Poor Bone Quality in Patients With Amyotrophic Lateral Sclerosis

Causal relationships involving brain imaging-derived phenotypes based on UKB imaging cohort: a review of Mendelian randomization studies

The UK Biobank (UKB) has the largest adult brain imaging dataset, which encompasses over 40,000 participants. A significant number of Mendelian randomization (MR) studies based on UKB neuroimaging data have been published to validate potential causal relationships identified in observational studies. Relevant articles published before December 2023 were identified following the PRISMA protocol. Included studies (n = 34) revealed that there were causal relationships between various lifestyles, diseases, biomarkers, and brain image-derived phenotypes (BIDPs). In terms of lifestyle habits and environmental factors, there were causal relationships between alcohol consumption, tea intake, coffee consumption, smoking, educational attainment, and certain BIDPs. Additionally, some BIDPs could serve as mediators between leisure/physical inactivity and major depressive disorder. Regarding diseases, BIDPs have been found to have causal relationships not only with Alzheimer's disease, stroke, psychiatric disorders, and migraine, but also with cardiovascular diseases, diabetes, poor oral health, osteoporosis, and ankle sprain. In addition, there were causal relationships between certain biological markers and BIDPs, such as blood pressure, LDL-C, IL-6, telomere length, and more.

Metabolic Syndrome and Risk of Amyotrophic Lateral Sclerosis: Insights from a Large-Scale Prospective Study

OBJECTIVE

Although metabolic abnormalities are implicated in the etiology of neurodegenerative diseases, their role in the development of amyotrophic lateral sclerosis (ALS) remains a subject of controversy. We aimed to identify the association between metabolic syndrome (MetS) and the risk of ALS.

METHODS

This study included 395,987 participants from the UK Biobank to investigate the relationship between MetS and ALS. Cox regression model was used to estimate hazard ratios (HR). Stratified analyses were performed based on gender, body mass index (BMI), smoking status, and education level. Mediation analysis was conducted to explore potential mechanisms.

RESULTS

In this study, a total of 539 cases of ALS were recorded after a median follow-up of 13.7 years. Patients with MetS (defined harmonized) had a higher risk of developing ALS after adjusting for confounding factors (HR: 1.50, 95% CI: 1.19-1.89). Specifically, hypertension and high triglycerides were linked to a higher risk of ALS (HR: 1.53, 95% CI: 1.19-1.95; HR: 1.31, 95% CI: 1.06-1.61, respectively). Moreover, the quantity of metabolic abnormalities showed significant results. Stratified analysis revealed that these associations are particularly significant in individuals with a BMI <25. These findings remained stable after sensitivity analysis. Notably, mediation analysis identified potential metabolites and metabolomic mediators, including alkaline phosphatase, cystatin C, γ-glutamyl transferase, saturated fatty acids to total fatty acids percentage, and omega-6 fatty acids to omega-3 fatty acids ratio.

INTERPRETATION

MetS exhibits a robust association with an increased susceptibility to ALS, particularly in individuals with a lower BMI. Furthermore, metabolites and metabolomics, as potential mediators, provide invaluable insights into the intricate biological mechanisms. ANN NEUROL 2024.

Causal effects of osteoporosis on structural changes in specific brain regions: a Mendelian randomization study

Observational studies have reported that osteoporosis is associated with cortical changes in the brain. However, the inherent limitations of observational studies pose challenges in eliminating confounding factors and establishing causal relationships. And previous observational studies have not reported changes in specific brain regions. By employing Mendelian randomization, we have been able to infer a causal relationship between osteoporosis and a reduction in the surficial area (SA) of the brain cortical. This effect is partially mediated by vascular calcification. We found that osteoporosis significantly decreased the SA of global brain cortical (β = -1587.62 mm2, 95%CI: -2645.94 mm2 to -529.32 mm2, P = 0.003) as well as the paracentral gyrus without global weighted (β = - 19.42 mm2, 95%CI: -28.90 mm2 to -9.95 mm2, P = 5.85 × 10-5). Furthermore, we estimated that 42.25% and 47.21% of the aforementioned effects are mediated through vascular calcification, respectively. Osteoporosis leads to a reduction in the SA of the brain cortical, suggesting the presence of the bone-brain axis. Vascular calcification plays a role in mediating this process to a certain extent. These findings establish a theoretical foundation for further investigations into the intricate interplay between bone, blood vessels, and the brain.

Nutritional, Clinical and Sociodemographic Profiles of Spanish Patients with Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a chronic and progressive neurodegenerative disease that leads to the loss of motor neurons. The dietary intake of ALS patients is thought to influence the prognosis and progression of the disease. The aim of this study was to examine the nutritional, clinical and sociodemographic characteristics of ALS patients in Spain. A cross-sectional descriptive study with demographics, clinical anamnesis and anthropometric assessment was carried out. Nutritional intake was recorded and compared with dietary reference intakes (DRI). Forty subjects (25 males; 15 females) aged 54.7 ± 10.17 were included in the study. The mean weight and height were 67.99 ± 8.85 kg and 167.83 ± 8.79 cm, respectively. Clinical phenotype, time to diagnosis, year of onset and family history were not associated with the place of origin. Clinical phenotype had no influence on time of diagnosis. Caloric and protein intakes were adequate, while carbohydrate, vitamin B8 and iodine intakes were significantly lower than the DRI. Lipids; vitamins B1, B2, B3, B5, B6, B12, C and E; sodium; phosphorus; and selenium intakes were significantly higher than the recommended nutritional standards. ALS patients, who are homogeneously distributed throughout our national territory, should modify their dietary habits to minimize ultra-processed products and prioritize foods rich in healthy fats and fiber.

Amyotrophic lateral sclerosis and osteoporosis: a two-sample Mendelian randomization study

Background

A few observational studies revealed that amyotrophic lateral sclerosis (ALS) was tightly connected with osteoporosis. However, the results of previous studies were inconsistent, and the causal effect of ALS on osteoporosis has not been investigated. To do so, the two-sample Mendelian randomization (MR) method was employed to estimate the causality.

Methods

The instrumental variables (IVs) for ALS were selected from one GWAS summary dataset (27,205 ALS cases and 110,881 controls), and bone mineral density (BMD) in the femoral neck (FN), lumbar spine (LS), and forearm, extracted from another large-scale GWAS summary database (53,236 cases), were used as phenotypes for osteoporosis. Random-effects inverse variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode were conducted to evaluate the causality. Sensitivity analyses were further performed to explore heterogeneity and pleiotropy.

Results

A total of 10 qualified SNPs were finally selected as proxies for ALS. The results of random effects from IVW revealed that ALS has no causal effect on FN-BMD (beta: -0.038, 95% CI: -0.090 to 0.015, SE: 0.027, p = 0.158), LS-BMD (beta: -0.015, 95% CI: -0.076 to 0.046, SE: 0.031, p = 0.629), and forearm BMD (beta: 0.044, 95% CI: -0.063 to 0.152, SE: 0.055, p = 0.418). These results were confirmed using the MR-Egger, weighted median, simple model, and weighted model. No heterogeneity or pleiotropy was detected (p > 0.05 for all).

Conclusion

Contrary to previous observational studies, our study figured out that no causal effect existed between ALS and osteoporosis. The disparity in results is probably attributed to secondary effects such as physical inactivity and muscle atrophy caused by ALS.

Evaluation of bone health in terms of osteoporosis in adult patients with neuromuscular disease

Background/aim

There are no current guidelines to help clinicians decide whether patients with adult neuromuscular disease (NMD) should be screened or treated for osteoporosis (OP). This study was undertaken to investigate the presence of OP in patients with various types of NMD and to examine the relationship between OP evaluation parameters and functional status, daily living activities, balance, and ambulation levels.

Materials and methods

This cross-sectional study included 45 patients with NMDs. The patients were divided into 3 groups, depending on the affected component of the motor unit (neuronopathy group, neuropathy group, and myopathy group). The laboratory and demographic data were recorded from patient files. Functional level, pain, muscular strength, balance, and daily living activity scores were evaluated. The presence of OP was quantified using bone densitometry, fracture history, and biochemical parameters. Clinical findings were correlated with laboratory and dual-energy X-ray absorptiometry (DEXA) findings.

Results

The mean hip T-score was -1.20, and the mean lumbar spine (L1-L4) T-score was -0.95 in all groups. Six patients with T-score values of -2.5 or below were detected. Vitamin D level was found to be low in all patient groups, especially in the myopathy group, but there was no significant difference (p > 0.05). There was a negative correlation between hip T-score and the frequency of falling (r = -0.604, p = 0.022), while a positive correlation was found between hip T-score and the age at which independent walking was no longer possible (r = 0.900, p = 0.037).

Conclusion

OP is often overlooked in NMD patients with neurological problems and a high risk of falling. These patients should be screened for bone health and fragility.

Causal associations of brain structure with bone mineral density: a large-scale genetic correlation study

In this study, we aimed to investigate the causal associations of brain structure with bone mineral density (BMD). Based on the genome-wide association study (GWAS) summary statistics of 1 325 brain imaging-derived phenotypes (BIDPs) of brain structure from the UK Biobank and GWAS summary datasets of 5 BMD locations, including the total body, femoral neck, lumbar spine, forearm, and heel from the GEFOS Consortium, linkage disequilibrium score regression (LDSC) was conducted to determine the genetic correlations, and Mendelian randomization (MR) was then performed to explore the causal relationship between the BIDPs and BMD. Several sensitivity analyses were performed to verify the strength and stability of the present MR outcomes. To increase confidence in our findings, we also performed confirmatory MR between BIDPs and osteoporosis. LDSC revealed that 1.93% of BIDPs, with a false discovery rate (FDR) < 0.01, were genetically correlated with BMD. Additionally, we observed that 1.31% of BIDPs exhibited a significant causal relationship with BMD (FDR < 0.01) through MR. Both the LDSC and MR results demonstrated that the BIDPs "Volume of normalized brain," "Volume of gray matter in Left Inferior Frontal Gyrus, pars opercularis," "Volume of Estimated Total Intra Cranial" and "Volume-ratio of brain segmentation/estimated total intracranial" had strong associations with BMD. Interestingly, our results showed that more left BIDPs were causally associated with BMD, especially within and around the left frontal region. In conclusion, a part of the brain structure causally influences BMD, which may provide important perspectives for the prevention of osteoporosis and offer valuable insights for further research on the brain-bone axis.

Bone Health Status in Individuals with Amyotrophic Lateral Sclerosis: A Cross-Sectional Study on the Role of the Trabecular Bone Score and Its Implications in Neurorehabilitation

Background and Objectives: Osteoporosis is a metabolic skeletal disease resulting in low bone mass with increased bone fragility and susceptibility to fractures. May lead to rapid loss of bone mineral density (BMD) due to physical inactivity and reduced muscle contractions. Generally, the diagnosis of osteoporosis is made using dual X-ray absorptiometry (DXA), by measuring BMD and the trabecular bone score (TBS), which can be useful for detecting bone fragility and susceptibility to fractures. Therefore, the aim of this study was to investigate, using BMD and TBS, the bone health status in a sample of amyotrophic lateral sclerosis (ALS) inpatients attending neurorehabilitation. Materials and Methods: Thirty-nine patients were included in the study and underwent electrocardiogram and blood tests, including calcium and parathyroid hormone, as well as vitamin D dosage, and DXA. Results: We found that the TBS of patients with osteoporosis was lower than that of those ALS patients with osteopenia or normal bone status, both in the lumbar spine and femoral neck, although no statistical significance was reached. In addition, Spearman's correlation coefficient indicated a moderate correlation between TBS and lumbar spine BMD (r = -0.34) and a mild correlation between TBS and femoral neck BMD (r = -0.28). Conclusions: This study confirmed the hypothesis that ALS patients may exhibit deteriorated bone health with lower bone density and focused on the possible role of the TBS in the multidisciplinary approach to ALS.

Amyotrophic lateral sclerosis (ALS) and the endocrine system: Are there any further ties to be explored?

Amyotrophic Lateral Sclerosis (ALS) belongs to the family of neurodegenerative disorders and is classified as fronto-temporal dementia (FTD), progressive muscular atrophy, primary lateral sclerosis, and pseudobulbar palsy. Even though endocrine dysfunction independently impacts the ALS-related survival rate, the complex connection between ALS and the endocrine system has not been studied in depth. Here we review earlier and recent findings on how ALS interacts with hormones a) of the hypothalamus and pituitary gland, b) the thyroid gland, c) the pancreas, d) the adipose tissue, e) the parathyroid glands, f) the bones, g) the adrenal glands, and h) the gonads (ovaries and testes). Of note, endocrine issues should always be explored in patients with ALS, especially those with low skeletal muscle and bone mass, vitamin D deficiency, and decreased insulin sensitivity (diabetes mellitus). Because ALS is a progressively deteriorating disease, addressing any potential endocrine co-morbidities in patients with this malady is quite important for decreasing the overall ALS-associated disease burden. Importantly, as this burden is estimated to increase globally in the decades to follow, in part because of an increasingly aging population, it is high time for future multi-center, multi-ethnic studies to assess the link between ALS and the endocrine system in significantly larger patient populations. Last, the psychosocial stress experienced by patients with ALS and its psycho-neuro-endocrinological sequelae, including hypothalamic-pituitaryadrenal dysregulation, should become an area of intensive study in the future.