A case-control study of the association between the gut microbiota and colorectal cancer: exploring the roles of diet, stress, and race

BACKGROUND

The gut microbiota is associated with risk for colorectal cancer (CRC), a chronic disease for which racial disparities persist with Black Americans having a higher risk of CRC incidence and mortality compared to other groups. Given documented racial differences, the gut microbiota may offer some insight into previously unexplained racial disparities in CRC incidence and mortality. A case-control analysis comparing 11 women newly diagnosed with CRC with 22 cancer-free women matched on age, BMI, and race in a 1:2 ratio was conducted. Information about participants' diet and perceived stress levels were obtained via 24-h Dietary Recall and Perceived Stress Scale-10 survey, respectively. Participants provided stool samples from which microbial genomic DNA was extracted to reveal the abundance of 26 genera chosen a priori based on their previously observed relevance to CRC, anxiety symptoms, and diet.

RESULTS

Significantly lower alpha diversity was observed among cancer-free Black women compared to all other race-cancer status combinations. No group differences were observed when comparing beta diversity. Non-Hispanic White CRC cases tended to have higher relative abundance of Fusobacteria, Gemellaceae, and Peptostreptococcus compared to all other race-cancer combination groups. Perceived stress was inversely associated with alpha diversity and was associated with additional genera.

CONCLUSIONS

Our findings suggest that microbiome-CRC associations may differ by racial group. Additional large, racially diverse population-based studies are needed to determine if previously identified associations between characteristics of the gut microbiome and CRC are generalizable to Black women and other racial, ethnic, and gender groups.

Associations of serum trimethylamine N-oxide and its precursors with colorectal cancer risk in the Prostate, Lung, Colorectal, Ovarian Cancer Screening Trial Cohort

BACKGROUND

Dietary intake influences gut microbiome composition, which in turn may be associated with colorectal cancer (CRC). Associations of the gut microbiome with colorectal carcinogenesis may be mediated through bacterially regulated, metabolically active metabolites, including trimethylamine N-oxide (TMAO) and its precursors, choline, L-carnitine, and betaine.

METHODS

Prospective associations of circulating TMAO and its precursors with CRC risk were investigated. TMAO, choline, betaine, and L-carnitine were measured in baseline serum samples from 761 incident CRC cases and 1:1 individually matched controls in the prospective Prostate, Lung, Colorectal, Ovarian Cancer Screening Trial Cohort using targeted fully quantitative liquid chromatography tandem mass spectrometry panels. Prospective associations of the metabolites with CRC risk, using multivariable conditional logistic regression, were measured. Associations of a priori-selected dietary exposures with the four metabolites were also investigated.

RESULTS

TMAO and its precursors were not associated with CRC risk overall, but TMAO and choline were positively associated with higher risk for distal CRC (continuous ORQ90 vs. Q10  [95% CI] = 1.90 [CI, 1.24-2.92; p = .003] and 1.26 [1.17-1.36; p < .0001], respectively). Conversely, choline was inversely associated with rectal cancer (ORQ90 vs. Q10 [95% CI] = 0.77 [0.76-0.79; p < .001]). Red meat, which was previously associated with CRC risk in the Prostate, Lung, Colorectal, Ovarian Cancer Screening Trial Cohort , was positively associated with TMAO (Spearman rho = 0.10; p = .0003).

CONCLUSIONS

Serum TMAO and choline may be associated with higher risk of distal CRC, and red meat may be positively associated with serum TMAO. These findings provide insight into a potential microbially mediated mechanism underlying CRC etiology.

Total Energy Intake: Implications for Epidemiologic Analyses

In 1986, Willett and Stampfer (Am J Epidemiol. 1986;124(1):17-27) propelled the nutritional epidemiology field forward by publishing a commentary emphasizing the importance of analyzing diet in relation to total energy intake in epidemiologic analyses of diet and disease, detailing the value of accounting for body size, physical activity, and metabolic efficiency in diet-disease analyses via energy intake adjustment. Their publication has since been cited over 2,886 times and has inarguably advanced methodology for studying diet-disease associations, with most nutritional epidemiology studies standardly including some form of energy adjustment. However, there remains debate regarding the best scenarios and methods for energy adjustment. The goals of this commentary are to provide an updated review on factors that account for interindividual differences in energy intake, provide a balanced discussion regarding the considerations for or against adjustment for energy intake, and provide an updated examination of the commonly employed methods for the analysis of nutrient-disease associations. The principles of energy adjustment continue to be relevant nearly 25 years later, as it remains a critical method to account for potentially confounding interindividual variations in body size and physical activity.

Associations of Circulating Estrogens and Estrogen Metabolites with Fecal and Oral Microbiome in Postmenopausal Women in the Ghana Breast Health Study

The human fecal and oral microbiome may play a role in the etiology of breast cancer through modulation of endogenous estrogen metabolism. This study aimed to investigate associations of circulating estrogens and estrogen metabolites with the fecal and oral microbiome in postmenopausal African women. A total of 117 women with fecal (N = 110) and oral (N = 114) microbiome data measured by 16S rRNA gene sequencing, and estrogens and estrogen metabolites data measured by liquid chromatography tandem mass spectrometry were included. The outcomes were measures of the microbiome and the independent variables were the estrogens and estrogen metabolites. Estrogens and estrogen metabolites were associated with the fecal microbial Shannon index (global P < 0.01). In particular, higher levels of estrone (β = 0.36, P = 0.03), 2-hydroxyestradiol (β = 0.30, P = 0.02), 4-methoxyestrone (β = 0.51, P = 0.01), and estriol (β = 0.36, P = 0.04) were associated with higher levels of the Shannon index, while 16alpha-hydroxyestrone (β = -0.57, P < 0.01) was inversely associated with the Shannon index as indicated by linear regression. Conjugated 2-methoxyestrone was associated with oral microbial unweighted UniFrac as indicated by MiRKAT (P < 0.01) and PERMANOVA, where conjugated 2-methoxyestrone explained 2.67% of the oral microbial variability, but no other estrogens or estrogen metabolites were associated with any other beta diversity measures. The presence and abundance of multiple fecal and oral genera, such as fecal genera from families Lachnospiraceae and Ruminococcaceae, were associated with several estrogens and estrogen metabolites as indicated by zero-inflated negative binomial regression. Overall, we found several associations of specific estrogens and estrogen metabolites and the fecal and oral microbiome. IMPORTANCE Several epidemiologic studies have found associations of urinary estrogens and estrogen metabolites with the fecal microbiome. However, urinary estrogen concentrations are not strongly correlated with serum estrogens, a known risk factor for breast cancer. To better understand whether the human fecal and oral microbiome were associated with breast cancer risk via the regulation of estrogen metabolism, we conducted this study to investigate the associations of circulating estrogens and estrogen metabolites with the fecal and oral microbiome in postmenopausal African women. We found several associations of parent estrogens and several estrogen metabolites with the microbial communities, and multiple individual associations of estrogens and estrogen metabolites with the presence and abundance of multiple fecal and oral genera, such as fecal genera from families Lachnospiraceae and Ruminococcaceae, which have estrogen metabolizing properties. Future large, longitudinal studies to investigate the dynamic changes of the fecal and oral microbiome and estrogen relationship are needed.

The intratumor microbiome is associated with microsatellite instability

Intratumoral microbes may have multifunctional roles in carcinogenesis. Microsatellite instability (MSI) is associated with higher tumor immunity and mutational burden. Using whole transcriptome and whole genome sequencing microbial abundance data, we investigated associations of intratumoral microbes with MSI, survival, and MSI-relevant tumor molecular characteristics across multiple cancer types including colorectal cancer (CRC), stomach adenocarcinoma, and endometrial carcinoma. Among 451 CRC patients, our key finding was strong associations of multiple CRC-associated genera, including Dialister and Casatella, with MSI. Dialister and Casatella abundance was associated with improved overall survival (hazard ratiomortality = 0.56, 95% confidence interval = 0.34 to 0.92, and hazard ratiomortality = 0.44, 95% confidence interval = 0.27 to 0.72), respectively, comparing higher relative to lower quantiles. Multiple intratumor microbes were associated with immune genes and tumor mutational burden. Diversity of oral cavity-originating microbes was also associated with MSI among CRC and stomach adenocarcinoma patients. Overall, our findings suggest the intratumor microbiota may differ by MSI status and play a role in influencing the tumor microenvironment.

Gut microbiome and cancer implications: Potential opportunities for fermented foods

There is a critical opportunity to improve response to immunotherapies and overall cancer survivorship via dietary interventions targeted to modify the gut microbiome, and in turn, potentially enhance anti-cancer immunity. A promising dietary intervention is fermented foods, which may alter gut microbiome composition and, in turn, improve immunity. In this article, we summarize the state of the literature pertaining to the gut microbiome and response to immunotherapy and other cancer treatments, potential clinical implications of utilizing a fermented foods dietary approach to improve cancer treatment outcomes, and existing gaps in the literature regarding the implementation of fermented food interventions among individuals with cancer or with a history of cancer. This review synthesizes a compelling rationale across different disciplines to lay a roadmap for future fermented food dietary intervention research aimed at modulating the gut microbiome to reduce cancer burden.

Abstract NG09: A biobank of Fecal Immunochemical Tests (FIT) for gut microbiome measurement: A paradigm for studying the microbiome and cancer

The broad and long-term goal of this study is to support the biobanking of fecal samples for development of prospective microbiome cohorts in large and diverse study populations. The gut microbiome, comprising trillions of microbes residing in the gut, is involved in the etiology of multiple health conditions, with emerging evidence for a role in cancer. Establishing a role for the microbiome in cancer risk has been difficult since, at present, availability of pre-diagnostic fecal specimens is severely limited in existing cohorts to study prospective microbiome-cancer associations. To advance knowledge in the field, it is critical to establish prospective microbiome cohorts that include samples from diverse study populations. Mounting evidence supports that the collective activity of the gut microbiota may influence development and progression of colorectal cancer (CRC), the second overall leading cause of cancer death in the United States. There are persistent CRC disparities in the US-with African Americans and those living in rural areas suffering higher CRC incidence and mortality. Explanations for CRC disparities are likely multifactorial, involving differences in lifestyle, socioeconomic, social, and other environmental exposures. These exposures likely act individually and interact to affect gut microbiome composition, resulting in the variation of microbiome-CRC associations across race/ethnicity and geographic location. Yet, microbiome-mediated mechanisms for CRC disparities remain largely unstudied. To advance knowledge in the field, future microbiome studies should encompass diverse study populations, include those with limited access to direct-to-colonoscopy screening, and collect detailed data on targetable exposures that alter the microbiome and drive CRC disparities. Moffitt Cancer Center is presently implementing multilevel, evidence-based CRC screening intervention programs aiming to expand access to CRC screening and improve screening rates in the community setting. These programs leverage fecal immunochemical tests (FIT), which are cost-effective and preferable for CRC screening in diverse patient populations without access to colonoscopy. Our preliminary data indicate that the fecal microbiome can be characterized in residual FIT samples using both 16S rRNA and metagenomic sequencing. The FIT microbial profiles were stable after multiple days at room temperature and were comparable to the field ‘gold-standard’. Therefore, CRC screening programs to improve FIT screening uptake provide ideal infrastructure to prospectively collect fecal specimens in diverse, unreached populations. Extending our findings of the suitability of FIT for microbiome assessment is a critical first step to move the field forward and to establish infrastructure for future population-based research on the microbiome and cancer disparities. As a speaker in a major session at AACR, I will describe our efforts to support large, multicenter grants that focus on establishing prospective microbiome and cancer cohorts. I will update the audience on our progress in completing the following specific aims:

Specific Aim 1: Implementing baseline and repeat collection and storage of residual FIT samples in community clinics in the Tampa Bay Area leveraging existing FIT screening infrastructure. Subjects complete FIT testing following standard protocols, and, after hemoglobin testing, the residual sample is processed and stored in -80°C freezers at Moffitt Cancer Center. Participants complete baseline questionnaires and data are linked to medical record and Florida cancer registry data for active prospective follow-up. We began our pilot study in a small, low-traffic clinic to establish our study workflow. We have recently expanded the study, recruiting N=37 participants. With continued expansion to larger clinics in the Tampa Bay Area, we estimate we will have recruited &gt; 100 participants by March 2023.

Specific Aim 2: To inform larger-scale studies,we will validate the use of FIT samples for investigating associations of the microbiome with colorectal neoplasms. To do this, we will pilot a shotgun metagenomic sequencing approach to characterize the fecal microbiome in residual FIT samples from Aim 1. We will sequence the metagenome among 1) those who tested positive on the FIT and subsequently were diagnosed with advanced adenoma, an established precursor to CRC, via colonoscopy (N=20); 2) those who tested negative on the FIT at baseline (N=20); and 3) those who tested negative on the FIT at baseline with a second negative FIT collected 2-years after baseline (N=20 repeat samples). Then, we will quantify the percentage of FIT samples successfully metagenomically sequenced, compare our microbiome-adenoma findings to previous fecal microbiome studies, and estimate stability of the FIT microbiome over 2 years.

Impact and future directions: We will demonstrate support for expanding collection and use of residual FIT samples as a practical, cost-effective approach for investigating associations of the microbiome with disease in diverse study populations. In the future, our biobank will serve as a distinctive resource to study prospective microbiome-disease associations. Future directions include additional pilot studies supporting the use FIT samples for microbiome research, establishing multicenter collaborations, and larger-scale investigations of prospective associations of the FIT microbiome with CRC.

Citation Format: Doratha A. Byrd. A biobank of Fecal Immunochemical Tests (FIT) for gut microbiome measurement: A paradigm for studying the microbiome and cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr NG09.

Abstract 3055: Associations of the mucosal microbiome and circulating bile acids with colorectal adenoma among average-risk women

Background: The gut microbiome (GM) and the metabolites it produces and regulates, such as bile acids (BAs), may act individually or interact to influence colorectal cancer development. We used data from a multi-center screening study to investigate the associations of the normal colon tissue microbiome and circulating BAs with colorectal adenoma.

Methods: We used data from the multi-center Colorectal Neoplasia Screening with Colonoscopy in Average-Risk Women Regional Navy/Army Medical Centers study (CONCeRN), comprising women undergoing complete colonoscopies. We individually matched women with adenoma (n=165 cases) to those without adenoma (n=311 controls). We extracted DNA using the Animal Tissue DNA Extraction Kit (AutoGene) and sequenced the V4 region of the 16S rRNA gene to characterize normal colonic mucosal bacteria, including alpha and beta diversity, taxonomic abundance, and co-abundance groups (CAGs). Fasting serum collected before colonoscopy underwent targeted quantitative liquid chromatography-tandem mass spectrometry to measure 13 primary and secondary BAs. We used multivariable conditional logistic regression, partial Pearson’s correlations, and linear regression to estimate interrelationships among the GM, BAs, and adenoma.

Results: Multiple genera were statistically significantly associated with adenomas. For example, for the centered log-ratio transformed relative abundance of Phascolarctobacterium, Parvimonas, and Porphymonas, the ORs (95% CIs) were 0.75 (0.60-0.95, P=0.02), 0.71 (0.55-0.92; P=0.01), and 0.67 (0.49-0.93; P=0.02), respectively. A CAG comprising phylum Firmicutes, Actinobacteria, Proteobacteria, and Fusobacteria was less abundant among cases than controls (log2folddiff=-0.80, P=0.002). Alpha and beta diversity associations were close to null and not statistically significant. However, alpha diversity metrics were inversely associated with primary BAs [e.g., for Shannon (R2=-0.13, P=0.01)] and positively associated with secondary BAs [e.g., for Shannon (R2=0.16, P=0.001)]. Though no circulating BAs were statistically significantly associated with adenomas, those in the highest relative to lowest tertile of taurine-conjugated (TC) BAs, primary BAs, and secondary BAs had a 44% (95% CI: 0.85-2.46), 24% (95% CI: 0.73-2.12), and 11% (95% CI: 0.61-2.01) higher odds of adenoma, respectively. We found that TCBAs, primary BAs, and secondary BAs were inversely associated with the abundance of Parvimonas [e.g., for TCBAs (R2=-0.11, P=0.02)] and Porphyromonas [e.g., for TCBAs (R2=-0.11, P=0.02)].

Conclusions: We found short-chain fatty acid-producing and oral-originating bacteria were inversely associated with adenomas. Our oral bacteria findings are contrary to findings from prior studies. Our findings suggest potential interrelationships among the GM and BAs in adenoma development.

Citation Format: Maria F. Gomez, Doratha A. Byrd, Stephanie R. Hogue, Jessica R. Burns, Nathan Smith, Joshua Sampson, Erikka Loftfield, Andrew Warner, Casey Dagnall, Kristine Jones, Belynda Hicks, Yunhu Wan, Youngchul Kim, Jin Xu, Rashmi Sinha, Emily Vogtmann. Associations of the mucosal microbiome and circulating bile acids with colorectal adenoma among average-risk women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3055.

Prospective and Cross-sectional Associations of the Rectal Tissue Microbiome with Colorectal Adenoma Recurrence

BACKGROUND

The gut microbiome is plausibly associated with colorectal cancer risk; however, previous studies mostly investigated this association cross-sectionally. We investigated cross-sectional and prospective associations of the rectal tissue microbiome with adenoma recurrence in the Polyp Prevention Trial (PPT).

METHODS

PPT is a 4-year randomized clinical trial of the effect of a dietary intervention on adenoma recurrence among community members. We extracted DNA from rectal biopsies at baseline, end of year 1, and end of year 4 among 455 individuals and sequenced the V4 region of the 16S rRNA gene. At each timepoint, we investigated associations of alpha diversity, beta diversity, and presence and relative abundance of select taxa with adenoma recurrence using multivariable logistic regression.

RESULTS

Variation in beta diversity was primarily explained by subject and minimally by year of collection or time between biopsy and colonoscopy. Cross-sectionally, year 4 alpha diversity was strongly, inversely associated with adenoma prevalence [ORQ3 vs. Q1 Shannon index = 0.40 (95% confidence interval, CI: 0.21-0.76)]. Prospective alpha diversity associations (i.e., baseline/year 1 alpha diversity with adenoma recurrence 3-4 years later) were weak or null, as were cross-sectional and prospective beta diversity-adenoma associations. Bacteroides abundance was more strongly, positively associated with adenoma prevalence cross-sectionally than prospectively.

CONCLUSIONS

Rectal tissue microbiome profiles may be associated with prevalent adenomas, with little evidence supporting prospective associations.

IMPACT

Additional prospective studies, with serial fecal and tissue samples, to explore microbiome-colorectal cancer associations are needed. Eventually, it may be possible to use microbiome characteristics as intervenable risk factors or screening tools.

Stability of the Fecal and Oral Microbiome over 2 Years at -80°C for Multiple Collection Methods

BACKGROUND

In prospective cohorts, biological samples are generally stored over long periods before an adequate number of cases have accrued. We investigated the impact of sample storage at -80°C for 2 years on the stability of the V4 region of the 16S rRNA gene across seven different collection methods (i.e., no additive, 95% ethanol, RNAlater stabilization solution, fecal occult blood test cards, and fecal immunochemical test tubes for feces; OMNIgene ORAL tubes and Scope mouthwash for saliva) among 51 healthy volunteers.

METHODS

Intraclass correlation coefficients (ICC) were calculated for the relative abundance of the top three phyla, the 20 most abundant genera, three alpha-diversity metrics, and the first principal coordinates of three beta-diversity matrices.

RESULTS

The subject variability was much higher than the variability introduced by the sample collection type, and storage time. For fecal samples, microbial stability over 2 years was high across collection methods (range, ICCs = 0.70-0.99), except for the samples collected with no additive (range, ICCs = 0.23-0.83). For oral samples, most microbiome diversity measures were stable over time with ICCs above 0.74; however, ICCs for the samples collected with Scope mouthwash were lower for two alpha-diversity measures, Faith's phylogenetic diversity (0.23) and the observed number of operational taxonomic units (0.23).

CONCLUSIONS

Fecal and oral samples in most used collection methods are stable for microbiome analyses after 2 years at -80°C, except for fecal samples with no additive.

IMPACT

This study provides evidence that samples stored for an extended period from prospective studies are useful for microbiome analyses.

Associations of dietary and lifestyle inflammation scores with mortality due to CVD, cancer, and all causes among Black and White American men and women

One potential mechanism by which diet and lifestyle may affect chronic disease risk and subsequent mortality is through chronic systemic inflammation. In this study, we investigated whether the inflammatory potentials of diet and lifestyle, separately and combined, were associated with all-cause, all-CVD and all-cancer mortality risk. We analysed data on 18 484 (of whom 4103 died during follow-up) Black and White men and women aged ≥45 years from the prospective REasons for Geographic and Racial Differences in Stroke study. Using baseline (2003-2007) Block 98 FFQ and lifestyle questionnaire data, we constructed the previously validated inflammation biomarker panel-weighted, 19-component dietary inflammation score (DIS) and 4-component lifestyle inflammation score (LIS) to reflect the overall inflammatory potential of diet and lifestyle. From multivariable Cox proportional hazards models, the hazards ratios (HR) and their 95 % CI for the DIS-all-cause mortality and LIS-all-cause mortality risk associations were 1·32 (95 % CI (1·18, 1·47); Pfor trend < 0·01) and 1·25 (95 % CI (1·12, 1·38); Pfor trend < 0·01), respectively, among those in the highest relative to the lowest quintiles. The findings were similar by sex and race and for all-cancer mortality, but weaker for all-CVD mortality. The joint HR for all-cause mortality among those in the highest relative to the lowest quintiles of both the DIS and LIS was 1·91 (95 % CI 1·57, 2·33) (Pfor interaction < 0·01). Diet and lifestyle, via their contributions to systemic inflammation, separately, but perhaps especially jointly, may be associated with higher mortality risk among men and women.

A case-control study of the association between the gut microbiota and colorectal cancer: exploring the roles of diet, stress, and race

Background

The gut microbiota is associated with risk for colorectal cancer (CRC), a chronic disease for which racial disparities persist with Black Americans having a higher risk of CRC incidence and mortality compared to other groups. Given documented racial differences, the gut microbiota may offer some insight into previously unexplained racial disparities in CRC incidence and mortality. A case-control analysis comparing 11 women newly diagnosed with CRC with 22 cancer-free women matched on age, BMI, and race in a 1:2 ratio was conducted. Information about participants' diet and perceived stress levels were obtained via 24-hour Dietary Recall and Perceived Stress Scale-10 survey, respectively. Participants provided stool samples from which microbial genomic DNA was extracted to reveal the abundance of 26 genera chosen a priori based on their previously observed relevance to CRC, anxiety symptoms, and diet.

Results

Significantly lower alpha diversity was observed among cancer-free Black women compared to all other race-cancer status combinations. No group differences were observed when comparing beta diversity. Non-Hispanic White CRC cases tended to have higher relative abundance of Fusobacteria, Gemellaceae, and Peptostreptococcus compared to all other race-cancer combination groups. Perceived stress was inversely associated with alpha diversity and was associated with additional genera.

Conclusions

Our findings suggest that microbiome-CRC associations may differ by racial group. Additional large, racially diverse population-based studies are needed to determine if previously identified associations between characteristics of the gut microbiome and CRC are generalizable to Black women and other racial, ethnic, and gender groups.

The oral microbiome and breast cancer and nonmalignant breast disease, and its relationship with the fecal microbiome in the Ghana Breast Health Study

The oral microbiome, like the fecal microbiome, may be related to breast cancer risk. Therefore, we investigated whether the oral microbiome was associated with breast cancer and nonmalignant breast disease, and its relationship with the fecal microbiome in a case-control study in Ghana. A total of 881 women were included (369 breast cancers, 93 nonmalignant cases and 419 population-based controls). The V4 region of the 16S rRNA gene was sequenced from oral and fecal samples. Alpha-diversity (observed amplicon sequence variants [ASVs], Shannon index and Faith's Phylogenetic Diversity) and beta-diversity (Bray-Curtis, Jaccard and weighted and unweighted UniFrac) metrics were computed. MiRKAT and logistic regression models were used to investigate the case-control associations. Oral sample alpha-diversity was inversely associated with breast cancer and nonmalignant breast disease with odds ratios (95% CIs) per every 10 observed ASVs of 0.86 (0.83-0.89) and 0.79 (0.73-0.85), respectively, compared to controls. Beta-diversity was also associated with breast cancer and nonmalignant breast disease compared to controls (P ≤ .001). The relative abundances of Porphyromonas and Fusobacterium were lower for breast cancer cases compared to controls. Alpha-diversity and presence/relative abundance of specific genera from the oral and fecal microbiome were strongly correlated among breast cancer cases, but weakly correlated among controls. Particularly, the relative abundance of oral Porphyromonas was strongly, inversely correlated with fecal Bacteroides among breast cancer cases (r = -.37, P ≤ .001). Many oral microbial metrics were strongly associated with breast cancer and nonmalignant breast disease, and strongly correlated with fecal microbiome among breast cancer cases, but not controls.

Circulating Bile Acids and Adenoma Recurrence in the Context of Adherence to a High-Fiber, High-Fruit and Vegetable, and Low-Fat Dietary Intervention

INTRODUCTION

Diet may affect bile acid (BA) metabolism and signaling. In turn, BA concentrations may be associated with cancer risk. We investigated (i) associations of BA concentrations with adenoma recurrence and (ii) the effect of a high-fiber, high-fruit and vegetable, and low-fat dietary intervention on serum BA concentrations.

METHODS

The Polyp Prevention Trial is a 4-year randomized, controlled trial that investigated the effect of a high-fiber, high-fruit and vegetable, and low-fat diet on colorectal adenoma recurrence. Among 170 participants who reported adhering to the intervention and 198 comparable control arm participants, we measured 15 BAs in baseline, year 2, and year 3 serum using targeted, quantitative liquid chromatography-tandem mass spectrometry. We estimated associations of BAs with adenoma recurrence using multivariable logistic regression and the effect of the dietary intervention on BA concentrations using repeated-measures linear mixed-effects models. In a subset (N = 65), we investigated associations of BAs with 16S rRNA gene sequenced rectal tissue microbiome characteristics.

RESULTS

Baseline total BA concentrations were positively associated with adenoma recurrence (odds ratio Q3 vs Q1 = 2.17; 95% confidence interval = 1.19-4.04; Ptrend = 0.03). Although we found no effect of the dietary intervention on BA concentrations, pretrial dietary fiber intake was inversely associated with total baseline BAs (Spearman = -0.15; PFDR = 0.02). BA concentrations were associated with potential colorectal neoplasm-related microbiome features (lower alpha diversity and higher Bacteroides abundance).

DISCUSSION

Baseline circulating BAs were positively associated with adenoma recurrence. Although the dietary intervention did not modify BA concentrations, long-term fiber intake may be associated with lower concentrations of BAs that are associated with higher risk of adenoma recurrence.

Associations of Evolutionary-Concordance Diet and Lifestyle Pattern Scores with Incident, Sporadic Colorectal Adenoma in a Pooled Case-Control Study

Differences in diet and lifestyle relative to those of our Paleolithic-era ancestors may explain current high incidences of chronic diseases, including colorectal cancer (CRC), in Westernized countries. Previously reported evolutionary-concordance diet and lifestyle pattern scores, reflecting closeness of diet and lifestyle patterns to those of Paleolithic-era humans, were associated with lower CRC incidence. Separate and joint associations of the scores with colorectal adenoma among men and women are unknown. To address this, we pooled data from three case-control studies of incident, sporadic colorectal adenomas (n = 771 cases, 1,990 controls), used participants' responses to food frequency and lifestyle questionnaires to calculate evolutionary-concordance diet and lifestyle pattern scores, and estimated the scores' associations with adenomas using multivariable unconditional logistic regression. The multivariable-adjusted odds ratios comparing those in the highest relative to the lowest diet and lifestyle score quintiles were 0.84 (95% confidence interval [CI] 0.62, 1.12; P_trend:0.03) and 0.41 (95% CI 0.29, 0.59; P_trend:<0.0001), respectively. The inverse associations were stronger for high-risk adenomas, and among those with both high relative to those with both low diet and lifestyle scores. These results suggest that more evolutionary-concordant diet and lifestyle patterns, separately and jointly, may be associated with lower risk for incident, sporadic colorectal adenoma.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.2002919 .

Associations of Novel Lifestyle- and Whole Foods-Based Inflammation Scores with Incident Colorectal Cancer Among Women

BACKGROUND

Chronic inflammation, associated with lifestyle and dietary factors, may contribute to colorectal carcinogenesis. To address this, we investigated associations of previously validated, inflammation biomarker panel-weighted, novel, 4-component lifestyle (LIS) and 19-component predominately whole foods-based dietary (DIS) inflammation scores with incident colorectal cancer (CRC) in the prospective Iowa Women's Health Study (IWHS; 1986-2012; n = 34,254, of whom 1,632 developed CRC).

METHODS

We applied the published scores' components' weights, summed the weighted components to constitute the scores (higher scores reflect a higher balance of pro-inflammatory exposures), and investigated LIS- and DIS-CRC associations using multivariable Cox proportional hazards regression.

RESULTS

The multivariable-adjusted hazards ratios (HR) and their 95% confidence intervals (CI) for CRC among participants in the highest relative to the lowest LIS and DIS quintiles were 1.47 (1.26, 1.72; P_trend < 0.01) and 1.07 (0.91, 1.25; P_trend = 0.22), respectively. The corresponding findings for distal colon cancers were HR 1.78 (1.29, 2.47) and HR 1.34 (0.98, 1.84), respectively. Among those in the highest relative to the lowest joint LIS/DIS quintile, the HR for CRC was 1.60 (95% CI 1.30, 1.98).

CONCLUSIONS

Our results suggest that a more pro-inflammatory lifestyle, alone and jointly with a more pro-inflammatory diet, may be associated with higher CRC risk.

An investigation of cross-sectional associations of a priori-selected dietary components with circulating bile acids

BACKGROUND

A growing body of literature suggests chronically higher bile acid (BA) concentrations may be associated with multiple health conditions. Diet may affect BA metabolism and signaling; however, evidence from human populations is lacking.

OBJECTIVES

We systematically investigated cross-sectional associations of a priori-selected dietary components (fiber, alcohol, coffee, fat) with circulating BA concentrations.

METHODS

We used targeted, quantitative LC-MS/MS panels to measure 15 circulating BAs in a subset of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC; n = 2224) and Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO; n = 986) comprising Finnish male smokers and United States men and women, respectively. We used multivariable linear regression to estimate associations of each dietary component with log-transformed BAs; exponentiated coefficients estimate proportional differences. We included the median of the dietary component quartile in linear regression models to test for trend.

RESULTS

In ATBC, fiber was inversely associated with multiple circulating BAs. The proportional difference was -10.09% (95% CI: -19.29 to 0.16; P-trend = 0.04) when comparing total BAs among those in the highest relative to the lowest fiber quartile. Alcohol, trans fat, and polyunsaturated fat were positively associated with BAs in ATBC. The proportional difference comparing total BAs among those in the highest relative to the lowest alcohol quartile was 8.76% (95% CI: -3.10 to 22.06; P-trend = 0.03). Coffee and monounsaturated fat were inversely associated with BAs. The proportional difference comparing total BAs among those in the highest relative to the lowest coffee quartile was -24.03% (95% CI: -31.57 to -15.66; P-trend < 0.0001). In PLCO, no dietary components were associated with BAs except fiber, which was inversely associated with tauroursodeoxycholic acid.

CONCLUSIONS

Alcohol, coffee, certain fat subtypes, and fiber were associated with circulating concentrations of multiple BAs among Finnish male smokers. Given the potential role of BAs in disease risk, further investigation of the effects of diet on BAs in humans is warranted.

Effects of processed meat and drinking water nitrate on oral and fecal microbial populations in a controlled feeding study

BACKGROUND

One mechanism that can explain the link between processed meat consumption and colorectal cancer (CRC) is the production of carcinogenic N-nitroso compounds (NOCs) in the gastrointestinal tract. Oral and gut microbes metabolize ingested proteins (a source of secondary and tertiary amines and amides) and can reduce nitrate to nitrite, generating potentially carcinogenic NOCs.

OBJECTIVE

We evaluated whether nitrate/nitrite in processed meat or water influences the fecal or salivary microbiota.

DESIGN

In this dietary intervention study, 63 volunteers consumed diets high in conventional processed meats for two weeks, switched to diets high in poultry for two weeks, and then consumed phytochemical-enriched conventional processed or low-nitrite processed meat diets for two weeks. During the intervention, they drank water with low nitrate concentrations and consumed a healthy diet with low antioxidants. Then the volunteers drank nitrate-enriched water for 1 week, in combination with one of the four different diets. We measured creatinine-adjusted urinary nitrate levels and characterized the oral and fecal microbiota using 16S rRNA amplicon sequencing.

RESULTS

Using linear mixed models, we found that, compared to baseline, urinary nitrate levels were reduced during the phytochemical-enriched low-nitrite meat diet (p-value = 0.009) and modestly during the poultry diet (p-value = 0.048). In contrast, urinary nitrate increased after 1-week of drinking nitrate-enriched water (p-value<10^-5). Nitrate-enriched water, but not processed meats with or without phytochemicals, altered the saliva microbial population (p-value ≤0.001), and significantly increased abundance of 8 bacterial taxa, especially genus Neisseria and other nitrate-reducing taxa. Meats, phytochemicals and nitrate-enriched water had no significant effects on saliva alpha diversity or any diversity parameter measured for the fecal microbiota.

CONCLUSION

These findings support the hypothesis that drinking high nitrate water increases oral nitrate-reducing bacteria, which likely results in increased NOC. However, meat nitrate/nitrite at the levels tested had no effect on either the gut or oral bacteria. CLINICALTRIALS.

GOV IDENTIFIER

NCT04138654.

Associations of fecal microbial profiles with breast cancer and nonmalignant breast disease in the Ghana Breast Health Study

The gut microbiota may play a role in breast cancer etiology by regulating hormonal, metabolic and immunologic pathways. We investigated associations of fecal bacteria with breast cancer and nonmalignant breast disease in a case-control study conducted in Ghana, a country with rising breast cancer incidence and mortality. To do this, we sequenced the V4 region of the 16S rRNA gene to characterize bacteria in fecal samples collected at the time of breast biopsy (N = 379 breast cancer cases, N = 102 nonmalignant breast disease cases, N = 414 population-based controls). We estimated associations of alpha diversity (observed amplicon sequence variants [ASVs], Shannon index, and Faith's phylogenetic diversity), beta diversity (Bray-Curtis and unweighted/weighted UniFrac distance), and the presence and relative abundance of select taxa with breast cancer and nonmalignant breast disease using multivariable unconditional polytomous logistic regression. All alpha diversity metrics were strongly, inversely associated with odds of breast cancer and for those in the highest relative to lowest tertile of observed ASVs, the odds ratio (95% confidence interval) was 0.21 (0.13-0.36; Ptrend < .001). Alpha diversity associations were similar for nonmalignant breast disease and breast cancer grade/molecular subtype. All beta diversity distance matrices and multiple taxa with possible estrogen-conjugating and immune-related functions were strongly associated with breast cancer (all Ps < .001). There were no statistically significant differences between breast cancer and nonmalignant breast disease cases in any microbiota metric. In conclusion, fecal bacterial characteristics were strongly and similarly associated with breast cancer and nonmalignant breast disease. Our findings provide novel insight into potential microbially-mediated mechanisms of breast disease.

Novel Dietary and Lifestyle Inflammation Scores Directly Associated with All-Cause, All-Cancer, and All-Cardiovascular Disease Mortality Risks Among Women

BACKGROUND

Exogenous exposures collectively may contribute to chronic, low-grade inflammation and increase risks for major chronic diseases and mortality. We previously developed, validated, and reported a novel, FFQ-based and lifestyle questionnaire-based, inflammation biomarker panel-weighted, predominantly whole foods-based 19-component dietary inflammation score (DIS) and 4-component lifestyle inflammation score (LIS; comprising physical activity, alcohol intake, BMI, and current smoking status). Both scores were more strongly associated with circulating biomarkers of inflammation in 3 populations than were previously reported dietary inflammation indices. Associations of the DIS and LIS with mortality risk have not been reported.

OBJECTIVES

To investigate separate and joint associations of the DIS and LIS with all-cause, all-cancer, and cardiovascular disease (CVD) mortality risks in the prospective Iowa Women's Health Study (1986-2012; n = 33,155 women, ages 55-69 years, of whom 17,431 died during follow-up, including 4379 from cancer and 6574 from CVD).

METHODS

We summed each study participant's scores' components, weighted by their published weights, to yield the participant's inflammation score; a higher score was considered more pro-inflammatory. We assessed DIS and LIS mortality associations using multivariable Cox proportional hazards regression.

RESULTS

Among participants in the highest relative to the lowest DIS and LIS quintiles, the adjusted HRs for all-cause mortality were 1.11 (95% CI: 1.05-1.16) and 1.60 (95% CI: 1.53-1.68), respectively; for all-cancer mortality were 1.07 (95% CI: 0.97-1.17) and 1.51 (95% CI: 1.38-1.66), respectively; and for CVD mortality were 1.12 (95% CI: 1.03-1.21) and 1.79 (95% CI: 1.66-1.94), respectively (all Ptrend values < 0.01). Among those in the highest relative to the lowest joint LIS/DIS quintiles, the HRs for all-cause, all-cancer, and all-CVD mortality were 1.88 (95% CI: 1.71-2.08), 1.82 (95% CI: 1.50-2.20), and 1.92 (95% CI: 1.64-2.24), respectively.

CONCLUSIONS

More pro-inflammatory diets and lifestyles, separately but especially jointly, may be associated with higher all-cause, all-cancer, and all-CVD mortality risks among women.

Association of Body Mass Index with Fecal Microbial Diversity and Metabolites in the Northern Finland Birth Cohort

BACKGROUND

Obesity is an established risk factor for multiple cancer types. Lower microbial richness has been linked to obesity, but human studies are inconsistent, and associations of early-life body mass index (BMI) with the fecal microbiome and metabolome are unknown.

METHODS

We characterized the fecal microbiome (n = 563) and metabolome (n = 340) in the Northern Finland Birth Cohort 1966 using 16S rRNA gene sequencing and untargeted metabolomics. We estimated associations of adult BMI and BMI history with microbial features and metabolites using linear regression and Spearman correlations (rs ) and computed correlations between bacterial sequence variants and metabolites overall and by BMI category.

RESULTS

Microbial richness, including the number of sequence variants (rs = -0.21, P < 0.0001), decreased with increasing adult BMI but was not independently associated with BMI history. Adult BMI was associated with 56 metabolites but no bacterial genera. Significant correlations were observed between microbes in 5 bacterial phyla, including 18 bacterial genera, and metabolites in 49 of the 62 metabolic pathways evaluated. The genera with the strongest correlations with relative metabolite levels (positively and negatively) were Blautia, Oscillospira, and Ruminococcus in the Firmicutes phylum, but associations varied by adult BMI category.

CONCLUSIONS

BMI is strongly related to fecal metabolite levels, and numerous associations between fecal microbial features and metabolite levels underscore the dynamic role of the gut microbiota in metabolism.

IMPACT

Characterizing the associations between the fecal microbiome, the fecal metabolome, and BMI, both recent and early-life exposures, provides critical background information for future research on cancer prevention and etiology.

Associations of Novel Dietary and Lifestyle Inflammation Scores with Incident, Sporadic Colorectal Adenoma

BACKGROUND

Colorectal carcinogenesis is mechanistically linked to inflammation and is highly associated with diet and lifestyle factors that may affect chronic inflammation. We previously developed dietary (DIS) and lifestyle (LIS) inflammation scores, comprising inflammation biomarker-weighted components, to characterize the collective contributions of 19 food groups and four lifestyle exposures to systemic inflammation. Both scores were more strongly directly associated with circulating inflammation biomarkers in three validation populations, including a subset of the study population described below, than were the previously reported dietary inflammatory index and empirical dietary inflammatory pattern.

METHODS

We calculated the DIS and LIS in three pooled case-control studies of incident, sporadic colorectal adenoma (N = 765 cases and 1,986 controls) with extensive dietary and lifestyle data, and investigated their associations with adenoma using multivariable unconditional logistic regression.

RESULTS

For those in the highest (more proinflammatory) relative to the lowest (more anti-inflammatory) quintiles of the DIS and LIS, the multivariable-adjusted ORs were 1.31 [95% confidence interval (CI), 0.98-1.75; P _trend = 0.09] and 1.98 (95% CI, 1.48-2.66; P _trend < 0.001), respectively. These associations were strongest for adenomas with high-risk characteristics and among men. Those in the highest relative to the lowest joint DIS/LIS quintile had a 2.65-fold higher odds (95% CI, 1.77-3.95) of colorectal adenoma.

CONCLUSIONS

These results support that diets and lifestyles with higher balances of pro- to anti-inflammatory exposures may be associated with higher risk for incident, sporadic colorectal adenoma.

IMPACT

Our findings support further investigation of the DIS and LIS in relation to colorectal neoplasms.

Health Behaviors of Cancer Survivors and Population Controls From the National Health Interview Survey (2005-2015)

Background

Population-based data from the National Health Interview Survey were examined to provide estimates of a wide range of health behaviors in cancer survivors (ie, physical activity, sun protection, alcohol use, cigarette and e-cigarette use, sleep, and diet) and trends over time.

Methods

Data were collected from 92 257 participants across 3 waves of the National Health Interview Survey. A total of 8050 participants reported having had cancer (2428 in 2005, 2333 in 2010, 3289 in 2015). Weighted and adjusted odds ratios (OR) between cancer survivors and controls were calculated using logistic and multivariable regressions in SPSS, and trend analyses from 2005 to 2015 were conducted. All statistical tests are 2-sided.

Results

After adjusting for demographics (2005-2015), cancer survivors, compared with controls, were more likely to wear sunscreen (OR = 1.41, 95% confidence interval [CI] = 1.32 to 1.51) and protect their skin (P < .001) and were less likely to tan indoors (OR = 0.81, 95% CI = 0.69 to 0.95), but reported less sleep (OR = 0.91, 95% CI = 0.85 to 0.98). In adjusted models, no differences were found for physical activity, sunburns, alcohol use, smoking, e-cigarette use, and diet. Smoking rates for cancer survivors decreased from 2005 to 2015 (P < .001) and physical activity increased (P = .02), but physical activity was not statistically significant after adjusting for multiple comparisons. All other health behavior rates for cancer survivors were unchanged from 2005 to 2015 (P > .14).

Conclusion

After adjusting for covariates, cancer survivors exhibited healthier sun protection, but not sleep behaviors, compared with controls. Cancer survivors (and controls) exhibited decreased smoking rates over time. These results may inform interventions focused on improving cancer control and prevention of other chronic conditions among cancer survivors.

Associations of Novel Dietary and Lifestyle Inflammation Scores With Incident Colorectal Cancer in the NIH-AARP Diet and Health Study

Background

Chronically higher inflammation, likely contributed to by dietary and lifestyle exposures, may increase risk for colorectal cancer (CRC). To address this, we investigated associations of novel dietary (DIS) and lifestyle (LIS) inflammation scores with incident CRC in the prospective National Institutes of Health–American Association of Retired Persons Diet and Health Study (N = 453 465).

Methods

The components of our previously developed and externally validated 19-component DIS and 4-component LIS were weighted based on their strengths of associations with a panel of circulating inflammation biomarker concentrations in a diverse subset (N = 639) of participants in the REasons for Geographic and Racial Differences in Stroke Study cohort. We calculated the components and applied their weights in the National Institutes of Health-American Association of Retired Persons cohort at baseline, summed the weighted components (higher scores reflect a higher balance of proinflammatory exposures), and investigated associations of the scores with incident CRC using Cox proportional hazards regression. All statistical tests were two-sided.

Results

Over a mean 13.5 years of follow-up, 10 336 participants were diagnosed with CRC. Among those in the highest relative to the lowest DIS and LIS quintiles, the multivariable-adjusted hazards ratios (HRs) and their 95% confidence intervals (CIs) were HR = 1.27 (95% CI = 1.19 to 1.35; P_trend < .001) and 1.38 (95% CI = 1.30 to 1.48; P_trend < .001), respectively. The associations were stronger among men and for colon cancers. The hazards ratio for those in the highest relative to the lowest joint DIS and LIS quintile was HR = 1.83 (95% CI = 1.68 to 1.99; P_interaction < .001).

Conclusions

Aggregates of proinflammatory dietary and lifestyle exposures may be associated with higher risk for CRC.

Comparison of Methods To Collect Fecal Samples for Microbiome Studies Using Whole-Genome Shotgun Metagenomic Sequencing

Few previous studies have assessed stability and "gold-standard" concordance of fecal sample collection methods for whole-genome shotgun metagenomic sequencing (WGSS), an increasingly popular method for studying the gut microbiome. We used WGSS data to investigate ambient temperature stability and putative gold-standard concordance of microbial profiles in fecal samples collected and stored using fecal occult blood test (FOBT) cards, fecal immunochemical test (FIT) tubes, 95% ethanol, or RNAlater. Among 15 Mayo Clinic employees, for each collection method, we calculated intraclass correlation coefficients (ICCs) to estimate stability of fecal microbial profiles after storage for 4 days at ambient temperature and concordance with immediately frozen, no-solution samples (i.e., the putative gold standard). ICCs were estimated for multiple metrics, including relative abundances of select phyla, species, KEGG k-genes (representing any coding sequence that had >70% identity and >70% query coverage with respect to a known KEGG ortholog), KEGG modules, and KEGG pathways; species and k-gene alpha diversity; and Bray-Curtis and Jaccard species beta diversity. ICCs for microbial profile stability were excellent (≥90%) for fecal samples collected via most of the collection methods, except those preserved in 95% ethanol. Concordance with the immediately frozen, no-solution samples varied for all collection methods, but the number of observed species and the beta diversity metrics tended to have higher concordance than other metrics. Our findings, taken together with previous studies and feasibility considerations, indicated that FOBT cards, FIT tubes, and RNAlater are acceptable choices for fecal sample collection methods in future WGSS studies.IMPORTANCE A major direction for future microbiome research is implementation of fecal sample collections in large-scale, prospective epidemiologic studies. Studying microbiome-disease associations likely requires microbial data to be pooled from multiple studies. Our findings suggest collection methods that are most optimal to be used standardly across future WGSS microbiome studies.

Development and Validation of Novel Dietary and Lifestyle Inflammation Scores

BACKGROUND

Chronically higher inflammation, which may partly result from diet and lifestyle, is implicated in risk for multiple chronic diseases. The dietary inflammatory index (DII) and empirical dietary inflammatory pattern (EDIP), developed to characterize dietary contributions to systemic inflammation, have several limitations. There are no scores to characterize contributions of lifestyle to inflammation.

OBJECTIVES

To reflect dietary/lifestyle contributions to inflammation, we developed novel, inflammation biomarker panel-weighted, dietary (DIS) and lifestyle (LIS) inflammation scores in a subset (n = 639) of the Reasons for Geographic and Racial Differences in Stroke Study (REGARDS) cohort.

METHODS

We selected a priori 19 food groups and 4 lifestyle characteristics to comprise the DIS and LIS, respectively. We calculated the components' weights based on their strengths of association with an inflammation biomarker score [comprising high-sensitivity C-reactive protein (hsCRP), IL-6, IL-8, and IL-10] using multivariable linear regression. The sums of the weighted components constitute the scores, such that higher scores reflect, on balance, more proinflammatory exposures. We calculated the DIS, LIS, DII, and EDIP with cross-sectional data from the remaining REGARDS cohort (  n = 14,210 with hsCRP measurements) and 2 other study populations with hsCRP and/or an 8-component inflammation biomarker panel, and investigated their associations with circulating inflammation biomarker concentrations using multivariable logistic regression.

RESULTS

In REGARDS, those in the highest relative to the lowest DIS, LIS, DII, and EDIP quintiles had statistically significant 1.66-, 4.29-, 1.56-, and 1.32-fold higher odds of a high hsCRP concentration (>3 mg/dL), respectively (all P-trend < 0.001). Those in the highest relative to the lowest joint DIS/LIS quintile had a statistically significant 7.26-fold higher odds of a high hsCRP concentration. Similar findings were noted in the other 2 validation populations.

CONCLUSION

Our results support that dietary and lifestyle exposures collectively contribute substantially to systemic inflammation, and support the use of our novel DIS and LIS.

Reproducibility, stability, and accuracy of microbial profiles by fecal sample collection method in three distinct populations

The gut microbiome likely plays a role in the etiology of multiple health conditions, especially those affecting the gastrointestinal tract. Little consensus exists as to the best, standard methods to collect fecal samples for future microbiome analysis. We evaluated three distinct populations (N = 132 participants) using 16S rRNA gene amplicon sequencing data to investigate the reproducibility, stability, and accuracy of microbial profiles in fecal samples collected and stored via fecal occult blood test (FOBT) or Flinders Technology Associates (FTA) cards, fecal immunochemical tests (FIT) tubes, 70% and 95% ethanol, RNAlater, or with no solution. For each collection method, based on relative abundance of select phyla and genera, two alpha diversity metrics, and four beta diversity metrics, we calculated intraclass correlation coefficients (ICCs) to estimate reproducibility and stability, and Spearman correlation coefficients (SCCs) to estimate accuracy of the fecal microbial profile. Comparing duplicate samples, reproducibility ICCs for all collection methods were excellent (ICCs ≥75%). After 4–7 days at ambient temperature, ICCs for microbial profile stability were excellent (≥75%) for most collection methods, except those collected via no-solution and 70% ethanol. SCCs comparing each collection method to immediately-frozen no-solution samples ranged from fair to excellent for most methods; however, accuracy of genus-level relative abundances differed by collection method. Our findings, taken together with previous studies and feasibility considerations, indicated that FOBT/FTA cards, FIT tubes, 95% ethanol, and RNAlater are excellent choices for fecal sample collection methods in future microbiome studies. Furthermore, establishing standard collection methods across studies is highly desirable.

Perceived Racial/Ethnic Discrimination Predicts Worse Global Cognition in a Diverse Sample

Objective

While perceived racial/ethnic discrimination (PD) and HIV can be independently detrimental to cognitive function, it is unclear whether persons living with HIV (PLWH) who experience PD may be at risk for greater cognitive dysfunction than HIV- persons. In a diverse sample, we hypothesized that PD would be related to worse cognition and that this effect would be moderated by HIV status.

Participants and Method

This cross-sectional study included 53 participants (57% PLWH; 77% African American and 23% Latinx; 45% male; M Age = 54.5 ± 6.1 years; M Education = 12.4 ± 2.2 years) who completed the Perceived Ethnic Discrimination Questionnaire (PEDQ) and a neurocognitive (NC) battery. Variables included education (years); HIV status; PEDQ Total Score and global NC T-score (averaged, demographically-corrected T-scores for all tests). A general linear model examined main and interaction effects of HIV status and PD on global cognitive function. Covariates included depression and urine toxicology status for cocaine and marijuana.

Results

Greater PD was associated with higher education and greater depression. The model showed that greater PD (β = -.48, p &lt; .05) and lower education (β = -19.0, p &lt; .01) were related to worse global cognitive function. This relationship was moderated by education (β = .59, p &lt; .01), such that the relationship between PD and global cognitive function was stronger in those with higher education. There was no main effect of HIV or HIV*PD interaction on global cognitive function.

Conclusions

This study demonstrated that greater PD is related to worse global cognitive function and this relationship is stronger in those with more education. While no causal factors can be attributed, racial/ethnic minorities with higher education may be granted greater access to areas with greater structural racism and/or microagressions (i.e., predominantly white workplaces). Future studies should evaluate the role of socioeconomic and workplace diversity when considering discrimination.

Updated research nosology for HIV-associated neurocognitive disorders

In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.

Tpr, a large coiled coil protein whose amino terminus is involved in activation of oncogenic kinases, is localized to the cytoplasmic surface of the nuclear pore complex

From a panel of monoclonal antibodies raised against fractions of rat liver nuclear envelopes (NEs), we have identified an antibody, RL30, which reacts with novel nuclear pore complex (NPC) antigens that are not O-glycosylated. By immunofluorescence staining of cultured cells, RL30 reacts exclusively with the NE in a punctate pattern that largely coincides with that of identified NPC proteins. RL30 labels only the cytoplasmic surface of the NPC in immunogold electron microscopy, predominantly in peripheral regions nearby the cytoplasmic ring. In immunoblots of isolated rat liver NEs and cultured rat cells, RL30 recognizes a 265-kD band, as well as a series of 175-265-kD bands in rat liver NEs that are likely to be proteolytic products of p265. Sequencing of peptides from the 175- and 265-kD RL30 antigens of rat liver revealed that they are both closely related to human Tpr, a protein whose amino-terminal 150-250 amino acids appear in oncogenic fusions with the kinase domains of the met, trk, and raf protooncogenes. We found that in vitro translation of human Tpr mRNA yields a major 265-kD band. Considered together, these data indicate that the 265-kD RL30 antigen in the NPC is the rat homologue of Tpr. Interestingly, Tpr contains an exceptionally long predicted coiled coil domain (approximately 1600 amino acids). The localization and predicted structure of Tpr suggest that it is a component of the cytoplasmic fibrils of the NPC implicated in nuclear protein import. Immunofluorescence microscopy shows that during NPC reassembly at the end of mitosis, Tpr becomes concentrated at the NE significantly later than O-linked glycoproteins, including p62. This indicates that reassembly of the NPC after mitosis is a stepwise process, and that the Tpr-containing peripheral structures are assembled later than p62.