Odds Of Essential Tremor Research Articles

The effect of regional white matter hyperintensities on essential tremor subtypes and severity.

To investigate the effect of regional white matter hyperintensities (WMHs) on Essential tremor (ET) subtypes and to explore the association between WMHs load and the severity of motor and non-motor symptoms in patients with ET. A cohort of 176 patients with ET (including 86 patients with pure ET and 90 patients with ET plus) and 91 normal controls (NC) was consecutively recruited. Demographic, clinical, and imaging characteristics were compared between individuals with pure ET, ET plus, and NC. The cross-sectional association among regional WMHs and the severity of tremor and non-motor symptoms were assessed within each group. Compared with the pure ET subgroup, the ET plus subgroup demonstrated higher TETRAS scores, NMSS scores, and lower MMSE scores (all P < 0.05). Periventricular and lobar WMHs' loads of pure ET subgroup intermediated between NC subjects and ET plus subgroup. WMHs in the frontal horn independently increased the odds of ET (OR = 1.784, P < 0.001). The age (P = 0.021), WMHs in the frontal lobe (P = 0.014), and WMHs in the occipital lobe (P = 0.020) showed a significant impact on TETRAS part II scores in the ET plus subgroup. However, only the disease duration was positively associated with TETRAS part II scores in patients with pure ET (P = 0.028). In terms of non-motor symptoms, NMSS scores of total patients with ET were associated with disease duration (P = 0.029), TETRAS part I scores (P = 0.017), and WMH scores in the frontal lobe (P = 0.033). MMSE scores were associated with age (P = 0.027), body mass index (P = 0.006), education level (P < 0.001), and WMHs in the body of the lateral ventricle (P = 0.005). Our results indicated that the WMHs in the frontal horn could lead to an increased risk of developing ET. WMHs may be used to differentiate pure ET and ET plus. Furthermore, WMHs in the frontal and occipital lobes are strong predictors of worse tremor severity in the ET plus subgroup. Regional WMHs are associated with cognitive impairment in patients with ET.

Serious head trauma preceding essential tremor: A population-based study (NEDICES)

BackgroundAn association between head trauma and essential tremor (ET) has not been formally assessed. Our purpose was to assess the association between serious head trauma and ET. MethodsHistory of head trauma was assessed in 274 ET cases and 3201 controls in the Neurological Disorders in Central Spain (NEDICES) study, a population-based study in central Spain. Head trauma was defined as serious only if the subject reported that the trauma resulted in loss of consciousness, hospitalization, or a visit to the emergency department. ResultsThirty-two (11.7%) of 274 ET cases vs. 260 (8.1%) of 3201 controls reported a history of serious head trauma (p=0.04). In an adjusted logistic regression analysis, participants who reported serious head trauma were 52% more likely to have ET (odds ratio [OR] 1.52; 95% confidence interval [CI] 1.02–2.27, p=0.04). The odds of ET increased with increasing age of head trauma: adjusted ORs=1.23 (95% CI 0.43–3.46, p = 0.70) for serious head trauma that occurred before age 18years, adjusted OR=1.49 (95% CI 0.62–3.55, p = 0.37) for serious head trauma between ages 18 to 39years, and adjusted OR=1.61 (95% CI 1.00–2.57, p = 0.04) for serious head trauma at age 40years or older. ConclusionsOur study suggests that serious head trauma, especially when it occurs after 40years, is associated with increased odds of ET. Additional studies are needed to reproduce this novel finding.

White matter hyperintensity burden on magnetic resonance imaging in essential tremor.

Whereas structural abnormalities in the cerebellum have been associated with essential tremor (ET), the contribution of vascular disease via white matter hyperintensities (WMHs) and strokes has not been examined. In this study, we have explored these potential associations and hypothesized that ET would be associated with greater overall WMH volume, greater cerebellar WMH volume, and greater infarct presence. In a cross-sectional magnetic resonance imaging (MRI) study of 540 community-dwelling elderly persons in northern Manhattan, New York, brain measures of total WMH volume and regional WMH volume were derived from T(2)-weighted fluid attenuated inverse recovery-weighted MR images. The presence of cerebral infarcts on MRI was determined as well. Total WMH volume was greater among 33 ET cases than 507 controls in both univariate (OR = 1.41, p = 0.038) and fully adjusted analyses (OR = 1.44, p = 0.03). Cerebellar WMH volume was associated with marginally increased odds of ET in a univariate model (OR = 1.52, p = 0.11) and significantly increased odds in a fully adjusted multivariate model (OR = 1.74, p = 0.049). Temporal lobe WMH volume was associated with significantly increased odds of ET in both univariate (OR = 3.36, p<0.001) and fully adjusted models (OR = 3.73, p<0.001). Large strokes were significantly more common in cases than in controls in unadjusted analyses (OR = 3.04, p = 0.02) and marginally in adjusted analyses (OR = 2.56-2.57, p = 0.045-0.056). The distribution of strokes did not differ by diagnosis. MRI data in this study indicated that ET was associated with greater total WMH volume, greater cerebellar WMH volume and possibly more strokes. Cerebrovascular disease could play a role in the development of ET.

Prevalence of Essential Tremor in a Multiethnic, Community-Based Study in Northern Manhattan, New York, N.Y.

Background: Our aims were to: (1) estimate the prevalence of essential tremor (ET) in a community-based study in northern Manhattan, New York, N.Y., USA; (2) compare prevalence across ethnic groups, and (3) provide prevalence estimates for the oldest old. Methods: This study did not rely on a screening questionnaire. Rather, as part of an in-person neurological evaluation, each participant produced several handwriting samples, from which ET diagnoses were assigned. Results: There were 1,965 participants (76.7 ± 6.9 years, range = 66–102 years); 108 had ET [5.5%, 95% confidence interval (CI) = 4.5–6.5%]. Odds of ET were robustly associated with Hispanic ethnicity versus white ethnicity [odds ratio (OR) = 2.19, 95% CI = 1.03–4.64, p = 0.04] and age (OR = 1.14, 95% CI = 1.03–1.26, p = 0.01), i.e. with every 1 year advance in age, the odds of ET increased by 14%. Prevalence reached 21.7% among the oldest old (age ≥95 years). Conclusions: This study reports a significant ethnic difference in the prevalence of ET. The prevalence of ET was high overall (5.5%) and rose markedly with age so that in the oldest old, more than 1 in 5 individuals had this disease.

Dietary Epidemiology of Essential Tremor: Meat Consumption and Meat Cooking Practices

Background/Aim: Harmane [1-methyl-9H-pyrido(3,4-b)indole] is a tremor-producing neurotoxin. Blood harmane concentrations are elevated in essential tremor (ET) patients for unclear reasons. Potential mechanisms include increased dietary harmane intake (especially through well-cooked meat) or genetic-metabolic factors. We tested the hypothesis that meat consumption and level of meat doneness are higher in ET cases than in controls. Methods: Detailed data were collected using the Lawrence Livermore National Laboratory Meat Questionnaire. Results: Total current meat consumption was greater in men with than without ET (135.3 ± 71.1 vs. 110.6 ± 80.4 g/day, p = 0.03) but not in women with versus without ET (80.6 ± 50.0 vs. 79.3 ± 51.0 g/day, p = 0.76). In an adjusted logistic regression analysis in males, higher total current meat consumption was associated with ET (OR = 1.006, p = 0.04, i.e., with 10 additional g/day of meat, odds of ET increased by 6%). Male cases had higher odds of being in the highest than lowest quartile of total current meat consumption (adjusted OR = 21.36, p = 0.001). Meat doneness level was similar in cases and controls. Conclusion: This study provides evidence of a dietary difference between male ET cases and male controls. The etiological ramifications of these results warrant additional investigation.

Population‐based case–control study of cigarette smoking and essential tremor

Parkinson's disease (PD) is inversely associated with smoking cigarettes. Despite long-standing clinical links between PD and essential tremor (ET), there are surprisingly few data on smoking in ET. We studied whether smoking cigarettes is inversely associated with ET. Using a population-based, case-control design, cigarette smoking habits were assessed in 221 prevalent ET cases (75.5 +/- 7.1 years old) and 663 matched controls (74.6 +/- 7.0 years old). In logistical regression analyses, diagnosis (ET vs. control) was the dependent variable, and cigarette smoking status, the independent variable. Ever smokers were marginally less likely to have ET than were never smokers (22.0% vs. 27.0%, odds ratio [OR] 0.76, 95% confidence interval [CI] 0.55-1.04, P = 0.09). In an analysis that adjusted for confounding factors (drink-years and depressive symptoms), ever smokers were nearly half less likely to have ET than the never smokers (OR 0.58, 95% CI 0.40-0.84, P = 0.004). There was a strong inverse association between pack-years and odds of ET (adjusted OR 0.991, 95% CI 0.984-0.997, P = 0.005, i.e., with every 10 pack-year increase, odds of ET were lowered 10%). Ever smokers in the highest pack-year tertile were one-third as likely to have ET than the never smokers (adjusted OR 0.39, 95% CI 0.22-0.69, P = 0.001). We demonstrated an inverse association between ever smoking and ET. Additional studies are needed to reproduce these findings and assess whether this association is due to a biologically protective effect.

Elevated blood harmane (1-methyl-9H-pyrido[3,4- b]indole) concentrations in essential tremor

Essential tremor (ET) is a widespread late-life neurological disease. Genetic and environmental factors likely play an etiological role. Harmane (1-methyl-9H-pyrido[3,4- b]indole) is a potent tremor-producing neurotoxin. In 2002, we demonstrated elevated blood harmane concentrations in an initial sample of 100 ET cases compared to 100 controls. Between 2002 and 2007, we assembled a new and larger sample of ET cases and controls. We now attempt to replicate our previous findings. Cases and controls were frequency-matched on age, gender, and race. Blood harmane concentrations were quantified by high-performance liquid chromatography. Subjects comprised 150 ET cases and 135 controls (mean age 65.3 ± 15.5 vs. 65.5 ± 14.2 years, p = 0.94). Mean log blood harmane concentration was ∼50% higher in cases than controls (0.50 ± 0.54 g −10/ml vs. 0.35 ± 0.62 g −10/ml, p = 0.038). In a logistic regression analysis, log blood harmane concentration was associated with ET (OR adjusted 1.56, 95% CI 1.01–2.42, p = 0.04), and odds of ET was 1.90 (95% CI 1.07–3.39, p = 0.029) in the highest versus lowest log blood harmane tertile. Log blood harmane was highest in ET cases with familial ET (0.53 ± 0.57 g −10/ml), intermediate in cases with sporadic ET (0.43 ± 0.45 g −10/ml) and lowest in controls (0.35 ± 0.62 g −10/ml) (test for trend, p = 0.026). Blood harmane appears to be elevated in ET. The higher concentrations in familial ET suggests that the mechanism may involve genetic factors.

Interaction between blood lead concentration and δ‐amino‐levulinic acid dehydratase gene polymorphisms increases the odds of essential tremor

Blood lead (BPb) concentrations are elevated in essential tremor (ET) cases. The delta-amino-levulinic acid dehydratase (ALAD) gene codes for ALAD, the principal enzyme involved in lead kinetics. Carriers of the ALAD-2 allele may be more susceptible to lead toxicity. The objective of this study was to test, using a case-control design, whether an interaction between BPb concentration and ALAD allele status increases the odds of ET. Mean log BPb concentration was significantly higher in 63 cases than 101 controls (0.47+/-0.26 vs. 0.35+/-0.25 microg/dl). Eighteen (28.6%) cases vs. 17 (16.8%) controls had an ALAD-2 allele (OR=1.98; 95% CI=0.93--4.21). In an adjusted logistic regression analysis, the interaction term (ALAD allele status x log BPb concentration) was associated with increased odds for ET. In stratified analyses, log BPb concentration was not associated with odds of ET in individuals with two ALAD-1 alleles (OR=2.69; 95% CI=0.61--11.82), but in individuals with an ALAD-2 allele, BPb concentration was significantly associated with odds of ET (OR=80.29; 95% CI=3.08--2,096.36). There was an interaction between BPb concentration and ALAD allele status; the odds of ET were greatly elevated in individuals with both an ALAD-2 allele and an elevated BPb concentration. The presence of increased circulating BPb concentrations along with a greater potential for lead toxicity (ALAD-2 allele) could result in greater cerebellar damage, thereby increasing the risk of developing tremor.

Association between male gender and pediatric essential tremor

Approximately 5% of new essential tremor (ET) cases arise during childhood. The goal of the current report was to examine the possible association between male gender and pediatric ET, using data from 95 pediatric ET cases seen at three medical centers (two in the United States and one in Spain). The odds of ET in our sample of cases were threefold higher in boys compared to girls. Whether this association between male gender and pediatric ET represents a selection bias or a true gender-mediated biological difference in disease expression is not known, although some data support the latter possibility.