Covid-19: Fat, Obesity, Inflammation, Ethnicity, and Sex Differences

New insights into the pathogenesis of SARS-CoV-2 during and after the COVID-19 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the respiratory distress condition known as COVID-19. This disease broadly affects several physiological systems, including the gastrointestinal, renal, and central nervous (CNS) systems, significantly influencing the patient's overall quality of life. Additionally, numerous risk factors have been suggested, including gender, body weight, age, metabolic status, renal health, preexisting cardiomyopathies, and inflammatory conditions. Despite advances in understanding the genome and pathophysiological ramifications of COVID-19, its precise origins remain elusive. SARS-CoV-2 interacts with a receptor-binding domain within angiotensin-converting enzyme 2 (ACE2). This receptor is expressed in various organs of different species, including humans, with different abundance. Although COVID-19 has multiorgan manifestations, the main pathologies occur in the lung, including pulmonary fibrosis, respiratory failure, pulmonary embolism, and secondary bacterial pneumonia. In the post-COVID-19 period, different sequelae may occur, which may have various causes, including the direct action of the virus, alteration of the immune response, and metabolic alterations during infection, among others. Recognizing the serious adverse health effects associated with COVID-19, it becomes imperative to comprehensively elucidate and discuss the existing evidence surrounding this viral infection, including those related to the pathophysiological effects of the disease and the subsequent consequences. This review aims to contribute to a comprehensive understanding of the impact of COVID-19 and its long-term effects on human health.

Association of excess visceral fat and severe illness in hospitalized COVID-19 patients in Japan: a retrospective cohort study

BACKGROUND/OBJECTIVES

Obesity, defined by body mass index (BMI), is a well-known risk factor for the severity of coronavirus disease 2019 (COVID-19). Adipose tissue distribution has also been implicated as an important factor in the body's response to infection, and excess visceral fat (VF), which is prevalent in Japanese, may contribute significantly to the severity. Therefore, this study aimed to evaluate the association of obesity and VF with COVID-19 severe illness in Japan.

SUBJECTS/METHODS

This retrospective cohort study involved 550 COVID-19 patients admitted to a tertiary care hospital with BMI and body composition data, including VF. The primary endpoint was severe illness, including death, due to COVID-19 during hospitalization. Logistic regression analysis was applied to examine the quartiles of BMI and VF on severe illness after adjusting for covariates such as age, sex, subcutaneous fat, paraspinal muscle radiodensity, and comorbidities affecting VF (COPD, cancer within 5 years, immunosuppressive agent use).

RESULTS

The median age was 56.0 years; 71.8% were males. During hospitalization, 82 (14.9%) experienced COVID-19 severe illness. In the multivariate logistic regression analysis, Q4 of BMI was not significantly associated with severe illness compared to Q1 of BMI (OR 1.03; 95% CI 0.37-2.86; p = 0.95). Conversely, Q3 and Q4 of VF showed a higher risk for severe illness compared to Q1 of VF (OR 2.68; 95% CI 1.01-7.11; p = 0.04, OR 3.66; 95% CI 1.30-10.26; p = 0.01, respectively). Stratified analysis by BMI and adjusted for covariates showed the positive association of VF with severe illness only in the BMI < 25 kg/m2 group.

CONCLUSIONS

High BMI was not an independent risk factor for COVID-19 severe illness in hospitalized patients in Japan, whereas excess VF significantly influenced severe illness, especially in patients with a BMI < 25 kg/m2.

Visceral fat area measured by electrical bioimpedance as an aggravating factor of COVID-19: a study on body composition

INTRODUCTION

Severe forms of COVID-19 are more common in patients with abnormal fat distribution, particularly high visceral adiposity. The patient's muscle strength may be reduced during the acute phase of the infection. Electrical bioimpedance (BIA) is a non-invasive method for measuring body compartments and estimating visceral fat area (VFA) that can be used at the bedside.

OBJECTIVE

To assess the association between several body composition parameters, primarily high adipose tissue and high VFA, in patients with and without a diagnosis of COVID-19 infection, and whether it worsened the severity parameters.

METHODS

This retrospective cohort study was conducted in a private hospital in the city of São Paulo from March 2020 to August 2021. The demographic and clinical data was collected from medical reports. Body composition is assessed using the InBODY® model S10 bioelectrical impedance device and a Jamar® digital hydraulic manual dynamometer with a scale from 0 to 90 kg is used to measure handgrip strength (HGS).

RESULTS

A total of 96 patients with a mean age of 69.1 years (SD 15) were divided into two groups of 48 individuals, with and without COVID-19 infection. Body mass index (odds ratio [OR]: 4.47, 95% confidence interval [CI]: 1.69, 11.83), fat mass (OR: 2.03, 95% CI: 0.48, 8.55), and VFA (OR: 1.08, 95% CI: 0.33, 3.53) were all higher in the infection group. When COVID-19 patients were evaluated, those with higher VFA had longer hospital stays (OR: 0.99, 95% CI: 0.97, 1.01) and used more vasoactive drugs (p = 0.043). Patients with COVID-19 with poor handgrip strength were 3.29 times more likely to require a prolonged intensive care unit (ICU) stay.

CONCLUSION

The study concluded that excess weight and body fat are significantly associated with COVID-19 involvement, but the severity is primarily related to a greater area of visceral fat. The use of bioimpedance for visceral fat measurement was effective, as it is a simple method performed in the hospital setting that does not require the use of radiation.

Determinants of survival in patients on extracorporeal membrane oxygenation therapy due to severe covid-19

BACKGROUND

Severe acute respiratory distress syndrome (ARDS) due to Coronavirus Disease-19 (COVID-19) is associated with high mortality. Although survival on mechanical circulatory support has improved, determinants for better prognosis are still unclear. Here, we report on the outcome of our patient population with the need for mechanical circulatory support due to severe COVID-19 (sCOVID-19) induced ARDS.

METHODS

All patients treated with extracorporeal membrane oxygenation (ECMO) for severe ARDS due to sCOVID-19 were analysed. Patients > 18 years of age at the time of initiation of ECMO were included. Pre-existing comorbidities, complications during ECMO implantation, and ECMO runtime were reviewed. The latency to intubation, proning, tracheotomy, and ECMO implantation was analysed. Furthermore, the survival and non-survival population were compared to determine factors in favour of a better outcome.

RESULTS

In total, 85 patients were treated with veno-venous membrane oxygenation (vv-ECMO) for severe ARDS in our medical centre. The patient population was predominantly male (83.5%) with a mean patient age of 54.9 years. A history of cardiovascular disease (p = .01), smoking (p < .05), need for vasopressor- (p < .05), and renal replacement therapy (p < .001) was associated with a worse prognosis. Overall survival was 50%. The survival population was significantly younger (p = .004), had a significantly higher body weight (p = .02) and body mass index (BMI) (p = .01). Furthermore, survival was significantly better when vv-ECMO was initiated within 48 h after admission (p < .001).

CONCLUSIONS

Pre-existing cardiovascular disease, higher age, history of nicotine abuse, and development of renal failure are associated with poor outcome. Early start of vv-ECMO therapy may lead to better survival in sCOVID-19 patients, although complications during ECMO therapy are associated with a worse prognosis.

What is the role of brown adipose tissue in metabolic health: lessons learned and future perspectives in the long COVID?

Metabolic physiology plays a key role in maintaining our health and resilience. Metabolic disorders can lead to serious illnesses, including obesity. The pathogenesis of the new long COVID syndrome in individuals with long-term recovery after SARS-Co-2 infection is still incomplete. Thus there is growing attention in the study of adipose tissue activities, especially brown adipose tissue (BAT) and associated resilience which plays a crucial role in different types of obesity as potential targets for pharmacologic and nutritional interventions in the context of obesity and long COVID. The number of studies examining mechanisms underlying BAT has grown rapidly in the last 10 years despite of role of BAT in individuals with COVID-19 and long COVID is modest. Therefore, this review aims to sum up data examining BAT activities, its resilience in health, obesity, and the possible link to long COVID. The search was conducted on studies published in English mostly between 2004 and 2022 in adult humans and animal models. Database searches were conducted using PubMed, Scopus, and Google Scholar for key terms including adipose tissue, BAT, adipokines, obesity, VPF/VEGF, and pathogenesis. From the initial search through the database were identified relevant articles that met inclusion and exclusion criteria and our data regarding adipose tissues were presented in this review. It will discuss adiposity tissue activities. Current literature suggests that there are BAT integral effects to whitening and browning fat phenomena which reflect the homeostatic metabolic adaptive ability for environmental demand or survival/adaptive mechanisms. We also review neural and vascular impacts in BAT that play a role in resilience and obesity. Finally, we discuss the role of BAT in the context of long COVID in basic research and clinical research.

What is the role of brown adipose tissue in metabolic health: lessons learned and future perspectives in the long COVID?

Metabolic physiology plays a key role in maintaining our health and resilience. Metabolic disorders can lead to serious illnesses, including obesity. The pathogenesis of the new long COVID syndrome in individuals with long-term recovery after SARS-Co-2 infection is still incomplete. Thus there is growing attention in the study of adipose tissue activities, especially brown adipose tissue (BAT) and associated resilience which plays a crucial role in different types of obesity as potential targets for pharmacologic and nutritional interventions in the context of obesity and long COVID. The number of studies examining mechanisms underlying BAT has grown rapidly in the last 10 years despite of role of BAT in individuals with COVID-19 and long COVID is modest. Therefore, this review aims to sum up data examining BAT activities, its resilience in health, obesity, and the possible link to long COVID. The search was conducted on studies published in English mostly between 2004 and 2022 in adult humans and animal models. Database searches were conducted using PubMed, Scopus, and Google Scholar for key terms including adipose tissue, BAT, adipokinins, obesity, VPF/VEGF, and pathogenesis. From the initial search through the database were identified relevant articles that met inclusion and exclusion criteria and our data regarding adipose tissues were presented in this review. It will discuss adiposity tissue activities. Current literature suggests that there are BAT integral effects to whitening and browning fat phenomenons which reflect the homeostatic metabolic adaptive ability for environmental demand or survival/adaptive mechanisms. We also review neural and vascular impacts in BAT that play a role in resilience and obesity. Finally, we discuss the role of BAT in the context of long COVID in basic research and clinical research.

How culturally unique are pandemic effects? Evaluating cultural similarities and differences in effects of age, biological sex, and political beliefs on COVID impacts

Despite being bio-epidemiological phenomena, the causes and effects of pandemics are culturally influenced in ways that go beyond national boundaries. However, they are often studied in isolated pockets, and this fact makes it difficult to parse the unique influence of specific cultural psychologies. To help fill in this gap, the present study applies existing cultural theories via linear mixed modeling to test the influence of unique cultural factors in a multi-national sample (that moves beyond Western nations) on the effects of age, biological sex, and political beliefs on pandemic outcomes that include adverse financial impacts, adverse resource impacts, adverse psychological impacts, and the health impacts of COVID. Our study spanned 19 nations (participant N = 14,133) and involved translations into 9 languages. Linear mixed models revealed similarities across cultures, with both young persons and women reporting worse outcomes from COVID across the multi-national sample. However, these effects were generally qualified by culture-specific variance, and overall more evidence emerged for effects unique to each culture than effects similar across cultures. Follow-up analyses suggested this cultural variability was consistent with models of pre-existing inequalities and socioecological stressors exacerbating the effects of the pandemic. Collectively, this evidence highlights the importance of developing culturally flexible models for understanding the cross-cultural nature of pandemic psychology beyond typical WEIRD approaches.

COVID-19, Anosmia, and Allergies: Is There a Relationship? A Pediatric Perspective

Background: Between June and July 2020, we evaluated children and adolescents concerning post-infection surveillance after a COVID-19 positivity during the lockdown. We aimed to assess whether the anamnestic presence of allergies could correlate with the presence of SARS-CoV-2 symptoms, and in particular with anosmia. Material and methods: For each patient, we collected anamnestic data, the presence of allergies documented by performing skin prick tests, and COVID-19 symptoms. Then, if over six years of age, each patient underwent an active anterior rhinomanometry. Results: A total of 296 patients were enrolled, of whom 105 (35.4%) reported allergies. Considering COVID-19 symptoms, 74 subjects (25%) presented an asymptomatic form, 222 (75%) reported symptoms, and anosmia recurred in 60 subjects (27.03%). A statistically significant relationship was found between allergies and symptomatic COVID-19 (p = 0.042), allergies, and anosmia (p = 0.05), and allergies and anosmia in males (p = 0.007). Moreover, anosmic patients presented a higher body mass index, older age, and a longer COVID-19 duration with statistical significance (p = 0.001, 0.001, 0.006, respectively). Conclusions: Allergic subjects seem to develop symptomatic COVID-19 more frequently and allergies appear to be a protective factor from anosmia’s onset in males.

Determining whether ethnic minorities with severe obesity face a disproportionate risk of serious disease and death from COVID-19: outcomes from a Southern California-based retrospective cohort study

OBJECTIVE

Obesity has been recognised as a risk factor for poor outcomes associated with COVID-19. Ethnic minorities with COVID-19 have been independently found to fare poorly. We aim to determine if ethnic minorities with severe obesity-defined as a body mass index (BMI) above 40 kg/m²-experience higher rates of hospitalisation, invasive ventilation and death.

DESIGN AND SETTING

Retrospective cohort study from 1 March 2020 to 28 February 2021 within an integrated healthcare organisation in Southern California.

PARTICIPANTS

We identified 373 831 patients by COVID-19 diagnosis code or positive laboratory test.

METHODS

Multivariable Poisson regression with robust error variance estimated adjusted risks of hospitalisation, invasive ventilator use and death within 30 days. Risks were stratified by ethnicity and BMI.

RESULTS

We identified multiple differences in risk of poor outcomes across BMI categories within individual ethnic groups. Hospitalisation risk with a BMI over 45 kg/m² was greater in Asian (RR 2.31, 95% CI 1.53 to 3.49; p<0.001), Hispanic (RR 3.22, 95% CI 2.99 to 3.48; p<0.001) and Pacific Islander (RR 3.79, 95% CI 2.49 to 5.75; p<0.001) patients compared with White (RR 2.04, 95% CI 1.79 to 2.33; p<0.001) and Black (RR 2.00, 95% CI 1.70 to 2.34; p<0.001) patients. A similar trend was observed with invasive ventilation risk. The risk of death was greater in Asian (RR 3.96, 95% CI 1.88 to 8.33; p<0.001), Hispanic (RR 3.03, 95% CI 2.53 to 3.61; p<0.001) and Pacific Islander (RR 4.60, 95% CI 1.42 to 14.92; p=0.011) patients compared with White (RR 1.47, 95% CI 1.13 to 1.91; p=0.005) and Black (RR 2.83, 95% CI 1.99 to 4.02; p<0.001) patients with a BMI over 45 kg/m².

CONCLUSIONS

Ethnic minorities with severe obesity, particularly Asian, Hispanic and Pacific Islander patients, had a statistically significant higher risk of hospitalisation, invasive ventilator use and death due to COVID-19. Potential explanations include differences in adipose tissue deposition, overall inflammation and ACE-2 receptor expression.

Ethnicity-Specific Features of COVID-19 Among Arabs, Africans, South Asians, East Asians, and Caucasians in the United Arab Emirates

Background

Dubai (United Arab Emirates; UAE) has a multi-national population which makes it exceptionally interesting study sample because of its unique demographic factors.

Objective

To stratify the risk factors for the multinational society of the UAE.

Methods

A retrospective chart review of 560 patients sequentially admitted to inpatient care with laboratory confirmed COVID-19 was conducted. We studied patients’ demographics, clinical features, laboratory results, disease severity, and outcomes. The parameters were compared across different ethnic groups using tree-based estimators to rank the ethnicity-specific disease features. We trained ML classification algorithms to build a model of ethnic specificity of COVID-19 based on clinical presentation and laboratory findings on admission.

Results

Out of 560 patients, 43.6% were South Asians, 26.4% Middle Easterns, 16.8% East Asians, 10.7% Caucasians, and 2.5% are under others. UAE nationals represented half of the Middle Eastern patients, and 13% of the entire cohort. Hypertension was the most common comorbidity in COVID-19 patients. Subjective complaint of fever and cough were the chief presenting symptoms. Two-thirds of the patients had either a mild disease or were asymptomatic. Only 20% of the entire cohort needed oxygen therapy, and 12% needed ICU admission. Forty patients (~7%) needed invasive ventilation and fifteen patients died (2.7%). We observed differences in disease severity among different ethnic groups. Caucasian or East-Asian COVID-19 patients tended to have a more severe disease despite a lower risk profile. In contrast to this, Middle Eastern COVID-19 patients had a higher risk factor profile, but they did not differ markedly in disease severity from the other ethnic groups. There was no noticeable difference between the Middle Eastern subethnicities—Arabs and Africans—in disease severity (p = 0.81). However, there were disparities in the SOFA score, D-dimer (p = 0.015), fibrinogen (p = 0.007), and background diseases (hypertension, p = 0.003; diabetes and smoking, p = 0.045) between the subethnicities.

Conclusion

We observed variations in disease severity among different ethnic groups. The high accuracy (average AUC = 0.9586) of the ethnicity classification model based on the laboratory and clinical findings suggests the presence of ethnic-specific disease features. Larger studies are needed to explore the role of ethnicity in COVID-19 disease features.

Adipose tissue and blood leukocytes ACE2 DNA methylation in obesity and after weight loss

BACKGROUND

Obesity was consistently associated with a poor prognosis in patients with COVID-19. Epigenetic mechanisms were proposed as the link between obesity and comorbidities risk.

AIM

To evaluate the methylation levels of angiotensin-converting enzyme 2 (ACE2) gene, the main entry receptor of SARS-CoV-2, in different depots of adipose tissue (AT) and leukocytes (PBMCs) in obesity and after weight loss therapy based on a very-low-calorie ketogenic diet (VLCKD), a balanced hypocaloric diet (HCD) or bariatric surgery (BS).

MATERIALS AND METHODS

DNA methylation levels of ACE2 were extracted from our data sets generated by the hybridization of subcutaneous (SAT) (n = 32) or visceral (VAT; n = 32) adipose tissue, and PBMCs (n = 34) samples in Infinium HumanMethylation450 BeadChips. Data were compared based on the degree of obesity and after 4-6 months of weight loss either by following a nutritional or surgical treatment and correlated with ACE2 transcript levels.

RESULTS

As compared with normal weight, VAT from patients with obesity showed higher ACE2 methylation levels. These differences were mirrored in PBMCs but not in SAT. The observed obesity-associated methylation of ACE2 was reversed after VLCKD and HCD but not after BS. Among the studied CpG sites, cg16734967 and cg21598868, located at the promoter, were the most affected and correlated with BMI. The observed DNA methylation pattern was inversely correlated with ACE2 expression.

CONCLUSION

Obesity-related VAT shows hypermethylation and downregulation of the ACE2 gene that is mirrored in PBMCs and is restored after nutritional weight reduction therapy. The results warrant the necessity to further evaluate its implication for COVID-19 pathogenesis.

Investigation on the Factors Associated with the Persistence of Anosmia and Ageusia in Saudi COVID-19 Patients

The Coronavirus Disease 2019 (COVID-19) outbreak caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) resulted in a worldwide pandemic of a highly infectious disease. The difficulty of dealing with COVID-19 is the broad spectrum of clinical manifestations that involves various pathophysiological mechanisms, severities, duration, and complications. This study aims to help emphasize the factors related to the persistence and duration of anosmia (loss of smell) and ageusia (loss of taste) as part of post-acute COVID-19 syndrome in Saudi COVID-19 patients via a retrospective cross-sectional design. Eight hundred and eighty-one participants were recruited between March and April 2021. Those participants were 18 years or older, recovered from the COVID-19 infection, and completed 14 days after the onset of the acute phase of the disease. Among the 881 recruited participants, 808 have submitted eligible responses and were included in data analyses. The most common persistent symptoms in post-acute COVID-19 syndrome were anosmia (33.8%) and ageusia (26.4%). The data also showed a significant association between female sex and the incidence and the persistence of anosmia and ageusia. In multivariable analysis, anosmia during the acute phase was associated with BMI, asthma and shortness of breath, while anosmia during the post-acute phase was associated with sex. Ageusia during the acute phase was associated with sex, myalgia and arthralgia, while ageusia in the post-acute phase was associated with sex.

Dysautonomia and Implications for Anosmia in Long COVID-19 Disease

Long COVID-19 patients often reported anosmia as one of the predominant persisting symptoms. Recent findings have shown that anosmia is associated with neurological dysregulations. However, the involvement of the autonomic nervous system (ANS), which can aggregate all the long COVID-19 neurological symptoms, including anosmia, has not received much attention in the literature. Dysautonomia is characterized by the failure of the activities of components in the ANS. Long COVID-19 anosmia fatigue could result from damage to olfactory sensory neurons, leading to an augmentation in the resistance to cerebrospinal fluid outflow by the cribriform plate, and further causing congestion of the glymphatic system with subsequent toxic build-up in the brain. Studies have shown that anosmia was an important neurologic symptom described in long COVID-19 in association with potential COVID-19 neurotropism. SARS-CoV-2 can either travel via peripheral blood vessels causing endothelial dysfunction, triggering coagulation cascade and multiple organ dysfunction, or reach the systemic circulation and take a different route to the blood–brain barrier, damaging the blood–brain barrier and leading to neuroinflammation and neuronal excitotoxicity. SARS-CoV-2 entry via the olfactory epithelium and the increase in the expression of TMPRSS2 with ACE2 facilitates SARS-CoV-2 neurotropism and then dysautonomia in long COVID-19 patients. Due to this effect, patients with anosmia persisting 3 months after COVID-19 diagnosis showed extensive destruction of the olfactory epithelium. Persistent anosmia observed among long COVID-19 patients may be involved by a cascade of effects generated by dysautonomia leading to ACE2 antibodies enhancing a persistent immune activation.

An Overview of Adipose Tissue ACE2 Modulation by Diet and Obesity. Potential Implications in COVID-19 Infection and Severity

The present review is aimed at analysing the current evidence concerning the potential modulation of obesity and/or diet in adipose tissue ACE2. Additionally, the potential implications of these effects on COVID-19 are also addressed. The results published show that diet and obesity are two factors that effectively influence the expression of Ace2 gene in adipose tissue. However, the shifts in this gene do not always occur in the same direction, nor with the same intensity. Additionally, there is no consensus regarding the implications of increased adipose tissue ACE2 expression in health. Thus, while in some studies a protective role is attributed to ACE2 overexpression, other studies suggest otherwise. Similarly, there is much debate regarding the role played by ACE2 in COVID-19 in terms of degree of infection and disease outcomes. The greater risk of infection that may hypothetically derive from enhanced ACE2 expression is not clear since the functionality of the enzyme seems to be as important as the abundance. Thus, the greater abundance of ACE2 in adipose tissue of obese subjects may be counterbalanced by its lower activation. In addition, a protective role of ACE2 overexpression has also been suggested, associated with the increase in anti-inflammatory factors that it may produce.

Cross-National Variations in COVID-19 Mortality: The Role of Diet, Obesity and Depression

Background: The COVID-19 pandemic has been characterized by wide variations in mortality across nations. Some of this variability may be explained by medical comorbidities such as obesity and depression, both of which are strongly correlated with dietary practices such as levels of sugar and seafood consumption. Methods: COVID-19 mortality indices for 156 countries were obtained from the Johns Hopkins University’s data aggregator. Correlations between these variables and (a) per capita consumption of sugar and seafood, and (b) country-wise prevalence of depression and obesity were examined. Results: Sugar consumption (r = 0.51, p < 0.001) and prevalence of obesity (r = 0.66, p < 0.001) and depression (r = 0.56, p < 0.001) were positively correlated with crude mortality rates, while seafood consumption was negatively correlated with the infection fatality rate (r = −0.28, p = 0.015). These effects were significant even after correcting for potential confounders. The associations with depression and obesity remained significant upon multivariate regression. Conclusions: Both obesity and depression, which are associated with inflammatory dysregulation, may be related to cross-national variations in COVID-19 mortality, while seafood consumption may be protective. These findings have implications in terms of protecting vulnerable individuals during the current pandemic.

Do Islanders Have a More Reactive Behavioral Immune System? Social Cognitions and Preferred Interpersonal Distances During the COVID-19 Pandemic

Insular populations have traditionally drawn a lot of attention from epidemiologists as they provide important insights regarding transmission of infectious diseases and propagation of epidemics. There are numerous historical instances where isolated populations showed high morbidity once a new virus entered the population. Building upon that and recent findings that the activation of the behavioral immune system (BIS) depends both upon one's vulnerability and environmental context, we predicted that, during the COVID-19 pandemic, place of residence (island vs. mainland) explains a significant proportion of variance in preferred interpersonal distances, animosity toward strangers, and willingness to punish those who do not adhere to COVID-19 preventive measures. With 48 populated islands, Croatia provides a fruitful testing ground for this prediction. We also opted to explore relations among BIS-related variables (pathogen disgust, germ aversion, and perceived infectability) and social cognitions in a more natural context than has previously been done. The study was conducted online, on Croatian residents, during April and May 2020. As expected, the BIS variables contributed significantly to preferred interpersonal distances, negative emotions toward strangers, and willingness to punish those who do not adhere to COVID-19 preventive measures. Furthermore, our results showed that geographical location explained a significant amount of variance in preferred social (but not personal and intimate) distances and negative emotions toward foreigners. As Croatian islands are extremely frequent travel destinations, these differences between mainlanders and islanders cannot be explained by the lack of exposure to foreigners. Additionally, we found that scores on preferred interpersonal distances, pathogen disgust, and germ aversion were significantly higher compared to those obtained in Croatian samples before the COVID-19 pandemic. Furthermore, men scored higher in perceived infectability than before the COVID-19 pandemic, and women did not, which reflects the objectively higher risk of SARS-CoV-2 for men than for women. Taken together, our results support the notion that BIS is a highly adaptive and context-dependent response system, likely more reactive in more susceptible individuals.

The Inflammatory Profile of Obesity and the Role on Pulmonary Bacterial and Viral Infections

Obesity is a globally increasing health problem, entailing diverse comorbidities such as infectious diseases. An obese weight status has marked effects on lung function that can be attributed to mechanical dysfunctions. Moreover, the alterations of adipocyte-derived signal mediators strongly influence the regulation of inflammation, resulting in chronic low-grade inflammation. Our review summarizes the known effects regarding pulmonary bacterial and viral infections. For this, we discuss model systems that allow mechanistic investigation of the interplay between obesity and lung infections. Overall, obesity gives rise to a higher susceptibility to infectious pathogens, but the pathogenetic process is not clearly defined. Whereas, viral infections often show a more severe course in obese patients, the same patients seem to have a survival benefit during bacterial infections. In particular, we summarize the main mechanical impairments in the pulmonary tract caused by obesity. Moreover, we outline the main secretory changes within the expanded adipose tissue mass, resulting in chronic low-grade inflammation. Finally, we connect these altered host factors to the influence of obesity on the development of lung infection by summarizing observations from clinical and experimental data.

COVID-19 Pandemic on Fire: Evolved Propensities for Nocturnal Activities as a Liability Against Epidemiological Control

Humans have been using fire for hundreds of millennia, creating an ancestral expansion toward the nocturnal niche. The new adaptive challenges faced at night were recurrent enough to amplify existing psychological variation in our species. Night-time is dangerous and mysterious, so it selects for individuals with higher tendencies for paranoia, risk-taking, and sociability (because of security in numbers). During night-time, individuals are generally tired and show decreased self-control and increased impulsive behaviors. The lower visibility during night-time favors the partial concealment of identity and opens more opportunities for disinhibition of self-interested behaviors. Indeed, individuals with an evening-oriented chronotype are more paranoid, risk-taking, extraverted, impulsive, promiscuous, and have higher antisocial personality traits. However, under some circumstances, such as respiratory pandemics, the psychobehavioral traits favored by the nocturnal niche might be counter-productive, increasing contagion rates of a disease that can evade the behavioral immune system because its disease cues are often nonexistent or mild. The eveningness epidemiological liability hypothesis presented here suggests that during the COVID-19 pandemic, the evening-oriented psychobehavioral profile can have collectively harmful consequences: there is a clash of core tendencies between the nocturnal chronotype and the recent viral transmission-mitigating safety guidelines and rules. The pandemic safety protocols disrupt much normal social activity, particularly at night when making new social contacts is desired. The SARS-CoV-2 virus is contagious even in presymptomatic and asymptomatic individuals, which enables it to mostly evade our evolved contagious disease avoidance mechanisms. A growing body of research has indirectly shown that individual traits interfering with social distancing and anti-contagion measures are related to those of the nocturnal chronotype. Indeed, some of the social contexts that have been identified as superspreading events occur at night, such as in restaurants, bars, and nightclubs. Furthermore, nocturnal environmental conditions favor the survival of the SARS-CoV-2 virus much longer than daytime conditions. We compare the eveningness epidemiological liability hypothesis with other factors related to non-compliance with pandemic safety protocols, namely sex, age, and life history. Although there is not yet a direct link between the nocturnal chronotype and non-compliance with pandemic safety protocols, security measures and future empirical research should take this crucial evolutionary mismatch and adaptive metaproblem into account, and focus on how to avoid nocturnal individuals becoming superspreaders, offering secure alternatives for nocturnal social activities.

Pandemic Leadership: Sex Differences and Their Evolutionary-Developmental Origins

The COVID-19 pandemic has caused a global societal, economic, and social upheaval unseen in living memory. There have been substantial cross-national differences in the kinds of policies implemented by political decision-makers to prevent the spread of the virus, to test the population, and to manage infected patients. Among other factors, these policies vary with politicians' sex: early findings indicate that, on average, female leaders seem more focused on minimizing direct human suffering caused by the SARS-CoV-2 virus, while male leaders implement riskier short-term decisions, possibly aiming to minimize economic disruptions. These sex differences are consistent with broader findings in psychology, reflecting women's stronger empathy, higher pathogen disgust, health concern, care-taking orientation, and dislike for the suffering of other people-as well as men's higher risk-taking, Machiavellianism, psychopathy, narcissism, and focus on financial indicators of success and status. This review article contextualizes sex differences in pandemic leadership in an evolutionary framework. Evolution by natural selection is the only known process in nature that organizes organisms into higher degrees of functional order, or counteracts the unavoidable disorder that would otherwise ensue, and is therefore essential for explaining the origins of human sex differences. Differential sexual selection and parental investment between males and females, together with the sexual differentiation of the mammalian brain, drive sex differences in cognition and behavioral dispositions, underlying men's and women's leadership styles and decision-making during a global pandemic. According to the sexually dimorphic leadership specialization hypothesis, general psychobehavioral sex differences have been exapted during human evolution to create sexually dimorphic leadership styles. They may be facultatively co-opted by societies and/or followers when facing different kinds of ecological and/or sociopolitical threats, such as disease outbreaks or intergroup aggression. Early evidence indicates that against the invisible viral foe that can bring nations to their knees, the strategic circumspection of empathic feminine health "worriers" may bring more effective and humanitarian outcomes than the devil-may-care incaution of masculine risk-taking "warriors".

The Obesity Paradox Predicts the Second Wave of COVID-19 to Be Severe in Western Countries

While COVID-19 infection and mortality rates are soaring in Western countries, Southeast Asian countries have successfully avoided the second wave of the SARS-CoV-2 pandemic despite high population density. We provide a biochemical hypothesis for the connection between low COVID-19 incidence, mortality rates, and high visceral adiposity in Southeast Asian populations. The SARS-CoV-2 virus uses angiotensin-converting enzyme 2 (ACE2) as a gateway into the human body. Although the highest expression levels of ACE2 are found in people’s visceral adipose tissue in Southeast Asia, this does not necessarily make them vulnerable to COVID-19. Hypothetically, high levels of visceral adiposity cause systemic inflammation, thus decreasing the ACE2 amount on the surface of both visceral adipocytes and alveolar epithelial type 2 cells in the lungs. Extra weight gained during the pandemic is expected to increase visceral adipose tissue in Southeast Asians, further decreasing the ACE2 pool. In contrast, weight gain can increase local inflammation in fat depots in Western people, leading to worse COVID-related outcomes. Because of the biological mechanisms associated with fat accumulation, inflammation, and their differential expression in Southeast Asian and Western populations, the second wave of the pandemic may be more severe in Western countries, while Southeast Asians may benefit from their higher visceral fat depots.