Félix Bermejo-Pareja

Prevalence of essential tremor in three elderly populations of central Spain

Although essential tremor (ET) is considered the most prevalent adult movement disorder, the available information on its prevalence and distribution worldwide is not completely understood. We investigated the prevalence and distribution of ET in three elderly Spanish populations using a door‐to‐door, two‐phase approach. A brief screening instrument was administered on May 1, 1994 to subjects over 64 years old taken from the census of one urban municipality of Greater Madrid (quarter of Margaritas, Getafe), one urban district of Madrid (Lista), and one rural site (Arévalo county, Ávila) (N = 5,278). Study subjects were limited to those who screened positively (N = 472). To increase reliability, each patient was examined by 3 experienced neurologists, and was classified as having ET only when all 3 neurologists agreed (183 of 472). The present study was part of a large‐scale epidemiological survey of neurological diseases, and served as a baseline investigation in a 3‐year incidence study. Accordingly, 41 ET patients were identified when evaluating subjects who had screened positively for dementia, stroke, or parkinsonism, despite the fact that they had screened negatively for tremor; furthermore, 32 additional ET prevalent cases were detected when evaluating subjects who had screened positively for tremor in the second cross‐sectional study (May 1, 1997), although they had screened negatively for tremor in the first cross‐sectional study. We identified 256 persons (152 women, 104 men) with ET; of these, 87 patients (34.0%) reported having an affected relative. Two hundred and four (79.7%) of the subjects with ET were detected through this screening and had not been diagnosed previously. The prevalence of ET was 4.8% (95% CI = 4.2–5.4) for the total population; 4.6% (95% CI = 3.7–5.4) in men and 5.0% (95% CI = 4.2–5.8) in women. Age‐specific prevalence increased with advancing age for both men and women. Despite the variability in worldwide data, ET is a frequently encountered disorder in elderly people. Furthermore, as ET may be seen as a relatively benign condition, a large proportion of patients may never seek neurological attention.

Prevalence of PD and other types of parkinsonism in three elderly populations of central Spain.

The prevalence of Parkinsons disease (PD) and other types of parkinsonism in three elderly populations of central Spain was investigated using a door‐to‐door, two‐phase approach. This design called for the administration of a brief questionnaire to subjects 65 years of age or older taken from the census of one urban municipality of Greater Madrid (Margaritas, Getafe), one rural site (Arévalo County, Ávila), and one urban district of Madrid (Lista) in Spain (N = 5,278). Study neurologists extensively investigated those subjects who screened positively. The diagnoses, based on specified criteria, were reviewed to increase reliability across neurologists. We found 118 subjects with parkinsonism: 81 affected by PD (68.6%), 26 drug‐induced parkinsonism (22.0%), 6 parkinsonism in dementia (5.1%), 3 vascular parkinsonism (2.5%), and 2 unspecified parkinsonism (1.7%). The prevalence was 2.2% (95% confidence interval [CI], 1.8–2.6) for all types of parkinsonism and 1.5% (95% CI, 1.2–1.8) for PD. The prevalence estimates of parkinsonism and PD increased with age, declining at 85 years and over. Age prevalence ratios were higher for men. Twenty‐three subjects (28.4%) of the subjects with PD were detected through the screening and had not been diagnosed previously. Overall prevalence estimates of PD and other types of parkinsonism in central Spain rank at levels similar to those recently reported for other European and non‐European elderly populations. Despite improvement in access to health services, an important proportion of PD patients may never seek neurological attention.

Population-based case-control study of cognitive function in essential tremor

Objectives: To determine whether patients with essential tremor (ET) have cognitive deficits when compared with controls and whether the types of cognitive deficits reported previously are also found in this large sampling of patients with ET. Methods: A total of 232 patients with ET and 696 matched controls age 65 years or older (median 75 years) living in central Spain (the Neurologic Diseases in Central Spain study) underwent a neuropsychological assessment, including tests of global cognitive performance, frontal executive function, verbal fluency, and memory. Subjects also were asked whether they had forgetfulness. Results: Fifty-six patients with ET were previously undiagnosed; only 14 (6%) were taking medication for tremor. Adjusted for age, gender, education, premorbid intelligence, medications, and depressive symptoms, cases performed less well on most neuropsychological tests and especially tests of global cognitive performance (37-item Mini-Mental State Examination = 27.0 ± 6.7 in cases vs 28.9 ± 5.9 in controls, p < 0.001) and frontal executive function (Trail Making Test number of errors = 8.7 ± 11.0 in cases vs 3.8 ± 7.6 in controls, p < 0.001). Forgetfulness was reported in 117 (50.4%) patients with ET vs 300 (43.1%) controls (p = 0.05). Conclusions: In a population-based sample of largely untreated patients with essential tremor, cases performed more poorly on formal neuropsychological testing than did their counterparts without tremor. A complaint of forgetfulness was also marginally more common in patients with essential tremor.

Incidence of Parkinson disease and parkinsonism in three elderly populations of central Spain

Background: A two-phase investigation method (screening followed by detailed examination) is the most accurate epidemiologic approach to estimate the epidemiology of Parkinson disease (PD) and secondary parkinsonism. The scarcity of statistics on the incidence of PD and other types of parkinsonism using this methodology led the authors to estimate them in three elderly populations. Methods: A Spanish elderly parkinsonism-free cohort was followed for an average of 3 years. At the end of the follow-up, the cohort survivors were contacted by way of screening and clinical examination. Results: The cohort consisted of 5,160 subjects (ages 65 to 85 and over): Eight hundred twenty-eight died before the examination, 3,685 completed the screening procedure, and 647 could not be screened because they refused (108) or were unreachable (539). Sixty-eight incident cases of parkinsonism were found: 30 PD (44.1%), 22 drug-induced parkinsonism (32.3%), 8 parkinsonism with associated features (11.7%), and 3 vascular parkinsonism (4.4%). The remaining five cases (7.3%) were classified as unspecified parkinsonism. Average annual incidence rate (per 100,000 person-years) in the population aged 65 to 85 and over years, adjusted to the standard European population, was 409.9 (95% CI 299.0 to 520.8) for parkinsonism and 186.8 (95% CI 110.4 to 263.2) for PD. Incidence rates of parkinsonism increased with advancing age. For PD, incidence rates increased with age in men but decreased beyond the age of 79 in women. Age-adjusted relative risk in men compared with women was 1.56 (95% CI 0.97 to 2.51) for parkinsonism and 2.55 (95% CI 1.21 to 5.37) for PD. Sixteen (53.3%) patients with PD were detected through the screening and had not been diagnosed previously. Conclusions: Incidence estimates of PD based on two-phase investigation methodology are higher than those based on other approaches. Men had a risk of developing PD that was twice that of women. A large proportion of PD patients may never seek neurologic attention.

Risk of incident dementia in essential tremor: A population‐based study

Essential tremor (ET) is a late‐life neurological disease. Mild cognitive deficits as well as an association with prevalent dementia have been reported in recent case–control studies. We determined whether ET was associated with an increased risk of incident dementia. In a population‐based study of older people in central Spain (NEDICES), nondemented ET cases and controls were followed prospectively. Incident dementia at follow‐up was diagnosed using DSM‐IV criteria and the risk of incident dementia was estimated in ET cases versus controls using Cox proportional hazards models. 3,891 participants had a mean duration of follow‐up of 3.2 years. Sixteen (7.8%) of 206 ET cases developed incident dementia versus 145 (3.9%) of 3,685 controls (unadjusted relative risk [RR] = 2.08, 95% CI = 1.24–3.50, P = 0.006 and adjusted RR = 1.66, 95% CI = 0.99–2.80, P = 0.054). In an adjusted model, ET cases with tremor onset after age 65 years were twice as likely to develop incident dementia than were controls (RR = 1.98, 95% CI = 1.14–3.45, P = 0.01), whereas ET cases with tremor onset < age 65 years and controls were equally to develop incident dementia (RR = 0.74, 95% CI = 0.19–3.20, P = 0.79). Although ET is often considered a benign condition, in this prospective, population‐based study, elderly‐onset ET was associated with an increased risk of incident dementia. The basis for this dementia, which is not known, requires additional study.

Incidence and subtypes of dementia in three elderly populations of central Spain.

OBJECTIVE To assess age-, gender, and subtype-specific incidence rates of dementia in three populations in central Spain using data from the Neurological Disorders in Central Spain (NEDICES), a population-based survey of elderly participants. METHODS Individuals were evaluated at baseline (1994-1995) and at follow-up (a median of 3.2 years later in 1997-1998). The evaluation included a screening questionnaire for dementia and a neurological assessment, when possible. RESULTS Of 5278 participants evaluated at baseline, there were 306 prevalent dementia cases. One hundred and sixty-one incident dementia cases were identified among 3,891 individuals assessed at follow-up. The large majority had Alzheimers disease (AD): 115 (71.4%) AD, 18 (11.2%) vascular dementia (VaD), 11 (6.8%) dementia associated with parkinsonism, 11 (6.8%) undetermined etiology, and 6 (3.7%) secondary dementia. Average annual incidence rates (per 1,000 person-years) in the population aged 65 to 90 and over years, adjusted to the standard European population, were 10.6 (95% CI, 8.9 to 12.3) for dementia, 7.4 (95% CI=6.0 to 8.8) for AD, and 1.4 (95% CI=0.6 to 2.3) for VaD. Age-specific incidence rates of dementia and AD increased exponentially with advancing age. Age, stroke and illiteracy were independent risk factors for dementia and AD. Aggregation of vascular risk factors was related to a higher risk of both VaD and AD. CONCLUSIONS In the NEDICES study, incidence of dementia increased with age beyond age 85 and AD was the most frequent type of dementia. The risk of AD and VaD increased with the number of vascular risk factors.

Elderly-onset essential tremor is associated with dementia

Objective: To determine whether essential tremor (ET) is associated with prevalent dementia. Methods: The authors identified all persons with dementia and ET in a population-based study in central Spain (the Neurological Disorders in Central Spain [NEDICES] Study). Dementia was diagnosed using the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) criteria. Results: Thirty-one (11.4%) of 273 ET cases had dementia vs 204 (6.0%) of 3,382 non-ET subjects (controls) (odds ratio [OR] = 2.00, 95% CI = 1.34 to 2.98, p = 0.001). In a model that adjusted for age, stroke, and educational level, OR = 1.35, 95% CI = 0.87 to 2.18, and p = 0.17. In an adjusted model, ET cases with tremor onset after age 65 were 70% more likely to be demented than were controls (OR = 1.70, 95% CI = 1.04 to 2.76, p = 0.03), whereas ET cases with tremor onset at age ≤65 and controls were equally likely to be demented (OR = 0.38, 95% CI = 0.09 to 1.73, p = 0.21). Conclusions: Older-onset essential tremor (ET) was associated with dementia. Prospective studies are required to elucidate the association between ET and dementia.

Risk of incident Parkinson’s disease and parkinsonism in essential tremor: a population based study

Background: A longstanding literature suggests an association between essential tremor (ET) and Parkinson’s disease (PD). However, the risk of incident PD has not been quantified in cases of ET compared with controls. Objective: To estimate the risk of incident PD in a population based cohort study of 3813 older people (including ET cases and controls) in central Spain. Results: After a median of 3.3 years, 12 (5.8%) of 207 ET cases developed parkinsonism compared with 56 (1.6%) of 3606 controls (adjusted relative risk (RR) 3.47, 95% CI 1.82 to 6.59; p<0.001). Six (3.0%) of 201 ET cases developed incident PD versus 24 (0.7%) of 3574 controls (adjusted RR 4.27, 95% CI 1.72 to 10.61; p = 0.002). Conclusions: Patients with ET were four times more likely than controls to develop incident PD during prospective follow-up. These data confirm and begin to quantify the link between these two diseases.

Self‐reported depression and anti‐depressant medication use in essential tremor: cross‐sectional and prospective analyses in a population‐based study

There are few data on the co‐morbidity of essential tremor (ET) with depression. To assess the associations of ET with self‐reported depression and antidepressant medication use. In a population‐based study in central Spain, participants were evaluated at baseline (1994–1995) and 3 years later. Self‐reported depression and use of antidepressant medications were evaluated at each assessment. In cross‐sectional analyses, prevalent ET cases were twice more probably than controls to report depression [103 (43.8%) of 235 cases versus 1137 (26.0%) of 4379 controls; adjusted odds ratio (OR) 2.20, 95% confidence interval (CI) 1.66–2.93, P < 0.001] and three times more probably to be taking antidepressant medications [16 (6.8%) cases versus 113 (2.6%) controls; adjusted OR 3.33, 95% CI 1.91–5.82, P = 0.001]. In prospective analyses, baseline self‐reported depression (adjusted RR 1.78, 95% CI 1.11–2.89, P = 0.018) and, perhaps, baseline use of antidepressant medication (adjusted RR 1.90, 95% CI 0.59–6.05, P = 0.28) were associated with incident ET. Rather than being totally benign, ET seems to be associated with a mood disorder. Furthermore, as well as being a secondary response to disease manifestations, this mood disorder may be a primary feature of the underlying disease.

Prevalence of dementia and major dementia subtypes in Spanish populations: A reanalysis of dementia prevalence surveys, 1990-2008

BackgroundThis study describes the prevalence of dementia and major dementia subtypes in Spanish elderly.MethodsWe identified screening surveys, both published and unpublished, in Spanish populations, which fulfilled specific quality criteria and targeted prevalence of dementia in populations aged 70 years and above. Surveys covering 13 geographically different populations were selected (prevalence period: 1990-2008). Authors of original surveys provided methodological details of their studies through a systematic questionnaire and also raw age-specific data. Prevalence data were compared using direct adjustment and logistic regression.ResultsThe reanalyzed study population (aged 70 year and above) was composed of Central and North-Eastern Spanish sub-populations obtained from 9 surveys and totaled 12,232 persons and 1,194 cases of dementia (707 of Alzheimers disease, 238 of vascular dementia). Results showed high variation in age- and sex-specific prevalence across studies. The reanalyzed prevalence of dementia was significantly higher in women; increased with age, particularly for Alzheimers disease; and displayed a significant geographical variation among men. Prevalence was lowest in surveys reporting participation below 85%, studies referred to urban-mixed populations and populations diagnosed by psychiatrists.ConclusionPrevalence of dementia and Alzheimers disease in Central and North-Eastern Spain is higher in females, increases with age, and displays considerable geographic variation that may be method-related. People suffering from dementia and Alzheimers disease in Spain may approach 600,000 and 400,000 respectively. However, existing studies may not be completely appropriate to infer prevalence of dementia and its subtypes in Spain until surveys in Southern Spain are conducted.