Creation of a pandemic memory by tracing COVID-19 infections and immunity in Luxembourg (CON-VINCE)

BACKGROUND

During the COVID-19 pandemic swift implementation of research cohorts was key. While many studies focused exclusively on infected individuals, population based cohorts are essential for the follow-up of SARS-CoV-2 impact on public health. Here we present the CON-VINCE cohort, estimate the point and period prevalence of the SARS-CoV-2 infection, reflect on the spread within the Luxembourgish population, examine immune responses to SARS-CoV-2 infection and vaccination, and ascertain the impact of the pandemic on population psychological wellbeing at a nationwide level.

METHODS

A representative sample of the adult Luxembourgish population was enrolled. The cohort was followed-up for twelve months. SARS-CoV-2 RT-qPCR and serology were conducted at each sampling visit. The surveys included detailed epidemiological, clinical, socio-economic, and psychological data.

RESULTS

One thousand eight hundred sixty-five individuals were followed over seven visits (April 2020-June 2021) with the final weighted period prevalence of SARS-CoV-2 infection of 15%. The participants had similar risks of being infected regardless of their gender, age, employment status and education level. Vaccination increased the chances of IgG-S positivity in infected individuals. Depression, anxiety, loneliness and stress levels increased at a point of study when there were strict containment measures, returning to baseline afterwards.

CONCLUSION

The data collected in CON-VINCE study allowed obtaining insights into the infection spread in Luxembourg, immunity build-up and the impact of the pandemic on psychological wellbeing of the population. Moreover, the study holds great translational potential, as samples stored at the biobank, together with self-reported questionnaire information, can be exploited in further research.

TRIAL REGISTRATION

Trial registration number: NCT04379297, 10 April 2020.

Luxembourg Parkinson's study -comprehensive baseline analysis of Parkinson's disease and atypical parkinsonism

Background

Deep phenotyping of Parkinson's disease (PD) is essential to investigate this fastest-growing neurodegenerative disorder. Since 2015, over 800 individuals with PD and atypical parkinsonism along with more than 800 control subjects have been recruited in the frame of the observational, monocentric, nation-wide, longitudinal-prospective Luxembourg Parkinson's study.

Objective

To profile the baseline dataset and to explore risk factors, comorbidities and clinical profiles associated with PD, atypical parkinsonism and controls.

Methods

Epidemiological and clinical characteristics of all 1,648 participants divided in disease and control groups were investigated. Then, a cross-sectional group comparison was performed between the three largest groups: PD, progressive supranuclear palsy (PSP) and controls. Subsequently, multiple linear and logistic regression models were fitted adjusting for confounders.

Results

The mean (SD) age at onset (AAO) of PD was 62.3 (11.8) years with 15% early onset (AAO < 50 years), mean disease duration 4.90 (5.16) years, male sex 66.5% and mean MDS-UPDRS III 35.2 (16.3). For PSP, the respective values were: 67.6 (8.2) years, all PSP with AAO > 50 years, 2.80 (2.62) years, 62.7% and 53.3 (19.5). The highest frequency of hyposmia was detected in PD followed by PSP and controls (72.9%; 53.2%; 14.7%), challenging the use of hyposmia as discriminating feature in PD vs. PSP. Alcohol abstinence was significantly higher in PD than controls (17.6 vs. 12.9%, p = 0.003).

Conclusion

Luxembourg Parkinson's study constitutes a valuable resource to strengthen the understanding of complex traits in the aforementioned neurodegenerative disorders. It corroborated several previously observed clinical profiles, and provided insight on frequency of hyposmia in PSP and dietary habits, such as alcohol abstinence in PD.Clinical trial registration: clinicaltrials.gov, NCT05266872.

Machine learning for predicting neurodegenerative diseases in the general older population: a cohort study

BACKGROUND

In the older general population, neurodegenerative diseases (NDs) are associated with increased disability, decreased physical and cognitive function. Detecting risk factors can help implement prevention measures. Using deep neural networks (DNNs), a machine-learning algorithm could be an alternative to Cox regression in tabular datasets with many predictive features. We aimed to compare the performance of different types of DNNs with regularized Cox proportional hazards models to predict NDs in the older general population.

METHODS

We performed a longitudinal analysis with participants of the English Longitudinal Study of Ageing. We included men and women with no NDs at baseline, aged 60 years and older, assessed every 2 years from 2004 to 2005 (wave2) to 2016-2017 (wave 8). The features were a set of 91 epidemiological and clinical baseline variables. The outcome was new events of Parkinson's, Alzheimer or dementia. After applying multiple imputations, we trained three DNN algorithms: Feedforward, TabTransformer, and Dense Convolutional (Densenet). In addition, we trained two algorithms based on Cox models: Elastic Net regularization (CoxEn) and selected features (CoxSf).

RESULTS

5433 participants were included in wave 2. During follow-up, 12.7% participants developed NDs. Although the five models predicted NDs events, the discriminative ability was superior using TabTransformer (Uno's C-statistic (coefficient (95% confidence intervals)) 0.757 (0.702, 0.805). TabTransformer showed superior time-dependent balanced accuracy (0.834 (0.779, 0.889)) and specificity (0.855 (0.0.773, 0.909)) than the other models. With the CoxSf (hazard ratio (95% confidence intervals)), age (10.0 (6.9, 14.7)), poor hearing (1.3 (1.1, 1.5)) and weight loss 1.3 (1.1, 1.6)) were associated with a higher DNN risk. In contrast, executive function (0.3 (0.2, 0.6)), memory (0, 0, 0.1)), increased gait speed (0.2, (0.1, 0.4)), vigorous physical activity (0.7, 0.6, 0.9)) and higher BMI (0.4 (0.2, 0.8)) were associated with a lower DNN risk.

CONCLUSION

TabTransformer is promising for prediction of NDs with heterogeneous tabular datasets with numerous features. Moreover, it can handle censored data. However, Cox models perform well and are easier to interpret than DNNs. Therefore, they are still a good choice for NDs.

Age at onset as stratifier in idiopathic Parkinson’s disease – effect of ageing and polygenic risk score on clinical phenotypes

Several phenotypic differences observed in Parkinson’s disease (PD) patients have been linked to age at onset (AAO). We endeavoured to find out whether these differences are due to the ageing process itself by using a combined dataset of idiopathic PD (n = 430) and healthy controls (HC; n = 556) excluding carriers of known PD-linked genetic mutations in both groups. We found several significant effects of AAO on motor and non-motor symptoms in PD, but when comparing the effects of age on these symptoms with HC (using age at assessment, AAA), only positive associations of AAA with burden of motor symptoms and cognitive impairment were significantly different between PD vs HC. Furthermore, we explored a potential effect of polygenic risk score (PRS) on clinical phenotype and identified a significant inverse correlation of AAO and PRS in PD. No significant association between PRS and severity of clinical symptoms was found. We conclude that the observed non-motor phenotypic differences in PD based on AAO are largely driven by the ageing process itself and not by a specific profile of neurodegeneration linked to AAO in the idiopathic PD patients.

An individualized functional magnetic resonance imaging protocol to assess semantic congruency effects on episodic memory in an aging multilingual population

The cognitive stimulation induced by multilingualism may slow down age-related memory impairment. However, a suitable neuroscientific framework to assess the influence of multilingualism on age-related memory processes is missing. We propose an experimental paradigm that assesses the effects of semantic congruency on episodic memory using functional magnetic resonance imaging (fMRI). To this end, we modified the picture-word interference (PWI) task to be suitable for the assessment of older multilingual subjects undergoing fMRI. In particular, stimulus materials were prepared in multiple languages (French, German, Luxembourgish, English) and closely matched in semantic properties, thus enabling participants to perform the experiment in a language of their choice. This paradigm was validated in a group (n = 62) of healthy, older participants (over 64 years) who were multilingual, all practicing three or more languages. Consistent with the engagement of semantic congruency processes, we found that the encoding and recognition of semantically related vs. unrelated picture-word pairs evoked robust differences in behavior and the neural activity of parietal-temporal networks. These effects were negligibly modulated by the language used to perform the task. Based on this validation in a multilingual population, we conclude that the proposed paradigm will allow future studies to evaluate whether multilingualism aptitude engages neural systems in a manner that protects long-term memory from aging-related decline.

Prevalence and Cost of Care for Parkinson's Disease in Luxembourg: An Analysis of National Healthcare Insurance Data

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disorder, with an increasing prevalence worldwide. Estimates of the economic burden associated with PD vary widely across existing studies due to differences in setting and study design. The prevalence and cost of care for PD in Luxembourg are currently unknown.

OBJECTIVE

The aims of this study were to estimate (1) the prevalence of PD in Luxembourg and (2) the cost of care for PD to the national healthcare insurance based on routinely collected healthcare data.

METHODS

This analysis was based on individual patient-level data collected by the national healthcare insurance in Luxembourg during 2007-2017, which covers over 95% of the resident population. People with PD were identified based on drug reimbursement profiles. Cost of care was estimated according to a comparative analysis of the healthcare resources consumed by people with PD compared with an age- and sex-matched control group.

RESULTS

We determined a PD prevalence of 928 per 100,000 individuals aged 50 years and older in 2016, higher in men (1032 per 100,000) than in women (831 per 100,000). The total mean cost of care for PD was estimated at €22,673 per patient per year in 2016, with the highest costs being associated with long-term care (69%).

CONCLUSION

This was the first attempt to estimate the prevalence and cost of care of PD in Luxembourg. The work demonstrated the usefulness of routinely collected data in Luxembourg for such analyses. Our study confirms the significant burden of PD to the healthcare system, especially on long-term care.

Depression burden in luxembourg: Individual risk factors, geographic variations and the role of migration, 2013-2015 European Health Examination Survey

BACKGROUND

Depression is a complex mental disorder that affects an increasing proportion of the worldwide population. This study aims to estimate the prevalence of depressive symptoms in Luxembourg, associated risk factors and geographic variations. Additionally, it aims to assess whether first and second generation immigrants are at higher risk for depressive symptoms compared to non-immigrants.

METHODS

Representative cross-sectional data from 1499 residents of Luxembourg, aged 25-64 years, were collected from the Luxembourg European Health Survey (EHES-LUX). Depressive symptoms were defined as a score of ≥5 on the Patient Health Questionnaire for depression (PHQ-9) (i.e. mild, moderate or severe). Standard and Bayesian regression models were used to examine associations between depressive symptoms, immigration status and geographic distribution across Luxembourg.

RESULTS

The prevalence of depressive symptoms was 21.55% (15.54% mild, 3.54% moderate, and 2.49% moderately severe to severe). The odds of having depressive symptoms was higher among second generation immigrants compared to non-immigrants (OR: 1.58, 95% CI: 1.04, 2.41), independent of socioeconomic and behavioral characteristics. Healthier diet, higher social support and good health perception were protective towards experiencing depressive symptoms. One of the highest likelihoods of reporting depressive symptoms was observed in the South-West of the country with a positive effect at 80% credible region [CR] (1.42 [0.92, 2.73]).

LIMITATIONS

The participation rate was low (26.7%). The cross-sectional nature of the study does not allow us to establish causality.

CONCLUSIONS

Depression constitutes an important public health challenge in Luxembourg due to the impact on the overall health of the population. Social programs of health promotion should be developed to improve mental wellbeing in immigrants, especially those of second generation.

Lifelong exposure to multilingualism: new evidence to support cognitive reserve hypothesis

Objective

Investigate the protective effect of multilingualism on cognition in seniors.

Methods

As part of the MemoVie study conducted on 232 non-demented volunteers aged 65 and more, neurogeriatric and neuropsychological evaluations were performed. Participants were classified as presenting either cognitive impairment without dementia (CIND) or being free of any cognitive impairment (CIND-free). Language practices, socio-demographic data and lifestyle habits were recorded. In this retrospective nested case-control design, we used as proxies of multilingualism: number of languages practiced, age of acquisition and duration of practice, emphasizing the temporal pattern of acquisition, and the resulting practice of several languages sequentially or concomitantly during various periods of life. This special angle on the matter offered to our work a dimension particularly original and innovative.

Results

44 subjects (19%) had CIND, the others were cognitively normal. All practiced from 2 to 7 languages. When compared with bilinguals, participants who practiced more than 2 languages presented a lower risk of CIND, after adjustment for education and age (odds ratio (OR) = 0.30, 95% confidence limits (95%CL) = [0.10–0.92]). Progressing from 2 to 3 languages, instead of staying bilingual, was associated with a 7-fold protection against CIND (OR = 0.14, 95%CL = [0.04–0.45], p = 0.0010). A one year delay to reach multilingualism (3 languages practiced being the threshold) multiplied the risk of CIND by 1.022 (OR = 1.022, 95%CL = [1.01–1.04], p = 0.0044). Also noteworthy, just as for multilingualism, an impact of cognitively stimulating activities on the occurrence of CIND was found as well (OR = 0.979, 95%CL = [0.961–0.998], p = 0.033).

Conclusion

The study did not show independence of multilingualism and CIND. Rather it seems to show a strong association toward a protection against CIND. Practicing multilingualism from early life on, and/or learning it at a fast pace is even more efficient. This protection might be related to the enhancement of cognitive reserve and brain plasticity, thereby preserving brain functions from alterations during aging.

The epidemiology of mild cognitive impairment (MCI) and Alzheimer's disease (AD) in community-living seniors: protocol of the MemoVie cohort study, Luxembourg

Background

Cognitive impairment and Alzheimer’s disease (AD) are increasingly considered a major public health problem. The MemoVie cohort study aims to investigate the living conditions or risk factors under which the normal cognitive capacities of the senior population in Luxembourg (≥ 65 year-old) evolve (1) to mild cognitive impairment (MCI) – transitory non-clinical stage – and (2) to AD. Identifying MCI and AD predictors undeniably constitutes a challenge in public health in that it would allow interventions which could protect or delay the occurrence of cognitive disorders in elderly people. In addition, the MemoVie study sets out to generate hitherto unavailable data, and a comprehensive view of the elderly population in the country.

Methods/design

The study has been designed with a view to highlighting the prevalence in Luxembourg of MCI and AD in the first step of the survey, conducted among participants selected from a random sample of the general population. A prospective cohort is consequently set up in the second step, and appropriate follow-up of the non-demented participants allows improving the knowledge of the preclinical stage of MCI. Case-control designs are used for cross-sectional or retrospective comparisons between outcomes and biological or clinical factors. To ensure maximal reliability of the information collected, we decided to opt for structured face to face interviews. Besides health status, medical and family history, demographic and socio-cultural information are explored, as well as education, habitat network, social behavior, leisure and physical activities. As multilingualism is expected to challenge the cognitive alterations associated with pathological ageing, it is additionally investigated. Data relative to motor function, including balance, walk, limits of stability, history of falls and accidents are further detailed. Finally, biological examinations, including ApoE genetic polymorphism are carried out. In addition to standard blood parameters, the lipid status of the participants is subsequently determined from the fatty acid profiles in their red blood cells. The study obtained the legal and ethical authorizations.

Discussion

By means of the multidisciplinary MemoVie study, new insights into the onset of cognitive impairment during aging should be put forward, much to the benefit of intervention strategies as a whole.

Frequency and clinical outcomes of flares related to nucleos(t)ide analogue therapy in patients with chronic hepatitis B

Flares in chronic hepatitis B are often detrimental but sometimes lead to sustained immune control and disease remission. The aim of this study was to estimate the frequency of hepatitis flares which occur during and/or after cessation of nucleos(t)ide analogue (NA) therapy, and to assess their outcomes. In a single centre cohort study we investigated 227 patients who received a total of 351 NA treatment courses. NA therapy was discontinued after 149 treatment courses. In total, 27 flares were observed during 9779 on-treatment patient-months. The frequency was estimated as 3.2 per 100 person-years (95% CI 2.2-4.7). Lamivudine (LAM)-treated patients demonstrated the highest frequency (4.9/100 person-years, 95% CI 3.2-7.4). Twenty (74%) of 27 on-therapy flares were associated with development of genotypic resistance, which all occurred during LAM therapy. NA withdrawal flares occurred after a median post-treatment follow-up of 3.5 months in 17 (11%) of 149 treatment discontinuations. No flares were observed in patients who switched to another antiviral agent (n = 51). None of the on-therapy and withdrawal flares related to NA therapy were associated with sustained disease remission, and seven flares resulted in decompensated liver disease. In this study, flares related to NA therapy never led to immune control and sustained disease remission, and sometimes resulted in decompensated liver disease.

[Development of the medical treatment of diabetes in Luxembourg]

OBJECTIVES

The aims of the study were to estimate the prevalence of diabetes in Luxembourg in 2002, to compare it to the prevalence reported in 1991 and to evaluate if prescription attitudes have changed since 1991.

METHODS

The prevalence of diabetes was estimated using the drug sales data. The key parameters, total amount of antidiabetic drugs sold in one year and the average daily dose or Prescribed Daily Dose (PDD), have been obtained from the National Social Security Organization and by a standardized questionnaire sent to all general practitioners and all internists and endocrinologists of the country.

RESULTS

The PDD was calculated on 2,402 questionnaires on individual diabetic patients. By this mean, the proportion of patients only treated with appropriate diet could also be obtained. Compared to 1991, the total amount of antidiabetic drugs showed a four-fold increase in biguanides tablet prescriptions. A high percentage of combined treatments was found. The prevalence of diabetes in Luxembourg was found to be 3.05% of the total population.

CONCLUSIONS

Compared to the status in 1991, prevalence of diabetes increased by 63%, which seems mainly due to type 2 diabetic patients as orally-treated diabetic patients almost doubled (2.11% vs 1.16%). A substantial change in prescriptions for diabetes has occurred, suggesting a positive influence of studies like the United Kingdom Prospective Diabetes Study (UKPDS).

Changes in diabetes prevalence and treatment in the last ten years in Luxembourg. A lesson from the United Kingdom prospective diabetes study?

OBJECTIVES

The aims of the study were to estimate the prevalence of diabetes in Luxembourg in 2002, to compare it to the prevalence reported in 1991 and to evaluate if prescription attitudes have changed since 1991.

METHODS

The prevalence of diabetes was estimated using the drug sales data. The key parameters, total amount of antidiabetic drugs sold in one year and the average daily dose or Prescribed Daily Dose (PDD), have been obtained from the National Social Security Organization and by a standardized questionnaire sent to all general practitioners and all internists and endocrinologists of the country.

RESULTS

The PDD was calculated on 2, 402 questionnaires on individual diabetic patients. By this means, the proportion of patients only treated with appropriate diet could also be obtained. Compared to 1991, the total amount of antidiabetic drugs showed a four-fold increase in metformine tablet prescriptions. A high percentage of combined treatments was found. The prevalence of diabetes in Luxembourg was found to be 3.05% of the total population.

CONCLUSIONS

Compared to the status in 1991, prevalence of diabetes increased by 63%, which seems mainly due to type 2 diabetic patients as orally-treated diabetic patients almost doubled (2.11% vs 1.16%). A substantial change in prescriptions for diabetes has occurred, suggesting a positive influence of studies like the United Kingdom Prospective Diabetes Study (UKPDS).

The glutathione-related detoxification system is increased in human breast cancer in correlation with clinical and histopathological features

PURPOSE

The glutathione detoxification pathway includes glutathione S-transferase (GST) and peroxidase (GPX) isoenzymes as well as glutathione reductase (GSSR). Though well established from cultured cancer cell lines, its involvement in resistance is still unclear in the tumours. This study aimed to describe the parameters that influence the glutathione contents and associated activities in breast cancer.

METHODS

The components of the glutathione pathway were measured in the tumours from 41 women with primary breast cancer in comparison with those in the matched tumour-free samples. Appropriate statistical studies (regression analysis, Wilcoxon signed rank test) explored the influence of clinical and prognostic factors.

RESULTS

Reduced and total glutathione contents were largely increased (P < 0.0001) and all related activities were significantly enhanced in the tumours. Interindividual variations were described, probably due to various parameters (age, menopause, axillary lymph node status, S and G2 + M cell fractions, ER, cathepsin-D and c-ErbB-2 expressions) that influence particular components of the glutathione pathway, especially the glutathione levels.

CONCLUSIONS

The breast tumours improved their redox status and detoxification capacities depending on various parameters of significance for cell proliferation and aggressiveness, which supports the involvement of the glutathione pathway in malignant cell resistance to oxidative stress and apoptosis.

The glutathione-related detoxification pathway in the human breast: a highly coordinated system disrupted in the tumour tissues

Glutathione and the associated enzymes, glutathione S-transferases, peroxidases, and reductase, have been implicated in cancer chemoresistance. This pathway was investigated in paired cancerous and peritumoral breast samples from 41 women. The tumours exhibited a higher redox status as deduced from increased transferase, peroxidase, and reductase activities and from higher total and reduced glutathione contents. Several components were strongly correlated in peritumoral tissues, suggesting a highly co-ordinated glutathione pathway that appeared disrupted in breast tumours with only a few correlations left. Therefore, resistance could spontaneously result from deregulated variations in the glutathione pathway, which might be relevant to the malignant disease progression.

Anti-Hu antibody titre and brain metastases before and after treatment for small cell lung cancer

OBJECTIVES

To follow up the level of anti-Hu antibody titres during chemotherapy and to compare the pattern of metastases and other neurological complications before and after chemotherapy in patients with small cell lung cancer (SCLC) with and without low titre anti-Hu antibodies. Seventeen per cent of patients with SCLC without paraneoplastic syndromes have a low titre of anti-Hu antibodies in their serum. Previous studies suggested that these antibodies correlate with a more indolent tumour growth.

METHODS

The serum of 52 consecutive patients with SCLC were studied before and during chemotherapy, and the correlation with stage of disease and pattern of metastases was examined. All serum samples were investigated using western blot and enzyme linked immunosorbent assay (ELISA) with HuD recombinant protein. All patients with SCLC were investigated using MRI of the brain, CSF, bone marrow aspiration, ultrasound of the abdomen, and radionuclide bone scan.

RESULTS

Nine (17%) of 52 SCLC serum samples were positive by western blot. At the time of diagnosis none of the anti-Hu positive patients had either CNS (brain or leptomeningeal), epidural, adrenal, or bone marrow metastases and 56% had limited disease. In eight of 43 anti-Hu negative patients CNS metastases were found at the time of diagnosis, and only 30% had limited disease. The prevalence of bone and liver metastases was similar in both groups. Survival was 11 (SD ) months for the 43 anti-Hu negative and 10 (SD 6) months for the nine anti-Hu positive patients. Male:female ratio in the anti-Hu negative group was 4.4:1, and in the anti-Hu positive group 2:1.

CONCLUSIONS

No anti-Hu antibody positive serum, as tested by western blot, became negative during chemotherapy. Anti-Hu positive and anti-Hu negative patients had similar survival, but anti-Hu positive patients tended to be women, had limited disease at the time of tumour diagnosis, and initially metastases seemed to spare the nervous system.