Pitfalls and biases in neuroepidemiological studies of COVID-19 and the nervous system: a critical appraisal of the current evidence and future directions.

BACKGROUND: Neurological manifestations frequently occur in individuals with COVID-19, manifesting during the acute phase, persisting beyond the resolution of acute symptoms, and appearing days or weeks after the initial onset of COVID-19 symptoms. However, predicting the incidence, course, and outcome of these neurological manifestations at the individual patient level remains challenging. Biases in study design and limitations in data collection may contribute to the inconsistency and limited validity of the reported findings. Herein, we focused on critically appraising pitfalls and biases of prior reports and provide guidance for improving the quality and standardization of future research. Patients with COVID-19 exhibit diverse demographic features, sociocultural backgrounds, lifestyle habits, and comorbidities, all of which can influence the severity and progression of the infection and its impact on other organ systems. Overlooked or undocumented comorbidities and related treatments may contribute to neurological sequelae, which may not solely be attributable to COVID-19. It is crucial to consider the potential side effects of vaccines in relation to neurological manifestations. CONCLUSION: To investigate neurological manifestations of COVID-19, it is essential to employ valid and reliable diagnostic criteria and standard definitions of the factors of interest. Although population-based studies are lacking, well-defined inception cohorts, including hospitalized individuals, outpatients, and community residents, can serve as valuable compromises. These cohorts should be evaluated for the presence of common comorbidities, alongside documenting the primary non-neurological manifestations of the infectious disease. Lastly, patients with COVID-19 should be followed beyond the acute phase to assess the persistence, duration, and severity of neurological symptoms, signs, or diseases.

The impact of lifetime coffee and tea loads on Multiple Sclerosis severity.

BACKGROUND AND AIMS: The association between lifestyle factors and Multiple Sclerosis (MS) disease severity and progression has been investigated to a lesser extent compared with susceptibility to the disease. We aimed to assess the impact of lifetime coffee and tea consumption on MS severity. METHODS: Design: cross-sectional study. Two hundred and eight patients (139 females and 69 males) consecutively recruited at the Department of Neurology in Novara, Italy were asked about their lifetime consumption of coffee and tea. The lifetime intensity of consumption (cups/day) was estimated as the weighted sum of the mean number of standard cups drunk per day at different ages. A measure of cumulative lifetime load of the exposure was expressed in terms of cup-years. Disease severity was estimated by the Multiple Sclerosis Severity Score (MSSS). HLA-DRB1∗15 and HLA-A∗02 genotyping was performed in 167 patients. RESULTS: The MSSS was not associated with the status of coffee or tea consumer, or the amount of cups/day or cup-years. The Odds Ratios (OR) for falling in the upper tertile of the MSSS distribution was 1.30 (95% Confidence Interval (CI): 0.47-3.58) for coffee consumers of 1-3 cups/day and 1.14 (95%CI: 0.33-3.95) for 4-8 cups/day vs. non-consumers. The OR was 0.69 (95%CI: 0.35-1.34) for tea consumers vs. non-consumers. However, heavy consumers of coffee (4-8 cups/day) more frequently had a progressive form than small consumers (1-3 cups/day) and non-consumers (19% vs. 14% vs. 0%), and had a significantly higher age at MS onset (36.6 ± 10.3; 31.5 ± 9.5; 28.6 ± 8.1 years, p = 0.001). Although not reaching statistical significance, coffee consumers positive for HLA-A∗02 had a six-fold risk of being in the worst tertile compared to never consumers, whereas the risk was only 1.3 for coffee consumers negative for the same allele. CONCLUSIONS: Coffee or tea intake is not associated with different severity of MS. However, we cannot exclude a possible effect of higher doses of coffee for the subgroup of progressive patients.

Genomic and functional evaluation of TNFSF14 in multiple sclerosis susceptibility.

Among multiple sclerosis (MS) susceptibility genes, the strongest non-human leukocyte antigen (HLA) signal in the Italian population maps to the TNFSF14 gene encoding LIGHT, a glycoprotein involved in dendritic cell (DC) maturation. Through fine-mapping in a large Italian dataset (4,198 patients with MS and 3,903 controls), we show that the TNFSF14 intronic SNP rs1077667 is the primarily MS-associated variant in the region. Expression quantitative trait locus (eQTL) analysis indicates that the MS risk allele is significantly associated with reduced TNFSF14 messenger RNA levels in blood cells, which is consistent with the allelic imbalance in RNA-Seq reads (P < 0.0001). The MS risk allele is associated with reduced levels of TNFSF14 gene expression (P < 0.01) in blood cells from 84 Italian patients with MS and 80 healthy controls (HCs). Interestingly, patients with MS are lower expressors of TNFSF14 compared to HC (P < 0.007). Individuals homozygous for the MS risk allele display an increased percentage of LIGHT-positive peripheral blood myeloid DCs (CD11c+, P = 0.035) in 37 HCs, as well as in in vitro monocyte-derived DCs from 22 HCs (P = 0.04). Our findings suggest that the intronic variant rs1077667 alters the expression of TNFSF14 in immune cells, which may play a role in MS pathogenesis.

Coffee and Tea Consumption Impact on Amyotrophic Lateral Sclerosis Progression: A Multicenter Cross-Sectional Study.

Background/objectives: Amyotrophic lateral sclerosis (ALS) is a devastating and still untreatable motor neuron disease. The causes of ALS are unknown, but nutritional factors may impact the rate of disease progression. We aimed to ascertain the influence of coffee and tea consumption on ALS progression rate. Subjects/methods: In this multicenter cross-sectional study, we recruited 241 patients, 96 females, and 145 males; the mean age at onset was 59.9 ± 11.8 years. According to El Escorial criteria, 74 were definite ALS, 77 probable, 55 possible, and 35 suspected; 187 patients had spinal onset and 54 bulbar. Patients were categorized into three groups, according to their ΔFS (derived from ALS Functional Rating Scale-Revised score and disease duration from onset): slow (81), intermediate (80), and fast progressors (80). Results: Current coffee consumers were 179 (74.3%), 34 (14.1%) were non-consumers, and 22 (9.1%) were former consumers, whereas six (2.5%) consumed decaffeinated coffee only. The log-ΔFS was weakly correlated with the duration of coffee consumption (p = 0.034), but not with the number of cup-years, or the intensity of coffee consumption (cups/day). Current tea consumers were 101 (41.9%), 6 (2.5%) were former consumers, and 134 (55.6%) were non-consumers. Among current and former consumers, 27 (25.2%) consumed only green tea, 51 (47.7%) only black tea, and 29 (27.1%) both. The log-ΔFS was weakly correlated only with the consumption duration of black tea (p = 0.028) but not with the number of cup-years. Conclusions: Our study does not support the hypothesis that coffee or tea consumption is associated with the ALS progression rate.

The Impact of Lifetime Alcohol and Cigarette Smoking Loads on Amyotrophic Lateral Sclerosis Progression: A Cross-Sectional Study.

Background-Amyotrophic lateral sclerosis (ALS) is a devastating and untreatable motor neuron disease; smoking and alcohol drinking may impact its progression rate. Objective-To ascertain the influence of smoking and alcohol consumption on ALS progression rates. Methods-Cross-sectional multicenter study, including 241 consecutive patients (145 males); mean age at onset was 59.9 ± 11.8 years. Cigarette smoking and alcohol consumption data were collected at recruitment through a validated questionnaire. Patients were categorized into three groups according to ΔFS (derived from the ALS Functional Rating Scale-Revised and disease duration from onset): slow (n = 81), intermediate (80), and fast progressors (80). Results-Current smokers accounted for 44 (18.3%) of the participants, former smokers accounted for 10 (4.1%), and non-smokers accounted for 187 (77.6%). The age of ALS onset was lower in current smokers than non-smokers, and the ΔFS was slightly, although not significantly, higher for smokers of >14 cigarettes/day. Current alcohol drinkers accounted for 147 (61.0%) of the participants, former drinkers accounted for 5 (2.1%), and non-drinkers accounted for 89 (36.9%). The log(ΔFS) was weakly correlated only with the duration of alcohol consumption (p = 0.028), but not with the mean number of drinks/day or the drink-years. Conclusions: This cross-sectional multicenter study suggested a possible minor role for smoking in worsening disease progression. A possible interaction with alcohol drinking was suggested.

The Impact of Lifetime Alcohol and Cigarette Smoking Loads on Multiple Sclerosis Severity.

Background: The association between lifestyle factors and Multiple Sclerosis (MS) disease severity and progression has been investigated to a lesser extent compared with susceptibility to the disease. Objective: We aimed to assess the impact of lifetime alcohol and cigarette smoking load on MS severity. Methods: Design: a cross-sectional study. Three hundred fifty-one patients consecutively admitted to the Department of Neurology were asked to complete the "Questionnaire of Lifestyle" (part of the European Prospective Investigation into Cancer and Nutrition project). An estimation of the cumulative lifetime cigarette smoking and alcohol load was calculated as the weighted sum of the mean number of cigarettes smoked and standard alcoholic drinks consumed per day at different ages. The measure of exposure was expressed in terms of pack-year and drink-year. Disease severity was estimated by the Multiple Sclerosis Severity Score (MSSS). Logistic regression analyses were performed using MSSS (first tertile vs. third tertile) as the outcome. Results: The median MSSS was higher (3.2 vs. 2.3, p = 0.002) in ever- vs. never-smokers, but we did not find a difference between ever- and never-drinkers (2.7 vs. 2.8, p = ns). Ever-smokers were almost twice as likely to fall in the upper MSSS tertile than never-smokers. Ever-drinkers did not show a statistically significant association between alcohol intake and MS severity. The risk of falling in the worst MSSS tertile for smokers was 10.81 (2.0-58.48; p < 0.01) if they were never-drinkers, whereas it was only 1.65 (0.89-3.03, p = 0.11) if they were also drinkers. On the other side, the risk of falling in the worst MSSS tertile for drinkers did not change as much, whether they also were smokers (0.46; 0.13-1.65; p = 0.23) or not (1.49; 0.55-4.04, p = 0.43). Conclusions: Cigarette smoking, unlike alcohol consumption, is associated with MS severity. Alcohol consumption may attenuate the effect of smoking on disease severity, acting as an effect modifier. The biological background of this effect is unknown. The limitations of our study are mostly due to its cross-sectional design.

Risk factors for a first epileptic seizure symptomatic of brain tumour or brain vascular malformation. A case control study.

PRINCIPLES: The risk of seizures increases in patients with brain tumours (BT) and brain vascular malformations (BVM), but not all risk factors are known. We aimed to identify factors that increase the risk of a first seizure in patients with BT or BVM. METHODS: Multicentre case-control study; 102 cases with a first seizure as a presenting symptom of BT or BVM; 121 hospital controls with BT or BVM, but without seizures, matched by centre, gender and age. RESULTS: In the univariate analysis, the risk of first seizure (Odds Ratio, 95% Confidence Limits) was 6.4 (2.3-17.6) for supratentorial lesions, 4.7 (2.4-9.3) for cortical involvement, 2.5 (1.0-7.7) for family history of seizures, and 2.1 (1.2-4.1) for frontal location. The types of lesion with higher risk were low grade glioma (4.7; 1.7-13.9) and cavernous malformations (13.2; 2.1-58.0). After multivariate analysis, including all the imaging characteristics and family history, the strongest independent predictors of first seizure were cortical involvement (OR 4.0; 2.0-8.1) and type of lesion (low grade glioma: 4.0; 1.3-12.8; cavernous malformations: 12.6 (1.5-103.5). CONCLUSIONS: Cortical involvement and type of lesion are the independent risk factors for a first-ever seizure as a presenting symptom of BT or BVM.