An epidemiological study of motor neuron disease in Hong Kong

Epidemiology and distribution of 207 rare diseases in China: A systematic literature review

Epidemiological data on rare diseases in China are currently limited. The objective of this study was to provide a comprehensive understanding of the prevalence and incidence of rare diseases by systematically analyzing the available epidemiological data. We conducted a comprehensive search of English and Chinese databases, the Incidence and Prevalence Database, the Chinese Rare Disease Guideline, and the Taiwan Health Promotion Administration from 2010 to 2023. We identified the top diseases and regions based on epidemiological data and present the maximum, minimum, and median prevalence and incidence values in tables and forest plots. 1,264 prevalence and incidence data were retrieved from 277 studies, guidelines and official websites, covering 110 rare diseases (53.1%) and 32 regions (94.1%). In terms of geographical regions, incidence or prevalence data were available for 32 regions (94.1%), excluding Tibet Hui Autonomous Region and Macao Special Administrative Region. In terms of rate, 60 and 77 out of 207 diseases (29.0% and 37.2%) had available incidence and prevalence data, respectively. Eight diseases had an incidence rate equal to or greater than that of 1,000 patients per million. The present study provides a comprehensive epidemiological analysis and valuable insights into the prevalence and incidence of rare diseases in China. Our findings underscore the pressing need for sustained drug research and medical support for individuals and families impacted by rare diseases.

PCDHA9 as a candidate gene for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. To identify additional genetic factors, we analyzed exome sequences in a large cohort of Chinese ALS patients and found a homozygous variant (p.L700P) in PCDHA9 in three unrelated patients. We generated Pcdhα9 mutant mice harboring either orthologous point mutation or deletion mutation. These mice develop progressive spinal motor loss, muscle atrophy, and structural/functional abnormalities of the neuromuscular junction, leading to paralysis and early lethality. TDP-43 pathology is detected in the spinal motor neurons of aged mutant mice. Mechanistically, we demonstrate that Pcdha9 mutation causes aberrant activation of FAK and PYK2 in aging spinal cord, and dramatically reduced NKA-α1 expression in motor neurons. Our single nucleus multi-omics analysis reveals disturbed signaling involved in cell adhesion, ion transport, synapse organization, and neuronal survival in aged mutant mice. Together, our results present PCDHA9 as a potential ALS gene and provide insights into its pathogenesis.

Amyotrophic lateral sclerosis in seven provinces of Chinese mainland: A cross-sectional survey from 2015 to 2016

Background

The large-scale survey about amyotrophic lateral sclerosis (ALS) based on both population and hospitals in the Chinese mainland has been deficient at present. To this end, we conducted a cross-sectional survey about ALS based on the population and hospitals in seven provinces of the Chinese mainland in 2015–2016.

Methods

We surveyed patients with ALS in seven provinces in eastern, middle, and western China. Among them, 13 prefecture-level cities, 13 municipal districts, 13 counties, 26 streets, 52 communities, 39 towns, and 78 administrative villages were selected for the population-based survey. Totally, 13 class-3 general hospitals, 13 class-2 general hospitals, and 26 street health centers or community health service centers in urban districts, and 13 county-level general hospitals, 39 township health centers, and 78 village clinics in rural districts were recruited for the hospital-based survey.

Results

Among the Chinese mainland, the total prevalence of ALS was slightly lower than that of the world's other nations or districts. The male patients were more than female patients. The prevalence of rural residents was more than that of urban residents. The prevalence of farmers was higher than that of other professions. The majority of ALS was not accompanied by other chronic diseases. The peak onset age of ALS was higher, familial ALS (fALS) cases were slightly more, and the average survival duration of sporadic ALS (sALS) was slightly lower compared with the previous investigation data. The hospitalization expenses of almost 60% of ALS were not more than 10,000 Chinese Yuan.

Conclusion

Hospitalization expenses in our survey objectives were the lowest in the current reported countries and districts. A farmer was a possible higher risk profession for ALS, the majority of ALS were not accompanied by other chronic diseases. Our survey provided more information on the epidemiology of ALS worldwide and supplied the deficiency of epidemiology survey about ALS from the Chinese mainland.

Estimated Prevalence and Incidence of Amyotrophic Lateral Sclerosis and SOD1 and C9orf72 Genetic Variants

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a rare neurological disorder characterized by progressive deterioration of motor neurons. Assessment of the size/geographic distribution of the ALS population, including ALS with genetic origin, is needed to understand the burden of the disease and the need for clinical intervention and therapy.

OBJECTIVES

The main objective of this study was to estimate the number of prevalent and incident ALS cases overall and superoxide dismutase 1 (SOD1) and chromosome 9 open reading frame 72 (C9orf72) ALS in 22 countries across Europe (Belgium, France, Germany, Ireland, Italy, Netherlands, Norway, Russia, Spain, Sweden, and UK), North America (USA and Canada), Latin America (Argentina, Brazil, Colombia, Mexico, and Uruguay), and Asia (China, Japan, South Korea, and Taiwan).

METHODS

A comprehensive literature search was conducted to identify population-based studies reporting ALS prevalence and/or incidence rates. Pooled prevalence and incidence rates were obtained using a meta-analysis approach at the country and regional geographic level. A country-level pooled estimate was used when ≥2 studies were available per country and geographic regional pooled estimates were used otherwise. The proportion of cases with a SOD1 or C9orf72 mutation among sporadic (sALS) and familial (fALS) cases were obtained from a previous systematic review and meta-analysis.

RESULTS

Pooled prevalence rates (per 100,000 persons) and incidence rates (per 100,000 person-years) were 6.22 and 2.31 for Europe, 5.20 and 2.35 for North America, 3.41 and 1.25 for Latin America, 3.01 and 0.93 for Asian countries excluding Japan, and 7.96 and 1.76 for Japan, respectively. Significant heterogeneity in reported incidence and prevalence was observed within and between countries/geographic regions. The estimated number of 2020 ALS cases across the 22 countries is 121,028 prevalent and 41,128 incident cases. The total estimated number of prevalent SOD1 cases is 2,876 cases, of which, 1,342 (47%) were fALS and 1,534 (53%) were sALS, and the number of incident SOD1 cases is 946 (434 [46%] fALS and 512 [54%] sALS). The total estimated number of prevalent C9orf72 cases is 4,545 (1,198 [26%] fALS, 3,347 [74%] sALS), and the number of incident C9orf72 cases is 1,706 (450 [26%] fALS and 1,256 [74%] sALS).

DISCUSSION

The estimated number of patients with SOD1 and C9orf72 ALS suggests that although the proportions of SOD1 and C9orf72 are higher among those with fALS, the majority of SOD1 and C9orf72 ALS cases may be found among those with sALS (about 53 and 74%, respectively). These results suggest that classification of fALS based on reported family history does not capture the full picture of ALS of genetic origin.

Trends in the clinical features of amyotrophic lateral sclerosis: A 14-year Chinese cohort study

BACKGROUND AND PURPOSE

The aim was to determine the transitional patterns in the clinical characteristics, treatments and comorbidities in amyotrophic lateral sclerosis (ALS) patients over the past 14 years using data from a large clinical cohort in mainland China.

METHODS

Sporadic ALS patients who visited the Peking University Third Hospital from January 2005 to December 2018 were included in this study. The 14 years were divided into three periods, and changes in the baseline characteristics of the participants were analyzed at 5-year intervals.

RESULTS

In total, 3410 patients with sporadic ALS were recruited: 2181 were men and 1229 were women. The proportion of patients with bulbar-onset ALS increased from 13.0% in 2005-2009 to 19.5% in 2015-2018 (p < 0.001). The mean (standard deviation) age at onset increased from 49.5 (11.4) years in 2005-2009 to 53.0 (11.0) years in 2015-2018 (p < 0.001). ALS patients with diabetes or hypertension showed a delay in ALS onset, and the delay was even more apparent when the patients had both comorbidities. The proportion of riluzole users in 2015-2018 was approximately 2.5-fold of that in 2005-2009 (p < 0.001).

CONCLUSIONS

In the context of a lack of clinical data on ALS in mainland China, this study evaluated a large cohort of patients diagnosed over a 14-year period. The age at onset and percentage of patients who used riluzole both increased over the study period. Additionally, it was found that patients with comorbidities such as diabetes and hypertension had a delayed age of ALS onset.

Incidence and prevalence of amyotrophic lateral sclerosis in urban China: a national population-based study

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease and information on disease burden of ALS in mainland China was limited. We aimed to estimate the prevalence and incidence of ALS in China.

METHODS

We used 2012-2016 data from China's Urban Employee Basic Medical Insurance and Urban Residence Basic Medical Insurance, covering approximately 0.43 billion individuals. ALS cases were identified by the primary diagnosis (International Classification of Diseases code or text of diagnosis) in the insurance database.

RESULTS

The crude prevalence and incidence in 2016 were 2.91 per 100 000 person-years (95% CI 2.31 to 3.58) and 1.65 (95% CI 1.33 to 2.01), respectively. The standardised prevalence and incidence based on 2010 Chinese census data were 2.97 (95% CI 2.91 to 3.03) and 1.62 (95% CI 1.58 to 1.67), respectively. The annual prevalence between 2013 and 2016 remained relatively constant, ranging from 2.91 (95% CI 2.31 to 3.58) in 2016 to 3.29 (95% CI 2.51 to 4.17) in 2014 (linear regression: β=-0.129, p=0.104). Both rates peaked in the group aged 75-79 years.

CONCLUSIONS

The prevalence and incidence of ALS in mainland China were lower than those in developed countries, and maintained a relatively stable trend. The age at onset and age at diagnosis for ALS patients were younger than those in developed countries. Further research is expected to clarify the potential pathophysiological mechanism of ALS.

Incidence and prevalence of 121 rare diseases in China: Current status and challenges

In order to ascertain the current status of and challenges posed by the incidence and prevalence of rare diseases in China, this study teases out data on the incidence and prevalence of 121 rare diseases listed in China's First List of Rare Disease to provide rationales and references for the development and promotion of rare-disease-related policies. The National Health Commission of the People's Republic of China issued the Rare Disease Diagnosis and Treatment Guide (2019) (denoted here as China's Rare Disease Diagnosis and Treatment Guide), which cited data on the incidence/prevalence of 21 rare diseases (21 of 121 rare diseases, 17.36%). Data on 68 diseases (56.20%) were found in monographs, literature databases, and official websites. Data on the incidence/prevalence of 70 diseases were compiled, though no data were available for the 51 remaining diseases. There are published data on the incidence/prevalence of only 14 diseases at the national level. Sources of data on the incidence and prevalence of rare diseases mainly include cases counts from hospitals (40.56%), other sources of data (24.48%), screening (20.98%), cross-sectional studies (8.39%), and estimates from models (7.69%). Data on the incidence/prevalence of rare diseases in China are limited and typically lack accuracy, uniformity, and timeliness. Epidemiological data at the national level are greatly lacking, and data are not amenable to comparison. China recently initiated epidemiological studies of rare diseases at the national and regional level. The country will continue to promote, use, and update its list of common rare diseases, actively encourage the coding and registration of cases of rare diseases, and take actions to collect, share, and use that information.

Epidemiology of ALS in Korea using nationwide big data

OBJECTIVE

This study aimed to determine the incidence, prevalence and survival time of Korean patients with amyotrophic lateral sclerosis (ALS) using National Health Insurance Service (NHIS) data.

METHODS

Using NHIS data, the Korean nationwide health dataset, we identified patients with motor neuron diseases who were first diagnosed with a KCD-6 code (G12.20-G12.28; modified from ICD-10 codes) between 2011 and 2015. ALS (G12.21 code) epidemiological characteristics, including annual incidence, prevalence, mortality rates and survival time, were analysed and compared with sociodemographic variables.

RESULTS

New patients with ALS (n=3049) were enrolled over 5 years. The mean annual incidence was 1.20/100 000, and the sex ratio was 1.60 (male:female). The mean age at the time of diagnosis was 61.4 years. The prevalence rate was 3.43/100 000 in 2015. In this period, riluzole was prescribed to 53.6% of patients with ALS. Furthermore, 20.3% of patients with ALS underwent tracheostomy. When analysed for age and socioeconomic status, ALS prevalence rate was 10.71 in the aged group (≥60) in 2015 and was lowest in the middle-income group compared with that in the high-income and low-income groups. The estimated mean survival time in this population was 50.0 months, and the 3-year and 5-year mortality rates were 52.1% and 63.7%, respectively.

CONCLUSIONS

This study is the first nationwide survey for epidemiological characteristics of ALS in Korea using national data. The use of these data substantially advances the understanding of Korean and Asian ALS epidemiology and its relationship with socioeconomic status, age and sex.

Amyotrophic lateral sclerosis in Beijing: Epidemiologic features and prognosis from 2010 to 2015

OBJECTIVE

To determine the incidence of amyotrophic lateral sclerosis (ALS) in Beijing from 2010 to 2015 and to address the issue of prognosis.

METHODS

The number of patients diagnosed with ALS was generated from two aspects, namely, diagnostic hospitals and assisted care institutions. By examining the consistency of the overlapping data in terms of age and gender distributions, the number of ALS patients in Beijing was estimated to analyze the incidence. Finally, a prognosis study was carried out by sorting the clinical data of deceased patients to associate time to death with the demographic characteristics, including gender, age at diagnosis, site of onset, body mass index, and lag from onset to diagnosis.

RESULTS

The average yearly incidence was 0.8/100,000 persons, the male-female ratio was 1.63:1, and the mean age at diagnosis was 54.11 years. The mean time from symptom onset to diagnosis was 14.8 months, and the median survival time from diagnosis was 49.4 months. In addition, each of the identified clinical features was related to the survival of the patients with ALS.

CONCLUSIONS

The incidence of ALS in Beijing is similar to the rates in Hong Kong and Taiwan but is lower than the rates in Europe and America. In addition, the mean age at onset of the patients in Beijing was early, and overall ALS prognosis appears to be comparable to those reported in recent publications.

The epidemiology and genetics of Amyotrophic lateral sclerosis in China

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder associated with loss of motor neurons. Previous knowledge of the disease has been mainly based on studies from Caucasian ALS patients of European descent. Here we review the epidemiological characteristics of ALS among the Chinese population in order to compare the similarities and differences between Chinese ALS cases and those from other countries. We describe a potential lower incidence and prevalence of ALS, a younger age of onset and a lower proportion of familial ALS cases in the Chinese population. Additionally, we highlight potential genetic differences between Chinese and Caucasian ALS patients. Most notably, the frequency of GGGGCC repeat expansions in C9ORF72 in Chinese ALS is significantly lower than in Caucasians. Since some conclusions might not be consistent across all of the studies around China to date, we suggest that it is necessary to carry out a prospective population-based study and large-scale gene sequencing around to better define epidemiological and genetic features of Chinese ALS patients.

Age-specific ALS incidence: a dose-response meta-analysis

To evaluate the association between worldwide ALS incidence rates and age, using a dose-response meta-analysis. We reviewed Medline and Embase up to July 2016 and included all population-based studies of newly-diagnosed cases, using multiple sources for case ascertainment. A dose-response meta-analysis was performed. A meta-regression investigated potential sources of heterogeneity. Of 3254 articles identified in the literature, we included 41 incidence studies covering 42 geographical areas. Overall, the fit between observed and predicted age-specific rates was very good. The expected variation of ALS incidence with age was characterized, in each study, by a progressive increase in the incidence from the 40s leading to a peak in the 60s or 70s, followed by a sharp decrease. Cochran's Q test suggested a significant heterogeneity between studies. Overall, estimated patterns of ALS age-specific incidence (at which the peak was reached) were similar among subcontinents of Europe and North America: peak of ALS incidence ranged in these areas between 6.98 and 8.17/100,000 PYFU, which referred to age in the range 71.6-77.4 years. The relationship between age and ALS incidence appeared different for Eastern Asia which was characterized by a peak of ALS incidence at 2.20/100,000 PYFU around 75 years of age. This study confirms the consistency of the age-specific ALS incidence pattern within different subcontinents. Age-specific incidence appears lower in Eastern Asia as compared to Europe and North America.

Variation in worldwide incidence of amyotrophic lateral sclerosis: a meta-analysis

Background

To assess the worldwide variation of amyotrophic lateral sclerosis (ALS) incidence, we performed a systematic review and meta-analysis of population-based data published to date.

Methods

We reviewed Medline and Embase up to June 2015 and included all population-based studies of newly diagnosed ALS cases, using multiple sources for case ascertainment. ALS crude and standardized incidence (on age and sex using the US 2010 population) were calculated. Random effect meta-analysis and meta-regression were performed using the subcontinent as the main study level covariate. Sources of heterogeneity related to the characteristics of the study population and the study methodology were investigated.

Results

Among 3216 records, 44 studies were selected, covering 45 geographical areas in 11 sub-continents. A total of 13 146 ALS cases and 825 million person-years of follow-up (PYFU) were co-nsidered. The overall pooled worldwide crude ALS incidence was at 1.75 (1.55–1.96)/100 000 PYFU; 1.68 (1.50–1.85)/100 000 PYFU after standardization. Heterogeneity was identified in ALS standardized incidence between North Europe [1.89 (1.46–2.32)/100 000 PYFU] and East Asia [0.83 (0.42–1.24)/100 000 PYFU, China and Japan P = 0.001] or South Asia [0.73 (0.58–0.89)/100 000/PYFU Iran, P = 0.02]. Conversely, homogeneous rates have been reported in populations from Europe, North America and New Zealand [pooled ALS standardized incidence of 1.81 (1.66-1.97)/100 000 PYFU for those areas].

Conclusion

This review confirms a heterogeneous distribution worldwide of ALS, and sets the scene to sustain a collaborative study involving a wide international consortium to investigate the link between ancestry, environment and ALS incidence.

Using the Capture-Recapture Method to Estimate the Incidence of Amyotrophic Lateral Sclerosis in Beijing, China

BACKGROUND

To assess the total, gender-related and ageing process-related incidence rates of amyotrophic lateral sclerosis (ALS) in Beijing, China. Determine whether the decreased male to female ratio among postmenopausal age groups.

METHODS

We used the 2-source capture-recapture method to estimate the incidence of ALS in Beijing. The primary and secondary data sources were from diagnostic hospitals and assisted care institutions in the same area from 2010 to 2015.

RESULTS

A total of 562 cases and 283 cases were extracted from 2 data sources, and a total of 962 patients diagnosed with ALS within the 6-year period were estimated (95% CI 883-1041). The average yearly incidence was 0.77/100,000 persons (95% CI 0.71-0.83). The female to male ratio was 1.63. The incidence was associated with age and peaked in the 55-64 year age group. There was no obvious decline in the male:female ratio among postmenopausal age groups.

CONCLUSIONS

The total incidence of ALS in Beijing is similar to international reports. The onset of ALS is not merely the result of ageing.

Burden of rare variants in ALS genes influences survival in familial and sporadic ALS

Genetic variants are implicated in the development of amyotrophic lateral sclerosis (ALS), but it is unclear whether the burden of rare variants in ALS genes has an effect on survival. We performed whole genome sequencing on 8 familial ALS (FALS) patients with superoxide dismutase 1 (SOD1) mutation and whole exome sequencing on 46 sporadic ALS (SALS) patients living in Hong Kong and found that 67% had at least 1 rare variant in the exons of 40 ALS genes; 22% had 2 or more. Patients with 2 or more rare variants had lower probability of survival than patients with 0 or 1 variant (p = 0.001). After adjusting for other factors, each additional rare variant increased the risk of respiratory failure or death by 60% (p = 0.0098). The presence of the rare variant was associated with the risk of ALS (Odds ratio 1.91, 95% confidence interval 1.03-3.61, p = 0.03), and ALS patients had higher rare variant burden than controls (MB, p = 0.004). Our findings support an oligogenic basis with the burden of rare variants affecting the development and survival of ALS.

Accuracy of routinely-collected healthcare data for identifying motor neurone disease cases: A systematic review

Background

Motor neurone disease (MND) is a rare neurodegenerative condition, with poorly understood aetiology. Large, population-based, prospective cohorts will enable powerful studies of the determinants of MND, provided identification of disease cases is sufficiently accurate. Follow-up in many such studies relies on linkage to routinely-collected health datasets. We systematically evaluated the accuracy of such datasets in identifying MND cases.

Methods

We performed an electronic search of MEDLINE, EMBASE, Cochrane Library and Web of Science for studies published between 01/01/1990-16/11/2015 that compared MND cases identified in routinely-collected, coded datasets to a reference standard. We recorded study characteristics and two key measures of diagnostic accuracy—positive predictive value (PPV) and sensitivity. We conducted descriptive analyses and quality assessments of included studies.

Results

Thirteen eligible studies provided 13 estimates of PPV and five estimates of sensitivity. Twelve studies assessed hospital and/or death certificate-derived datasets; one evaluated a primary care dataset. All studies were from high income countries (UK, Europe, USA, Hong Kong). Study methods varied widely, but quality was generally good. PPV estimates ranged from 55–92% and sensitivities from 75–93%. The single (UK-based) study of primary care data reported a PPV of 85%.

Conclusions

Diagnostic accuracy of routinely-collected health datasets is likely to be sufficient for identifying cases of MND in large-scale prospective epidemiological studies in high income country settings. Primary care datasets, particularly from countries with a widely-accessible national healthcare system, are potentially valuable data sources warranting further investigation.

Risk factors for respiratory failure of motor neuron disease in a multiracial Asian population

BACKGROUND

Motor neuron disease (MND) is a devastating degenerative disorder. Amyotrophic Lateral Sclerosis (ALS) is the most common and severe form of MND. Respiratory failure arising from ventilator musculature atrophy is the most common cause of death for ALS patients. Exploring the factors correlated with respiratory failure can contribute to disease management.

PURPOSE

To characterize the clinical features of MND and determine the factors that may affect respiratory failure of MND patients.

METHODS

The case records of all MND patients seen in Singapore General Hospital (SGH) between January 2004 and December 2014 were examined. Demographic, clinical information were collected by reviewing case records. Mortality data, if not available from records, were obtained via phone call interview of family members. Demographic data and clinical treatments were compared between Respiratory support group and Non-respiratory support group.

RESULTS

There were 73 patients included in our study. 49 (67.1%) patients died during follow-up. The mean age of onset was 58±11.1years. With regard to treatment, 63% needed feeding support, and 42.5% required ventilation aid. The median overall survival was 36months from symptom onset. Chi-square tests showed there was significantly higher percentage of respiratory support needed in Chinese than in other races (P=0.016). Compared with non-feeding support patients, patients with feeding support were more likely to require assisted ventilation (P=0.001).

CONCLUSIONS

We report for the first time that the need of feeding support is significantly associated with assisted ventilation. Chinese MND patients may be more inclined to require respiratory support.

Projected increase in amyotrophic lateral sclerosis from 2015 to 2040

Although amyotrophic lateral sclerosis (ALS) is relatively rare, the socioeconomic significance of the disease is extensive. It is therefore vital to project the epidemiologic trend of ALS. To date, there have been few published studies attempting to estimate the number and distribution of ALS cases in the upcoming years. Here we show that the number of ALS cases across the globe will increase from 222,801 in 2015 to 376,674 in 2040, representing an increase of 69%. This increase is predominantly due to ageing of the population, particularly among developing nations. This projection is likely an underestimate due to improving healthcare and economic conditions. The results should be used to inform healthcare policy to more efficiently allocate healthcare resources.

The socioeconomic burden of amyotrophic lateral sclerosis (ALS) is high, but the projected number of cases in the upcoming years is unclear. Here, the authors estimate the number and distribution of ALS cases to 2040, and show that cases are projected to increase, particularly in developing nations.

Amyotrophic lateral sclerosis and motor neuron syndromes in Asia

While the past 2 decades have witnessed an increasing understanding of amyotrophic lateral sclerosis (ALS) arising from East Asia, particularly Japan, South Korea, Taiwan and China, knowledge of ALS throughout the whole of Asia remains limited. Asia represents >50% of the world population, making it host to the largest patient cohort of ALS. Furthermore, Asia represents a diverse population in terms of ethnic, social and cultural backgrounds. In this review, an overview is presented that covers what is currently known of ALS in Asia from basic epidemiology and genetic influences, through to disease characteristics including atypical phenotypes which manifest a predilection for Asians. With the recent establishment of the Pan-Asian Consortium for Treatment and Research in ALS to facilitate collaborations between clinicians and researchers across the region, it is anticipated that Asia and the Pacific will contribute to unravelling the uncertainties in ALS.

Results of Florida's Amyotrophic Lateral Sclerosis Surveillance Project, 2009-2011

OBJECTIVE

Studies to determine the incidence and prevalence of amyotrophic lateral sclerosis (ALS) in defined geographic areas in the USA are needed. The Florida Department of Health received funding from the federal Agency for Toxic Substances and Disease Registry to implement a state-wide ALS Surveillance Project. The objectives of the project were to describe the demographic characteristics of ALS cases and to calculate the incidence and prevalence of ALS in Florida.

SETTING/PARTICIPANTS

All neurologists were asked to submit case reports for persons with ALS diagnosed and/or under their care during 1 January 2009 through 31 December 2011. A medical record verification form and an electromyogram (EMG) report were requested for a sample of cases and reviewed by an independent consulting neurologist to confirm ALS diagnosis. Death data were used to aid with case report collection.

PRIMARY AND SECONDARY OUTCOME MEASURES

Demographics, relevant history and clinical characteristics, El Escorial classifications, time from symptom onset to diagnosis, crude annual incidence rates and 2009 period prevalence are presented.

RESULTS

The 1450 reported ALS cases were more likely to be older, male, white and non-Hispanic. Slightly more than 4% of cases were reported as also having dementia, and 4.8% were reported to have an immediate family member diagnosed with ALS. Incidence rates ranged from 1.7 to 1.9 per 100,000 person-years during the project period and the 2009 period prevalence was 4.0 per 100,000 persons.

CONCLUSIONS

Project findings are generally consistent with findings of population-based studies in Europe, as well as geographically limited studies in the USA. Our findings add to the growing body of epidemiological literature about ALS in the USA. Future epidemiological studies in the USA should focus on identifying cases from minority groups and those that may have limited access to healthcare, and should consider conducting capture-recapture analysis to assess case ascertainment.

Aspirin use associated with amyotrophic lateral sclerosis: a total population-based case-control study

Background

The association of aspirin use and nonsteroid anti-inflammatory drug (NSAID) use with amyotrophic lateral sclerosis (ALS) risk is unclear. This study determined whether use of any individual compound is associated with ALS risk by conducting a total population-based case-control study in Taiwan.

Methods

A total of 729 patients with newly diagnosed ALS who had a severely disabling disease certificate between January 1, 2002, and December 1, 2008, comprised the case group. These cases were compared with 7290 sex-, age-, residence-, and insurance premium-matched controls. Drug use by each Anatomical Therapeutic Chemical code was analyzed using conditional logistic regression models. False discovery rate (FDR)-adjusted P values were reported in order to avoid inflating false positives.

Results

Of the 1336 compounds, only the 266 with use cases exceeding 30 in our database were included in the screening analysis. Without controlling for steroid use, the analysis failed to reveal any compound that was inversely associated with ALS risk according to FDR criteria. After controlling for steroid use, we found use of the following compounds to be associated with ALS risk: aspirin, diphenhydramine (one of the antihistamines), and mefenamic acid (one of the NSAIDs). A multivariate analysis revealed that aspirin was independently inversely associated with ALS risk after controlling for diphenhydramine, mefenamic acid, and steroid use. The inverse association between aspirin and ALS was present predominately in patients older than 55 years.

Conclusions

The results of this study suggested that aspirin use might reduce the risk of ALS, and the benefit might be more prominent for older people.

Racial and ethnic differences among amyotrophic lateral sclerosis cases in the United States

Our objective was to describe racial and ethnic differences of amyotrophic lateral sclerosis (ALS) in distinct geographic locations around the United States (U.S.). ALS cases for the period 2009–2011 were identified using active case surveillance in three states and eight metropolitan areas. Of the 5883 unique ALS cases identified, 74.8% were white, 9.3% were African-American/black, 3.6% were Asian, 12.0% were an unknown race, and 0.3% were marked as some other race. For ethnicity, 77.5% were defined as non-Hispanic, 10.8% Hispanic, and 11.7% were of unknown ethnicity. The overall crude average annual incidence rate was 1.52 per 100,000 person-years and the rate differed by race and ethnicity. The overall age-adjusted average annual incidence rate was 1.44 per 100,000 person-years and the age-adjusted average incidence rates also differed by race and ethnicity. Racial differences were also found in payer type, time from symptom onset to diagnosis, reported El Escorial criteria, and age at diagnosis.

In conclusion, calculated incidence rates demonstrate that ALS occurs less frequently in African-American/blacks and Asians compared to whites, and less frequently in Hispanics compared to non-Hispanics in the U.S. A more precise understanding of racial and ethnic variations in ALS may help to reveal candidates for further studies of disease etiology and disease progression.

Prevalence of amyotrophic lateral sclerosis in the city of Porto Alegre, in Southern Brazil

Objective : To determine the prevalence of amyotrophic lateral sclerosis (ALS) in the city of Porto Alegre, Brazil. Method : We conducted an extensive investigation in clinics and hospitals that provide specialized assistance to these patients, contacted neurologists and the regional association of people with ALS. Results : On July 31, 2010, 70 patients were alive and diagnosed with amyotrophic lateral sclerosis. Considering the population living in the city in the same period (1,409,351), the estimated prevalence was 5.0 cases per 100,000 people (95% CI, 3.9-6.2), being higher for men (5.2/100,000 95% CI, 3.6-7.2) than for women (4.8/100,000 95% CI, 3.4-6.5). The prevalence increased with age peaking in the age group 70-79 years in both genders. Conclusion : The prevalence of ALS in the city of Porto Alegre is similar to that reported in other parts of the world.

The epidemiology of ALS: a conspiracy of genes, environment and time

Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease of motor neurons, resulting in worsening weakness of voluntary muscles until death from respiratory failure occurs after about 3 years. Although great advances have been made in our understanding of the genetic causes of ALS, the contribution of environmental factors has been more difficult to assess. Large-scale studies of the clinical patterns of ALS, individual histories preceding the onset of ALS, and the rates of ALS in different populations and groups have led to improved patient care, but have not yet revealed a replicable, definitive environmental risk factor. In this Review, we outline what is currently known of the environmental and genetic epidemiology of ALS, describe the current state of the art with respect to the different types of ALS, and explore whether ALS should be considered a single disease or a syndrome. We examine the relationship between genetic and environmental risk factors, and propose a disease model in which ALS is considered to be the result of environmental risks and time acting on a pre-existing genetic load, followed by an automatic, self-perpetuating decline to death.

Underlying cause and place of death among patients with amyotrophic lateral sclerosis in Taiwan: a population-based study, 2003-2008

BACKGROUND

Few studies have assessed cause of death among patients with amyotrophic lateral sclerosis (ALS). We investigated underlying cause and place of death among patients with ALS in Taiwan during 2003-2008.

METHODS

The data source was the Taiwan National Health Insurance database for the period 2003-2008. In total, 751 patients older than 15 years with a primary diagnosis of ALS were included and followed until 2008 in the national mortality database. Crude mortality rates (per 100 person-years) and standardized mortality ratios (SMRs) were calculated in relation to cause of death, sex, and age group (15-44, 45-64, 65+ years).

RESULTS

In total, 297 (39.6%) patients died during the follow-up period, an age- and sex-standardized mortality rate 13 times (95% CI, 10.6-15.6) that of the Taiwanese general population. The leading cause of death among the patients was respiratory diseases, and the second most frequent cause was cardiovascular diseases. During the first year after an ALS diagnosis, suicide was much more frequent (SMR, 6.9; 95% CI, 1.9-17.6) than among the general population.

CONCLUSIONS

During 2003-2008, respiratory diseases and cardiovascular diseases were the most frequent causes of death among Taiwanese patients with ALS. In addition, our findings indicate that suicide prevention is an urgent priority during the period soon after an ALS diagnosis.

Global epidemiology of amyotrophic lateral sclerosis: a systematic review of the published literature

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is relatively rare, yet the economic and social burden is substantial. Having accurate incidence and prevalence estimates would facilitate efficient allocation of healthcare resources.

OBJECTIVE

To provide a comprehensive and critical review of the epidemiological literature on ALS.

METHODS

MEDLINE and EMBASE (1995-2011) databases of population-based studies on ALS incidence and prevalence reporting quantitative data were analyzed. Data extracted included study location and time, design and data sources, case ascertainment methods and incidence and/or prevalence rates. Medians and interquartile ranges (IQRs) were calculated, and ALS case estimates were derived using 2010 population estimates.

RESULTS

In all, 37 articles met the inclusion criteria. In Europe, the median incidence rate (/100,000 population) was 2.08 (IQR 1.47-2.43), corresponding to an estimated 15,355 (10,852-17,938) cases. Median prevalence (/100,000 population) was 5.40 (IQR 4.06-7.89), or 39,863 (29,971-58,244) prevalent cases.

CONCLUSIONS

Disparity in rates among ALS incidence and prevalence studies may be due to differences in study design or true variations in population demographics such as age and geography, including environmental factors and genetic predisposition. Additional large-scale studies that use standardized case ascertainment methods are needed to more accurately assess the true global burden of ALS.

Incidence, prevalence, and medical expenditures of classical amyotrophic lateral sclerosis in Taiwan, 1999-2008

BACKGROUND/PURPOSE

Amyotrophic lateral sclerosis (ALS) is a rare disease, which makes the estimation of incidence and prevalence difficult in Taiwan. This study was conducted to investigate the incidence, prevalence, and medical expenditure of ALS in Taiwan.

METHODS

Patients who had at least one service claim either as an outpatient or inpatient between the years 2004 and 2007 and were over 15 years of age with a primary diagnosis of ALS were identified from the National Health Insurance Research Database. Additionally, ALS patients with serious disability database certificates over 15 years of age were included for the calculation of incidence and prevalence between the years 1999 and 2008. Lastly, the total medical expenditure, including ventilator use and riluzole, were reported.

RESULTS

In 2006 and 2008, the average annual incidence and prevalence of ALS was 0.51 and 1.97 (per 10(5)), respectively, in Taiwan. The male-to-female ratio of incidence for ALS was 1.67. The average medical expenditure for ALS patients stayed steady at 16-fold greater than the general population of Taiwan in 2008. The percentage of ventilator and riluzole expenditure as a proportion of total medical expense decreased from 55% in 2000 to 33% in 2008.

CONCLUSION

The incidence and average medical expenditure of ALS patients remained stable over the years in Taiwan, however, as a proportion of total medical expenses, expenditure on ventilator and riluzole decreased over the study period.

Riluzole and prognostic factors in amyotrophic lateral sclerosis long-term and short-term survival: a population-based study of 1149 cases in Taiwan

Background

Amyotrophic lateral sclerosis (ALS) is a rare disease in Taiwan; thus, estimation of ALS mortality is difficult. We evaluated factors associated with ALS survival in Taiwan.

Methods

The study enrolled 1149 Taiwanese with a primary diagnosis of ALS during 1999–2008. Follow-up information was available for all patients; mean (SD) duration of follow-up was 2.91 (2.62) years. Medical interventions, including noninvasive positive pressure ventilation (NIPPV), tracheotomy, gastrostomy, and riluzole, were included in time-dependent survival analysis.

Results

Of the 1149 ALS patients, 438 (38.12%) died during follow-up. Mortality in the first year was 16%, which was 13 times (95% CI 11.1–15.2) the age- and sex-standardized rate of the general population in Taiwan. The average annual crude mortality rate was 13.1% (person-years). Factors significantly associated with increased mortality were male sex, advanced age, rural residence, lower economic status, no tracheotomy, and no riluzole treatment. Significant predictors of long-term versus average survival were younger age at diagnosis, being a dependent or receiving social welfare, and NIPPV support. Significant predictors of short-term versus average survival were older age, being employed, no tracheotomy, and no riluzole use.

Conclusions

The results support the use of riluzole to improve ALS survival. Patients who received riluzole and underwent tracheotomy had the best survival.

Identification of a novel missense mutation in angiogenin in a Chinese amyotrophic lateral sclerosis cohort

Abstract Angiogenin (ANG) gene mutations have been identified in both familial and sporadic amyotrophic lateral sclerosis (ALS) patients from multiple European and North American populations. However, no ANG mutation has yet been reported in Asian ALS populations. Here, we screened for ANG mutations in a Chinese ALS cohort. The entire coding region of the ANG gene was sequenced in 10 familial ALS pedigrees, 202 sporadic ALS patients, and 151 healthy controls. All patients were negative for SOD1, FUS, and TARDBP mutations. We identified a novel missense mutation, c.379G > A (p.V103I), in one sporadic ALS patient, but not in the controls. No mutations were found in the familial ALS patients. A novel missense variant, c.323A > G (p.H84R), was detected in one healthy individual. We identified the presence of the known single nucleotide polymorphism, rs11701 (T/G), in both ALS cases and controls. However, no significant association of the G allele with ALS susceptibility was demonstrated. In conclusion, ANG mutations accounted for 0.5% of our SOD1-, FUS-, TARDBP- mutation-negative ALS cohort. Our findings highlight that the genetic background of ALS differs between different populations, and suggest that ANG mutation may be involved in the aetiology of ALS in the Han Chinese population.

Survival and prognostic factors of motor neuron disease in a multi-ethnic Asian population

Our objective was to determine the survival and prognostic factors of motor neuron disease (MND) in a multi-ethnic cohort of Malaysian patients. All patients seen at a university medical centre between January 2000 and December 2009 had their case records reviewed for demographic, clinical and follow-up data. Mortality data, if unavailable from records, were obtained by telephone interview of relatives or from the national mortality registry. Of the 73 patients, 64.4% were Chinese, 19.2% Malays and 16.4% Indians. Male: female ratio was 1.43: 1. Mean age at onset was 51.5 + 11.3 years. Onset was spinal in 75.3% and bulbar in 24.7% of the patients; 94.5% were ALS and 5.5% were progressive muscular atrophy (PMA). Overall median survival was 44.9 + 5.8 months. Ethnic Indians had shorter interval from symptom onset to diagnosis and shorter median survival compared to non-Indians. On Cox proportional hazards analysis, poor prognostic factors were bulbar onset, shorter interval from symptom onset to diagnosis and worse functional score at presentation. In conclusion, age of onset and median survival duration are similar to previous reports in Asians. Clinical features and prognostic factors are similar to other populations. In our cohort, ethnic Indians had more rapid disease course accounting for their shorter survival.

Clinical phenotypes of a large Chinese multigenerational kindred with autosomal dominant familial ALS due to Ile149Thr SOD1 gene mutation

About 10% of amyotrophic lateral sclerosis (ALS) cases are familial. We identified a five-generation Chinese family with autosomal dominant familial ALS (FALS). We performed a detailed family study, clinical and electromyographic validation, and SOD1, VEGF and CNTF mutation analyses. Forty-five living members (16 affected) were studied and DNA samples collected. Genealogical data were collected for deceased members. Based on the duration between symptom onset to ventilator dependence, they were divided into rapidly progressive (range 1-18 months, mean (SD) duration = 12.08 (+/-6.10) months, mean (SD) age of symptom onset = 39.75 (+/-9.84) years) and slowly progressive groups (>18 months; mean (SD) age of onset = 37.25 (+/-5.32) years old). We identified a heterozygous mutation of ATT to ACT of SOD1 gene at codon 149 in exon 5 resulting in substitution of isoleucine to threonine. It co-segregated with all affected members and 11 non-symptomatic members. We report a large multigenerational Chinese FALS kindred with I149T mutation in SOD1. No polymorphisms or mutations were found to date in two known modifier genes, namely, VEGF and CNTF, which were associated with heterogeneity in the phenotype within this kindred. Follow-up of the family will be helpful to explore any potential disease markers.