Prevalence of essential tremor in urban Lagos, Nigeria: a door-to-door community-based study

Abstract

BackgroundEssential tremor (ET) is one of the commonest movement disorders though the prevalence varies globally. There is paucity of data on ET prevalence in sub-Saharan Africa. The study aimed to determine the prevalence of ET in a Nigerian community.MethodsThis door-to-door survey was conducted in two stages. In Stage 1, 3000 randomly selected residents of an urban centre in Lagos, Nigeria, were screened using a questionnaire to detect symptoms of movement disorder. 234 participants who responded positively regarding presence of tremors were rescreened using an ET-specific questionnaire, a face-to-face interview and neurological examination. Diagnosis of ET was based on the Movement Disorders Society (MDS) consensus diagnostic criteria for ET.ResultsOf the 3000 participants, forty responded positively to the ET screening questionnaire, of which 36 (19 females and 17 males) had a final diagnosis of ET, giving a crude prevalence of 12 per 1000 (95% CI = 8.1- 15.9). Gender specific prevalence was 10.3 /1000 in males and 14.3/1000 in females. Age specific prevalence increased with advancing age in both sexes. Age adjusted prevalence (WHO New world population) was 23.8 per 1000.ConclusionsWe documented a high prevalence of ET in this study, with typical increasing prevalence with advancing age as previously reported in other populations.

Prevalence of Tremor Disorders in Young Male Population of Turkey

“…Similar to our study, there are few young individuals' tremor prevalence studies compared to older population, and in these studies, the prevalence between the ages 17-39 changes between 0.481%-2.7% [6][7][8][9][10] (Table 2). In a study where Sur et al [7] included also the young individuals, the results were less than our study, while in the study of Küsbeci et al [8] in 221 young individuals (17-26 years of age), the ET prevalence was found similar to ours (3%).…”

“…The physiological tremor (PT) is defined as the postural tremor with low amplitude at classically [8][9][10][11][12] Hz frequency that may be seen in everybody and may increase with anxiety and fatigue [1,11]. Healthy people may show some tremor but this condition does not cause any complaint.…”

“…The mean ET prevalence that increases with age is calculated as 0.9% for all ages and 4.6% for individuals at age 65 or higher [4]. It is reported that the prevalence rate under 45 years changes between 0.481% and 2.7% [6][7][8][9][10].…”

How Many People in the USA Have Essential Tremor? Deriving a Population Estimate Based on Epidemiological Data

“…1,[9][10][11][12][13][14] Of these 34 studies, 16 were identified in which: 1) the method of case ascertainment involved either neurological examination of all subjects in a population sample or administration of a screening questionnaire followed by neurological examination, and the sensitivity of the screen was provided, and 2) estimates of prevalence were provided within age strata. 5,6,11,12,14,[16][17][18][19][20][21][22][23][24][25][26] Of these 16, 5,6,11,12,14,[16][17][18][19][20][21][22][23][24][25][26] 12 used diagnostic criteria for ET that are not ideally suited to epidemiological investigations (e.g., the Consensus Statement of the Movement Disorder Society 27 ) because they do not sufficiently separate ET from other entities such as enhanced physiological tremor, and/or used non-neurologists to assign ET diagnoses, which is not optimal. Four studies remained; these were conducted in Israel, 18 Turkey, 5,20 and Spain.…”

“…8 The search yielded 34 population-based prevalence studies. 1,[9][10][11][12][13][14] The methodology of each identified study was assessed, and methodologically more rigorous studies were selected for further review. The methodological issues of greatest importance were as follows: 1) all subjects in the sample received an in-person neurological examination or the study provided information to indicate that the sensitivity of the screening questionnaire used during the first phase of case ascertainment was high, 2) neurologists assigned the ET diagnoses, 3) the study used diagnostic criteria that sufficiently separate ET from other entities such as enhanced physiological tremor, which are common in the population, and 4) the study provided separate age-specific estimates of prevalence.…”