Statins, diabetes mellitus and prognosis of amyotrophic lateral sclerosis: data from 501 patients of a population-based registry in southwest Germany

The role of statins in amyotrophic lateral sclerosis: protective or not?

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of motor neurons characterized by muscle weakness, muscle twitching, and muscle wasting. ALS is regarded as the third-most frequent neurodegenerative disease, subsequent to Alzheimer's disease (AD) and Parkinson's disease (PD). The World Health Organization (WHO) in 2007 declared that prolonged use of statins may induce development of ALS-like syndrome and may increase ALS risk. Subsequently, different studies have implicated statins in the pathogenesis of ALS. In contrast, results from preclinical and clinical studies highlighted the protective role of statins against ALS neuropathology. Recently, meta-analyses and systematic reviews illustrated no association between long-term use of statins and ALS risk. These findings highlighted controversial points regarding the effects of statins on ALS pathogenesis and risk. The neuroprotective effects of statins against the development and progression of ALS may be mediated by regulating dyslipidemia and inflammatory changes. However, the mechanism for induction of ALS neuropathology by statins may be related to the dysregulation of liver X receptor signaling (LXR) signaling in the motor neurons and reduction of cholesterol, which has a neuroprotective effect against ALS neuropathology. Nevertheless, the exact role of statins on the pathogenesis of ALS was not fully elucidated. Therefore, this narrative review aims to discuss the role of statins in ALS neuropathology.

Genetic variation in targets of lipid-lowering drugs and amyotrophic lateral sclerosis risk: a Mendelian randomization study

BACKGROUND

The use of lipid-lowering drugs is still highly controversial in patients with amyotrophic lateral sclerosis (ALS). We performed a drug-target Mendelian randomization (MR) analysis to investigate the effect of targeted lipid-lowering drugs on the risk of ALS.

METHODS

First, we evaluated the causal relationship between HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase (HMGCR) inhibitors-taking trait and ALS using a bidirectional two-sample MR study. Second, we investigated the causal relationship between lipid-lowering drugs and ALS through a drug-target MR approach. The summary data for HMGCR inhibitors-taking traits were extracted from a genome-wide association study (GWAS) of medication use and associated disease in the UK Biobank. The summary data for low-density lipoprotein cholesterol and apolipoprotein B (apoB) were extracted from a meta-analysis of GWAS in individuals of European ancestry in the UKB. The GWAS summary data of ALS were obtained from the Project MinE.

RESULTS

Our bidirectional two-sample MR showed that genetically determined increased HMGCR inhibitors-taking trait was an independent risk factor for ALS (odds ratio [OR] = 1.090, 95% confidence interval [CI] = 1.035-1.150, p = 0.001). The results of drug-target MR showed that the increased expression of the HMGCR gene in blood with the higher risk of ALS (OR = 1.21, 95% CI = 1.01-1.46; p = 0.042) through SMR method and the apoB level mediated by the APOB gene increased the risk of ALS (OR = 1.15; 95% CI =1.05-1.25; p = 0.001) through inverse-variance weighted MR method.

CONCLUSION

This present study provides genetic support for a positive causal effect of HMGCR inhibitors-taking trait and ALS. The reason for this may be due to the underlying disease condition behind the medication, rather than the medication itself. Our findings also suggested that HMGCR and apoB inhibitors may have potential protective effects on ALS.

Higher Glycemic Index and Glycemic Load Diet Is Associated with Slower Disease Progression in Amyotrophic Lateral Sclerosis

OBJECTIVE

High-caloric diets may slow the progression of amyotrophic lateral sclerosis; however, key macronutrients have not been identified. We examined whether dietary macronutrients are associated with the rate of progression and length of survival among the prospective cohort study participants.

METHODS

Participants with a confirmed diagnosis of sporadic amyotrophic lateral sclerosis enrolled in the Multicenter Cohort Study of Oxidative Stress were included (n = 304). We evaluated baseline macronutrient intake assessed by food frequency questionnaire in relation to change in revised amyotrophic lateral sclerosis functional rating scale total-score, and tracheostomy-free survival using linear regression and Cox proportional hazard models. Baseline age, sex, disease duration, diagnostic certainty, body mass index, bulbar onset, revised amyotrophic lateral sclerosis functional rating scale total-score, and forced vital capacity were included as covariates.

RESULTS

Baseline higher glycemic index and load were associated with less decline of revised amyotrophic lateral sclerosis functional rating scale total score at 3-month follow-up (β = -0.13, 95% CI -0.2, -0.01, p = 0.03) and (β = -0.01, 95% CI -0.03, -0.0007, p = 0.04), respectively. Glycemic index second-quartile, third-quartile, and fourth-quartile groups were associated with less decline at 3 months by 1.9 (95% CI -3.3, -0.5, p = 0.008), 2.0 (95% CI -3.3, -0.6, p = 0.006), and 1.6 (95% CI -3.0, -0.2, p = 0.03) points compared with the first-quartile group; the glycemic load fourth-quartile group had 1.4 points less decline compared with the first-quartile group (95% CI -2.8, 0.1, p = 0.07). Higher glycemic index was associated with a trend toward longer tracheostomy-free survival (HR 0.97, 95% CI 0.93, 1.00, p = 0.07).

INTERPRETATION

Higher dietary glycemic index and load are associated with slower disease progression in amyotrophic lateral sclerosis. ANN NEUROL 2024;95:217-229.

Associations between body mass index and all-cause mortality: A systematic review and meta-analysis

Fasting insulin and c-reactive protein confound the association between mortality and body mass index. An increase in fat mass may mediate the associations between hyperinsulinemia, hyperinflammation, and mortality. The objective of this study was to describe the "average" associations between body mass index and the risk of mortality and to explore how adjusting for fasting insulin and markers of inflammation might modify the association of BMI with mortality. MEDLINE and EMBASE were searched for studies published in 2020. Studies with adult participants where BMI and vital status was assessed were included. BMI was required to be categorized into groups or parametrized as non-first order polynomials or splines. All-cause mortality was regressed against mean BMI squared within seven broad clinical populations. Study was modeled as a random intercept. β coefficients and 95% confidence intervals are reported along with estimates of mortality risk by BMIs of 20, 30, and 40 kg/m2 . Bubble plots with regression lines are drawn, showing the associations between mortality and BMI. Splines results were summarized. There were 154 included studies with 6,685,979 participants. Only five (3.2%) studies adjusted for a marker of inflammation, and no studies adjusted for fasting insulin. There were significant associations between higher BMIs and lower mortality risk in cardiovascular (unadjusted β -0.829 [95% CI -1.313, -0.345] and adjusted β -0.746 [95% CI -1.471, -0.021]), Covid-19 (unadjusted β -0.333 [95% CI -0.650, -0.015]), critically ill (adjusted β -0.550 [95% CI -1.091, -0.010]), and surgical (unadjusted β -0.415 [95% CI -0.824, -0.006]) populations. The associations for general, cancer, and non-communicable disease populations were not significant. Heterogeneity was very large (I2  ≥ 97%). The role of obesity as a driver of excess mortality should be critically re-examined, in parallel with increased efforts to determine the harms of hyperinsulinemia and chronic inflammation.

Phase 1/2a clinical trial in ALS with ropinirole, a drug candidate identified by iPSC drug discovery

iPSC-based drug discovery led to a phase 1/2a trial of ropinirole in ALS. 20 participants with sporadic ALS received ropinirole or placebo for 24 weeks in the double-blind period to evaluate safety, tolerability, and therapeutic effects. Adverse events were similar in both groups. During the double-blind period, muscle strength and daily activity were maintained, but a decline in the ALSFRS-R, which assesses the functional status of ALS patients, was not different from that in the placebo group. However, in the open-label extension period, the ropinirole group showed significant suppression of ALSFRS-R decline and an additional 27.9 weeks of disease-progression-free survival. iPSC-derived motor neurons from participants showed dopamine D2 receptor expression and a potential involvement of the SREBP2-cholesterol pathway in therapeutic effects. Lipid peroxide represents a clinical surrogate marker to assess disease progression and drug efficacy. Limitations include small sample sizes and high attrition rates in the open-label extension period, requiring further validation.

The Management of Hypercholesterolemia in Patients with Neuromuscular Disorder

PURPOSE OF REVIEW

We describe and discuss the safety of statins and non-statin drugs in neuromuscular disorders (NMDs). We also propose a pragmatic model of care for the management of such cases.

RECENT FINDINGS

Patients with both NMD and hypercholesterolemia may be particularly disadvantaged owing to the toxic effects of cholesterol-lowering therapy and the inability to take medication. Specifically, the management of hypercholesterolemia in patients with NMD is complicated by the increased risk of statin-related myotoxicity and concerns that statins may aggravate or possibly induce the onset of a specific NMD. The most severe form of statin-related myotoxicity is immune-mediated necrotizing myopathy. Management of hypercholesterolemia in patients with NMDs include treating modifiable factors, consideration of toxicity risk of statin, use of non-statin lipid lowering agents, noting possible drug interactions, and careful monitoring.

Protective Effects of Lovastatin in a Population-Based ALS Study and Mouse Model

OBJECTIVE

The objective of this study was to use a novel combined pharmacoepidemiologic and amyotrophic lateral sclerosis (ALS) mouse model approach to identify potential motor neuron protective medications.

METHODS

We constructed a large, population-based case-control study to investigate motor neuron disease (MND) among US Medicare beneficiaries aged 66 to 90 in 2009. We included 1,128 incident MND cases and 56,400 age, sex, race, and ethnicity matched controls. We calculated MND relative risk for >1,000 active ingredients represented in Part D (pharmacy) claims in 2006 to 2007 (>1 year before diagnosis/reference). We then applied a comprehensive screening approach to select medications for testing in SOD1^G93A mice: sulfasalazine, telmisartan, and lovastatin. We treated mice with the human dose equivalent of the medication or vehicle via subcutaneous osmotic pump before onset of weakness. We then assessed weight, gait, and survival. In additional mice, we conducted histological studies.

RESULTS

We observed previously established medical associations for MND and an inverse dose-response association between lovastatin and MND, with 28% reduced risk at 40 mg/day. In SOD1^G93A mouse studies, sulfasalazine and telmisartan conferred no benefit, whereas lovastatin treatment delayed onset and prolonged survival. Lovastatin treated mice also had less microgliosis, misfolded SOD1, and spinal motor neuron loss in the ventral horn.

INTERPRETATION

Lovastatin reduced the risk of ALS in humans, which was confirmed in an ALS mouse model by delayed symptom onset, prolonged survival, and preservation of motor neurons. Although further studies to understand the mechanism are required, lovastatin may represent a potential neuroprotective therapy for patients with ALS. These data demonstrate the utility of a combined pharmacoepidemiologic and mouse model approach. ANN NEUROL 2023.

Risk factors of amyotrophic lateral sclerosis: a global meta-summary

Background

The etiology of amyotrophic lateral sclerosis (ALS) remains largely unknown. This study aimed to summarize the relationship between ALS and its genetic and non-genetic risk factors.

Method

A search of relevant literature from PubMed, Embase, and Cochrane Database from inception to December 2022 was performed. Random-effects or fixed-effects models were performed by Stata MP 15.0 to pool multivariate or adjusted ratios (OR). PROSPERO registration number: CRD42022301549.

Results

230 eligible studies were included, of which 67 involved 22 non-genetic factors, and 163 involved genetic factors. Four aspects of non-genetic factors, including lifestyle, environmental and occupational exposures, pre-existing diseases/comorbidity and medical exposures, and others, were analyzed. Exposure to heavy metals (OR = 1.79), pesticides (OR = 1.46), solvents (OR = 1.37), previous head trauma (OR = 1.37), military service (OR = 1.29), stroke (OR = 1.26), magnetic field (OR = 1.22) and hypertension (OR = 1.04) are significant risk factors, but use of antidiabetics (OR = 0.52), high BMI (OR = 0.60 for obese and overweight vs. normal and underweight), living in urban (OR = 0.70), diabetes mellitus (OR = 0.83), and kidney disease (OR = 0.84) decrease the risk for ALS. In addition, eight common ALS-related genes were evaluated, the mutation frequencies of these genes were ranked from highest to lowest as SOD1 (2.2%), C9orf72 (2.1%), ATXN2 (1.7%), FUS (1.7%), TARDBP (0.8%), VCP (0.6%), UBQLN2(0.6%) and SQSTM1 (0.6%) in all the ALS patients.

Conclusions

Our findings suggested that effective intervention for risk exposure and timely modification of lifestyle might prevent the occurrence of ALS. Genetic mutations are important risk factors for ALS and it is essential to detect genetic mutations correctly and scientifically.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=301549, identifier: CRD42022301549.

Association between vascular risk factors and cognitive impairment in amyotrophic lateral sclerosis: a case-control study

Objective: The disease-modifying effects of type 2 diabetes mellitus (T2DM), and hyperlipidemia on the risk and prognosis of amyotrophic lateral sclerosis (ALS) have gained significant attention. We aim to evaluate the association between common vascular risk factors and cognitive impairment in patients with ALS. Methods: Patients with ALS were consecutively recruited between June 2012 and November 2019 from a tertiary referral center for ALS at the West China Hospital. Vascular risk factors (hypertension, T2DM, hyperlipidemia, overweight, and smoking) were confirmed based on clinical data. Cognitive function was evaluated by the Chinese version of Addenbrooke's Cognitive Examination-revised. With careful confounder adjustment, multivariable logistic regression analysis was performed separately and accumulatively to determine the association between cognitive impairment and vascular risk factors in ALS. Results: Of 870 patients, 266 (30.6%) had cognitive impairment. No cognitive burden from vascular risk factors was found in patients with ALS. On the contrary, we first observed that T2DM (odds ratio [OR], 0.50; 95% confidence interval [CI], 0.25-0.98; p = 0.04) and hyperlipidemia (OR, 0.50; 95% CI, 0.26-0.97; p = 0.04) showed protective effects against cognitive decline in ALS, adjusted for age, sex, educational level, site of onset, Revised-ALS Functional Rating Scale score, predominant upper motor neuron phenotype, family history of ALS, and the remaining vascular risk factors. Sensitivity analyses of sex did not substantially reverse the risk estimates. Conclusions: T2DM and hyperlipidemia decrease the risk of cognitive impairment in patients with ALS. The fitness hypothesis in ALS has been tested and expanded in our work.

Statin Medications and Amyotrophic Lateral Sclerosis Incidence and Mortality

Studies of statins and amyotrophic lateral sclerosis (ALS) incidence and survival have had conflicting findings possibly related to difficulties with confounding by indication. We considered potency of statins used and duration of use to explore confounding by indication. Within the Clalit Health Services in Israel, we identified 948 ALS case patients from 2004 through 2017 and matched them with 1,000 control subjects each. Any statin use up to 3 years before ALS onset was not associated with ALS incidence but was associated with a reduced hazard ratio (HR) for death. Odds of ALS did not vary by statin potency, but use of only lower-potency statins was associated with longer survival (HR = 0.82, 95% CI: 0.68, 0.98), whereas the association with higher-potency statins was null compared with those case patients who did not use statins. However, duration of statin use appeared to account for these findings. Those who used statins only up to 3 years had longer survival (HR = 0.77, 95% CI: 0.61, 0.96) than did case patients who did not use statins, but those who used statins for >3 years did not. Although other explanations are possible, these findings could suggest a protective effect of statins on ALS survival that is partially masked by a worse prognosis from underlying reasons for taking statins that deserves further exploration.

Body fat compartment determination by encoder-decoder convolutional neural network: application to amyotrophic lateral sclerosis

The objective of this study was to automate the discrimination and quantification of human abdominal body fat compartments into subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from T1-weighted MRI using encoder-decoder convolutional neural networks (CNN) and to apply the algorithm to a diseased patient sample, i.e., patients with amyotrophic lateral sclerosis (ALS). One-hundred-and-fifty-five participants (74 patients with ALS and 81 healthy controls) were split in training (50%), validation (6%), and test (44%) data. SAT and VAT volumes were determined by a novel automated CNN-based algorithm of U-Net like architecture in comparison with an established protocol with semi-automatic assessment as the reference. The dice coefficients between the CNN predicted masks and the reference segmentation were 0.87 ± 0.04 for SAT and 0.64 ± 0.17 for VAT in the control group and 0.87 ± 0.08 for SAT and 0.68 ± 0.15 for VAT in the ALS group. The significantly increased VAT/SAT ratio in the ALS group in comparison to controls confirmed the previous results. In summary, the CNN approach using CNN of U-Net architecture for automated segmentation of abdominal adipose tissue substantially facilitates data processing and offers the opportunity to automatically discriminate abdominal SAT and VAT compartments. Within the research field of neurodegenerative disorders with body composition alterations like ALS, the unbiased analysis of body fat components might pave the way for these parameters as a potential biological marker or a secondary read-out for clinical trials.

Life Course of Physical Activity and Risk and Prognosis of Amyotrophic Lateral Sclerosis in a German ALS Registry

BACKGROUND AND OBJECTIVES

Whether physical activity (PA) is a risk factor for amyotrophic lateral sclerosis (ALS) is controversial because data on lifelong PA are rare. The main objective of this study is to provide insight into PA as a potential risk factor for ALS, reporting data on cumulative PA, leisure-time PA, and occupational PA. This study also aims to gather evidence on the role of PA as a prognostic factor in disease course.

METHODS

Lifetime PA values collected by questionnaires addressing work and leisure time were quantified into metabolic equivalents (METs). A population-based case-control study embedded in the ALS Registry Swabia served to calculate the odds ratio (OR) of ALS by PA in different time intervals and prognosis.

RESULTS

In ALS cases (393 cases, 791 age- and sex-matched controls), we observed reduced total PA at interview and up to 5 years before interview compared to controls. Total PA was not associated with ALS risk 5 to 55 years before interview. Heavy occupational work intensity was associated with increased ALS risk (OR 1.97, 95% confidence interval 1.34, 2.89). Total PA levels were associated with survival in a nonlinear manner: inactive patients and highest activity levels (25 MET-h/wk) revealed the worst survival time of 15.4 and 19.3 months, respectively. Best median survival with 29.8 months was seen at 10.5 MET-h/wk after adjustment for other prognostic factors.

DISCUSSION

Lifetime combined PA decreased sharply several years before disease onset compared to controls. The risk of developing ALS was not associated with former total PA levels 5 to 55 years before interview in contrast to occupational PA, probably reflecting work-associated exposures. We found a strong nonlinear association of current and prediagnostic PA level and survival in ALS cases with the best survival with moderate PA. PA intensity may be a disease-modifying factor with an unfavorable outcome in sedentary and hyperactive behavior.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that PA was not associated with the development of ALS.

Type 2 Diabetes Mellitus and Amyotrophic Lateral Sclerosis: Genetic Overlap, Causality, and Mediation

CONTEXT

Understanding phenotypic connection between type II diabetes (T2D) mellitus and amyotrophic lateral sclerosis (ALS) can offer valuable sight into shared disease etiology and have important implication in drug repositioning and therapeutic intervention.

OBJECTIVE

This work aims to disentangle the nature of the inverse relationship between T2D mellitus and ALS.

METHODS

Depending on summary statistics of T2D (n = 898 130) and ALS (n = 80 610), we estimated the genetic correlation between them and prioritized pleiotropic genes through a multiple-tissue expression quantitative trait loci-weighted integrative analysis and the conjunction conditional false discovery rate (ccFDR) method. We implemented mendelian randomization (MR) analyses to evaluate the causal relationship between the 2 diseases. A mediation analysis was performed to assess the mediating role of T2D in the pathway from T2D-related glycemic/anthropometric traits to ALS.

RESULTS

We found supportive evidence of a common genetic foundation between T2D and ALS (rg = -0.223, P = .004) and identified 8 pleiotropic genes (ccFDR < 0.10). The MR analyses confirmed that T2D exhibited a neuroprotective effect on ALS, leading to an approximately 5% (95% CI, 0% ~ 9.6%, P = .038) reduction in disease risk. In contrast, no substantial evidence was observed that supported the causal influence of ALS on T2D. The mediation analysis revealed T2D can also serve as an active mediator for several glycemic/anthropometric traits, including high-density lipoprotein cholesterol, overweight, body mass index, obesity class 1, and obesity class 2, with the mediation effect estimated to be 0.024, -0.022, -0.041, -0.016, and -0.012, respectively.

CONCLUSION

We provide new evidence supporting the observed inverse link between T2D and ALS, and revealed that a shared genetic component and causal association commonly drove such a relationship. We also demonstrate the mediating role of T2D standing in the pathway from T2D-related glycemic/anthropometric traits to ALS.

Statins and risk of amyotrophic lateral sclerosis: a systematic review and meta-analysis

Amyotrophic lateral sclerosis (ALS) is a paralytic, heterogeneous and progressive disease characterized by the degeneration of both upper and lower motor neurons. Several studies about the effects of statins drug on the risk of ALS showed contradictory results and evidence for this is inconclusive. So we aimed to perform a meta-analysis on previous studies to clarify the association between statin use and risk of ALS. The databases including PubMed, Scopus, and Web of science were searched in February 2021 for studies that reported the association between statin use and risk of ALS. The eligible studies had to provide a report on the effect of statin and the incidence of ALS while comparing it to the control group. Articles that had low statin exposure time, the absence of a control group and an unknown number of ALS patients were excluded. The rate ratio and 95% confidence interval (CI) were used for association measures in case-control and cohort studies. After full-text and abstract review, data from 8 studies with a total of 547,622 participants and 13,890 cases of ALS were entered in the present meta-analysis. We combined eight studies using a random-effect model and the RR for statin users among groups was 0.98 (95% CI 0.80-1.20) which indicates no association between statin and incidence of ALS. Also high heterogeneity was detected across the studies (Q value = 26.62, P = .00; I² = 72.71%). In our meta-analysis study, we found no association between statin use and an increase in ALS incidence. This result is in line with some previous studies and provides strong evidence that denies the possible association between statin uptake and disease induction.

Metabolic Abnormalities, Dietary Risk Factors and Nutritional Management in Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a devastating progressive neurodegenerative disease that affects motor neurons, leading to a relentless paralysis of skeletal muscles and eventual respiratory failure. Although a small percentage of patients may have a longer survival time (up to 10 years), in most cases, the median survival time is from 20 to 48 months. The pathogenesis and risk factors for ALS are still unclear: among the various aspects taken into consideration, metabolic abnormalities and nutritional factors have been the focus of recent interests. Although there are no consistent findings regarding prior type-2 diabetes, hypercholesterolemia and ALS incidence, abnormalities in lipid and glucose metabolism may be linked to disease progression, leading to a relatively longer survival (probably as a result of counteract malnutrition and cachexia in the advanced stages of the disease). Among potential dietary risk factors, a higher risk of ALS has been associated with an increased intake of glutamate, while the consumption of antioxidant and anti-inflammatory compounds, such as vitamin E, n-3 polyunsaturated fatty acids, and carotenoids, has been related to lower incidence. Poor nutritional status and weight loss in ALS resulting from poor oral intake, progressive muscle atrophy, and the potential hypermetabolic state have been associated with rapid disease progression. It seems important to routinely perform a nutritional assessment of ALS patients at the earliest referral: weight maintenance (if adequate) or gain (if underweight) is suggested from the scientific literature; evidence of improved diet quality (in terms of nutrients and limits for pro-inflammatory dietary factors) and glucose and lipid control is yet to be confirmed, but it is advised. Further research is warranted to better understand the role of nutrition and the underlying metabolic abnormalities in ALS, and their contribution to the pathogenic mechanisms leading to ALS initiation and progression.

Diabetes Mellitus and Amyotrophic Lateral Sclerosis: A Systematic Review

BACKGROUND

Amyotrophic Lateral Sclerosis (ALS) is a degenerative disorder which affects the motor neurons. Growing evidence suggests that ALS may impact the metabolic system, including the glucose metabolism. Several studies investigated the role of Diabetes Mellitus (DM) as risk and/or prognostic factor. However, a clear correlation between DM and ALS has not been defined. In this review, we focus on the role of DM in ALS, examining the different hypotheses on how perturbations of glucose metabolism may interact with the pathophysiology and the course of ALS.

METHODS

We undertook an independent PubMed literature search, using the following search terms: ((ALS) OR (Amyotrophic Lateral Sclerosis) OR (Motor Neuron Disease)) AND ((Diabetes) OR (Glucose Intolerance) OR (Hyperglycemia)). Review and original articles were considered.

RESULTS

DM appears not to affect ALS severity, progression, and survival. Contrasting data suggested a protective role of DM on the occurrence of ALS in elderly and an opposite effect in younger subjects.

CONCLUSIONS

The actual clinical and pathophysiological correlation between DM and ALS is unclear. Large longitudinal prospective studies are needed. Achieving large sample sizes comparable to those of common complex diseases like DM is a challenge for a rare disease like ALS. Collaborative efforts could overcome this specific issue.