results. In addition, these studies ascertained participants either from treatment settings (ie, service-based studies) or by using a records linkage system (ie, medical records of patients evaluated at clinics or hospitals) and, therefore, were prone to selection bias. Our purpose was to estimate the risk of cancer mortality in a large population-based sample of elderly people, comparing participants with symptomatic atherosclerotic disease (atherosclerotic stroke and coronary disease) to their counterparts without symptomatic atherosclerotic disease (ie, controls) in the same population.In this population-based, prospective study (Neurological Disorders of Central Spain, NEDICES), 5262 elderly community-dwelling participants with and without symptomatic atherosclerotic disease were identified and followed for a median of 12.1 years, after which the death certificates of those who died were reviewed.A total of 2701 (53.3%) of 5262 participants died, including 314 (68.6%) of 458 participants with symptomatic atherosclerotic disease and 2387 (49.7%) of 4804 controls. Cancer mortality was reported significantly less often in those with symptomatic atherosclerotic disease (15.6%) than in controls (25.6%) (P < 0.001). In an unadjusted Cox model, risk of cancer-specific mortality was decreased in participants with symptomatic atherosclerotic disease (HR = 0.74, 95% confidence interval [CI], 0.55-0.98, P = 0.04) vs. those without symptomatic atherosclerotic disease (reference group). In an adjusted Cox model, HR = 0.58; 95% CI, 0.38-0.89; P = 0.01.This population-based, prospective study suggests that there is an inverse association between symptomatic atherosclerotic disease and risk of cancer mortality.

Self-rated health and risk of incident essential tremor: A prospective, population-based study (NEDICES)

BACKGROUND

Essential tremor (ET), a highly-prevalent, progressive, aging-associated neurological disease, poses a significant public health challenge. Aside from its associated motor features, the disease affects cognition in some patients, mood, and morale, and has been associated with increased risk of mortality in the elderly. Studies have not investigated the relationship between self-rated health and risk of ET. We determined whether baseline poor self-rated health was associated with increased risk of incident ET.

METHODS

In this prospective, population-based study of people ≥65 years of age, subjects were evaluated at baseline and 3 years later. At baseline, subjects were asked to rate their health using a single-item health question. Hazard ratios (HR) of ET according to baseline self-rated health (very good, good, fair, poor, and very poor) were estimated with Cox models.

RESULTS

The 3853 subjects had a median follow-up duration of 3.2 years. There were 82 incident ET cases. Compared to subjects who rated their health as good or very good, the risk of ET was increased for subjects who rated their health as fair (HR = 1.69, p = 0.03), and for subjects who rated their health as poor or very poor (HR = 2.12, p = 0.02). In a fully adjusted model, the risk remained increased for subjects who rated their health as poor or very poor (HR = 2.34, p = 0.01).

CONCLUSIONS

Subjects rating their health as poor/very poor at baseline were at increased risk of incident ET at follow-up. Premotor and/or early motor symptoms of ET could negatively influence self-perceptions of health status.

Polypharmacy in the Elderly: A Marker of Increased Risk of Mortality in a Population-Based Prospective Study (NEDICES)

BACKGROUND

Little information is available on the potential association between polypharmacy and risk of mortality.

OBJECTIVE

To determine in a population-based study whether polypharmacy is associated with increased risk of mortality in elderly persons.

METHODS

In this population-based, prospective study of 5,052 people aged 65 years and older (Neurological Disorders in Central Spain), current medications were recorded. Cox proportional hazards models, adjusted for sociodemographics and comorbidity factors, were used to assess the risk of death up to 13.3 years later, comparing the polypharmacy group (≥6 drugs) to those who were taking 1-5 drugs and those in a nonmedicated group (0 drugs).

RESULTS

Out of 5,052 participants, 2,550 (50.5%) died over a median follow-up of 6.5 years, including 361 (28.8%) deaths among 931 nonmedicated participants, 1,946 (51.4%) deaths among 3,787 participants taking 1-5 drugs daily, and 243 (72.8%) among 334 participants on polypharmacy. In an unadjusted Cox model, risk of mortality was increased in participants on polypharmacy [hazard ratio (HR) = 2.78, 95% confidence interval [CI]: 2.36-3.27, p < 0.001) and in those taking between 1 and 5 drugs (HR = 1.47, 95% CI: 1.31-1.64, p < 0.001) versus those who were nonmedicated (reference group). In a Cox model that adjusted for a variety of demographic factors and comorbidities, HR remained increased in participants on polypharmacy (HR = 1.83, 95% CI: 1.51-2.21, p < 0.001).

CONCLUSION

This study provides evidence that polypharmacy is associated with increased risk of mortality in elderly people. The extent to which polypharmacy is the proximate cause rather than a marker of this increase risk remains to be determined.

Long sleep duration in elders without dementia increases risk of dementia mortality (NEDICES)

OBJECTIVE

To determine in a population-based study whether long sleep duration was associated with increased risk of dementia mortality.

METHODS

In this prospective, population-based study of 3,857 people without dementia aged 65 years and older (NEDICES [Neurological Disorders in Central Spain]), participants reported their daily sleep duration. The average daily total sleep duration was grouped into 3 categories: ≤5 hours (short sleepers), 6-8 hours (reference category), and ≥9 hours (long sleepers). Community-dwelling elders were followed for a median of 12.5 years, after which the death certificates of those who died were examined.

RESULTS

A total of 1,822 (47.2%) of 3,857 participants died, including 201 (11.0%) deaths among short sleepers, 832 (45.7%) among long sleepers, and 789 (43.3%) among those participants in the reference category. Of 1,822 deceased participants, 92 (5.1%) had a dementia condition reported on the death certificate (49 [53.3%] were long sleepers, 36 [39.1%] reported sleeping between 6 and 8 hours, and 7 [7.6%] were short sleepers). In an unadjusted Cox model, risk of dementia-specific mortality was increased in long sleepers (hazard ratio for dementia mortality in long sleepers = 1.58, p = 0.04) when compared with the reference group. In a Cox model that adjusted for numerous demographic factors and comorbidities, the hazard ratio for dementia mortality in long sleepers was 1.63 (p = 0.03).

CONCLUSIONS

Self-reported long sleep duration was associated with 58% increased risk of dementia-specific mortality in this cohort of elders without dementia. Future studies are required to confirm these findings.

Age-period-cohort effects on mortality from cerebrovascular disease in southern Spain

BACKGROUND

The aim of this article is to evaluate the age-period-cohort effects on mortality from cerebrovascular disease in Andalusia (southern Spain) as a whole and in each of its 8 provinces during the period 1981-2008.

METHODS

A population-based ecologic study was conducted. In all, 145,867 deaths were analyzed for individuals between the ages of 15 and 84 years who died in Andalusia in the period of study. A nonlinear regression model was estimated for each gender group and geographic area. The effects of age, year of death, and birth cohort were parameterized using spline smoothing functions.

RESULTS

There is an upward trend in mortality from the age of 25 years. The risk of death was downward for cohorts born after 1896, decreasing after 1970 with steep slope. The analysis of the period effect showed that death rate first declined from 1981 to 1995 and then increased between 1995 and 2000, only to decrease again until 2008.

CONCLUSIONS

There is a similar age-period-cohort effect on male and female mortality from cerebrovascular disease in all the provinces of Andalusia and for Andalusia as a whole. A significant reduction of male and female mortality has been observed during the last decade.

Faster cognitive decline in elders without dementia and decreased risk of cancer mortality: NEDICES Study

OBJECTIVE

To assess whether faster cognitive decline in elders without dementia is associated with decreased risk of cancer mortality.

METHODS

In this population-based, prospective study of 2,627 people without dementia aged 65 years and older (Neurological Disorders in Central Spain), a 37-item version of the Mini-Mental State Examination (37-MMSE) was administered at 2 visits (baseline and follow-up, approximately 3 years later). We divided change in 37-MMSE into tertiles (lower tertile ≥ 2 point improvement in score, higher tertile ≥ 2 point decline in score). Community-dwelling elders were followed for a median of 12.9 years, after which the death certificates of those who died were examined.

RESULTS

A total of 1,003 (38.2%) died, including 339 (33.8%) deaths among participants who were in the higher tertile of 37-MMSE change and 664 (66.2%) deaths among those in the remaining tertiles. Cancer was reported significantly less often in those in the higher tertile of MMSE change (20.6%) than in those in the remaining tertiles (28.6%): in an unadjusted Cox model, hazard ratio for cancer mortality in participants within the higher tertile = 0.75 (p = 0.04) compared with the participants within the remaining tertiles. In a Cox model that adjusted for a variety of demographic factors and comorbidities, hazard ratio for cancer mortality in participants within the higher tertile = 0.70 (p = 0.01).

CONCLUSION

In this population-based, prospective study of community-dwelling elders without dementia, faster cognitive decline was associated with a decreased risk of cancer mortality. Further studies are required to elucidate this inverse association in elders without dementia.

Cognitive decline in short and long sleepers: a prospective population-based study (NEDICES)

BACKGROUND

It is not clear whether cognitive decline progresses more quickly in long sleepers than in short sleepers or than in participants with usual sleep duration. We assessed cognitive decline as a function of self-reported sleep duration in a prospective population-based cohort (NEDICES).

METHODS

Participants were evaluated at baseline and 3 years later. Baseline demographic variables were recorded and participants indicated their daily sleep usual duration as the sum of nighttime sleep and daytime napping. The average daily total usual sleep duration was grouped into three categories: ≤ 5 h (short sleepers), 6-8 h (reference category), and ≥ 9 h (long sleepers). At baseline and at follow-up, a 37-item version of the Mini-Mental State Examination (37-MMSE) was administered.

RESULTS

The final sample, 2715 participants (72.9 ± 6.1 years), comprised 298 (11%) short sleepers, 1086 (40%) long sleepers, and 1331 (49%) in the reference group (6-8 h). During the three year follow-up period, the 37-MMSE declined by 0.5 ± 4.0 points in short sleepers, 0.6 ± 4.3 points in long sleepers, and 0.2 ± 3.8 points in the reference group (p = 0.08). The difference between short sleepers and the reference group was not significant (p = 0.142); however, the difference between long sleepers and the reference group was significant (p = 0.040). In analyses adjusted for baseline age and other potential confounders, this difference remained robust.

CONCLUSIONS

In this study, cognitive test scores among long sleepers declined more rapidly than observed in a reference group. Additional studies are needed to confirm these results.

Health impact assessment of increasing public transport and cycling use in Barcelona: a morbidity and burden of disease approach

OBJECTIVE

Quantify the health impacts on morbidity of reduced car trips and increased public transport and cycling trips.

METHODS

A health impact assessment study of morbidity outcomes related to replacing car trips in Barcelona metropolitan (3,231,458 inhabitants). Through 8 different transport scenarios, the number of cases of disease or injuries related to physical activity, particulate matter air pollution <2.5 μm (PM2.5) and traffic incidents in travelers was estimated. We also estimate PM2.5 exposure and cases of disease in the general population.

RESULTS

A 40% reduction in long-duration car trips substituted by public transport and cycling trips resulted in annual reductions of 127 cases of diabetes, 44 of cardiovascular diseases, 30 of dementia, 16 minor injuries, 0.14 major injuries, 11 of breast cancer and 3 of colon-cancer, amounting to a total reduction of 302 Disability Adjusted Life Years per year in travelers. The reduction in PM2.5 exposure in the general population resulted in annual reductions of 7 cases of low birth weight, 6 of preterm birth, 1 of cardiovascular disease and 1 of lower respiratory tract infection.

CONCLUSIONS

Transport policies to reduce car trips could produce important health benefits in terms of reduced morbidity, particularly for those who take up active transportation.

Rate of cognitive decline during the premotor phase of essential tremor: a prospective study

OBJECTIVE

To characterize the rate of cognitive decline during the premotor phase of essential tremor (ET) in comparison to prevalent ET cases and controls.

METHODS

In this population-based, prospective study of people aged 65 years and older (Neurological Disorders in Central Spain), a 37-item version of the Mini-Mental State Examination was administered at 2 visits (baseline and follow-up, approximately 3 years later). We compared the rate of cognitive decline in 3 groups: prevalent ET cases (i.e., participants diagnosed with ET at baseline and at follow-up), "premotor" ET cases (i.e., participants diagnosed with incident ET at follow-up, but not at baseline), and controls (i.e., participants not diagnosed with ET at baseline or follow-up).

RESULTS

The 2,375 participants included 135 prevalent ET cases, 56 premotor ET cases, and 2,184 controls. During the follow-up period of 3.4 ± 0.5 years (mean ± SD), the 37-item version of the Mini-Mental State Examination declined by 0.7 ± 3.3 points (0.2 ± 1.0 points/year) in prevalent ET cases, 1.1 ± 3.5 points (0.3 ± 1.0 points/year) in premotor ET cases, and 0.1 ± 3.9 points (0.0 ± 1.2 points/year) in controls (p = 0.014). The difference between premotor ET cases and controls was significant (p = 0.046), as was the difference between prevalent ET cases and controls (p = 0.027).

CONCLUSIONS

In this prospective cohort, cognitive test scores in premotor and prevalent ET cases declined at a faster rate than in elders without this disease. A decline in global cognitive function may occur in a premotor phase of ET.

The NEDICES Study: Recent Advances in the Understanding of the Epidemiology of Essential Tremor

BACKGROUND

Essential tremor (ET) is the most common tremor disorder. ET has classically been viewed as a benign monosymptomatic condition. Yet over the past 10 years, a growing body of evidence indicates that this is a progressive condition that is clinically heterogeneous, and may be associated with a variety of different features. Large epidemiological studies such as the Neurological Disorders of Central Spain (NEDICES), a longitudinal, population-based survey, have contributed significantly to the changing view of the disease. Our aim is to review some of the main results of NEDICES within the larger framework of the epidemiology of ET.

METHODS

Data for this review were gathered from all our articles published up to October 2011 regarding NEDICES study and "Essential Tremor".

RESULTS

We have published 18 articles up to October 2011. The prevalence, incidence, and mortality of ET were analyzed in this cohort. In addition, ET was found to be associated with increased frailty and low morale, as well as with a series of non-motor manifestations, including cognitive deficits, mild cognitive impairment, dementia, depressive symptoms, and hearing impairment. Finally, the link between ET and Parkinson's disease (PD) was formally quantified in the NEDICES study, which demonstrated that the risk of developing incident PD was 4.3 times higher in prevalent ET cases than in age-matched controls without ET.

CONCLUSIONS

This review highlights the contributions of NEDICES towards the advancement of current knowledge of the epidemiology and clinical features of ET, and emphasizes the importance of population-based studies towards the understanding of complex, ageing-related diseases.

Premotor cognitive status in a cohort of incident Parkinson disease patients (NEDICES)

BACKGROUND

A variety of symptoms may precede the classical motor features of Parkinson disease (PD). However, it is not known whether cognitive dysfunction precedes the motor phase of PD. We examined whether patients with incident PD had had global cognitive function disturbances three years prior to diagnosis when compared with matched controls in a cohort of community-dwelling subjects.

METHODS

All participants were age 65 years or older (median 76 years) and were enrolled in the Neurological Disorders in Central Spain (NEDICES) study in central Spain. We identified all participants with incident PD (N=23), diagnosed in the follow-up examination (1997-1998), who had performed an expanded 37-item version of the Mini-Mental State Examination (37-MMSE) at the baseline evaluation (1994-1995). These 23 were 1:4 matched to 92 controls.

RESULTS

Baseline 37-MMSE scores were 27.9±4.9 (28) in PD patients and 28.7±6.5 (31) in controls (p=0.212). There were no patient-control differences in orientation, immediate recall, attention and calculation, memory recall, language, or visuospatial copying. In analyses that adjusted for several possible confounding factors, there were no case-control differences.

CONCLUSIONS

In this population-based sample, patients with incident PD did not have evidence of significant global cognitive function disturbances three years prior to their diagnosis when compared with matched controls. Our data suggest that global cognitive dysfunction does not precede the diagnosis of PD.

Methods and design of the baseline survey of the neurological disorders in Salamanca (NEDISA) cohort: a population-based study in Central-Western Spain

BACKGROUND

To describe the design of the baseline assessment of an epidemiological study of elderly persons living in Salamanca, central-western Spain: the Neurological Diseases in Salamanca (NEDISA) study. We assessed the epidemiology of stroke, cognitive disorders, essential tremor (ET), Parkinson's disease (PD) and restless legs syndrome.

METHODS

In phase 1 (February 1 to May 31, 2007), 4 neurologists and 2 trained general physicians examined and performed phlebotomy on all participants. In phase 2 (June 1, 2007, to June 1, 2008), the participants were reexamined and had a complete neuropsychological assessment. Neuroimaging was performed in participants with cognitive disorders, ET and PD.

RESULTS

The registered study population consisted of 1,077 individuals, but 45 people were ineligible (address change, refusals or death), leaving a final sample of 1,032 (95.8%). The main demographic data on the 1,032 participants (408 men, 624 women) are provided.

CONCLUSIONS

Most of the registered study population was enrolled, and this may have been due to the close relationship between NEDISA researchers and the general physicians in the area of study. The NEDISA study will likely improve our knowledge of prevalence rates of the neurological diseases chosen for study as well as the set of risk factors that predispose individuals in Spain to these disorders.