Accuracy of Death Certificates for Amyotrophic Lateral Sclerosis Varies Significantly from North to South of Italy: Implications for Mortality Studies

A systematic review on the risk of neurodegenerative diseases and neurocognitive disorders in professional and varsity athletes

Objective

The aim of this systematic review (SR) was to gather all available epidemiological evidence on former participation in any type of sport, at a professional and varsity level, as a potential risk factor for neurodegenerative diseases (NDs) and neurocognitive disorders (NCDs).

Design

Systematic searches were performed on PubMed, the Cochrane databases, and the ISI Web of Knowledge databases. Included studies were assessed using the NOS checklist.

Eligibility criteria for selecting studies

All epidemiological studies reporting data on the possible association between a clinical diagnosis of amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND), dementia or mild cognitive impairment (MCI), Parkinson’s disease (PD), chronic traumatic encephalopathy (CTE) at any stage and with any clinical pattern and the former participation in any types of sport at a varsity and professional level were included.

Results

Data from the 17 included studies showed a higher frequency of NDs and NCDs in former soccer and American football players. Updating the previous SR confirmed a higher frequency of ALS/MND in former soccer players. Data reported a significantly higher risk of dementia/AD in former soccer players, and of MCI in former American football players. Results also showed a significantly higher risk of PD in former soccer and American football players, and a significantly higher risk of CTE in former boxers and American football players.

Summary/conclusions

This SR confirmed a higher risk of NDs and NCDs in former professional/varsity athletes. However, the pathological mechanisms underlying this association remain unclear, and further high-quality studies should be performed to clarify whether the association could be sport specific.

Analysis of incidence of motor neuron disease in England 1998-2019: use of three linked datasets

Objective: This study uses three linked datasets to provide an estimate of incidence of motor neuron disease (MND) in England from 1998 to 2019. Comparison is made to previous British studies. It examines age at diagnosis and ethnicity of those affected.

Methods: The literature was searched for studies of MND incidence in Great Britain from 1995 to date. The QResearch and linked Hospital Episode Statistics and Death register databases were searched from 1998 to 2019 for cases of MND, and incidence calculated from 16.8 million adults and 112 million adult years of data.

Results: We found 6437 adults with a diagnosis of MND giving an incidence of MND of 5.69/100,000 person years (95% CI 5.51–5.88); 6.57 (6.41–6.99) in men and 4.72 (4.49–4.97) in women when age-standardized to the 2011 UK population. The median age of diagnosis was 72 years. Peak incidence occurred in the 80–84 year age group in men and 75–79 in women. Age-standardized incidence was as high in Bangladeshi, Black Caribbean, Indian, other Asian and Pakistani people as in White people. Black African and Chinese people had a lower incidence.

Conclusion: The use of three linked national datasets captured 33% more people than a primary care dataset alone. Patients were older than in previous studies and rates were high in all ethnic groups studied except Black African and Chinese people. We present the highest incidence of MND reported globally in the past 50 years. Methodological differences may in part explain differences with previous reports. The use of national datasets may have captured additional MND patients with serious comorbidities who have not seen a neurologist before death. A limitation of this approach is that unlike population registers, which minimize false positive diagnosis by neurologist review of each patient, we cannot review diagnosis for individuals as data are anonymized.

Survival and Cause of Death among a Cohort of Confirmed Amyotrophic Lateral Sclerosis Cases

Introduction

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder. Estimates of survival from disease onset range from 20 to 48 months and have been generated using clinical populations or death records alone.

Methods

Data on a cohort of ALS cases diagnosed between 2009–2011 were collected as part of the Los Angeles and San Francisco Bay Area Metropolitan ALS Surveillance projects; death records 2009–2013 were linked to these confirmed cases to determine survival post diagnosis and factors associated with survival time.

Results

There were 618 cases identified and 283 of these died during the follow up time period. Median age at death was 64.3 years, and median survival time post-diagnosis was 2.6 years. Age at diagnosis and year of diagnosis were predictors of survival time in adjusted models; those diagnosed at age 80 or older had shorter survival than those diagnosed at age 50 or younger. Most (92%) had ALS noted as a cause of death.

Discussion

Survival post-diagnosis may be improved compared with previous reports. Age at diagnosis continues to be the strongest predictor of prognosis; recall case reporting bias may play a role in estimates of survival time.

Population-based epidemiology of amyotrophic lateral sclerosis (ALS) in an ageing Europe--the French register of ALS in Limousin (FRALim register)

BACKGROUND AND PURPOSE

The main objective of establishing the French register of amyotrophic lateral sclerosis (ALS) in the Limousin region (FRALim), was to assess the incidence of ALS, in this ageing region of Europe, over a 12-year period (2000-2011).

METHODS

Patients were included if they lived in Limousin at the time of diagnosis of ALS according to El Escorial revised criteria and were identified by at least one of the following sources: (i) the French national body coordinating ALS referral centres; (ii) public and private hospitals in the region; (iii) health insurance data related to long-term diseases.

RESULTS

The FRALim register identified 279 incident cases (2000-2011). The crude and European population standardized incidences of ALS were as high as 3.19/100,000 person-years of follow-up (95% CI 2.81-3.56) and 2.58/100,000 person-years of follow-up (95% CI 2.27-2.89) respectively. Median age at onset was 70.8 years (interquartile range 63.1-77.1). The standardized sex incidence ratio (male/female) was 1.3 overall, but 1.1 under the age of 65 years, 1.7 between 65 and 75 years and 1.9 above 75 years. The exhaustiveness of the register has been estimated at 98.4% (95% CI 95.6-99.4) by capture-recapture analysis.

CONCLUSION

It was possible for the first time in France to monitor accurately the incidence of ALS over a long time period. It appears to be in the upper range of data reported in western countries. Patterns displayed here might anticipate the epidemiology of ALS in ageing western countries.

Encephalitis-associated hospitalizations among American Indians and Alaska Natives

Encephalitis produces considerable morbidity in the United States, but morbidity rates among American Indian/Alaska Native (AI/AN) people have not been described. Hospitalization records listing an encephalitis diagnosis were analyzed by using Indian Health Service direct/contract inpatient data. For 1998-2010, there were 436 encephalitis-associated hospitalizations among AI/AN people, an average annual age-adjusted hospitalization rate of 3.1/100,000 population. The rate for infants (11.9) was more than double that for any other age group. Death occurred for 4.1% of hospitalizations. Consistent with reports for the general U.S. population, the rate was high among infants and most (53.9%) hospitalizations were of unexplained etiology. The average annual rate during the study period appeared lower than for the general U.S. population, due particularly to lower rates in the elderly. Future community-based surveillance and mortality studies are needed to confirm these findings and examine reasons underlying the low rates of encephalitis in AI/AN people.

Amyotrophic Lateral Sclerosis: An update for 2013 Clinical Features, Pathophysiology, Management and Therapeutic Trials

Amyotrophic lateral sclerosis (ALS), first described by Jean-Martin Charcot in the 1870s, is an age-related disorder that leads to degeneration of motor neurons. The disease begins focally in the central nervous system and then spreads relentlessly. The clinical diagnosis, defined by progressive signs and symptoms of upper and lower motor neuron dysfunction, is confirmed by electromyography. Additional testing excludes other conditions. The disease is heterogeneous, but most patients die of respiratory muscle weakness less than 3 years from symptom-onset. Like other age-related neurodegenerative diseases, ALS has genetic and environmental triggers. Of the five to 10% of cases that are inherited, mutations have been discovered for a high proportion. In addition to genetic factors, age, tobacco use, and athleticism may contribute to sporadic ALS, but important etiologies are unidentified for most patients. Complex pathophysiological processes, including mitochondrial dysfunction, aggregation of misfolded protein, oxidative stress, excitotoxicity, inflammation and apoptosis, involve both motor neurons and surrounding glial cells. There is clinical and pathological overlap with other neurodegenerative diseases, particularly frontotemporal dementia. The mechanisms leading to disease propagation in the brain are a current focus of research. To date, one medication, riluzole, licensed in 1996, has been proved to prolong survival in ALS. Numerous clinical trials have so far been unable to identify another neuroprotective agent. Researchers now aim to slow disease progression by targeting known pathophysiological pathways or genetic defects. Current approaches are directed at muscle proteins such as Nogo, energetic balance, cell replacement, and abnormal gene products resulting from mutations. Until better understanding of the causes and mechanisms underlying progression lead to more robust neuroprotective agents, symptomatic therapies can extend life and improve quality of life. Palliative care programs such as hospice give emotional and physical support to patients and families throughout much of the disease course.

Mortality of French participants in the Tour de France (1947-2012)

AIMS

In the context of recent concerns regarding performance enhancing techniques and potential negative health effects of high-level physical activity, data on the long-term outcomes and causes of death in elite endurance cyclists are of particular interest.

METHODS AND RESULTS

Characteristics and vital status of all French participants in the Tour de France were collected for the 1947-2012 period. Causes of death were obtained from 1968. Overall and disease-specific mortalities were compared with the French male population using overall and specific standardized mortality ratios (SMRs) with their 95% confidence intervals (CIs). Among the 786 French cyclists who participated at least once between 1947 and 2012, 208 (26%) died by 1 September 2012. Neoplasms and cardiovascular diseases accounted for 61% of deaths. We observed a 41% lower mortality in French cyclists (SMR: 0.59, 95% CI: 0.51-0.68, P < 0.0001), which did not change over time (P = 0.70). It was observed for main mortality causes: for neoplasms (SMR: 0.56; 95% CI: 0.42-0.72, P < 0.0001) and for cardiovascular death (SMR: 0.67; 95% CI: 0.50-0.88, P = 0.004), except mortality related to external causes (SMR: 1.06, 95% CI: 0.71-1.53, P = 0.80).

CONCLUSION

We observed a substantially and significantly lower mortality in participants in the Tour de France, compared with the general male population. However, our results do not allow us to assess in detail the balance between positive effects of high-level sports activity and selection of healthy elite athletes, vs. any potential deleterious effects of excessive physical exercise or alleged doping.

Accuracy and usefulness of ICD-10 death certificate coding for the identification of patients with ALS: results from the South Carolina ALS Surveillance Pilot Project

The purpose if this study was to investigate the positive predictive value and sensitivity of the ICD-10 code G12.2, which is used to identify patients who have possibly died from ALS. All patients with a motor neuron disease diagnosis code during the study period (2001-2005) were identified using administrative data. South Carolina death certificate data were used to assess the positive predictive value and sensitivity of the ICD-10 code G12.2. Two hundred and seventy known cases of ALS linked to the death certificate data file. G12.2 was coded as either the underlying or contributing cause of death for 229 cases, sensitivity = 85%. There were 318 deaths due to ALS identified by the G12.2 code where a medical record was available for review. Of those, 205 contained information supporting the diagnosis of ALS, positive predictive value = 65%. This evaluation raises questions concerning the validity of using mortality data in forming epidemiological conclusions in this patient population. However, it does appear that mortality data can be used in the development of case-finding algorithms to identify ALS patients through the use of administrative data sets.

Changing mortality for motor neuron disease in France (1968-2007): an age-period-cohort analysis

The incidence and mortality of motor neuron disease (MND) increase with age and appear to have increased with time. The examination of period and cohort effects using age-period-cohort (APC) models can help characterize temporal trends. Our objective was to describe mortality from MND in France (1968-2007), and to examine the role of age, period of death, and birth-cohort on changes in mortality. The number of people who died from MND and population statistics (1968-2007) were extracted from French national records. Annual standardized (age/sex) mortality ratios (SMRs) were computed. Using Poisson regression, APC models examined the relationship between mortality rates and age, period of death, and birth-cohort in subjects aged 40-89 years. Deviance/degrees-of-freedom ratios evaluated model fit; ratios close to one indicated adequate fit. Between 1968 and 2007, 38,863 individuals died from MND (mortality rate = 1.74/100,000); 37,624 were aged 40-89 years. SMRs increased from 54 (95% CI = 49-59) in 1968 to 126 (120-132) in 2007. Male-to-female ratios declined from 1.80 in 1968 to 1.45 in 2007. Changing mortality rates were best explained by cohort effects (deviance/degrees-of-freedom = 1.09). The relative risk of dying from MND increased markedly for persons born between 1880 and 1920, and more slowly after 1920. In conclusion, mortality rates for MND increased between 1968 and 2007, and more rapidly in women than men. This increase was better explained by the birth-cohort of individuals than by period effects. Changing environmental exposures may be a possible explanation and these findings warrant the continued search for environmental risk factors for MND.

Validating population-based registers for ALS: how accurate is death certification?

The purpose of this study was to determine the accuracy of death certification for amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND) as recorded by the Central Statistics Office in the Republic of Ireland, and to examine its utility in capture-recapture analysis. The database of the Irish Central Statistics Office (CSO) was searched for death certificates of individuals over 15 years of age for whom ALS/MND (ICD9) was listed as a primary, secondary or tertiary cause of death from 2002 to 2006. This dataset was compared with mortality data from the Irish Register for ALS/MND for the same period. Three hundred ninety-eight cases with a diagnosis of ALS were identified through the CSO. The cause of death as identified by the CSO was 318 out of 398 (80%) cases known to the Register during the study period. ALS/MND was listed as a cause of death by the CSO in 79 (20%) cases that were unknown to the ALS/MND Register. Of these, ALS/MND was listed as a secondary/tertiary cause of death in 76, and 75% of all such deaths occurred in rural areas. Capture-recapture analysis using the CSO and ALS Register as independent datasets generated a likely over-estimation of the crude incidence of ALS from 2.1/100,000 to 3.45/100,000 in Ireland. Population-based registers are most accurate when ascertaining from a wide network of inter-dependent sources. Death certification for ALS/MND lacks both sensitivity and specificity. Capture-recapture exercises using such data sources are likely to over-estimate the true incidence of disease.

The epidemiology of amyotrophic lateral sclerosis in Reggio Emilia, Italy

Incidence and mortality rates of amyotrophic lateral sclerosis (ALS) vary between countries, and in some studies appear to increase over time. We performed a study to assess ALS incidence in a northern Italy area over a 10-year period. We identified the new cases of probable or definite ALS diagnosed among residents in Reggio Emilia province between 1996 and 2005 using several sources of data, such as death certificates, clinical records, hospital discharge registers and drug prescriptions. A total of 94 newly-diagnosed patients were identified. The average standardized incidence in the period was 2.0 and 1.0 cases/100,000/year, using the Italian and the world population, respectively, as reference. There was no variation in rates over time. Incidence was 1.3 in males and 0.8 in females. No cases were observed in patients under 35 years of age. Incidence increased after the age of 55 years, reaching a peak in the group aged 70-74 years and declining thereafter. We concluded that ALS incidence in this population was similar to that observed in other Italian regions and European countries, and no variation was identified during the study period.

Causes of death amongst French patients with amyotrophic lateral sclerosis: a prospective study

BACKGROUND AND PURPOSE

To prospectively investigate causes of death and the circumstances surrounding death in 302 patients with amyotrophic lateral sclerosis (ALS). The functional status of patients immediately before death was also determined.

METHODS

Information was obtained from neurologists at ALS centres, patients' files, and, when deaths occurred outside a medical facility, attending physicians.

RESULTS

Most patients (63%) died in a medical facility. The most frequently reported cause of death was respiratory failure (77%), including terminal respiratory insufficiency (58%), pneumonia (14%), asphyxia due to a foreign body (3%) and pulmonary embolism (2%). Ten per cent of patients died from other causes: post-surgical or traumatic conditions (5%), cardiac causes (3.4%), suicide (1.3%) and sudden death of unknown origin (0.7%). The cause of death could not be determined in 13% of cases (6% inside a medical facility and 25% outside). At the time of death, only 55% of patients were receiving riluzole, 33% were undergoing non-invasive ventilation, 3% had a tracheotomy and 37% a gastrostomy.

CONCLUSION

The information provided by this study helps to improve our understanding of the natural history of the disease and may help optimize the quality of care we can offer patients at the end of life.

Association of lead exposure with survival in amyotrophic lateral sclerosis

BACKGROUND

Reasons for the variability in survival among ALS cases are unknown but may include exposure to environmental neurotoxicants.

OBJECTIVES

We aimed to determine whether lead exposure, assessed by measuring blood and bone lead levels, is associated with survival in amyotrophic lateral sclerosis (ALS).

METHODS

We evaluated the relationship of lead exposure to ALS survival in 110 cases from a case-control study conducted in New England in 1993-1996 that included measurements of blood and bone lead. We retrieved information on date and cause of death through 31 December 2003 from the National Death Index Plus and the Social Security Administration Death Index. We evaluated the relationship of survival to lead exposure using Cox proportional hazard analysis, with adjustment for age, sex, and smoking.

RESULTS

We found mortality data for 100 of 110 cases; 93 of 100 death certificates mentioned ALS. Median survival from diagnosis to death was 28 months. Shorter survival was associated with older age at diagnosis, female sex, bulbar onset, shorter interval between symptom onset and diagnosis, and reduced lung function. Shorter survival from diagnosis to death had a weak inverse association with blood lead (hazard ratio = 0.9; 95% confidence interval, 0.8-1.0) and a stronger inverse association with patella lead (0.5; 0.2-1.0) and tibia lead (0.3; 0.1-0.7); similar results were found for survival from symptom onset to death.

CONCLUSIONS

These results suggest that lead exposure is associated with longer survival in ALS cases and, if confirmed, may shed light on mechanisms involved in disease progression.

Geographic distribution of amyotrophic lateral sclerosis through motor neuron disease mortality data

Amyotrophic lateral sclerosis (ALS) is a rare and devastating neurological disorder of the adult age with a prognosis of about 2-3 years from the onset of the disease. No clear cause has been identified but it seems to be a multifactorial disease with genetic and environmental components involved. Increments of mortality rates were observed since 1980 both in Italy and in many other countries. The objective of the present study is to describe the distribution of ALS mortality in Italy in the period 1980-2001 detecting single municipalities or clusters with high mortality levels for motor neuron disease (MND). ALS represents the main part (85%) of the MND group which is globally identified by the IX ICD (International Classification of Diseases and Causes of Death) 335.2 code. Death numbers and standardized mortality ratios (SMR) for MND were calculated for all Italian municipalities through the ENEA mortality database system (data source: National Institute of Statistics-ISTAT), using national mortality rates as reference. Subsequently, in order to detect municipal clusters, spatial analysis was performed. Out of the 8,099 Italian municipalities, 132 where characterized by SMR values higher than expected. Moreover 16 clusters with significant high relative risk values (RR) were identified, 12 out of them including only a single municipality. Only 22 of the municipalities with high SMR were included in the clusters. In conclusion, the two different epidemiological methodologies demonstrated to be widely complementary in detecting the geographical distribution of the disease in terms of risk for populations. A first selection of the priority areas where analytical studies should be carried on, in order to identify risk factors associated to ALS, is tentatively suggested.

Amyotrophic lateral sclerosis mortality in 1.9 million US cancer survivors

BACKGROUND

Large cancer registries offer the opportunity to explore and generate hypotheses about the pathogenesis of cancer and other diseases, including neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS).

METHODS

Using data from nine population-based cancer registries of the Surveillance, Epidemiology, and End Results (SEER) Program of the US National Cancer Institute (NCI) and death certificates, we followed 1.9 million cancer survivors who were diagnosed between 1973 and 2000 and who survived at least 1 year, through the year 2000. The outcome of interest was the standardized mortality ratio (SMR) of observed to expected ALS deaths among cancer survivors. To assess the validity of the study design, we also examined associations with Parkinson's disease mortality, which we expected to be inversely associated with smoking-related cancers.

RESULTS

There was no significantly increased risk or deficit of ALS mortality for all cancer sites combined (SMR = 1.0). Parkinson's disease mortality was, as expected, significantly and inversely associated with smoking-related cancers. Both ALS and Parkinson's disease mortality were significantly elevated following melanoma (SMR = 1.6; 95% CI = 1.1-2.2; SMR = 1.5; 1.2-1.8, respectively). Contrary to previous hypotheses, ALS was unrelated to lymphomas or lymphoproliferative malignancies and was not associated with smoking-related cancers.

CONCLUSIONS

In this exploratory study, we observed a modest, significant association between melanoma and both ALS and Parkinson's disease mortality. It would be useful to explore these findings in other large national databases that are able to link cancer and ALS and Parkinson's disease.