key: cord-0267489-hz0mvxne authors: Xiong, J.; Ma, Z.; Miao, R.; Huang, J.; Kong, X.-J.; Qu, Y.; Yang, X. title: Genetically determined serum testosterone level and Covid-19 illness level: A mendelian randomization study date: 2021-10-13 journal: nan DOI: 10.1101/2021.10.10.21264779 sha: 02ba59ede91ca8cebc643cdf4b90b70c801e7dda doc_id: 267489 cord_uid: hz0mvxne Background: It is hypothesized that different levels of hormones especially serum testosterone level could explain the sex differences between men and women on the susceptibility and case fatality rate of COVID-19. However, traditional observational studies that support this hypothesis could not effectively establish the causal effects. Objective: Utilizing recently published genome-wide associations studies (GWAS) on serum Testosterone level and on COVID-19 related phenotypes, we sought to assess the causality through Mendelian Randomization (MR) analyses. We further applied a suite of statistical genomics methods to further explore the biological mechanisms. Results: We found that testosterone level is significantly associated with Covid-19 critical illness. All six MR methods yielded significant associations. There is no significant association between Testosterone and COVID-19 respiratory failure or COVID-19 susceptibility. Conclusion: Based on the GWAS currently available, we provide support for a causal role of Testosterone on COVID-19 critical illness. Nevertheless, we recognize that the COVID-19 susceptibility GWAS effort is still ongoing and there is no such strong locus as CCR5 for HIV discovered for COVID-19. It has been observed that men with COVID-19 are more at risk for worse outcomes and death, independent of age. 1 Furthermore, the case fatality rate in men is twice of that in women. One theory is that different levels of hormones especially serum testosterone could explain. However, it is apparent that sex difference is driven by and associated with many more other (risk) factors. Height is an obvious one: although height is also reported to be associated with Covid-19 susceptibility, the association is far too weak to explain the 2:1 ratio of case fatality between men and women. Within males, it is reported that low testosterone levels in the blood are linked to more severe progression of Covid-19. 2 Still, these types of studies could not conclude that this association is causal. While it is plausible that testosterone plays a protecting role, it was also reported that genetically predicted endogenous testosterone is detrimental for thromboembolism, heart failure, and myocardial infarction, especially in men 3 . Furthermore, observational studies could not tease apart reverse causation (the SARS-COV-2 virus induces an acute reduction in testosterone levels) and confounding effects (the low levels of testosterone could also be a marker of some other causal factors). Biologically, a high level of testosterone results in the upregulation of angiotensin-converting enzyme type 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) receptors. 4 Testosterone could affect both susceptibility to infection and disease severity through its effect on these two. 5, 6 Low levels of testosterone deregulates lung-protective pathways. 7, 8 Also, age-associated decreases in sex steroid hormones (estrogen and testosterone) may mediate proinflammatory increases in older adults that increases their risk of COVID-19 adverse outcomes. 4 All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted October 13, 2021. ; Therefore, it is imperative to assess the causal role of testosterone on Covid-19 progression. This will provide insights to ongoing clinical trials that investigates hormonal therapies that block or lower testosterone or increase estrogen as a treatment for Covid-19 patients. In this study, we apply mendelian randomization. We used 35 biomarkers, including estradiol IGF-1. We first used summary statistics data, and then we used individual level data. We run the GWAS for males and females separately, and we adjust for age, body mass index (BMI), and the other 34 biomarkers. We downloaded the Testosterone GWAS summary statistics from the Sinnott-Armstrong study, which studied and made publicly available 35 blood and urine biomarkers in the UK Biobank 9 . We merged the array data and the imputed data together. For the imputed data that does not come with rsID, we used a customized add_rsid module from pheweb to add_rsID. There are ~9 million SNPs for the merged data. We downloaded three COVID-19 GWAS summary statistics from GWAS Catalog: (1) COVID-19 critical illness 10 , (2) severe COVID-19 with respiratory failure 11 , (3) COVID-19 susceptibility 12 . For those without rsID, we used the add_rsID module mentioned above to add rsID. We used 113 independent lead SNPs associated with Testosterone level (P <5E-09) as instrumental variables. 9 Among them, 1, 12, 100 are All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted October 13, 2021. For all four GWAS, we used FUMA software 14 The Manhattan plot Testosterone GWAS was shown in Figure 1 . There is no significant association between Testosterone and COVID-19 All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted October 13, 2021. ; https://doi.org/10.1101/2021.10.10.21264779 doi: medRxiv preprint respiratory failure or COVID-19 susceptibility. Figure 3 shows the funnel plot of the MR analysis mentioned above. CCHCR1 that is genome-wide significant in both Testosterone and Covid-19 ICU GWAS (Figure 5) . The CCHCR1 gene (Coiled-Coil alpha-Helical Rod protein 1), also simplified as HCR gene, was shown to promote steroidogenesis by interacting with the steroidogenic acute regulator protein (StAR). A recent GWAS preprint by Genetics of Mortality in Clinical Care (GenOMICC) collaborators including HGI (https://genomicc.org) reported that among a few other genes CCHCR1 is associated with COVID-19 severity. 16 The lead SNP is rs72856706 (hg19 position chr6:31,120,729). It has a frequency of 0.08 for the non- (HCR) gene was reported to be relevant for skin steroidogenesis. We run a comprehensive set of statistical and bioinformatic analyses to assess the causal role of serum Testosterone level on COVID-19 related phenotypes. Our analyses results support a causal role. However, we realize the following limitations. First, the GWAS results on COVID-19 are inconsistent. The COVID-19 susceptibility GWAS effort is still ongoing and there is a lack of well-established loci. So, far, there is no such strong locus as CCR5 for HIV discovered for COVID-19. Although All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted October 13, 2021. ; it is reasonable to hypothesize that the disease severity of COVID-19 has a strong genetic underpinning, the GWAS on these traits published so far are also inconsistent. The two GWAS used by the current study 1011 don't have very consistent signals. Both studies only have thousands of cases, much smaller compared with many existing GWAS for other complex traits. Gender Differences in Patients With COVID-19: Focus on Severity and Mortality. Front Public Health 8 Association of Circulating Sex Hormones With Inflammation and Disease Severity in Patients With COVID-19 Association of genetically predicted testosterone with thromboembolism, heart failure, and myocardial infarction: mendelian randomisation study in UK Biobank Sex Hormones and Novel Corona Virus Infectious Disease Testosterone's Role in COVID-19 The Double Edge Sword of Testosterone's Role in the COVID-19 Pandemic ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19 Screening for low testosterone is needed for early identification and treatment of men at high risk of mortality from Covid-19 Genetics of 35 blood and urine biomarkers in the UK Biobank Genetic mechanisms of critical illness in COVID-19 Genomewide Association Study of Severe Covid-19 with Respiratory Failure The COVID-19 Host Genetics Initiative, a global initiative to elucidate the role of host genetic factors in susceptibility and severity of the SARS-CoV-2 virus pandemic MendelianRandomization v0.5.0: updates to an R package for performing Mendelian randomization analyses using summarized data Functional mapping and annotation of genetic associations with FUMA clusterProfiler 4.0: A universal enrichment tool for interpreting omics data Host Genetics at the Intersection of Autoimmunity and COVID-19: A Potential Key for Heterogeneous COVID-19 Severity No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity