Body mass index and risk of infections: a Mendelian randomization study of 101,447 individuals

Mendelian randomization analysis reveals causal association of anthropometric measures on sepsis risk and mortality

The objective of this study was to explore the potential causalities of fat mass, nonfat mass and height (henceforth, 'anthropometric measures') with sepsis risk and mortality. We conducted the Mendelian randomization (MR) investigation using genome-wide association study (GWAS) summary statistics of anthropometric measures, sepsis, and sepsis mortality. The GWAS summary data from the UK Biobank was used. Firstly, MR analysis was performed to estimate the causal effect of anthropometric measures on the risk of sepsis. The inverse-variance weighted (IVW) method was utilized as the primary analytical approach, together with weighted median-based method. Cochrane's Q test and MR-Egger intercept test were performed to assess heterogeneity and pleiotropy, respectively. Finally, we performed a series of sensitivity analyses to enhance the precision and veracity of our findings. The IVW method showed that genetically predicted weight-related measures were suggestively linked to an increased risk of sepsis. However, height displayed no causal association with sepsis risk and mortality. Furthermore, weight-related measures also displayed significant MR association with the sepsis mortality, except body nonfat mass and right leg nonfat mass. However, MVMR analysis indicated the observed effects for weight-related measures in the univariable MR analyses are more likely a bias caused by the interrelationship between anthropometric measures. According to the MR-Egger intercept assessment, our MR examination was not influenced by horizontal pleiotropy (all p>0.05). Moreover, the reliability of the estimated causal association was confirmed by the sensitivity analyses. In conclusion, these findings provided vital new knowledge on the role of anthropometric-related measures in the sepsis etiology.

Causal relationships between obesity-related anthropometric indicators and sepsis risk: a Mendelian-randomization study

Background

Previous studies have reported an association between obesity and risk of sepsis. However, the results have been inconsistent, and no causal inference can be drawn from them. Therefore, we conducted a Mendelian-randomization (MR) study to investigate causal relationships between available obesity-related anthropometric indicators and sepsis risk.

Methods

We performed MR analyses using genome-wide association study (GWAS) summary statistics on 14 anthropometric indicators [namely body mass index (BMI), waist and hip circumferences (WC, HC), basal metabolic rate (BMR), whole-body fat mass (WBFM), trunk fat mass (TFM), leg fat mass (LFM), arm fat mass (AFM), body fat percentage (BFP), whole-body fat-free mass (WBFFM), trunk fat-free mass (TFFM), leg fat-free mass (LFFM), arm fat-free mass (AFFM), and whole-body water mass (WBWM)], sepsis, critical care sepsis, and 28-day death due to sepsis from the UK Biobank and FinnGen cohort. The primary method of MR analysis was inverse variance-weighted average method. Sensitivity analyses, including heterogeneity and horizontal-pleiotropy tests, were conducted to assess the stability of the MR results. Additionally, we applied multiple-variable MR (MVMR) to evaluate the effect of BMI on the relationship between each anthropometric indicator and sepsis risk.

Results

Our MR analysis demonstrated causal relationships between 14 anthropometric indicators and sepsis of different severities. After we adjusted for BMI, MVMR analyses indicated that WC, BMR, LFM, WBFFM, TFFM, AFFM, and WBWM remained significantly associated with the presence of sepsis (all p < 0.05). A sensitivity analysis confirmed the reliability of our MR results, and no significant horizontal pleiotropy was detected.

Conclusion

This MR study revealed that increases in obesity-related anthropometric indicators had causal associations with a higher risk of sepsis, which might provide important insights for the identification of individuals at risk for sepsis in community and hospital settings.

Mendelian randomization analysis reveals higher whole body water mass may increase risk of bacterial infections

BACKGROUND AND PURPOSE

The association of water loading with several infections remains unclear. Observational studies are hard to investigate definitively due to potential confounders. In this study, we employed Mendelian randomization (MR) analysis to assess the association between genetically predicted whole body water mass (BWM) and several infections.

METHODS

BWM levels were predicted among 331,315 Europeans in UK Biobank using 418 SNPs associated with BWM. For outcomes, we used genome-wide association data from the UK Biobank and FinnGen consortium, including sepsis, pneumonia, intestinal infections, urinary tract infections (UTIs) and skin and soft tissue infections (SSTIs). Inverse-variance weighted MR analyses as well as a series of sensitivity analyses were conducted.

RESULTS

Genetic prediction of BWM is associated with an increased risk of sepsis (OR 1.34; 95% CI 1.19 to 1.51; P = 1.57 × 10- 6), pneumonia (OR: 1.17; 95% CI 1.08 to 1.29; P = 3.53 × 10- 4), UTIs (OR: 1.26; 95% CI 1.16 to 1.37; P = 6.29 × 10- 8), and SSTIs (OR: 1.57; 95% CI 1.25 to 1.96; P = 7.35 × 10- 5). In the sepsis and pneumonia subgroup analyses, the relationship between BWM and infection was observed in bacterial but not in viral infections. Suggestive evidence suggests that BWM has an effect on viral intestinal infections (OR: 0.86; 95% CI 0.75 to 0.99; P = 0.03). There is limited evidence of an association between BWM levels and bacteria intestinal infections, and genitourinary tract infection (GUI) in pregnancy. In addition, MR analyses supported the risk of BWM for several edematous diseases. However, multivariable MR analysis shows that the associations of BWM with sepsis, pneumonia, UTIs and SSTIs remains unaffected when accounting for these traits.

CONCLUSIONS

In this study, the causal relationship between BWM and infectious diseases was systematically investigated. Further prospective studies are necessary to validate these findings.

Causal relationship between type 1 diabetes mellitus and mycoses: a Mendelian randomization study

Background

Type 1 diabetes mellitus (T1DM) is frequently associated with various infections, including mycoses; however, the direct link between T1DM and fungal infections remains under-researched. This study utilizes a Mendelian randomization (MR) approach to investigate the potential causal relationship between T1DM and mycoses.

Methods

Genetic variants associated with T1DM were sourced from the European Bioinformatics Institute database, while those related to fungal infections such as candidiasis, pneumocystosis, and aspergillosis were obtained from the Finngen database, focusing on European populations. The primary analysis was conducted using the inverse variance weighted (IVW) method, with additional insight from Mendelian randomization Egger regression (MR-Egger). Extensive sensitivity analyses assessed the robustness, diversity, and potential horizontal pleiotropy of our findings. Multivariable Mendelian randomization (MVMR) was employed to adjust for confounders, using both MVMR-IVW and MVMR-Egger to evaluate heterogeneity and pleiotropy.

Results

Genetically, the odds of developing candidiasis increased by 5% in individuals with T1DM, as determined by the IVW method (OR = 1.05; 95% CI 1.02-1.07, p = 0.0001), with a Bonferroni-adjusted p-value of 0.008. Sensitivity analyses indicated no significant issues with heterogeneity or pleiotropy. Adjustments for confounders such as body mass index, glycated hemoglobin levels, and white blood cell counts further supported these findings (OR = 1.08; 95% CI:1.03-1.13, p = 0.0006). Additional adjustments for immune cell counts, including CD4 and CD8 T cells and natural killer cells, also demonstrated significant results (OR = 1.04; 95% CI: 1.02-1.06, p = 0.0002). No causal associations were found between T1DM and other fungal infections like aspergillosis or pneumocystosis.

Conclusion

This MR study suggests a genetic predisposition for increased susceptibility to candidiasis in individuals with T1DM. However, no causal links were established between T1DM and other mycoses, including aspergillosis and pneumocystosis.

A causal relationship between educational attainment and risk of infectious diseases: A Mendelian randomisation study

Background

Previous observational studies have investigated the association between educational attainment and sepsis, pneumonia, and urinary tract infections (UTIs). However, their findings have been susceptible to reverse causality and confounding factors. Furthermore, no study has examined the effect of educational level on the risk of infections of the skin and subcutaneous tissue (SSTIs). Thus, we aimed to evaluate the causal relationships between educational level and the risk of four infectious diseases using Mendelian randomisation (MR) techniques.

Methods

We used univariable MR analysis to investigate the causal associations between educational attainment (years of schooling (n = 766 345) and holding college or university degree (n = 334 070)) and four infectious diseases (sepsis (n = 486 484), pneumonia (n = 486 484), UTIs (n = 463 010), and SSTIs (n = 218 792)). We included genetic instrumental variables with a genome-wide significance (P < 5 × 10-8) in the study. We used inverse variance-weighted estimation in the primary analysis and explored the stability of the results using multivariable MR analysis after adjusting for smoking, alcohol consumption, and body mass index.

Results

Genetically predicted years of schooling were associated with a reduced risk of sepsis (odds ratio (OR) = 0.763; 95% confidence interval (CI) = 0.668-0.870, P = 5.525 × 10-5), pneumonia (OR = 0.637; 95% CI = 0.577-0.702, P = 1.875 × 10-19), UTIs (OR = 0.995; 95% CI = 0.993-0.997, P = 1.229 × 10-5), and SSTIs (OR = 0.696; 95% CI = 0.605-0.801, P = 4.034 × 10-7). We observed consistent results for the correlation between qualifications and infectious diseases. These findings remained stable in the multivariable MR analyses.

Conclusions

Our findings suggest that increased educational attainment may be causally associated with a decreased risk of sepsis, pneumonia, UTIs, and SSTIs.

Body mass index and risk of inflammatory breast disease: a Mendelian randomization study

Introduction

Introduction: in previous studies, obesity was identified as a risk factor for inflammatory breast disease, but its causality is uncertain. In the present study, we performed a two-sample Mendelian randomization (TSMR) analysis to investigate the causal relationship between obesity and inflammatory breast disease. Methods: we use body mass index (BMI) as a measure of obesity. Data for single nucleotide polymorphisms (SNPs) associated with BMI were obtained from UK Biobank. Data for single nucleotide polymorphisms (SNPs) associated with mastitis were obtained from FinnGen Biobank. We used several MR analysis methods, such as inverse-variance weighting (IVW), MR-Egger, weighted median, simple mode and weighted mode to make our results more convincing. We also performed MR-PRESSO test, MR-Egger test, heterogeneity test, pleiotropy test and leave-one-out analysis to make our analysis results more robust and credible. We used odds ratio (OR) to evaluate the causal relationship between BMI and mastitis. Results: based on the IVW random effects model, we found that a one-standard deviation (SD) increase in BMI increased the risk of mastitis by 62.1 % (OR = 1.621, 95 % CI: 1.262-2.083, p = 1.59E-4), which is almost consistent with the results of several other methods. Conclusions: in European individuals, an increase in the number of BMI increases the risk of inflammatory breast disease. People with high BMI need to control their weight to reduce the incidence of inflammatory breast disease.

Evaluating the risk of sepsis attributing to obesity: a two-sample Mendelian randomization study

BACKGROUND

Sepsis is a reaction to infection with high morbidity and mortality. It has been noted that patients with obesity were more likely to suffer from sepsis. However, the causality remains elucidating, as reverse causality and residual confounding could not be largely mitigated in conventional observational studies.

OBJECTIVE

To evaluate the risk of sepsis attributed to obesity phenotypes including body mass index (BMI), waist circumstance (WC), and WC adjusted for BMI (WCadjBMI) in a causal way.

METHODS

We conducted a two-sample Mendelian randomization (MR) study using large-scale genome-wide association study summary data with sample sizes ranging from 231 353 to 486 484. The inverse-weighted variance (IVW) was conducted as the primary approach. We also used the weighted median and MR-Egger for causal inference. A sensitivity analysis was conducted to evaluate the reliability of the MR estimates.

RESULTS

IVW detected that genetic liability for increased BMI [odds ratio (OR) = 1.40, 95% confidence interval (CI) = 1.20-1.63, P = 1.52 × 10-5] and WC (OR = 1.02, 95% CI = 1.01-1.03, P = 4.28 × 10-3) predicted a higher risk of sepsis. No evidence was observed for a causal effect of WCadjBMI on sepsis risk (OR = 1.01, 95% CI = 1.00-1.02, P = 0.08). Sensitivity analysis did not identify any bias in the MR results.

CONCLUSION

This MR study showed that obesity contributed to an increased risk of sepsis, indicating that obesity management might be beneficial for reducing sepsis risk. Key messages What is already known on this topic-Observational studies have reported the association between obesity and sepsis, but the causality has not been determined. What this study adds-This Mendelian randomization study demonstrated that obesity-related phenotypes, including body mass index and Waist circumstance, causally increased the risk of sepsis. How this study might affect research, practice, or policy-The findings of our study might have an implication for clinicians that obesity management might be a promised strategy for reducing the risk of sepsis.

The Medical Burden of Obesity and Overweight in the US Military: Association of BMI with Clinically Diagnosed Medical Conditions in United States Military Service Members

BACKGROUND

A high BMI is associated with various medical conditions, notably type 2 diabetes, cardiovascular disease, and mental health disorders. In the US military, BMI increased linearly between 1975 and 2015.

OBJECTIVE

This cross-sectional study investigated the associations between BMI and a comprehensive range of clinically diagnosed medical conditions (CDMCs) in US military service members (SMs).

METHODS

A stratified random sample of SMs (n=26,177) completed an online questionnaire reporting their height, weight, and demographic/lifestyle characteristics. Medical conditions for 6 mo before questionnaire completion were obtained from a comprehensive military electronic medical surveillance system and grouped into 39 CDMCs covering both broad (largely systemic) and specific medical conditions. BMI was calculated as weight/height2 (kg/m2). The prevalence of CDMCs was compared among normal weight (<25.0 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30 kg/m2) SMs.

RESULTS

After multivariable adjustment for demographic/lifestyle characteristics, higher BMI was associated with higher odds of a diagnosed medical condition in 30 of 39 CDMCs, with all 30 displaying dose-response relationships. The 5 major CDMCs with the largest odds ratios comparing obese to normal weight were endocrine/nutritional/metabolic diseases (OR=2.67, 95%CI=2.24-3.15), nervous system diseases (odds ratio [OR]=2.59, 95%CI=2.32-2.90), circulatory system diseases (OR=2.56, 95%CI=2.15-3.06), musculoskeletal system diseases (OR=1.92, 95%CI=1.76-2.09), and mental/behavioral disorders (OR=1.69, 95%CI=1.51-1.90). Compared with normal weight SMs, overweight or obese SMs had a higher number of CDMCs (1.8±1.9 vs. 2.0±2.0 and 2.5±2.3, mean ± standard deviation, respectively, P<0.01).

CONCLUSIONS

In a young, physically active population, higher BMI was associated with a host of medical conditions, even after adjustment for demographic/lifestyle characteristics. The US Department of Defense should improve nutrition education and modify other factors that contribute to overweight and obesity. This study demonstrates that the medical burden of obesity is substantial in overweight and obese SMs.

Lower respiratory tract infections among newly diagnosed sleep apnea patients

BACKGROUND

Sleep apnea is associated with chronic comorbidities and acute complications. Existing data suggest that sleep apnea may predispose to an increased risk and severity of respiratory tract infections.

METHODS

We investigated the incidence of lower respiratory tract infections in the first and second year before and after diagnosis of sleep apnea in a Finnish nationwide, population-based, retrospective case-control study based on linking data from the national health care registers for primary and secondary care from 2015-2019. Controls were matched for age, sex, hospital district, and multimorbidity status. We furthermore analysed the independent effect of comorbidities and other patient characteristics on the risk of lower respiratory tract infections, and their recurrence.

RESULTS

Sleep apnea patients had a higher incidence of lower respiratory tract infections than their matched controls within one year before (hazard ratio 1.35, 95% confidence interval 1.16-1.57) and one year after (hazard ratio1.39, 95% confidence interval1.22-1.58) diagnosis of sleep apnea. However, we found no difference in the incidence of lower respiratory tract infections within the second year before or after diagnosis of sleep apnea in comparison with matched controls. In sleep apnea, history of lower respiratory tract infection prior to sleep apnea, multimorbidity, COPD, asthma, and age greater than 65 years increased the risk of incident and recurrent lower respiratory tract infections.

CONCLUSIONS

Sleep apnea patients are at increased risk of being diagnosed with a lower respiratory tract infection within but not beyond one year before and after diagnosis of sleep apnea. Among sleep apnea patients, chronic comorbidities had a significant impact on the risk of lower respiratory tract infections and their recurrence.

Obesity and risk for respiratory diseases: a Mendelian randomization study

Background

No existing comprehensive Mendelian randomization studies have focused on how obesity affects respiratory diseases.

Methods

BMI and waist circumference, mainly from the UK Biobank, and 35 respiratory diseases from the FinnGen Biobank were subjected to Mendelian randomization analyses. In this study, the inverse variance weighting method was used as the predominant analysis method and was complemented by MR-Egger and weighted median methods. Horizontal pleiotropy and potential outliers were detected by employing the MR-PRESSO method.

Results

This study indicated that obesity rises the possibility of acute upper respiratory infections (BMI: OR=1.131, p<0.0001; WC: OR=1.097, p=0.00406), acute sinusitis (BMI: OR=1.161, p=0.000262; WC: OR=1.209, p=0.000263), acute pharyngitis (WC: OR=1.238, p=0.0258), acute laryngitis and tracheitis (BMI: OR=1.202, p=0.0288; WC: OR=1.381, p=0.00192), all influenza (BMI: OR=1.243, p=0.000235; WC: OR=1.206, p=0.0119), viral pneumonia (WC: OR=1.446, p=0.000870), all pneumoniae (BMI: OR=1.174, p <0.0001; WC: OR=1.272, p <0.0001), bacterial pneumoniae (BMI: OR=1.183, p=0.000290; WC: OR=1.274, p<0.0001), acute bronchitis (BMI: OR=1.252, p <0.0001; WC: OR=1.237, p=0.000268), acute unspecified lower respiratory infection (BMI: OR=1.303, p=0.000403), chronic tonsils and adenoids diseases (BMI: OR=1.236, p <0.0001; WC: OR=1.178, p=0.000157), chronic laryngotracheitis and laryngitis (WC: OR=1.300, p=0.00785), COPD (BMI: OR=1.429, p <0.0001; WC: OR=1.591, p <0.0001), asthma (BMI: OR=1.358, p <0.0001; WC: OR=1.515, p <0.0001), necrotic and suppurative conditions of lower respiratory tract (WC: OR=1.405, p=0.0427), pleural effusion (BMI: OR=1.277, p=0.00225; WC: OR=1.561, p<0.0001), pleural plaque (BMI: OR=1.245, p=0.0312), other diseases of the respiratory system (BMI: OR=1.448, p <0.0001; WC: OR=1.590, p <0.0001), and non-small cell lung cancer (BMI: OR=1.262, p=0.00576; WC: OR=1.398, p=0.00181). This study also indicated that obesity decreases the possibility of bronchiectasis (BMI: OR=0.705; p=0.00200).

Conclusion

This study revealed that obesity increases the risk of the majority of respiratory diseases (including 20 of all 35 respiratory diseases) and that obesity decreases the risk of bronchiectasis.

Genetic association of lipids and lipid-lowering drugs with sepsis: a Mendelian randomization and mediation analysis

Background

The impact of lipid-lowering medications on sepsis is still not well defined. A Mendelian randomization (MR) study was carried out to probe the causal connections between genetically determined lipids, lipid-reducing drugs, and the risk of sepsis.

Materials and methods

Data on total serum cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A-I (ApoA-I), apolipoprotein B (ApoB), and triglycerides (TG) were retrieved from the MR-Base platform and the Global Lipids Genetics Consortium in 2021 (GLGC2021). Our study categorized sepsis into two groups: total sepsis and 28-day mortality of sepsis patients (sepsis28). The inverse-variance weighted (IVW) method was the primary method used in MR analysis. Cochran's Q test and the MR-Egger intercept method were used to assess the heterogeneity and pleiotropy.

Results

In the MR analysis, we found that ApoA-I played a suggestively positive role in protecting against both total sepsis (OR, 0.863 per SD increase in ApoA-I; 95% CI, 0.780-0.955; P = 0.004) and sepsis28 (OR, 0.759; 95% CI, 0.598-0.963; P = 0.023). HDL-C levels were also found to suggestively reduce the incidence of total sepsis (OR, 0.891 per SD increase in HDL-C; 95% CI, 0.802-0.990; P = 0.031). Reverse-MR showed that sepsis28 led to a decrease in HDL-C level and an increase in TG level. In drug-target MR, we found that HMGCR inhibitors positively protected against total sepsis (1 OR , 0.719 per SD reduction in LDL-C; 95% CI, 0.540-0.958; P = 0.024). LDL-C and HDL-C proxied CETP inhibitors were found to have a protective effect on total sepsis, with only LDL-C proxied CETP inhibitors showing a suggestively protective effect on sepsis28. In Mediated-MR, BMI exhibited a negative indirect effect in HMGCR inhibitors curing sepsis. The indirect impact of ApoA-I explained over 50% of the curative effects of CETP inhibitors in sepsis.

Conclusions

Our MR study suggested that ApoA-I and HDL-C protected against sepsis, while HMGCR and CETP inhibitors showed therapeutic potential beyond lipid-lowering effects. ApoA-I explained the effects of CETP inhibitors. Our study illuminates how lipids affect sepsis patients and the effectiveness of new drugs, opening new avenues for sepsis treatment.

Obesity Paradox and Functional Outcomes in Sepsis: A Multicenter Prospective Study

OBJECTIVES

In Asian populations, the correlation between sepsis outcomes and body mass is unclear. A multicenter, prospective, observational study conducted between September 2019 and December 2020 evaluated obesity's effects on sepsis outcomes in a national cohort.

SETTING

Nineteen tertiary referral hospitals or university-affiliated hospitals in South Korea.

PATIENTS

Adult patients with sepsis ( n = 6,424) were classified into obese ( n = 1,335) and nonobese groups ( n = 5,089).

MEASUREMENTS AND RESULTS

Obese and nonobese patients were propensity score-matched in a ratio of 1:1. Inhospital mortality was the primary outcome. After propensity score matching, the nonobese group had higher hospital mortality than the obese group (25.3% vs 36.7%; p < 0.001). The obese group had a higher home discharge rate (70.3% vs 65.2%; p < 0.001) and lower median Clinical Frailty Scale (CFS) (4 vs 5; p = 0.007) at discharge than the nonobese group, whereas the proportion of frail patients at discharge (CFS ≥ 5) was significantly higher in the nonobese group (48.7% vs 54.7%; p = 0.011). Patients were divided into four groups according to the World Health Organization body mass index (BMI) classification and performed additional analyses. The adjusted odds ratio of hospital mortality and frailty at discharge for underweight, overweight, and obese patients relative to normal BMI was 1.25 ( p = 0.004), 0.58 ( p < 0.001), and 0.70 ( p = 0.047) and 1.53 ( p < 0.001), 0.80 ( p = 0.095), and 0.60 ( p = 0.022), respectively.

CONCLUSIONS

Obesity is associated with higher hospital survival and functional outcomes at discharge in Asian patients with sepsis.

Causal relationship between type 1 diabetes mellitus and six high-frequency infectious diseases: A two-sample mendelian randomization study

Purpose

Type 1 diabetes mellitus (T1DM) is associated with different types of infections; however, studies on the causal relationship between T1DM and infectious diseases are lacking. Therefore, our study aimed to explore the causalities between T1DM and six high-frequency infections using a Mendelian randomization (MR) approach.

Methods

Two-sample MR studies were conducted to explore the causalities between T1DM and six high-frequency infections: sepsis, acute lower respiratory infections (ALRIs), intestinal infections (IIs), infections of the genitourinary tract (GUTIs) in pregnancy, infections of the skin and subcutaneous tissues (SSTIs), and urinary tract infections (UTIs). Data on summary statistics for T1DM and infections were obtained from the European Bioinformatics Institute database, the United Kingdom Biobank, FinnGen biobank, and Medical Research Council Integrative Epidemiology Unit. All data obtained for summary statistics were from European countries. The inverse-variance weighted (IVW) method was employed as the main analysis. Considering the multiple comparisons, statistical significance was set at p< 0.008. If univariate MR analyses found a significant causal association, multivariable MR (MVMR) analyses were performed to adjust body mass index (BMI) and glycated hemoglobin (HbA1c). MVMR-IVW was performed as the primary analysis, and the least absolute shrinkage and selection operator (LASSO) regression and MVMR-Robust were performed as complementary analyses.

Results

MR analysis showed that susceptibility to IIs increased in patients with T1DM by 6.09% using the IVW-fixed method [odds ratio (OR)=1.0609; 95% confidence interval (CI): 1.0281-1.0947, p=0.0002]. Results were still significant after multiple testing. Sensitivity analyses did not show any significant horizontal pleiotropy or heterogeneity. After adjusting for BMI and HbA1c, MVMR-IVW (OR=1.0942; 95% CI: 1.0666-1.1224, p<0.0001) showed significant outcomes that were consistent with those of LASSO regression and MVMR-Robust. However, no significant causal relationship was found between T1DM and sepsis susceptibility, ALRI susceptibility, GUTI susceptibility in pregnancy, SSTI susceptibility, and UTI susceptibility.

Conclusions

Our MR analysis genetically predicted increased susceptibility to IIs in T1DM. However, no causality between T1DM and sepsis, ALRIs, GUTIs in pregnancy, SSTIs, or UTIs was found. Larger epidemiological and metagenomic studies are required to further investigate the observed associations between the susceptibility of certain infectious diseases with T1DM.

Exploring the Causality Between Body Mass Index and Sepsis: A Two-Sample Mendelian Randomization Study

Objective: Observational epidemiological studies have shown a link between obesity and sepsis, but any causal relationship is not clear. Our study aimed to explore the correlation and causal relationship between body mass index and sepsis by a two-sample Mendelian randomization (MR). Methods: In large sample genome-wide association studies, single-nucleotide polymorphisms related to body mass index were screened as instrumental variables. Three MR methods, MR-Egger regression, weighted median estimator, and inverse variance-weighted, were used to evaluate the causal relationship between body mass index and sepsis. Odds ratio (OR) and 95% confidence interval (CI) were used as the evaluation index of causality, and sensitivity analyses were conducted to assess pleiotropy and instrument validity. Results: By two-sample MR, the inverse variance weighting method results suggested that increased body mass index was associated with an increased risk of sepsis (odds ratio 1.32; 95% CI 1.21-1.44; p = 1.37 × 10^-9) and streptococcal septicemia (OR 1.46; 95% CI 1.11-1.91; p = 0.007), but there was no causal relationship with puerperal sepsis (OR, 1.06; 95% CI, 0.87-1.28; p = 0.577). Sensitivity analysis was consistent with the results, and there was no heterogeneity and level of pleiotropy. Conclusion: Our study supports a causal relationship between body mass index and sepsis. Proper control of body mass index may prevent sepsis.

Health profile of people living in the Gare Palma mining area of Tamnar block, Raigarh, Chhattisgarh, India

Introduction

A community-based health survey was conducted in Tamnar block, Raigarh district of Chhattisgarh, India.

Methodology

A total of 909 individuals (adults) were selected from 909 households from 33 sampled villages from March 2019 to February 2020. All individuals were clinically examined, and observations were recorded.

Results

Among adults older than 18 years, hypertension was observed in 21.7%. Type II diabetes was observed in only 4.0% of individuals. Tuberculosis was seen in 23 (2.5%) individuals.

Discussion

Common morbidities were similar in tribal and non-tribal communities living in the same area. For communicable diseases, being male, having nutritional deficiencies, and smoking were independent risk factors. For non-communicable diseases, the independent significant risk factors identified were being male, an altered body mass index, disturbed sleep, smoking, and nutritional deficiencies.

Association between Serum 25-Hydroxyvitamin D Concentrations and Respiratory Infection among United States Adults

BACKGROUND

Vitamin D plays an essential role in immune responses to infections. However, the association between serum 25(OH)D concentrations and respiratory infection remains unclear.

OBJECTIVES

The current study aimed to examine the association between serum 25(OH)D concentrations and respiratory infection among the United States adults.

METHODS

This cross-sectional study used data from the NHANES 2001-2014. Serum 25(OH)D concentrations were measured by radioimmunoassay or liquid chromatography-tandem mass spectrometry and were classified as ≥75.0 nmol/L (sufficiency), 50.0-74.9 nmol/L (insufficiency), 30.0-49.9 nmol/L (moderate deficiency), and <30 nmol/L (severe deficiency). The respiratory infections included self-reported head or chest cold as well as influenza, pneumonia, or ear infection within the last 30 d. The associations between serum 25(OH)D concentrations and respiratory infections were examined using weighted logistic regression models. Data are presented as ORs and 95% CIs.

RESULTS

This study included 31,466 United States adults ≥20 y of age (47.1 y, 55.5% women) with a mean serum 25(OH)D concentration of 66.2 nmol/L. After adjusting for sociodemographic characteristics, season of examination, lifestyle and dietary factors, and body mass index, compared with participants with a serum 25(OH)D concentration ≥75.0 nmol/L, those with a serum 25(OH)D concentration <30 nmol/L had higher risk of head or chest cold (OR: 1.17; 95% CI: 1.01, 1.36) and other respiratory diseases, including influenza, pneumonia, and ear infections (OR: 1.84; 95% CI: 1.35, 2.51). In the stratification analyses, lower serum 25(OH)D concentrations were associated with a higher risk of head or chest cold in obese adults but not in nonobese adults.

CONCLUSIONS

Serum 25(OH)D concentrations are inversely associated with respiratory infection occurrence among United States adults. This finding may shed light on the protective effect of vitamin D on the respiratory health.

Mendelian randomization highlights the causal association of obesity with periodontal diseases

AIM

The underlying mechanisms connecting obesity and periodontal diseases remain unclear. This study investigates the potential causal association of obesity with periodontal diseases using Mendelian randomization (MR).

MATERIALS AND METHODS

Single-nucleotide polymorphisms of obesity traits including body mass index (BMI), waist circumference (WC), and WC adjusted for BMI (WCadjBMI) from large-scale genome-wide association studies were screened for instrumental variables. The single trait periodontitis and the combined trait comprising periodontitis and loose teeth were adopted as surrogates for periodontal diseases. Inverse-variance weighted (IVW), series of sensitivity analyses and multivariable MR were employed to determine the association of obesity with periodontal diseases.

RESULTS

IVW results showed that per 1-SD increment in BMI (odds ratio, OR = 1.115; 95% confidence interval [CI] = 1.064-1.169; p < .001) and WC (OR = 1.117; 95% CI = 1.052-1.185; p < .001), but not WCadjBMI, were significantly associated with an increased risk of periodontitis/loose teeth. Moreover, the MR estimates were consistent across other MR sensitivity analyses and multivariable MR. However, a causal association of obesity with the single trait periodontitis was not identified.

CONCLUSIONS

The presented evidence supports previous epidemiological findings by showing a potential causal association of genetic liability to obesity with periodontal diseases. The biological mechanisms underlying this association warrant further investigation.

Risk of lower respiratory tract infections: a genome-wide association study with Mendelian randomization analysis in three independent European populations

OBJECTIVE

Lower respiratory tract infections (LRTIs) are a leading cause of morbidity and mortality worldwide. Few studies have previously investigated genetic susceptibility and potential risk factors for LRTI.

METHODS

We used data from the UK Biobank, Trøndelag Health Study (HUNT), and FinnGen to conduct a genome-wide association study (GWAS). Cases were subjects hospitalized with LRTI, and controls were subjects with no such hospitalization. We conducted stratification and interaction analyses to evaluate whether the genetic effect of LRTI differed by sex or smoking. Mendelian randomization (MR) analyses were conducted to identify the unconfounded relationship between cardiometabolic risk factors and LRTI.

RESULTS

A total of 25 320 cases and 575 294 controls were included. The 15q25.1 locus reached genome-wide significance in the meta-analysis (rs10519203: OR 0.94, p 3.87e-11). The protective effect of effect allele of rs10519203 was present among smokers (OR 0.90, 95%CI 0.87-0.92, p 1.38e-15) but not among never-smokers (OR 1.01, 95%CI 0.97-1.06, p 5.20e-01). In MR analyses, we found that increasing body mass index (OR 1.31, 95%CI 1.24-1.40, p 3.78e-18), lifetime smoking (OR 2.83, 95%CI 2.34-3.42, p 6.56e-27), and systolic blood pressure robustly increased the risk of LRTIs (OR 1.11, 95%CI 1.02-1.22, p 1.48e-02).

CONCLUSION

A region in 15q25.1 was strongly associated with LRTI susceptibility. Reduction in the prevalence of smoking, overweight, obesity, and hypertension may reduce the disease burden of LRTIs.

Mendelian Randomization: A Review of Methods for the Prevention, Assessment, and Discussion of Pleiotropy in Studies Using the Fat Mass and Obesity-Associated Gene as an Instrument for Adiposity

Pleiotropy assessment is critical for the validity of Mendelian randomization (MR) analyses, and its management remains a challenging task for researchers. This review examines how the authors of MR studies address bias due to pleiotropy in practice. We reviewed Pubmed, Medline, Embase and Web of Science for MR studies published before 21 May 2020 that used at least one single-nucleotide polymorphism (SNP) in the fat mass and obesity-associated (FTO) gene as instrumental variable (IV) for body mass index, irrespective of the outcome. We reviewed: 1) the approaches used to prevent pleiotropy, 2) the methods cited to detect or control the independence or the exclusion restriction assumption highlighting whether pleiotropy assessment was explicitly stated to justify the use of these methods, and 3) the discussion of findings related to pleiotropy. We included 128 studies, of which thirty-three reported one approach to prevent pleiotropy, such as the use of multiple (independent) SNPs combined in a genetic risk score as IVs. One hundred and twenty studies cited at least one method to detect or account for pleiotropy, including robust and other IV estimation methods (n = 70), methods for detection of heterogeneity between estimated causal effects across IVs (n = 72), methods to detect or account associations between IV and outcome outside thought the exposure (n = 85), and other methods (n = 5). Twenty-one studies suspected IV invalidity, of which 16 explicitly referred to pleiotropy, and six incriminating FTO SNPs. Most reviewed MR studies have cited methods to prevent or to detect or control bias due to pleiotropy. These methods are heterogeneous, their triangulation should increase the reliability of causal inference.

Toward more rigorous and informative nutritional epidemiology: The rational space between dismissal and defense of the status quo

To date, nutritional epidemiology has relied heavily on relatively weak methods including simple observational designs and substandard measurements. Despite low internal validity and other sources of bias, claims of causality are made commonly in this literature. Nutritional epidemiology investigations can be improved through greater scientific rigor and adherence to scientific reporting commensurate with research methods used. Some commentators advocate jettisoning nutritional epidemiology entirely, perhaps believing improvements are impossible. Still others support only normative refinements. But neither abolition nor minor tweaks are appropriate. Nutritional epidemiology, in its present state, offers utility, yet also needs marked, reformational renovation. Changing the status quo will require ongoing, unflinching scrutiny of research questions, practices, and reporting-and a willingness to admit that "good enough" is no longer good enough. As such, a workshop entitled "Toward more rigorous and informative nutritional epidemiology: the rational space between dismissal and defense of the status quo" was held from July 15 to August 14, 2020. This virtual symposium focused on: (1) Stronger Designs, (2) Stronger Measurement, (3) Stronger Analyses, and (4) Stronger Execution and Reporting. Participants from several leading academic institutions explored existing, evolving, and new better practices, tools, and techniques to collaboratively advance specific recommendations for strengthening nutritional epidemiology.

Discovery of a AHR pelargonidin agonist that counter-regulates Ace2 expression and attenuates ACE2-SARS-CoV-2 interaction

The severe acute respiratory syndrome (SARS)-CoV-2 is the pathogenetic agent of Corona Virus Induced Disease (COVID)19. The virus enters the human cells after binding to the angiotensin converting enzyme (ACE)2 receptor in target tissues. ACE2 expression is induced in response to inflammation. The colon expression of ACE2 is upregulated in patients with inflammatory bowel disease (IBD), highlighting a potential risk of intestinal inflammation in promoting viral entry in the human body. Because mechanisms that regulate ACE2 expression in the intestine are poorly understood and there is a need of anti-SARS-CoV-2 therapies, we have settled to investigate whether natural flavonoids might regulate the expression of Ace2 in intestinal models of inflammation. The results of these studies demonstrated that pelargonidin activates the Aryl hydrocarbon Receptor (AHR) in vitro and reverses intestinal inflammation caused by chronic exposure to high fat diet or to the intestinal braking-barrier agent TNBS in a AhR-dependent manner. In these two models, development of colon inflammation associated with upregulation of Ace2 mRNA expression. Colon levels of Ace2 mRNA were directly correlated with Tnf-α mRNA levels. Molecular docking studies suggested that pelargonidin binds a fatty acid binding pocket on the receptor binding domain of SARS-CoV-2 Spike protein. In vitro studies demonstrated that pelargonidin significantly reduces the binding of SARS-CoV-2 Spike protein to ACE2 and reduces the SARS-CoV-2 replication in a concentration-dependent manner. In summary, we have provided evidence that a natural flavonoid might hold potential in reducing intestinal inflammation and ACE2 induction in the inflamed colon in a AhR-dependent manner.

Safety and efficacy of omadacycline by BMI categories and diabetes history in two Phase III randomized studies of patients with acute bacterial skin and skin structure infections

OBJECTIVES

The objectives of this post-hoc analysis were to examine the safety and efficacy of omadacycline by BMI categories and diabetes history in adults with acute bacterial skin and skin structure infections (ABSSSI) from two pivotal Phase III studies.

PATIENTS AND METHODS

OASIS-1 (ClinicalTrials.gov identifier NCT02378480): patients were randomized 1:1 to IV omadacycline or linezolid for 7-14 days, with optional transition to oral medication. OASIS-2 (ClinicalTrials.gov identifier NCT02877927): patients received once-daily oral omadacycline or twice-daily oral linezolid for 7-14 days. Early clinical response (ECR) was defined as ≥20% reduction in lesion size 48-72 h after the first dose. Clinical success at post-treatment evaluation (PTE; 7-14 days after the last dose) was defined as symptom resolution such that antibacterial therapy was unnecessary. Safety was assessed by treatment-emergent adverse events and laboratory measures. Between-treatment comparisons were made with regard to WHO BMI categories and diabetes history.

RESULTS

Patients were evenly distributed among healthy weight, overweight and obese groups. Clinical success for omadacycline-treated patients at ECR and PTE was similar across BMI categories. Outcomes by diabetes status were similar in omadacycline- and linezolid-treated patients: at ECR, clinical success rates were lower for those with diabetes; at PTE, clinical success was similar between treatment groups regardless of diabetes history. The safety of omadacycline and linezolid was largely similar across BMI groups and by diabetes history.

CONCLUSIONS

Omadacycline efficacy in patients with higher BMI and in patients with diabetes was consistent with results from two pivotal Phase III ABSSSI trials. Fixed-dose omadacycline is an appropriate treatment for ABSSSI in adults regardless of BMI.

The effect of angiotensin-converting enzyme levels on COVID-19 susceptibility and severity: a Mendelian randomization study

Background

There has been uncertainty about the safety or benefit of angiotensin-converting enzyme (ACE) inhibitors during the COVID-19 pandemic. We used Mendelian randomization using genetic determinants of serum-ACE levels to test whether decreased ACE levels increase susceptibility to SARS-CoV-2 infection or COVID-19 severity, while reducing potential bias from confounding and reverse causation in observational studies.

Methods

Genetic variants strongly associated with ACE levels, which were nearby the ACE gene, were identified from the ORIGIN trial and a separate genome-wide association study (GWAS) of ACE levels from the AGES cohort. The ORIGIN trial included 4147 individuals of European and Latino ancestries. Sensitivity analyses were performed using a study of 3200 Icelanders. Cohorts from the COVID-19 Host Genetics Initiative GWAS of up to 960 186 individuals of European ancestry were used for COVID-19 susceptibility, hospitalization and severe-disease outcome.

Results

Genetic variants were identified that explain between 18% and 37% of variance in ACE levels. Using genetic variants from the ORIGIN trial, a standard-deviation decrease in ACE levels was not associated with an increase in COVID-19 susceptibility [odds ratio (OR): 1.02, 95% confidence interval (CI): 0.90, 1.15], hospitalization (OR: 0.86, 95% CI: 0.68, 1.08) or severe disease (OR: 0.74, 95% CI: 0.51, 1.06). Using genetic variants from the AGES cohort, the result was similar for susceptibility (OR: 0.98, 95% CI: 0.89, 1.09), hospitalization (OR: 0.86, 95% CI: 0.66, 1.11) and severity (OR: 0.75, 95% CI: 0.50, 1.14). Multiple-sensitivity analyses led to similar results.

Conclusion

Genetically decreased serum ACE levels were not associated with susceptibility to, or severity of, COVID-19 disease. These data suggest that individuals taking ACE inhibitors should not discontinue therapy during the COVID-19 pandemic.

Bariatric Surgery and Risk of New-onset Inflammatory Bowel Disease: A Nationwide Cohort Study

BACKGROUND AND AIMS

The aim of this study was to examine the risk of new-onset inflammatory bowel disease [IBD] following bariatric surgery.

METHODS

We conducted a nationwide population-based prospective cohort study of the entire Danish population 18 to 60 years of age, alive, and residing in Denmark, from 1996 to 2018. Bariatric surgery was included as a time-dependent variable, and Cox proportional hazards regression models were used to estimate hazard ratios [HRs] of IBD. We used a model adjusting for age, sex, and birth cohort and a multifactor-adjusted model additionally including educational status and number of obesity-related comorbidities.

RESULTS

We followed 3 917 843 individuals of whom 15 347 had a bariatric surgery, for development of new-onset IBD. During 106 420 person-years following bariatric surgery, 100 IBD events occurred [incidence rate 0.940/1000 person-years]. During 55 553 785 person-years without bariatric surgery, 35 294 events of IBD occurred [incidence rate 0.635/1000 person-years]. This corresponded to a multifactor-adjusted hazard ratio [HR] of 1.15 (95% confidence interval[CI], 0.94-1.40) for IBD. Multifactor-adjusted HRs of Crohn's disease [CD] and ulcerative colitis [UC] were 1.85 [95% CI, 1.40-2.44] and 0.81 [95% CI, 0.61-1.08], respectively. Among women, the multifactor-adjusted HR for CD was 2.18 [95% CI, 1.64-2.90]. When limiting the study population to individuals with a diagnosis of overweight/obesity, bariatric surgery remained associated with increased risk of CD, multifactor-adjusted HR 1.59 [95% CI, 1.18-2.13].

CONCLUSIONS

This nationwide cohort study shows that bariatric surgery is associated with increased risk of development of new-onset CD, but not of UC. The underlying mechanisms remain elusive.

Altered Intestinal ACE2 Levels Are Associated With Inflammation, Severe Disease, and Response to Anti-Cytokine Therapy in Inflammatory Bowel Disease

BACKGROUND AND AIMS

The host receptor for severe acute respiratory syndrome coronavirus 2, angiotensin-converting enzyme 2 (ACE2), is highly expressed in small bowel (SB). Our aim was to identify factors influencing intestinal ACE2 expression in Crohn's disease (CD), ulcerative colitis (UC), and non-inflammatory bowel disease (IBD) controls.

METHODS

Using bulk RNA sequencing or microarray transcriptomics from tissue samples (4 SB and 2 colonic cohorts; n = 495; n = 387 UC; n = 94 non-IBD), we analyzed the relationship between ACE2 with demographics and disease activity and prognosis. We examined the outcome of anti-tumor necrosis factor and anti-interleukin-12/interleukin-23 treatment on SB and colonic ACE2 expression in 3 clinical trials. Univariate and multivariate regression models were fitted.

RESULTS

ACE2 levels were consistently reduced in SB CD and elevated in colonic UC compared with non-IBD controls. Elevated SB ACE2 was also associated with demographic features (age and elevated body mass index) associated with poor coronavirus disease 2019 outcomes. Within CD, SB ACE2 was reduced in patients subsequently developing complicated disease. Within UC, colonic ACE2 was elevated in active disease and in patients subsequently requiring anti-tumor necrosis factor rescue therapy. SB and colonic ACE2 expression in active CD and UC were restored by anti-cytokine therapy, most notably in responders.

CONCLUSIONS

Reduced SB but elevated colonic ACE2 levels in IBD are associated with inflammation and severe disease, but normalized after anti-cytokine therapy, suggesting compartmentalization of ACE2-related biology in SB and colonic inflammation. The restoration of ACE2 expression with anti-cytokine therapy might be important in the context of severe acute respiratory syndrome coronavirus 2 infection and potentially explain reports of reduced morbidity from coronavirus disease 2019 in IBD patients treated with anti-cytokines.

Body mass index and risk of dying from a bloodstream infection: A Mendelian randomization study

BACKGROUND

In observational studies of the general population, higher body mass index (BMI) has been associated with increased incidence of and mortality from bloodstream infection (BSI) and sepsis. On the other hand, higher BMI has been observed to be apparently protective among patients with infection and sepsis. We aimed to evaluate the causal association of BMI with risk of and mortality from BSI.

METHODS AND FINDINGS

We used a population-based cohort in Norway followed from 1995 to 2017 (the Trøndelag Health Study [HUNT]), and carried out linear and nonlinear Mendelian randomization analyses. Among 55,908 participants, the mean age at enrollment was 48.3 years, 26,324 (47.1%) were men, and mean BMI was 26.3 kg/m2. During a median 21 years of follow-up, 2,547 (4.6%) participants experienced a BSI, and 451 (0.8%) died from BSI. Compared with a genetically predicted BMI of 25 kg/m2, a genetically predicted BMI of 30 kg/m2 was associated with a hazard ratio for BSI incidence of 1.78 (95% CI: 1.40 to 2.27; p < 0.001) and for BSI mortality of 2.56 (95% CI: 1.31 to 4.99; p = 0.006) in the general population, and a hazard ratio for BSI mortality of 2.34 (95% CI: 1.11 to 4.94; p = 0.025) in an inverse-probability-weighted analysis of patients with BSI. Limitations of this study include a risk of pleiotropic effects that may affect causal inference, and that only participants of European ancestry were considered.

CONCLUSIONS

Supportive of a causal relationship, genetically predicted BMI was positively associated with BSI incidence and mortality in this cohort. Our findings contradict the "obesity paradox," where previous traditional epidemiological studies have found increased BMI to be apparently protective in terms of mortality for patients with BSI or sepsis.

The Association Between Body Mass Index and the Risk of Hospitalization and Mortality due to Infection: A Prospective Cohort Study

Background

We aim to determine whether obesity increases the risk of various infections using a large prospective population-based cohort.

Methods

A total of 120 864 adults were recruited from the New Taipei City health screening program from 2005 to 2008. Statistics for hospitalization and mortality due to infection were obtained from the National Health Insurance Database and the National Death Registry in Taiwan.

Results

During a mean follow-up period of 7.61 years, there were 438, 7582, 5298, and 1480 first hospitalizations due to infection in the underweight, normal, overweight, and obese groups, respectively. Obesity significantly increases the risk of hospitalization for intra-abdominal infections (adjusted hazard ratio [aHR], 1.19; 95% CI, 1.00–1.40), including diverticulitis, liver abscess, acute cholecystitis and anal and rectal abscess, reproductive and urinary tract infection (aHR, 1.38; 95% CI, 1.26–1.50), skin and soft tissue infection (aHR, 2.46; 95% CI, 2.15–2.81), osteomyelitis (aHR, 1.70; 95% CI, 1.14–2.54), and necrotizing fasciitis (aHR, 3.54; 95% CI,1.87–6.67), and this relationship is dose-dependent. This study shows that there is a U-shaped association between body mass index (BMI) and hospitalization for lower respiratory tract infection, septicemia, and the summation of all infections and that underweight people are at the greatest risk, followed by obese people. There is a clear negative relationship between BMI and infection-related mortality.

Conclusions

The pattern that BMI affects the risk of hospitalization and mortality due to infection varies widely across infection sites. It is necessary to tailor preventive and therapeutic measures against different infections in hosts with different BMIs.