Dietary Nitrate Intake and
16S rRNA
‐Inferred Nitrite‐Generating Capacity of the Subgingival Microbiome May Influence Glucose Metabolism: Results From the Oral Infections Glucose Intolerance and Insulin Re
ABSTRACT Aims To investigate whether the association between the nitrite‐generating capacity of the subgingival microbiome and early cardiometabolic risk biomarkers varies by dietary nitrate intake. Materials and Methods Cross‐sectional data from 668 participants (mean age 31 ± 9 years, 73% women) were analysed. Dietary nitrate intake was calculated from food frequency questionnaires. Subgingival 16S rRNA sequencing (Illumina, MiSeq) and PICRUSt2 estimated microbial genes. The Microbiome‐Induced Nitric Oxide Enrichment Score (MINES) was calculated as a ratio of microbial gene abundances representing enhanced net capacity for NO generation. Adjusted multivariable linear models regressed cardiometabolic risk biomarkers (HbA1c, glucose, insulin, insulin resistance (HOMA‐IR), blood pressure) on nitrate intake and MINES together with a MINES × nitrate intake interaction term. Results Mean nitrate intake was 190 ± 171 mg/day. Significant interactions of MINES and nitrate intake were observed for insulin and HOMA‐IR ( p < 0.05). Among participants with a low MINES, higher nitrate intake was associated with lower HOMA‐IR (1.2 [1.1–1.4] vs. 1.5 [1.3–1.6]; p = 0.002), but levels were similar in those with high MINES ( p = 0.84). Conclusions A biomarker of higher microbial NO‐generating capacity in subgingival plaque is associated with lower insulin and insulin resistance among individuals with lower dietary nitrate intake. Future trials evaluating the cardiometabolic benefits of nitrate‐rich diets should incorporate measures of the entire oral microbiome.
Differences in COVID-19 Vaccination Behaviors Among Adults With Versus Without Chronic Lower Respiratory Diseases: The C4R Study
Abstract RATIONALE: Chronic lower respiratory diseases (CLRD) confer higher risks from respiratory viral infections, hence CLRD patients are prioritized for influenza, pneumococcal, and COVID-19 vaccination. Nonetheless, vaccine deferral and declination remain common. Given that COVID-19 vaccination is particularly polarizing, and attitudes toward it may differ from other vaccines, we assessed COVID-19 vaccination behaviors and attitudes in adults with versus without CLRD and/or smoking history, which is strongly associated with CLRD risk. METHODS: We pooled data from 10 cohorts participating in the Collaborative Cohort of Cohorts for COVID-19 Research (C4R) that collected pre-pandemic data on self-reported physician diagnosis of asthma or COPD. C4R assessed COVID-19 vaccination status through three waves of standardized questionnaires (2020-2022, 2021-2023, 2023-2024). Prompt COVID-19 vaccination was defined as self-report of receiving at least one COVID-19 vaccine by May 1, 2021. Cumulative COVID-19 vaccine count was self-reported on the Wave 3 Questionnaire. Vaccine attitudes and receipt of influenza and/or pneumococcal vaccines were self-reported on the Wave 1 or 2 Questionnaire. Age-adjusted Poisson regression was used to test associations of vaccination behaviors with CLRD and smoking status at the most recent pre-pandemic exam. RESULTS: Of 20,034 participants (pre-pandemic COPD, 9.3%; asthma, 11.7%; current smoking, 13.4%; former smoking, 36.3%), 64.2% reported prompt COVID-19 vaccination. Among the subset of 10,626 participants completing the Wave 3 Questionnaire in 2023-24, the median COVID-19 vaccine count was 3 (Q1:2, Q3:4). Compared to participants without CLRD, prompt vaccination was more likely in those with asthma (RR=1.04, 95%CI:1.01-1.07, p=0.008) and less likely with COPD (RR=0.94, 95%CI:0.91-0.98, p=0.001), but there were no differences in doses for asthma and COPD. Compared to never smokers, former smoking participants were more likely to receive prompt vaccination (RR=1.11, 95%CI:1.08-1.13, p<0.0001) and more vaccine doses (RR=1.03, 95%CI:1.01-1.05, p=0.015); conversely, current smoking was inversely associated with prompt vaccination (RR=0.94, 95%CI:0.91-0.97, p=0.001) and was associated with fewer doses (RR=0.93, 95%CI:0.89-0.96, p<0.0001). Participants with CLRD versus without CLRD were more likely to report receiving influenza and pneumococcal vaccines, but they were more likely to believe that vaccines are unsafe or ineffective (figure). CONCLUSIONS: COPD was associated with lower likelihood of prompt COVID-19 vaccination. Current smoking was associated with both lower likelihood of prompt COVID-19 vaccination and a lower number of COVID-19 vaccine doses by 2023-24. These associations may be partly attributed to negative vaccine attitudes and beliefs. How the COVID-19 pandemic may have influenced vaccine behaviors and attitudes merits additional study.
Socio-demographic and Clinical Factors Associated With COVID-19 Vaccine Uptake Among Multiethnic US Adults: The C4R Study
Abstract RATIONALE: Deferral and declination of the COVID-19 vaccine is correlated with many factors, including different health guidelines and difficulties accessing the vaccine. In the US, COVID-19 vaccines were made available in tranches of clinical risk starting in December 2020 and were available to all adults on April 19, 2021. In the post-pandemic period, repeating COVID-19 vaccination with updated formulations is broadly recommended. Given that the public health impact of vaccine allocation strategies depends on public acceptance of vaccination, we aimed to evaluate demographic, clinical and social correlates of (1) receiving at least one COVID-19 vaccine by May 1, 2021 (prompt vaccination) and (2) the total number of vaccine doses received (vaccine count) through 2023-2024. METHODS: The Collaborative Cohort of Cohorts for COVID-19 Research (C4R) is a prospective observational meta-cohort study comprising 14 extant NIH-funded population-based cohorts. C4R assessed COVID-19 vaccination using three waves of standardized questionnaires (2020-2021, 2021-2023, 2023-2024). Prompt vaccination was defined by participant self-report of vaccination before May 1, 2021; participants vaccinated after May1, 2021 were classified as non-prompt; participants with missing vaccination information were excluded. Vaccine count was defined by self-report on the 2023-2024 wave Questionnaire. Demographic, clinical and social factors were classified by self-report and/or objective measures from the most recent pre-pandemic cohort exam. Poisson models regressed either prompt vaccination or vaccine count on pre-pandemic factors. RESULTS: Of 17,866 participants (mean age, 6713 years; 60.1% female; 42.1% non-Hispanic White, 22.0% Black, 28.9% Hispanic/Latino, 3.4% American Indian, 2.3% South Asian, 1.4% East Asian), 11,481 (64.3%) reported prompt vaccination. Of the subset of 14,529 participants completing the Wave 3 questionnaire, the median vaccine count in 2023-24 was 3 (Q1, 2; Q3 4). Likelihood of prompt vaccination was higher with greater age, income, and education and with history of diabetes and hypertension; prompt vaccination was less likely with male sex, current smoking, and non-White race and ethnicity (table). Similar associations were observed with respect to vaccine count (table). CONCLUSIONS: In a diverse C4R cohort community-based sample, earlier and greater COVID-19 vaccination was associated with older age and several clinical comorbidities; in contrast, later and lesser vaccine uptake was observed among historically marginalized groups. Whether disparities in COVID-19 vaccination could contribute to disparities in post-COVID-19 conditions merits further investigation.
Associations of SARS-COV-2 Infection and Long COVID With Respiratory Health in the Collaborative Cohort of Cohorts for COVID-19 Research (C4R) Study
Abstract Rationale: SARS-CoV-2 infection may be associated with new or worsening respiratory symptoms that, if persistent, may contribute to “Long COVID.” Research is needed on the prevalence and risk determinants of Long COVID and related respiratory symptoms in adults with and without pre-existing obstructive lung disease or smoking history. Methods: C4R is a prospective, observational study that collected information on SARS-CoV-2 infection using standardized methods across 14 NIH-funded cohorts. The third wave of C4R questionnaires, administered June 2023 to January 2025, assessed self-reported Long COVID via the question, “Do you think that you are experiencing, or have ever experienced, what has been called “long COVID,” or symptoms related to COVID at least a month after your infection?” Questionnaires also assessed the presence (vs absence) of 22 symptoms that have been linked to Long COVID, including cough, shortness of breath, and post-exertional malaise. Pre-pandemic obstructive lung disease (COPD or asthma) and smoking status (ever/never) were harmonized from self-reported data collected at the most recent pre-pandemic cohort exam. Poisson regression was used to assess prevalence ratios (PRs) adjusting for age, sex, BMI, education, and pre-pandemic hypertension, diabetes, cardiovascular disease, and depressive symptoms. PRs for respiratory symptoms were tested according to self-reported Long COVID and history of non-hospitalized or hospitalized infection; effect modification by pre-pandemic lung disease and smoking was assessed by multiplicative interaction terms and in fully stratified models. Results: Among 23,434 questionnaire respondents, 1,484 (6.3%) self-reported Long COVID, including 246/1,262 (19.5%) with pre-pandemic lung disease and 664/4,018 (16.5%) with smoking history. The adjusted PR for Long COVID was 1.17 (95%CI:0.99-1.39;P=0.06) comparing participants with/without lung disease and 1.17 (95%CI:1.04-1.32;P=0.01) comparing participants with/without smoking history. Respiratory symptoms were more prevalent in those with self-reported Long COVID, as well as in those with a history of hospitalized or non-hospitalized infection (Table). Associations were generally stronger in participants without pre-pandemic lung disease (p-interaction<0.05 for all comparisons). Respiratory symptoms were also more prevalent with a history of repeated, and pre-Omicron infections, and were less prevalent among participants vaccinated prior to their first infection; findings were similar even after excluding participants with self-reported Long COVID. Conclusions: Long COVID is common, particularly in adults with pre-existing COPD or asthma or smoking history. Long COVID and history of SARS-CoV-2 infection, including non-hospitalized infections, was associated with greater respiratory symptom burden. Whether SARS-CoV-2 infection or Long COVID are associated with development or progression of obstructive lung diseases warrants future studies.
Associations of Prepandemic Chronic Kidney Disease Stages With Severe COVID-19 Incidence: The C4R Study
Abstract RATIONALE: Chronic kidney disease (CKD) is common in the general population and is associated with inflammation and compromised immune function. Since these mechanisms are hypothesized to promote severe COVID-19, we tested associations of pre-pandemic CKD with incident COVID-19 hospitalization or death in a large, multi-ethnic, US general population-based meta-cohort of adults. METHODS: Data were harmonized and pooled from 9 NIH-funded longitudinal cohorts participating in the Collaborative Cohort of Cohorts for COVID-19 Research (C4R). CKD was classified by KDIGO 2024 CKD guideline (Low Risk, Moderately Increased Risk, High Risk, Very High Risk) using pre-pandemic urinary albumin-to-creatinine ratio (uACR) and estimated glomerular filtration rate using creatinine (eGFRcr). Incident COVID-19 hospitalization or death was ascertained over 2020−2023 via self-report and active surveillance, with medical record adjudication in a subset. In our primary analysis, we assessed associations between CKD stages and incident COVID-19 hospitalization or death. A secondary analysis examined joint association of CKD stages and the number of comorbidities (obesity, hypertension, diabetes, and cardiovascular disease) with the severe COVID-19. Multivariable hazard ratios (HRs) were estimated by cause-specific Cox regression, adjusting for socio-demographics and smoking. RESULTS: Among 26,039 multi-ethnic adult participants (mean age 66.1±14.8, 60.6 % female, 28.6% Whites, 3.2% Asians, 20.6% Blacks, 41.3% Hispanics, 6.3% American Indians) with a median follow-up of 550 days since the onset of the pandemic (baseline: March 1, 2020), there were 734 incident COVID-19 hospitalizations or deaths. The mean time since CKD markers were measured before the baseline was 6.5 years. The cumulative incidence of severe COVID-19 was 2.3, 3.5, 6.5, and 7.3% across CKD risk stages, and similar patterns were observed within variant types (Figure 1). Compared to participants with Low Risk of CKD, there was a graded increased hazards of severe COVID-19 across CKD stages, with HRs (95% CIs) of 1.27 (1.03−1.55) for Moderately Increased Risk, 2.33 (1.77−3.06) for High Risk, and 2.72 (1.89−3.92) for Very High Risk. In a joint analysis, both increased CKD risk and a higher number of comorbidities were associated with a higher risk of severe COVID-19, showing the highest HR of 12.29 (5.75−26.27) in Very High Risk individuals with four comorbidities compared to Low Risk individuals with none. CONCLUSIONS: Higher CKD stages were associated with a greater risk of COVID-19 hospitalization or death and the risk is substantially heightened with additional comorbidities. These results suggest that adults with CKD and related comorbidities may merit enhanced COVID-19 risk mitigation.
Abstract P1062: Pre-Pandemic Thrombo-inflammatory Biomarkers and Risk of Severe Covid-19: the Collaborative Cohort of Cohorts for Covid-19 Research (C4R)
Background: Thrombo-inflammation is a hallmark of acute Covid-19, with higher thrombo-inflammatory markers during infection associated with adverse outcomes. We hypothesized that higher pre-pandemic biomarkers, reflecting a higher thrombo-inflammatory setpoint, might identify people at greater risk of severe manifestations of Covid-19. Hypothesis: Pre-pandemic inflammation markers are associated with risk of hospitalized or fatal (hereafter, “severe”) Covid-19 in a multi-ethnic US sample. Methods: From 2020-2023, C4R harmonized pre-pandemic measures and ascertained Covid-19 across 14 longstanding cohort studies. In 12 cohorts, we assessed biomarker data and covariates from the study visit closest to the pandemic for 6 analytes shown in the Table. HRs of severe Covid-19 by pre-pandemic biomarkers were estimated using cause-specific Cox regression, treating non-severe Covid-19 as a competing risk, and adjusting for pre-pandemic sociodemographic and clinical characteristics. Results: Biomarkers were measured a mean of 20 years before the pandemic with different sample sizes for each (Table footnote). Mean age at the start of the pandemic was in the 60s or 70s depending on the biomarker. The most represented race or ethnic groups were White and Black. The largest sample was for C-reactive protein, and there were 1,001 severe Covid-19 cases among 38,784 participants. In the adjusted models, considered individually, higher CRP, leukocyte count, factor VIII and fibrinogen, but not other markers, were associated with greater risk of severe Covid-19 (Table).Associations were robust across subgroups and time since biomarker measurement (example for C-reactive protein in Figure). Conclusions: In this prospective multi-study analysis of a multi-ethnic population, higher basal levels of thrombo-inflammation markers were associated with greater risk of severe Covid-19. Since we considered non-severe Covid-19 as a competing risk, associations may reflect factors related to progression to more serious Covid-19 illness.
Association Between Dietary Patterns and Subgingival Microbiota: Results From the Oral Infections, Glucose Intolerance, and Insulin Resistance Study (ORIGINS)
ABSTRACTObjectiveTo study the association between dietary patterns and subgingival microbiota.MethodsParticipants (n = 651) who were enrolled in the Oral Infections, Glucose Intolerance, and Insulin Resistance Study (ORIGINS) with subgingival plaque sampling (n = 890 plaques) and a dietary assessment were included. 16S rRNA gene amplicon sequences of subgingival plaque from sites with either probing depth <4 or ≥4 mm were processed separately and used to obtain α‐diversity metrics (Faith, Shannon, Simpson, Observed) and taxa ratios (Red Complex to Corynebacterium [RCLR], Treponema to Corynebacterium [TCLR], and Treponema to Neisseria [TNLR]). Food frequency questionnaires (FFQs) were processed to calculate Alternate Healthy Eating Index (AHEI) and A Priori Diet Quality Score (APDQS) scores. Mixed regression models examined the mean levels of microbial metrics across quartiles of diet quality. Means ± standard errors are reported along with p‐values.ResultsIn multivariable models assessing the association between diet scores and α‐diversity metrics, higher AHEI values were significantly associated with lower Faith (p‐value = 0.01) and Observed (p‐value = 0.04) diversity values; similar findings were observed for APDQS (p‐value = 0.01, p‐value = 0.04). In multivariable models assessing the association between diet scores (AHEI and APDQS) and taxa ratios (RCLR, TCLR and TNLR), as the AHEI quartile increased, all taxa ratios decreased significantly as follows: −1.06 ± 0.093 in Q1 to −1.34 ± 0.099 in Q4 (RCLR), −0.43 ± 0.077 in Q1 to −0.64 ± 0.083 in Q4 (TCLR) and −0.09 ± 0.083 in Q1 to −0.38 ± 0.089 in Q4 (TNLR), respectively. In contrast, as the APDQS quartiles increased, only TNLR decreased significantly from −0.08 ± 0.085 in Q1 to −0.34 ± 0.091 in Q4.ConclusionDiets rich in fruits, vegetables, whole grains and other nutritionally rich plant foods are associated with lower oral microbial diversity and favourable ratios of pathogenic to commensal microbiota.
Dysanapsis Genetic Risk Predicts Lung Function Across the Lifespan
Abstract Rationale Dysanapsis refers to a mismatch between airway tree caliber and lung size arising early in life. Dysanapsis assessed by computed tomography (CT) is evident by early adulthood and associated with chronic obstructive pulmonary disease (COPD) risk later in life. Objectives By examining the genetic factors associated with CT-assessed dysanapsis, we aimed to elucidate its molecular underpinnings and physiological significance across the lifespan. Methods We performed a genome-wide association study of CT-assessed dysanapsis in 11,951 adults, including individuals from two population-based and two COPD-enriched studies. We applied colocalization analysis to integrate genome-wide association study and gene expression data from whole blood and lung. Genetic variants associated with dysanapsis were combined into a genetic risk score that was applied to examine association with lung function in children from a population-based birth cohort (n = 1,278) and adults from the UKBiobank (n = 369,157). Measurements and Main Results CT-assessed dysanapsis was associated with genetic variants from 21 independent signals in 19 gene regions, implicating HHIP (hedgehog interacting protein), DSP, and NPNT as potential molecular targets based on colocalization of their expression. A higher dysanapsis genetic risk score was associated with obstructive spirometry among 5-year-old children and among adults in the fifth, sixth, and seventh decades of life. Conclusions CT-assessed dysanapsis is associated with variation in genes previously implicated in lung development, and dysanapsis genetic risk is associated with obstructive lung function from early life through older adulthood. Dysanapsis may represent an endophenotype link between the genetic variations associated with lung function and COPD.
Abstract P199: Oral Microbiome Potentially Modifies the Cardiometabolic Benefits of Nitrate Consumption: Results From the Oral Infections Glucose Intolerance and Insulin Resistance Study (ORIGINS)
Background: Dietary nitrate consumption is associated with cardiometabolic health in many but not all studies. The enterosalivary nitrate-nitrite-nitric oxide (NO 3 - NO 2 - NO) pathway requires the oral microbiome for NO production (a signaling molecule beneficial to cardiometabolic health) following nitrate intake. We hypothesize that the oral microbiome modifies the cardiometabolic benefits of nitrate intake. Methods: We analyzed cross-sectional data from 657 ORGINS participants. Dietary nitrate intakes and alternative healthy eating index (AHEI) scores were calculated from food frequency questionnaire responses and a US food database. Subgingival 16S rRNA microbial genes (Illumina, MiSeq) were sequenced, and PICRUSt2 estimated metagenomic content. The Microbiome Induced Nitric oxide Enrichment Score (MINES) was calculated as a microbial gene abundance ratio representing enhanced net capacity for NO generation. Cardiometabolic biomarker (systolic and diastolic blood pressure, HbA1C, glucose, insulin, and HOMA-IR) Z-scores were averaged to form a cardiometabolic Z-score (CMZ). Adjusted multivariable linear models regressed CMZ and individual Z-scores on nitrate intake tertiles. Results: Participants were mean age 31±9, 72% female, 31% White, 14% Black, and 28% Hispanic. Mean nitrate intake was 189±171 mg/day. Higher nitrate intake was significantly associated with lower CMZ, glucose, insulin, and HOMA-IR. Mean CMZ(SE) across dietary nitrate tertiles were 0.53(0.30), 0.35(0.31), and -0.11(0.30), p for trend=0.04; findings were attenuated after adjustment for AHEI (p for trend=0.12). In subgroup analysis by MINES level, higher nitrate intake was only associated with lower cardiometabolic biomarker levels among participants with a <median MINES even after AHEI adjustment (Table). Conclusion: Higher dietary nitrate intake was associated with lower cardiometabolic risk biomarker levels only among those with reduced potential for oral microbiome-dependent NO generation.
Non‐alcoholic fatty liver modifies associations of body mass index and waist circumference with cardiometabolic risk: The CARDIA study
Abstract Background Non‐alcoholic fatty liver disease (NAFLD) is recognized as a prevalent determinant of cardiometabolic diseases. The association between NAFLD and obesity warrants further research on how NAFLD modifies associations between body mass index (BMI) and Waist circumference (WC) with cardiometabolic risk (CMR). Objective This study assessed whether NAFLD modifies associations between BMI and WC with 5‐year changes in CMR in 2366 CARDIA study participants. Methods Non‐contrast CT was used to quantify liver attenuation, with ≤51 Hounsfield Units (HU) used to define NAFLD in the absence of secondary causes of excess liver fat. The dependent variable was the average Z score of fasting glucose, insulin, triglycerides [log], (−) high‐density lipoprotein cholesterol (HDL‐C), and systolic blood pressure(SBP). Multivariable linear regression was used to estimate the associations between BMI and WC with CMR. Effect modification by NAFLD was assessed by an interaction term between NAFLD and BMI or WC. Results The final sample had 539 (23%) NAFLD cases. NAFLD modified the association of BMI and WC with CMR (interaction p < 0.0001 for both). BMI and WC were associated with CMR in participants without NAFLD ( p < 0.001), but not among those with NAFLD. Participants with NAFLD and normal BMI and WC had CMR estimates that were higher than those without NAFLD in the obese categories. Among those without NAFLD the 5 years CMR change estimate was 0.09 (95% CI: 0.062, 0.125) for BMI ≥30 kg/m 2 compared to −0.06 (−0.092, −0.018) for BMI < 25 kg/m 2 , and among those with NAFLD, these estimates were 0.15 (0.108, 0.193) and 0.16 (−0.035, 0.363). Conclusions NAFLD modifies associations of BMI and WC with CMR. Compared with BMI and WC, NAFLD was more strongly associated with CMR. In the presence of NAFLD, BMI and WC were not associated with CMR. These findings have implications for clinical screening guidelines.