key: cord-0978280-110nqkej authors: Lansiaux, Édouard; Pébaÿ, Philippe P.; Picard, Jean-Laurent; Son-Forget, Joachim title: Covid-19 And Vit-D: Disease Mortality Negatively Correlates With Sunlight Exposure date: 2020-07-23 journal: Spat Spatiotemporal Epidemiol DOI: 10.1016/j.sste.2020.100362 sha: baaeae29536df8c08e2cc2b0596c3ffcb4de1ddd doc_id: 978280 cord_uid: 110nqkej The novel COVID-19 disease is a contagious acute respiratory infectious disease whose causative agent has been demonstrated to be a new virus of the coronavirus family, SARS-CoV-2. Alike with other coronaviruses, some studies show a COVID-19 neurotropism, inducing de-myelination lesions as encountered in Guillain-Barré syndrome. In particular, an Italian report concluded that there is a significant vitamin D deficiency in COVID-19 infected patients. In the current study, we applied a Pearson correlation test to public health as well as weather data, in order to assess the linear relationship between COVID-19 mortality rate and the sunlight exposure. For instance in continental metropolitan France, average annual sunlight hours are significantly (for a p-value of 1.532 × 10(−32)) correlated to the COVID-19 mortality rate, with a Pearson coefficient of -0.636. This correlation hints at a protective effect of sunlight exposure against COVID-19 mortality. This paper is proposed to foster academic discussion and its hypotheses and conclusions need to be confirmed by further research. The novel COVID-19 disease is a contagious acute respiratory infectious disease whose causative agent has been demonstrated to be a new virus of the coronavirus family, SARS-CoV-2. Alike with other coronaviruses, some studies show a COVID-19 neurotropism, inducing de-myelination lesions as encountered in Guillain-Barré syndrome. In particular, an Italian report concluded that there is a significant vitamin D deficiency in infected patients. In the current study, we applied a Pearson correlation test to public health as well as weather data, in order to assess the linear relationship between COVID-19 mortality rate and the sunlight exposure. For instance in continental metropolitan France, average annual sunlight hours are significantly (for a p-value of 1.532x10 -32 ) correlated to the COVID-19 mortality rate, with a Pearson coefficient of -0.636. This correlation hints at a protective effect of sunlight exposure against COVID-19 mortality. This paper is proposed to foster academic discussion and its hypotheses and conclusions need to be confirmed by further research. Keywords: COVID-19; Coronavirus; France; Correlation; Vitamin D; Phototherapy; UV. La nouvelle infection au COVID-19 est une maladie respiratoire infectieuse sévère dont l'agent causal a été identifié comme un nouveau virus de la famille des coronavirus , SARS-CoV-2. Comme les autres coronavirus, des études montrent un neurotropisme du COVID-19, induisant des lésions démyélinisantes comme dans le syndrome de Guillain-Barré. Plus particulièrement, une note italienne conclue qu'il y a un déficit significatif en vitamine D chez les patients infectés par le COVID-19. . Patients with the coronavirus pneumonia typically exhibit a fever, with temperature above 38 degrees © and other symptoms such as dry cough, fatigue, dyspnea, difficulty breathing, and diarrhea 1.5 . Furthermore, this diseases has a relatively high transmission rate as compared to other upper respiratory illnesses. As a result of this and other factors such as international travel and trade, the initial epidemic has turned into a pandemic in March 2020, with hundreds thousands of individuals confirmed to be infected worldwide -and most likely millions of unreported cases 5 . Similar to other coronaviruses-caused illnesses 6 , COVID-19 infection has shown some amount of neurotropism [7] [8] [9] , with lesions not unlike those of the Guillain-Barré demyelination 8 or hemorrhagic necrotizing encephalopathy 7, 9 . Meanwhile, it has long been noted that in the case of Guillain-Barré syndrome, vitamin D deficiency, in relation with high latitude climates, is both a causal and a risk factor 10, 11 . Furthermore, a recent Italian note has demonstrated a significant vitamin D deficiency in a cohort of COVID-19 infected elderly women 12 . Therefore, it is important to assess the effect of vitamin D blood levels on COVID-19 infection rate and disease course, as it may offer preventative and/or curative options in the context of the ongoing pandemic. Specifically in the context of continental metropolitan France, the correlation between sunlight exposure and SARS-CoV-2 infection will be studied in this article, by using an adjusted Pearson test applied to public health and weather data [13] [14] [15] . We conducted a descriptive observational cross-sectional study in order to define a hypothetical relationship between sunlight exposure and SARS-CoV-2 infection. The source and targeted populations are the whole humanity in view of the ongoing COVID-19 pandemic. The eligible population is constituted by the residents of metropolitan continental France. The study was conducted by a consortium of two data analysts, a MD-PhD specialized in radiology, and a medical student in clinical years. NexGen Analytics had no role in making the decision to submit manuscript to the publication, nor did it receive any fee or compensation in the context of this work. The first author vouches for the data and analyses, as well as for the fidelity of this report to the study protocol. We gathered COVID-19-related data from various public health and social sources 13, 15 . A parallel multiple group analysis was performed. We excluded the population from the non-metropolitan jurisdictions of France(Guyane, Mayotte, Martinique, Reunion, Guadeloupe, etc.), due to (1) the fact that their climates vastly differ from that of metropolitan France, and (2) the substantially lower access to healthcare in these areas. Moreover, albeit part of metropolitan France, the island of Corsica was excluded from this study because of poorer access to healthcare there than on the continent. We chose to use COVID-19 mortality rate as the primary variable to evaluate the role of SARS-CoV-2 infection in our hypothetical correlation. Sunlight exposure was evaluated by using the average annual hours of sunshine exposure, as reported by that country's national weather service ("Météo France") 14 . Our null hypothesis (H 0 ) was the non-correlation between average sunlight hours at the locality (X) and COVID-19 mortality rate (Y). In order to assess the potential effect of confounding factors, we also considered (1) Finally, in order to further sustain our analysis, we also considered the confirmed COVID-19 infection cases as well as the number of verified recovered COVID-19 patients. We began by computing several descriptive statistics for each variable: arithmetic mean, sample variance, standard deviation and the corresponding confidence intervals (justified by having Shapiro-Wilk tested each of these variables). Obviously unrelated to COVID-19 mortality, the 2019 birth and death rates were kept off the analysis. Furthermore, age was also eliminated from this analysis as the national statistics in this regard are provided in the form of age classes not directly usable in the context of Pearson correlation analysis. All other variables were treated using the Pearson correlation test, and the corresponding p-value are reported here in order to assess the statistical significance of these correlations. The This population was subsequently partitioned by region of residence (NB: "region" is the largest sub-national jurisdiction of France), as summarized in Table 1 . We note that none of the resulting subgroups was found to exhibit values significantly outside of their respective confidence intervals, per a MANOVA-Wilk test performed at the 5% significance level (Table 2) . The primary outcome of this analysis was the Pearson coefficient between sunlight exposure and COVID-19 mortality rate, for which we found a value of -0.6368. With a corresponding p-value 1.532*10 -32 , this allows us to reject the null hypothesis H 0 ( We have shown via Pearson correlation that sunlight exposure is significantly correlated (p-value: 1.532*10 -32 ) COVID-19 mortality rate in continental metropolitan France (Table 3) , which is the main outcome of this study. Besides, we acknowledge an interesting secondary finding: namely, the protective effect of life expectancy (Pearson r: 0.512; p-value: 7.951*10 -31 ) and discuss it further as it appears counter-intuitive, as older age is already been broadly documented as being associated with worse COVID-19 outcomes. However, we also note that in our sample life expectancy is strongly positively correlated with sunlight exposure (Pearson r: 1.628*10 (Table 3) , and possibly other unknown population confounding variables. Nevertheless, our regression, linked with the hypothesized physiopathological mechanism 12 , suggests a first order effect at least. We thus contend that the findings presented in our analysis should be taken into account, in order to envision possibly effective yet inexpensive diagnostic and therapeutic options against the novel COVID-19. Our conclusions could easily be tested and further assessed by screening the prevalence of COVID-19 infected among vitamin D deficient patients. In addition, in vitro cell studies and animal models could be of interest to test our statistical correlation and the physiopathological hypothesis. Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus-Infected Pneumonia in Wuhan, China Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. The Lancet Clinical Characteristics of Coronavirus Disease 2019 in China Epidemiologic and Clinical Characteristics of Novel Coronavirus Infections Involving 13 Patients Outside Wuhan, China HRCT Imaging Features in Representative Imported Cases of Le potentiel neurotrope des coronavirus. Médecine/sciences COVID-19-associated Acute Hemorragic Necrotizing Encephalopathy: CT and MRI Features. Radiol Guillain-Barré syndrome associated with SARS-CoV-2 infection: causality or coincidence? The Lancet Neurologic Manifestations of Hospitalized Patients With Coronavirus Disease Pulmonary activation of vitamin D3 and preventive effect against interstitial pneumonia Vitamin D Defiency in Patients With Primary-Immune Mediated