Military service, deployments, and exposures in relation to amyotrophic lateral sclerosis survival

Guidance for clinical management of pathogenic variant carriers at elevated genetic risk for ALS/FTD

There is a growing understanding of the presymptomatic stages of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and nascent efforts aiming to prevent these devastating neurodegenerative diseases have emerged. This progress is attributable, in no small part, to the altruism of people living with pathogenic variants at elevated genetic risk for ALS/FTD via their willingness to participate in natural history studies and disease prevention trials. Increasingly, this community has also highlighted the urgent need to develop paradigms for providing appropriate clinical care for those at elevated risk for ALS and FTD. This manuscript summarises recommendations emanating from a multi-stakeholder Workshop (Malvern, Pennsylvania, 2023) that aimed to develop guidance for at-risk carriers and their treating physicians. Clinical care recommendations span genetic testing (including counselling and sociolegal implications); monitoring for the emergence of early motor, cognitive and behavioural signs of disease; and the use of Food and Drug Administration-approved small molecule drugs and gene-targeting therapies. Lifestyle recommendations focus on exercise, smoking, statin use, supplement use, caffeine intake and head trauma, as well as occupational and environmental exposures. While the evidence base to inform clinical and lifestyle recommendations is limited, this guidance document aims to appraise carriers and clinicians of the issues and best available evidence, and also to define the research agenda that could yield more evidence-informed guidelines.

Epidemiology of Sarcoidosis in U.S. Veterans from 2003 to 2019

Rationale: United States veterans represent an important population to study sarcoidosis. Their unique history of environmental exposures, wide geographic distribution, and long-term enrollment in a single integrated healthcare system provides an unparalleled opportunity to understand the incidence, prevalence, and risk factors for sarcoidosis. Objectives: To determine the epidemiology, patient characteristics, geographic distribution, and associated risk factors of sarcoidosis among U.S. veterans. Methods: We used data from the Veterans Health Administration (VHA) electronic health record system between 2003 and 2019 to evaluate the annual incidence, prevalence, and geographic distribution of sarcoidosis (defined using the International Classification of Diseases codes). We used multivariate logistic regression to examine patient characteristics associated with sarcoidosis incidence. Results: Among more than 13 million veterans who received care through or paid for by the VHA, 23,747 (0.20%) incident diagnoses of sarcoidosis were identified. Compared with selected VHA control subjects using propensity score matching, veterans with sarcoidosis were more likely to be female (13.5% vs. 9.0%), of Black race (52.2% vs. 17.0%), and ever-tobacco users (74.2% vs. 64.5%). There was an increase in the annual incidence of sarcoidosis between 2004 and 2019 (from 38 to 52 cases/100,000 person-years) and the annual prevalence between 2003 and 2019 (from 79 to 141 cases/100,000 persons). In a multivariate logistic regression model, Black race (odds ratio [OR], 4.49; 95% confidence interval [CI], 4.33-4.65), female sex (OR, 1.64; 95% CI, 1.56-1.73), living in the Northeast compared with the western region (OR, 1.57; 95% CI, 1.48-1.67), history of tobacco use (OR, 1.36; 95% CI, 1.31-1.41), and serving in the Army, Air Force, or multiple branches compared with the Navy (OR, 1.08; 95% CI, 1.03-1.13; OR, 1.10; 95% CI, 1.04-1.17; OR, 1.27; 95% CI, 1.16-1.39, respectively) were significantly associated with incident sarcoidosis (P < 0.0001). Conclusions: The incidence and prevalence of sarcoidosis are higher among veterans than in the general population. Alongside traditionally recognized risk factors such as Black race and female sex, we found that a history of tobacco use within the Veterans Affairs population and serving in the Army, Air Force, or multiple service branches were associated with increased sarcoidosis risk.

Occupational lead exposure and survival with amyotrophic lateral sclerosis

Objective: Lead exposure has been hypothesized to increase the risk of ALS, but only two studies have examined the association with ALS survival, and with inconsistent results. The use of occupational history to assess lead exposure can avoid reverse causation that may occur in epidemiologic analyses that use biomarkers of lead exposure collected after ALS onset.Methods: We evaluated the relationship of occupational lead exposure to ALS survival among 135 cases from an international ALS cohort that included deep phenotyping, careful follow-up, and questionnaires to quantify participants' occupation history. ALS patients were recruited in 2015-2019. We determined occupational lead exposure using a job-exposure matrix. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for survival using Cox proportional hazard analysis with adjustment for covariates.Results: A total of 135 ALS patients completed the environmental questionnaires, among whom 38 reached a survival endpoint (death or permanent assisted ventilation). The median survival was 48.3 months (25th-75th percentile, 30.9-74.1). Older patients and those with initial symptom other than limb onset had shorter survival time. There were 36 ALS cases with occupational lead exposure. After adjusting for age, sex, site of onset, smoking, and military service, lead exposure was associated with an HR of 3.26 (95%CI 1.28-8.28). Results with adjustment for subsets of these covariates were similar.Conclusions: These results suggest that lead exposure prior to onset of ALS is associated with shorter survival following onset of ALS, and this association is independent of other prognostic factors.

Pesticides applied to crops and amyotrophic lateral sclerosis risk in the U.S

BACKGROUND

Environmental exposures are implicated in the etiology of amyotrophic lateral sclerosis (ALS). Application of insecticides, herbicides, and fungicides with neurotoxic properties to crops is permitted in the U.S., however reporting of the quantities is government mandated.

OBJECTIVE

To identify pesticides that may be associated with ALS etiology for future study.

METHODS

We geospatially estimated exposure to crop-applied pesticides as risk factors for ALS in a large de-identified medical claims database, the SYMPHONY Integrated Dataverse®. We extracted residence at diagnosis of ∼26,000 nationally distributed ALS patients, and matched non-ALS controls. We mapped county-level U.S. Geological Survey data on applications of 423 pesticides to estimate local residential exposure. We randomly broke the SYMPHONY dataset into two groups to form independent discovery and validation cohorts, then confirmed top hits using residential history information from a study of NH, VT, and OH.

RESULTS

Pesticides with the largest positive statistically significant associations in both the discovery and the validation studies and evidence of neurotoxicity in the literature were the herbicides 2,4-D (OR 1.25 95 % CI 1.17-1.34) and glyphosate (OR 1.29 95 %CI 1.19-1.39), and the insecticides carbaryl (OR 1.32 95 %CI 1.23-1.42) and chlorpyrifos (OR 1.25 95 %CI 1.17-1.33).

SIGNIFICANCE

Our geospatial analysis results support potential neurotoxic pesticide exposures as risk factors for sporadic ALS. Focused studies to assess these identified potential relationships are warranted.

Current and Future Projections of Amyotrophic Lateral Sclerosis in the United States Using Administrative Claims Data

BACKGROUND

Various methodologies have been reported to assess the real-world epidemiology of amyotrophic lateral sclerosis (ALS) in the United States. The aim of this study was to estimate the prevalence, incidence, and geographical distribution of ALS using administrative claims data and to model future trends in ALS epidemiology.

METHODS

We performed a retrospective analysis of deidentified administrative claims data for >100 million patients, using 2 separate databases (IBM MarketScan Research Databases and Symphony Health Integrated DataVerse [IDV]), to identify patients with ALS. We evaluated disease prevalence, annual incidence, age- and population-controlled geographical distribution, and expected future trends.

RESULTS

From 2013 to 2017, we identified 7,316 and 35,208 ALS patients from the MarketScan databases and IDV, respectively. Average annual incidence estimates were 1.48 and 1.37 per 100,000 and point prevalence estimates were 6.85 and 5.16 per 100,000 and in the United States for the MarketScan databases and IDV, respectively. Predictive modeling estimates are reported out to the year 2060 and demonstrate an increasing trend in both incident and prevalent cases.

CONCLUSIONS

This study provides incidence and prevalence estimates as well as geographical distribution for what the authors believe to be the largest ALS population studied to date. By using 2 separate administrative claims data sets, confidence in our estimates is increased. Future projections based on either database demonstrate an increase in ALS cases, which has also been seen in other large-scale ALS studies. These results can be used to help improve the allocation of healthcare resources in the future.

Neuropathological profile of long-duration amyotrophic lateral sclerosis in military Veterans

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting both the upper and lower motor neurons. Although ALS typically leads to death within 3 to 5 years after initial symptom onset, approximately 10% of patients with ALS live more than 10 years after symptom onset. We set out to determine similarities and differences in clinical presentation and neuropathology in persons with ALS with long vs. those with standard duration. Participants were United States military Veterans with a pathologically confirmed diagnosis of ALS (n = 179), dichotomized into standard duration (<10 years) and long-duration (≥10 years). The ALS Functional Rating Scale-Revised (ALSFRS-R) was administered at study entry and semi-annually thereafter until death. Microglial density was determined in a subset of participants. long-duration ALS occurred in 76 participants (42%) with a mean disease duration of 16.3 years (min/max = 10.1/42.2). Participants with long-duration ALS were younger at disease onset (P = 0.002), had a slower initial ALS symptom progression on the ALSFRS-R (P < 0.001) and took longer to diagnose (P < 0.002) than standard duration ALS. Pathologically, long-duration ALS was associated with less frequent TDP-43 pathology (P < 0.001). Upper motor neuron degeneration was similar; however, long-duration ALS participants had less severe lower motor neuron degeneration at death (P < 0.001). In addition, the density of microglia was decreased in the corticospinal tract (P = 0.017) and spinal cord anterior horn (P = 0.009) in long-duration ALS. Notably, many neuropathological markers of ALS were similar between the standard and long-duration groups and there was no difference in the frequency of known ALS genetic mutations. These findings suggest that the lower motor neuron system is relatively spared in long-duration ALS and that pathological progression is likely slowed by as yet unknown genetic and environmental modifiers.

Significant out-of-sample classification from methylation profile scoring for amyotrophic lateral sclerosis

We conducted DNA methylation association analyses using Illumina 450K data from whole blood for an Australian amyotrophic lateral sclerosis (ALS) case–control cohort (782 cases and 613 controls). Analyses used mixed linear models as implemented in the OSCA software. We found a significantly higher proportion of neutrophils in cases compared to controls which replicated in an independent cohort from the Netherlands (1159 cases and 637 controls). The OSCA MOMENT linear mixed model has been shown in simulations to best account for confounders. When combined in a methylation profile score, the 25 most-associated probes identified by MOMENT significantly classified case–control status in the Netherlands sample (area under the curve, AUC = 0.65, CI_95% = [0.62–0.68], p = 8.3 × 10⁻²²). The maximum AUC achieved was 0.69 (CI_95% = [0.66–0.71], p = 4.3 × 10⁻³⁴) when cell-type proportion was included in the predictor.

Increased risk of head and neck cancer in Agent Orange exposed Vietnam Era veterans

IMPORTANCE

United States military personnel during the Vietnam Era were potentially exposed to Agent Orange, a known carcinogen. The link between Agent Orange and head and neck cancers is largely unknown; laryngeal cancer is currently the only subsite with sufficient evidence of an Agent Orange association.

OBJECTIVE

We aim to determine the relationship between Agent Orange exposure and the incidence of head and neck cancers in Vietnam Era veterans as well as any relationship with head and neck cancer survival.

MATERIALS AND METHODS

The present study utilizes the Veterans Affairs Corporate Data Warehouse (VA CDW) to identify Vietnam Era veterans, their Agent Orange exposure status, limited demographic data, presence of head and neck cancer, and survival data.

RESULTS

Of 8,877,971 Vietnam Era veterans, 22% self-reported exposure to Agent Orange, and 54,717 had a diagnosis of head and neck cancer. Agent Orange exposure significantly predicted upper aerodigestive tract carcinoma, with a relative risk (RR) of 1.10. On subsite analysis, Agent Orange exposure (as well as race, gender, and substance use) was significantly associated with oropharyngeal (RR 1.16), nasopharyngeal (RR 1.22), laryngeal (1.11), and thyroid (1.24) cancers. Agent Orange exposure was associated with improved 10-year overall survival in upper aerodigestive tract cancer patients.

CONCLUSIONS AND RELEVANCE

Self-reported Agent Orange exposure correlated with increased risks of oropharyngeal, nasopharyngeal, laryngeal, and thyroid cancers, and predicted improved survival in upper aerodigestive tract cancer patients. These findings broaden our understanding of the risks of Agent Orange exposure.