Data resource profile: nutrition data in the VA million veteran program

Introduction

The Department of Veterans Affairs (VA) Million Veteran Program (MVP) nutrition data is derived from dietary food/beverage intake information collected through a semiquantitative food frequency questionnaire (SFFQ).

Methods

Estimates of dietary energy, nutrient, and non-nutritive food components intakes data were derived from an extensively validated SFFQ, which assessed the habitual frequency of consumption of 61 food items, added sugar, fried food frequency, and 21 nutritional supplements over the 12 months preceding questionnaire administration.

Results

Complete nutrition data was available for 353,418 MVP participants as of 30th September 2021. Overall, 91.5% of MVP participants with nutrition data were male with an average age of 65.7 years at enrollment. Participants who completed the SFFQ were primarily White (82.5%), and Blacks accounted for 13.2% of the responders. Mean ± SD energy intake for 353, 418 MVP participants was 1428 ± 616 kcal/day, which was 1434 ± 617 kcal/day for males and 1364 ± 601 kcal/day for females. Energy intake and information on 322 nutrients and non-nutritive food components is available through contact with MVP for research collaborations at www.research.va.gov/mvp.

Conclusions

The energy and nutrient data derived from MVP SFFQ are an invaluable resource for Veteran health and research. In conjunction with the MVP Lifestyle Survey, electronic health records, and genomic data, MVP nutrition data may be used to assess nutritional status and related risk factors, disease prevalence, and determinants of health that can provide scientific support for the development of evidence-based public health policy and health promotion programs and services for Veterans and general population.

Interplay between diet, circulating indolepropionate concentrations and cardiometabolic health in US populations

OBJECTIVES

To identify indolepropionate (IPA)-predicting gut microbiota species, investigate potential diet-microbiota interactions, and examine the prospective associations of circulating IPA concentrations with type 2 diabetes (T2D) and coronary heart disease (CHD) risk in free-living individuals.

DESIGN

We included 287 men from the Men's Lifestyle Validation Study, a substudy of the Health Professionals Follow-Up Study (HPFS), who provided up to two pairs of faecal samples and two blood samples. Diet was assessed using 7-day diet records. Associations between plasma concentrations of tryptophan metabolites and T2D CHD risk were examined in 13 032 participants from Nurses' Health Study (NHS), NHSII and HPFS.

RESULTS

We identified 17 microbial species whose abundance was significantly associated with plasma IPA concentrations. A significant association between higher tryptophan intake and higher IPA concentrations was only observed among men who had higher fibre intake and a higher microbial species score consisting of the 17 species (p-interaction<0.01). Dietary and plasma concentrations of tryptophan and most kynurenine pathway metabolites were positively associated with T2D risk (HRQ5 vs Q1 ranged from 1.17 to 1.46) while a significant inverse association was found for IPA (HRQ5 vs Q1 (95% CI) 0.70 (0.56 to 0.88)). No associations were found in CHD for any plasma tryptophan metabolites.

CONCLUSIONS

Specific microbial species and dietary fibre jointly predicted significantly higher circulating IPA concentrations at higher tryptophan intake. Dietary and plasma tryptophan, as well as its kynurenine pathway metabolites, demonstrated divergent associations from those for IPA, which was significantly predictive of lower risk of T2D.

Association of dietary fatty acids with the risk of atherosclerotic cardiovascular disease in a prospective cohort of United States veterans

BACKGROUND

Atherosclerotic cardiovascular diseases (ASCVDs) are the leading cause of worldwide adult mortality. Although broad classes of dietary fats have been shown to alter ASCVD risk, the roles that individual dietary fatty acids play in influencing ASCVD risk are unclear.

OBJECTIVES

The aim of this prospective cohort study was to examine the relationships of the total fat classes and individual fatty acids with the risk of ASCVD.

METHODS

The Million Veteran Program is a prospective cohort whereby dietary intake of fatty acids was assessed in 158,198 participants that had enrolled between January 2011 and November 2018 and were free of ASCVD at baseline. Incident ASCVD was ascertained from the Veterans Affairs electronic health records and the National Death Index. Multivariable-adjusted hazard ratios (HRs) for the relationship between fat intake and ASCVD risk were computed using Cox regression models.

RESULTS

The mean age was 61 years, 88% were males. A total of 11,771 ASCVD events were identified during the follow-up. When compared with the lowest quintile, participants in the highest quintile of dietary trans-monounsaturated fats and conjugated linoleic acids had an increased risk (HR [95% CI]) of ASCVD events: 1.10 (1.04, 1.17) and 1.11 (1.05, 1.18), respectively. When compared with low consumers, participants in the highest quintile of total cis-polyunsaturated fatty acid intake had a lower risk of experiencing an ASCVD event 0.93 (0.87, 0.99).

CONCLUSION

Although higher intakes of specific trans-fatty acids and conjugated linoleic were associated with an increased risk of ASCVD, the same cannot be said for all other fat classes. This work suggests that care must be taken when drawing general conclusions regarding the health effects of dietary individual fatty acids.

You are What You Drink? How Associations Between Profiles of Beverage Consumption and Type 2 Diabetes Risk are Mediated by Biomarker Networks

BACKGROUND

Multiple studies have independently investigated the associations of the consumption of individual beverage types and specific plasma biomarkers with the risk of type 2 diabetes (T2D). However, as individuals do not consume single beverage types exclusively and plasma biomarkers do not act in isolation, it remains unclear how patterns of beverage consumption and plasma biomarker networks associate both with each other and T2D risk.

OBJECTIVES

We aimed to elucidate potential dietary determinants of T2D risk by defining a model that describes habitual beverage consumption profiles in relation to identified networks of circulating plasma biomarkers.

METHODS

This study included 1,461 case and 1,568 control participants from case-control studies of T2D nested within the Nurses' Health Study. Participants completed validated semiquantitative food frequency questionnaires that assessed habitual beverage consumption, and they provided blood samples from which 27 plasma biomarkers of cardiometabolic risk were identified. Common exploratory factor analysis (EFA) identified factors that separately described beverage consumption profiles and biomarker networks. Multivariable-adjusted regression elucidated the relationships between beverage and biomarker factors and T2D risk.

RESULTS

EFA revealed five factors describing unique beverage consumption profiles and seven factors describing biomarker networks. The factor describing alcoholic beverage consumption was associated with a reduced risk of T2D (odds ratio [OR]: 0.50 [0.40, 0.64], P<0.001) mediated, in part, by the factor describing increased concentrations of adiponectin biomarkers (19.9% [12.0, 31.1] P = 0.004). The factor describing low-calorie sweetened beverage (LCSBs) consumption was associated with an increased risk of T2D (OR: 1.33 [1.03, 1.72], P = 0.021), and the factor describing lower concentrations of insulin-like growth factor binding proteins 1 and 2, and soluble leptin receptor, and increased leptin concentrations (P = 0.005).

CONCLUSIONS

Moderate alcohol consumption was associated with reduced T2D risk, mediated in part by increased circulating adiponectin. LCSB consumption was associated with both increased T2D risk and perturbed insulin-like growth factor and leptin signaling.

Abstract P271: Spatiotemporal Trends of Cardiovascular Incidence in U.S. Veterans From 2003-2018

Introduction: Cardiovascular disease (CVD) is the leading cause of mortality and disability in the United States. Spatiotemporal modeling of disease incidence may guide prevention efforts toward regions most at risk in the future.

Methods: We examined spatiotemporal trends in composite CVD events, defined as myocardial infarction, ischemic stroke, atrial fibrillation, heart failure, coronary artery disease, or cardiovascular death, using electronic health records from 9,718,107 U.S. Veterans who used VA healthcare facilities from 2003-2018. Age-standardized annual incidence by state was modeled using the Bernardinelli model, a Bayesian Poisson regression with linear temporal trends for the US and individual states.

Results: There were 626,271 CVD events over 16 years of follow up and annual incidence fell gradually from 11.5% in 2003 to 6.6% in 2018. Incidence among all US veterans decreased an estimated 3.1% [95% CI: -3.3%, -2.9%] per year (RR year = 0.969). State-level incidences also decreased monotonically over the follow-up period (Figure panel A ), ranging from an absolute decrease 5.0% (RI) to 1.7% (OR). Estimated incidence for the five states most above (RI, FL, NC, MT, LA) and most below (OR, NV, CT, OK, MI) the national trend are plotted against the US average in Figure panel B . These outlying states differed significantly from the overall trend (posterior probabilities ≥ 99.7%), and the magnitude of trend was loosely correlated with initial incidence rate (in 2003). Notably, four states crossed the national average over the study period: CT and OK started below average in 2003 but ended above in 2018, whereas RI and NC started with high incidence and ended with below average incidence in 2018.

Conclusions: Among US veterans, there was significant geographic variation in the rate of decline of incident CVD from 2003-2018. Future research will investigate the mechanisms underpinning the observed trends, particularly prevalence and control of risk factors.

Abstract MP66: The Interplay Between Diet, Circulating Indolepropionate Concentrations, and Cardiometabolic Health in US Populations

Background: Indolepropionate (IPA), a tryptophan metabolite of human gut microbiota origin, is associated with lower risk of type 2 diabetes (T2D) in humans. The complex interplay among tryptophan intake, the gut microbiome, prebiotics, circulating IPA concentrations, and T2D risk has not been investigated.

Objectives: We aimed to identify IPA-producing gut microbiota species and investigate potential diet-microbiota interaction on circulating IPA concentrations.

Methods: We included 287 men from the Men’s Lifestyle Validation Study, a sub-study of the Health Professionals Follow-Up Study (HPFS), who provided up to two pairs of fecal samples and two blood samples approximately six months apart. Dietary intake was assessed using 7-day diet records. We identified microbial taxonomic features associated with plasma IPA concentrations using generalized linear regression and calculated a rank-based species score to reflect IPA-producing potential. Associations between plasma concentrations of tryptophan metabolites and T2D risk were examined in 13,032 participants from Nurses’ Health Study (NHS), NHSII, and HPFS.

Results: Plasma IPA concentrations were associated with overall gut microbial profiles (permutational analysis of variance test, p=0.001). We identified 17 microbial species, such as Eubacterium eligens, Butyrivibrio crossotus , and Faecalibacterium prausnitzii , whose abundance was significantly associated with increased plasma IPA concentrations (false discovery rate < 0.05). A significant association between higher tryptophan intake and higher IPA concentrations was only observed among men who had higher fiber intake and a higher microbial species score consisting of the 17 species (p-interaction < 0.01). Similar modulation was also observed for major tryptophan food contributors including vegetables (p-interaction < 0.01), red/processed meat (p-interaction = 0.02), egg (p-interaction 0.01), dairy (p-interaction = 0.01), and whole grain (p-interaction < 0.01). Moreover, interactions persisted for all fiber subtypes (soluble/insoluble fiber and pectin). We documented 1,744 incident T2D cases during 218,603 person-years of follow-up. Plasma concentrations of tryptophan and three kynurenine-pathway metabolites (kynurenine, xanthurenate, and quinolinate) were positively associated with T2D risk while an inverse association was found for IPA.

Conclusions: Specific microbial species and dietary fiber jointly modulate the associations between tryptophan intake and circulating IPA concentrations. In a subsequent analysis, IPA levels were predictive of lower T2D risk. Our findings suggest that the health effects of dietary tryptophan may depend on both gut microbiome composition and prebiotic consumption.

Abstract P328: Higher Intake of Dietary Cholesterol Was Associated With Increased Risk of Myocardial Infarction in the Million Veteran Program

Background: Association of dietary cholesterol with coronary artery disease (CAD) remains inconsistent. We examined the relation of dietary cholesterol with incidence of myocardial infarction (MI), among participants of the Million Veteran Program (MVP).

Methods: The MVP is a nationally representative, prospective cohort study of Veterans which started in 2011 and by 2020 had over 800,000 enrollees and looked at factors, that could be associated to their chronic conditions. Dietary intake was one of these characteristics and was collected by self-reported semi-quantitative food frequency questionnaire. MI cases were identified by Surrogate-Assisted Feature Extraction (SAFE) method which is an algorithm approach combing ICD codes, natural language processing and medical record review labels. All information regarding MI were reviewed by combining the VA Corporate Data Warehouse (VDW), which consist of VA EHR and Medicaid/Medicare database, and National Death index databases.

Results: Among the 180,156 Veterans with data on dietary cholesterol, mean age was 62 years, 90% men, and 80% White. Mean follow up was 3.5 years. We observed a linear, dose-response, association between dietary cholesterol intake and the risk of MI ( P for linear trend =0.003) (Figure 1). When adjusting for age and sex every increase of 100 mg/day of dietary cholesterol was associated with a 9% higher risk of MI (RR: 1.07, 95%CI: 1.06-1.12). Participants with a cholesterol intake ≥300 mg/day had a 15% higher risk of MI compared to participants whose cholesterol intake was no more than 300 mg/day (RR: 1.15, 95%CI: 1.06-1.25).

Conclusion: In our study, increased intakes of dietary cholesterol were associated with a higher risk of MI among US Veterans.

Interplay between diet and gut microbiome, and circulating concentrations of trimethylamine N-oxide: findings from a longitudinal cohort of US men

OBJECTIVES

Gut-produced trimethylamine N-oxide (TMAO) is postulated as a possible link between red meat intake and poor cardiometabolic health. We investigated whether gut microbiome could modify associations of dietary precursors with TMAO concentrations and cardiometabolic risk markers among free-living individuals.

DESIGN

We collected up to two pairs of faecal samples (n=925) and two blood samples (n=473), 6 months apart, from 307 healthy men in the Men's Lifestyle Validation Study. Diet was assessed repeatedly using food-frequency questionnaires and diet records. We profiled faecal metagenome and metatranscriptome using shotgun sequencing and identified microbial taxonomic and functional features.

RESULTS

TMAO concentrations were associated with the overall microbial compositions (permutational analysis of variance (PERMANOVA) test p=0.001). Multivariable taxa-wide association analysis identified 10 bacterial species whose abundance was significantly associated with plasma TMAO concentrations (false discovery rate <0.05). Higher habitual intake of red meat and choline was significantly associated with higher TMAO concentrations among participants who were microbial TMAO-producers (p<0.05), as characterised based on four abundant TMAO-predicting species, but not among other participants (for red meat, P-interaction=0.003; for choline, P-interaction=0.03). Among abundant TMAO-predicting species, Alistipes shahii significantly strengthened the positive association between red meat intake and HbA1c levels (P-interaction=0.01). Secondary analyses revealed that some functional features, including choline trimethylamine-lyase activating enzymes, were associated with TMAO concentrations.

CONCLUSION

We identified microbial taxa that were associated with TMAO concentrations and modified the associations of red meat intake with TMAO concentrations and cardiometabolic risk markers. Our data underscore the interplay between diet and gut microbiome in producing potentially bioactive metabolites that may modulate cardiometabolic health.

A Phenome-Wide Association Study of genes associated with COVID-19 severity reveals shared genetics with complex diseases in the Million Veteran Program

The study aims to determine the shared genetic architecture between COVID-19 severity with existing medical conditions using electronic health record (EHR) data. We conducted a Phenome-Wide Association Study (PheWAS) of genetic variants associated with critical illness (n = 35) or hospitalization (n = 42) due to severe COVID-19 using genome-wide association summary data from the Host Genetics Initiative. PheWAS analysis was performed using genotype-phenotype data from the Veterans Affairs Million Veteran Program (MVP). Phenotypes were defined by International Classification of Diseases (ICD) codes mapped to clinically relevant groups using published PheWAS methods. Among 658,582 Veterans, variants associated with severe COVID-19 were tested for association across 1,559 phenotypes. Variants at the ABO locus (rs495828, rs505922) associated with the largest number of phenotypes (nrs495828 = 53 and nrs505922 = 59); strongest association with venous embolism, odds ratio (ORrs495828 1.33 (p = 1.32 x 10-199), and thrombosis ORrs505922 1.33, p = 2.2 x10-265. Among 67 respiratory conditions tested, 11 had significant associations including MUC5B locus (rs35705950) with increased risk of idiopathic fibrosing alveolitis OR 2.83, p = 4.12 × 10-191; CRHR1 (rs61667602) associated with reduced risk of pulmonary fibrosis, OR 0.84, p = 2.26× 10-12. The TYK2 locus (rs11085727) associated with reduced risk for autoimmune conditions, e.g., psoriasis OR 0.88, p = 6.48 x10-23, lupus OR 0.84, p = 3.97 x 10-06. PheWAS stratified by ancestry demonstrated differences in genotype-phenotype associations. LMNA (rs581342) associated with neutropenia OR 1.29 p = 4.1 x 10-13 among Veterans of African and Hispanic ancestry but not European. Overall, we observed a shared genetic architecture between COVID-19 severity and conditions related to underlying risk factors for severe and poor COVID-19 outcomes. Differing associations between genotype-phenotype across ancestries may inform heterogenous outcomes observed with COVID-19. Divergent associations between risk for severe COVID-19 with autoimmune inflammatory conditions both respiratory and non-respiratory highlights the shared pathways and fine balance of immune host response and autoimmunity and caution required when considering treatment targets.

Dietary lignans, plasma enterolactone levels, and metabolic risk in men: exploring the role of the gut microbiome

BACKGROUND

The conversion of plant lignans to bioactive enterolignans in the gastrointestinal tract is mediated through microbial processing. The goal of this study was to examine the relationships between lignan intake, plasma enterolactone concentrations, gut microbiome composition, and metabolic risk in free-living male adults.

RESULTS

In 303 men participating in the Men's Lifestyle Validation Study (MLVS), lignan intake was assessed using two sets of 7-day diet records, and gut microbiome was profiled through shotgun sequencing of up to 2 pairs of fecal samples (n = 911). A score was calculated to summarize the abundance of bacteria species that were significantly associated with plasma enterolactone levels. Of the 138 filtered species, plasma enterolactone levels were significantly associated with the relative abundances of 18 species at FDR < 0.05 level. Per SD increment of lignan intake was associated with 20.7 nM (SEM: 2.3 nM) higher enterolactone concentrations among participants with a higher species score, whereas the corresponding estimate was 4.0 nM (SEM: 1.7 nM) among participants with a lower species score (P for interaction < 0.001). A total of 12 plasma metabolites were also significantly associated with these enterolactone-predicting species. Of the association between lignan intake and metabolic risk, 19.8% (95%CI: 7.3%-43.6%) was explained by the species score alone, 54.5% (95%CI: 21.8%-83.7%) by both species score and enterolactone levels, and 79.8% (95%CI: 17.7%-98.6%) by further considering the 12 plasma metabolites.

CONCLUSION

We identified multiple gut bacteria species that were enriched or depleted at higher plasma levels of enterolactone in men. These species jointly modified the associations of lignan intake with plasma enterolactone levels and explained the majority of association between lignan intake and metabolic risk along with enterolactone levels and certain plasma metabolites.

Dietary Gluten Intake Is Not Associated With Risk of Inflammatory Bowel Disease in US Adults Without Celiac Disease

BACKGROUND & AIMS

Diet is thought to play a role in the development of inflammatory bowel disease (IBD), though it is unknown whether gluten intake confers risk of IBD. The aim of this study was to determine the relationship between gluten intake and risk of incident Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We performed a prospective cohort study of 208,280 US participants from the Nurses' Health Study (1986-2016), Nurses' Health Study II (1991-2017), and the Health Professionals Follow-up Study (1986-2016) who did not have IBD at baseline or celiac disease, and who completed semiquantitative food frequency questionnaires. We used Cox proportional hazards modeling to estimate the risk of IBD according to quintiles of cumulative average energy-adjusted dietary gluten intake over the follow-up period.

RESULTS

We documented 337 CD cases and 447 UC cases over 5,115,265 person-years of follow-up evaluation. Dietary gluten intake was not associated with risk of IBD. Compared with participants in the lowest quintile of gluten intake, the adjusted hazard ratios and 95% CIs for participants in the highest quintile of gluten intake were 1.16 (95% CI, 0.82-1.64; P_trend = .41) for CD and 1.04 (95% CI, 0.75-1.44; P_trend = .64) for UC. Adjusting for primary sources of gluten intake did not materially change our estimates.

CONCLUSIONS

In 3 large adult US prospective cohorts, gluten intake was not associated with risk of CD or UC. Our findings are reassuring at a time when consumption of gluten has been increasingly perceived as a trigger for chronic gastrointestinal diseases.

Association of Nut Consumption with Risk of Stroke and Cardiovascular Disease: The Million Veteran Program

Cardiovascular disease (CVD), including stroke and coronary artery disease (CAD), is the major cause of mortality for Americans. Nuts have been shown to improve a variety of cardiovascular disease risk factors. This study aimed to test the hypothesis that nut consumption is inversely associated with risk of incidence of stroke, CAD, and CVD mortality in the prospective Million Veterans Program (MVP). A total of 179,827 MVP participants enrolled between 2011 and 2018 were free of CVD prior to assessment of nut consumption via the food frequency questionnaire. Incident stroke and CVD events were ascertained from the Veterans Affairs electronic medical health records and the National Death Index. We used the Cox regression model to compute multivariable adjusted hazard ratios. Over the 3.5-year median follow-up, 3362 new cases of ischemic stroke were identified. When compared with participants who rarely or never consumed nuts, those consuming nuts ≥ 5 times per week were 19% less likely to experience a stroke (95% CI: 8% to 28%); 22% less likely to suffer from CAD (95% CI: 16% to 28%); and 24% less likely to die from CVD (95% CI: 7% to 37%). Consumption of peanut butter was not associated with risk of stroke. Increased dietary intake of nuts, but not peanut butter, was associated with a lower risk of stroke, CAD, and CVD death.

The effects of increasing fruit and vegetable intake in children with asthma: A randomized controlled trial

BACKGROUND

A high fruit and vegetable (F&V) diet reduces asthma exacerbations in adults; this has not been examined in children to date.

OBJECTIVE

To investigate the effect of a 6-month, high F&V diet on the time to first asthma exacerbation in children with asthma, in a parallel-group, randomized, controlled trial.

METHODS

Children (aged 3-11 years) with asthma, history of exacerbations and usual low F&V intake (≤3 serves/day) were randomized to the intervention (high F&V diet) or control group (usual diet) for 6 months. The primary outcome was time to first exacerbation requiring medical intervention. Secondary outcomes included exacerbation rate, lung function, plasma TNF-α, CRP, and IL-6, faecal microbiota and peripheral blood mononuclear cell (PBMC) histone deacetylase (HDAC) activity and G-protein coupled receptor (GPR) 41/43 and HDAC (1-11) expression.

RESULTS

67 children were randomized between September 2015 and July 2018. F&V intake (difference in change (∆): 3.5 serves/day, 95% CI: [2.6, 4.4] p < 0.001) and plasma total carotenoids (∆: 0.44 µg/ml [0.19, 0.70] p = 0.001) increased after 6 months (intervention vs control). Time to first exacerbation (HR: 0.81, 95% CI: [0.38, 1.69], p = 0.569) and exacerbation rate (IRR: 0.84, [0.47, 1.49], p = 0.553) were similar between groups. In per-protocol analysis, airway reactance z-scores increased (X₅ ∆: 0.76 [0.04, 1.48] p = 0.038, X₂₀ ∆: 0.93 [0.23, 1.64] p = 0.009) and changes in faecal microbiota were observed, both in the intervention versus control group, though there was no difference between groups in systemic inflammation or molecular mechanisms. In the control group, CRP and HDAC enzyme activity increased, while GPR41 expression decreased. No adverse events attributable to the interventions were observed.

CONCLUSION & CLINICAL RELEVANCE

A high F&V diet did not affect asthma exacerbations over the 6-month intervention, though warrants further investigation as a strategy for improving lung function and protecting against systemic inflammation in children with asthma.

Dietary fiber intake, the gut microbiome, and chronic systemic inflammation in a cohort of adult men

BACKGROUND

A higher intake of dietary fiber is associated with a decreased risk of chronic inflammatory diseases such as cardiovascular disease and inflammatory bowel disease. This may function in part due to abrogation of chronic systemic inflammation induced by factors such as dysbiotic gut communities. Data regarding the detailed influences of long-term and recent intake of differing dietary fiber sources on the human gut microbiome are lacking.

METHODS

In a cohort of 307 generally healthy men, we examined gut microbiomes, profiled by shotgun metagenomic and metatranscriptomic sequencing, and long-term and recent dietary fiber intake in relation to plasma levels of C-reactive protein (CRP), an established biomarker for chronic inflammation. Data were analyzed using multivariate linear mixed models.

RESULTS

We found that inflammation-associated gut microbial configurations corresponded with higher CRP levels. A greater intake of dietary fiber was associated with shifts in gut microbiome composition, particularly Clostridiales, and their potential for carbohydrate utilization via polysaccharide degradation. This was particularly true for fruit fiber sources (i.e., pectin). Most striking, fiber intake was associated with significantly greater CRP reduction in individuals without substantial Prevotella copri carriage in the gut, whereas those with P. copri carriage maintained stable CRP levels regardless of fiber intake.

CONCLUSIONS

Our findings offer human evidence supporting a fiber-gut microbiota interaction, as well as a potential specific mechanism by which gut-mediated systemic inflammation may be mitigated.

Plant-Based Diet Index and Metabolic Risk in Men: Exploring the Role of the Gut Microbiome

BACKGROUND

Healthy plant-based diet index (hPDI) is associated with a lower risk of cardiometabolic conditions, but its association as well as interactions with microbiome have not been elucidated.

OBJECTIVES

We aimed to investigate the interrelations between hPDI, gut microbiome, and cardiometabolic risk markers.

METHODS

hPDI was derived from dietary assessments by a validated FFQ and was examined in relation to metagenomic profiles of 911 fecal samples collected from 303 men aged 71 ± 4 y with an average BMI (in kg/m2) of 25.2 ± 3.6 in the Men's Lifestyle Validation Study. Principal coordinate (PCo) analysis based on Bray-Curtis dissimilarity was conducted, and interactions between hPDI and PCo were examined by using a metabolic risk score composed of blood lipids, BMI, and glycated hemoglobin.

RESULTS

After multivariable adjustment, hPDI was significantly associated with the relative abundance of 7 species and 9 pathways. In particular, higher hPDI was significantly associated with a higher relative abundance of Bacteroides cellulosilyticus and Eubacterium eligens, amino acid biosynthesis pathways (l-isoleucine biosynthesis I and III and l-valine biosynthesis), and the pathway of pyruvate fermentation to isobutanol. A favorable association between hPDI and the metabolic risk score was more pronounced among men with a higher PCo characterized by higher abundance of Bacteroides uniformis and lower abundance of Prevotella copri. At the individual species level, a similar interaction was also observed between hPDI and P. copri, as well as with Clostridium clostridioforme or Blautia hydrogenotrophica (all P-interaction < 0.01).

CONCLUSION

A greater adherence to a healthy plant-based diet by older men was associated with a microbial profile characterized by a higher abundance of multiple species, including B. cellulosilyticus and E. eligens, as well as pathways in amino acid metabolism and pyruvate fermentation. In addition, inverse associations between healthy plant-based diet and human metabolic risk may partially depend on microbial compositions.

Reproducibility and Validity of a Semiquantitative Food Frequency Questionnaire in Men Assessed by Multiple Methods

Among 626 participants of the Men's Lifestyle Validation Study (2011-2013), we evaluated the validity and reproducibility of a self-administered 152-item semiquantitative food frequency questionnaire (SFFQ) using two 7-day dietary records (7DDRs), 4 Automated Self-Administered 24-hour dietary recalls (ASA24s), four 24-hour urine samples, 1 doubly labeled water measurement (repeated in 104 participants), and 2 fasting blood samples, collected over 15 months. Compared with 7DDRs, SFFQs underestimated energy intake, macronutrients, and sodium intake but overestimated some micronutrients. The mean of the Spearman correlation coefficients was 0.66 (range, 0.38-0.88) between 46 energy-adjusted nutrients estimated from 7DDRs and the final SFFQ, deattenuated for within-person variation in the 7DDRs. These deattenuated correlations were similar using ASA24s as the comparison. Relative to biomarkers, SFFQs underestimated energy, sodium, and protein intakes, as well as the sodium:potassium ratio. The energy-adjusted correlations between the final SFFQ and the biomarkers were slightly lower than the correlations between the SFFQ and 7DDRs. Using the method of triads to calculate validity coefficients, the median validity coefficient between SFFQ and true intake was 0.65 and 0.69 using 7DDRs and ASA24s, respectively, as the third method. These data indicate that this SFFQ provided reasonably valid estimates for a wide range of nutrients when evaluated by multiple comparison methods.

Dietary yogurt is distinct from other dairy foods in its association with circulating lipid profile: Findings from the Million Veteran Program

BACKGROUND & AIMS

Dyslipidemia is a major cardiovascular disease risk factor. Research has proposed mechanisms whereby yogurt may improve circulating lipid concentrations. However, at the population level, the association of yogurt, as distinct from other dairy foods, with these important risk factors is poorly understood. This study aimed to determine whether the circulating lipid profile associated with yogurt is different to the circulating lipid profile that is associated with non-yogurt dairy products, specifically milk and cheese.

METHODS

The current study included the 192,564 US Veterans enrolled in the Million Veteran Program who reported frequency of yogurt consumption (assessed via food frequency questionnaire) and had lipid concentrations assessed. Trends were evaluated with linear regression. Mean age was 65 (SD = 11) years [20, 100 years].

RESULTS

A one serve/day higher yogurt consumption was positively associated (coefficient ± SE) with the concentration of high-density lipoprotein cholesterol (HDLC) in individuals who were not (0.26 ± 0.12 mg/dL, P value = 0.025), and who were (0.25 ± 0.09, P value = 0.004), using antilipemic agents. Furthermore, higher yogurt consumption was inversely associated with the concentration of triglycerides, but only in individuals who were not using antilipemic agents (-1.46 ± 0.58, P value = 0.012).

CONCLUSION

These apparent beneficial associations of yogurt with HDLC and triglycerides were independent of consumption of non-yogurt dairy foods and were not observed for consumption of either milk or cheese. In this prospective cohort study of U.S. Veterans, we found a beneficial relationship between higher frequency of yogurt consumption with circulating HDLC and triglyceride concentrations that was distinct from non-yogurt dairy foods.

Intestinal microbiology shapes population health impacts of diet and lifestyle risk exposures in Torres Strait Islander communities

Poor diet and lifestyle exposures are implicated in substantial global increases in non-communicable disease burden in low-income, remote, and Indigenous communities. This observational study investigated the contribution of the fecal microbiome to influence host physiology in two Indigenous communities in the Torres Strait Islands: Mer, a remote island where a traditional diet predominates, and Waiben a more accessible island with greater access to takeaway food and alcohol. Counterintuitively, disease markers were more pronounced in Mer residents. However, island-specific differences in disease risk were explained, in part, by microbiome traits. The absence of Alistipes onderdonkii, for example, significantly (p=0.014) moderated island-specific patterns of systolic blood pressure in multivariate-adjusted models. We also report mediatory relationships between traits of the fecal metagenome, disease markers, and risk exposures. Understanding how intestinal microbiome traits influence response to disease risk exposures is critical for the development of strategies that mitigate the growing burden of cardiometabolic disease in these communities.

Association of diet with circulating trimethylamine-N-oxide concentration

BACKGROUND

Trimethylamine-N-oxide (TMAO) is a compound that is present in seafood and produced through human gut microbial metabolism of its precursors. Previous studies have suggested that elevated TMAO concentrations are associated with an increased risk of cardiovascular events. However, the association between diet and TMAO concentrations in free-living adult populations has not been adequately described.

OBJECTIVES

The objective of this study was to identify dietary predictors of plasma TMAO concentrations.

METHODS

TMAO concentrations were assessed in 2 fasting plasma samples collected 6 mo apart among 620 healthy men. Short-term and long-term dietary intakes were assessed during the same time-frame of blood collections via repeated 7-d dietary records (7DDRs) and a semiquantitative food-frequency questionnaire (SFFQ), respectively. We grouped individual food items into 21 groups and regressed against averaged TMAO concentrations. We also assessed the association between dietary scores and TMAO concentrations.

RESULTS

In models adjusted for demographic characteristics and mutually adjusted for food groups, SFFQ-assessments of fish and egg intakes were significantly associated with increased TMAO concentration (β = 0.082; 95% CI: 0.021, 0.14; P = 0.009 for fish; β = 0.065; 95% CI: 0.004, 0.13; P = 0.039 for egg). The positive association between fish consumption and TMAO concentration was replicated in the 7DDR-assessments (β = 0.12; 95% CI: 0.060, 0.18; P < 0.001). There was no association between red meat intake and TMAO concentrations. The unhealthful plant-based diet index (uPDI) was inversely associated (β = -0.013; 95% CI: -0.021, -0.005; P = 0.001) and healthy dietary scores were positively correlated with TMAO concentration.

CONCLUSIONS

TMAO concentration was significantly associated with fish intake, but not with red meat consumption. uPDI, an unhealthy dietary pattern, was inversely related to TMAO concentration. As such, this study suggests that in free-living populations, higher circulating concentrations of TMAO cannot simply be interpreted as a marker of unhealthy food intake or an unhealthy dietary pattern.

A lipid-related metabolomic pattern of diet quality

BACKGROUND

Adherence to a healthy diet has been associated with reduced risk of chronic diseases. Identifying nutritional biomarkers of diet quality may be complementary to traditional questionnaire-based methods and may provide insights concerning disease mechanisms and prevention.

OBJECTIVE

To identify metabolites associated with diet quality assessed via the Alternate Healthy Eating Index (AHEI) and its components.

METHODS

This cross-sectional study used FFQ data and plasma metabolomic profiles, mostly lipid related, from the Nurses' Health Study (NHS, n = 1460) and Health Professionals Follow-up Study (HPFS, n = 1051). Linear regression models assessed associations of the AHEI and its components with individual metabolites. Canonical correspondence analyses (CCAs) investigated overlapping patterns between AHEI components and metabolites. Principal component analysis (PCA) and explanatory factor analysis were used to consolidate correlated metabolites into uncorrelated factors. We used stepwise multivariable regression to create a metabolomic score that is an indicator of diet quality.

RESULTS

The AHEI was associated with 83 metabolites in the NHS and 96 metabolites in the HPFS after false discovery rate adjustment. Sixty-three of these significant metabolites overlapped between the 2 cohorts. CCA identified "healthy" AHEI components (e.g., nuts, whole grains) and metabolites (n = 27 in the NHS and 33 in the HPFS) and "unhealthy" AHEI components (e.g., red meat, trans fat) and metabolites (n = 56 in the NHS and 63 in the HPFS). PCA-derived factors composed of highly saturated triglycerides, plasmalogens, and acylcarnitines were associated with unhealthy AHEI components while factors composed of highly unsaturated triglycerides were linked to healthy AHEI components. The stepwise regression analysis contributed to a metabolomics score as a predictor of diet quality.

CONCLUSION

We identified metabolites associated with healthy and unhealthy eating behaviors. The observed associations were largely similar between men and women, suggesting that metabolomics can be a complementary approach to self-reported diet in studies of diet and chronic disease.

Association Between Sulfur-Metabolizing Bacterial Communities in Stool and Risk of Distal Colorectal Cancer in Men

BACKGROUND & AIMS

Sulfur-metabolizing microbes, which convert dietary sources of sulfur into genotoxic hydrogen sulfide (H2S), have been associated with development of colorectal cancer (CRC). We identified a dietary pattern associated with sulfur-metabolizing bacteria in stool and then investigated its association with risk of incident CRC using data from a large prospective study of men.

METHODS

We collected data from 51,529 men enrolled in the Health Professionals Follow-up Study since 1986 to determine the association between sulfur-metabolizing bacteria in stool and risk of CRC over 26 years of follow-up. First, in a subcohort of 307 healthy men, we profiled serial stool metagenomes and metatranscriptomes and assessed diet using semiquantitative food frequency questionnaires to identify food groups associated with 43 bacterial species involved in sulfur metabolism. We used these data to develop a sulfur microbial dietary score. We then used Cox proportional hazards modeling to evaluate adherence to this pattern among eligible individuals (n = 48,246) from 1986 through 2012 with risk for incident CRC.

RESULTS

Foods associated with higher sulfur microbial diet scores included increased consumption of processed meats and low-calorie drinks and lower consumption of vegetables and legumes. Increased sulfur microbial diet scores were associated with risk of distal colon and rectal cancers, after adjusting for other risk factors (multivariable relative risk, highest vs lowest quartile, 1.43; 95% confidence interval 1.14-1.81; P-trend = .002). In contrast, sulfur microbial diet scores were not associated with risk of proximal colon cancer (multivariable relative risk 0.86; 95% CI 0.65-1.14; P-trend = .31).

CONCLUSIONS

In an analysis of participants in the Health Professionals Follow-up Study, we found that long-term adherence to a dietary pattern associated with sulfur-metabolizing bacteria in stool was associated with an increased risk of distal CRC. Further studies are needed to determine how sulfur-metabolizing bacteria might contribute to CRC pathogenesis.

Total bacterial load, inflammation, and structural lung disease in paediatric cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is characterised by reduced airway clearance, microbial accumulation, inflammation, and lung function decline. Certain bacterial species may contribute disproportionately to worsening lung disease. However, the relative importance of these microorganisms compared to the absolute abundance of all bacteria is uncertain. We aimed to identify the characteristics of lower airway microbiology that best reflect CF airway inflammation and disease in children.

METHODS

Analysis was performed on bronchoalveolar lavage (BAL) fluid from 78 participants of the Australasian CF Bronchoalveolar Lavage (ACFBAL) clinical trial, aged 4.5-5.5 years. Universal bacterial quantitative PCR (qPCR), species-specific qPCR, and 16S rRNA gene sequencing were performed on DNA extracts to determine total bacterial load, species-specific load and taxa relative abundance. Quantification of pre-specified pathogens was performed by culture-based methods. Bacteriological data were related to neutrophil counts, interleukin-8, lung function, and two computed-tomography based measures, CF-CT (as the primary measure) and PRAGMA.

RESULTS

Of all bacteriological measures assessed, total bacterial load determined by qPCR correlated most strongly with structural disease (CF-CT total score, r_s=0.30, P=0.0095). Specifically, total bacterial load correlated with bronchiectasis, airway wall thickening, mucus plugging and parenchymal disease sub-scores. In contrast, culture-based quantification, microbiota-derived measures, and pathogen-specific qPCR-based quantification were weakly associated with total CF-CT. Regression analyses supported correlation findings, with total bacterial load explaining the greatest variance in total CF-CT (R²=0.097, P=0.0061). Correlations with PRAGMA score were comparable to CF-CT total score.

CONCLUSIONS

Within the ACFBAL trial, culture-independent quantification of total bacteria provided the most clinically-informative bacteriological measure in 5-year-old CF patients.

DNA extraction approaches substantially influence the assessment of the human breast milk microbiome

In addition to providing nutritional and bioactive factors necessary for infant development, human breast milk contains bacteria that contribute to the establishment of commensal microbiota in the infant. However, the composition of this bacterial community differs considerably between studies. We hypothesised that bacterial DNA extraction methodology from breast milk samples are a substantial contributor to these inter-study differences. We tested this hypothesis by applying five widely employed methodologies to a mock breast milk sample and four individual human breast milk samples. Significant differences in DNA yield and purity were observed between methods (P < 0.05). Microbiota composition, assessed by 16S rRNA gene amplicon sequencing, also differed significantly with extraction methodology (P < 0.05), including in the contribution of contaminant signal. Concerningly, many of the bacterial taxa identified here as contaminants have been reported as components of the breast milk microbiome in other studies. These findings highlight the importance of using stringent, well-validated, DNA extraction methodologies for analysis of the breast milk microbiome, and exercising caution interpreting microbiota data from low-biomass contexts.

A Network Analysis of Biomarkers for Type 2 Diabetes

Numerous studies have investigated individual biomarkers in relation to risk of type 2 diabetes. However, few have considered the interconnectivity of these biomarkers in the etiology of diabetes as well as the potential changes in the biomarker correlation network during diabetes development. We conducted a secondary analysis of 27 plasma biomarkers representing glucose metabolism, inflammation, adipokines, endothelial dysfunction, IGF axis, and iron store plus age and BMI at blood collection from an existing case-control study nested in the Nurses' Health Study (NHS), including 1,303 incident diabetes case subjects and 1,627 healthy women. A correlation network was constructed based on pairwise Spearman correlations of the above factors that were statistically different between case and noncase subjects using permutation tests (P < 0.0005). We further evaluated the network structure separately among diabetes case subjects diagnosed <5, 5-10, and >10 years after blood collection versus noncase subjects. Although pairwise biomarker correlations tended to have similar directions comparing diabetes case subjects to noncase subjects, most correlations were stronger in noncase than in case subjects, with the largest differences observed for the insulin/HbA_1c and leptin/adiponectin correlations. Leptin and soluble leptin receptor were two hubs of the network, with large numbers of different correlations with other biomarkers in case versus noncase subjects. When examining the correlation network by timing of diabetes onset, there were more perturbations in the network for case subjects diagnosed >10 years versus <5 years after blood collection, with consistent differential correlations of insulin and HbA_1c C-peptide was the most highly connected node in the early-stage network, whereas leptin was the hub for mid- or late-stage networks. Our results suggest that perturbations of the diabetes-related biomarker network may occur decades prior to clinical recognition. In addition to the persistent dysregulation between insulin and HbA_1c, our results highlight the central role of the leptin system in diabetes development.

Dietary Gluten Intake and Risk of Microscopic Colitis Among US Women without Celiac Disease: A Prospective Cohort Study

OBJECTIVE

Microscopic colitis is a common cause of chronic watery diarrhea among the elderly. Although the prevalence of celiac disease appears to be higher in patients with microscopic colitis, the relationship between dietary gluten intake and risk of microscopic colitis among individuals without celiac disease has not been explored.

METHODS

We conducted a prospective study of 160,744 US women without celiac disease enrolled in the Nurses' Health Study (NHS) and the NHSII. Dietary gluten intake was estimated using validated food frequency questionnaires every 4 years. Microscopic colitis was confirmed through medical records review. We used Cox proportional hazard modeling to estimate the multivariable-adjusted hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

We documented 219 incident cases of microscopic colitis over more than 20 years of follow-up encompassing 3,716,718 person-years (crude incidence rate: 5.9/100,000 person-years) in NHS and NHSII. Dietary gluten intake was not associated with risk of microscopic colitis (Ptrend = 0.88). Compared to individuals in the lowest quintile of energy-adjusted gluten intake, the adjusted HR of microscopic colitis was 1.18 (95% CI: 0.77-1.78) for the middle quintile and 1.03 (95% CI: 0.67-1.58) for the highest quintile. Additional adjustment for primary dietary sources of gluten including refined and whole grains did not materially alter the effect estimates (All Ptrend ≥ 0.69). The null association did not differ according to lymphocytic or collagenous subtypes (Pheterogeneity = 0.72) and was not modified by age, smoking status, or body mass index (All Pinteraction ≥ 0.17).

CONCLUSIONS

Dietary gluten intake during adulthood was not associated with risk of microscopic colitis among women without celiac disease.

Prospective study of flavonoid intake and risk of primary open-angle glaucoma

PURPOSE

To evaluate the association between flavonoid intake and incident primary open-angle glaucoma (POAG).

METHODS

We followed 65 516 women from the Nurses' Health Study (from 1984) and 42 156 men from the Health Professionals Follow-up Study (from 1986) biennially to 2012, who were 40+ years old, free of POAG, and reported eye examinations. Dietary flavonoid intake was assessed with validated repeated semi-quantitative food frequency questionnaires. Incident POAG cases (n = 1575) were confirmed with medical record review. Cohort-specific multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) were calculated and meta-analysed.

RESULTS

Total flavonoid intake was not associated with risk of POAG development [RR for highest (Q5: median ~645 mg/day) versus lowest quintile (Q1: ~130 mg/day) = 0.91 (95% CI = 0.77, 1.08); p for trend (p-trend) = 0.19]; the flavonoid subclasses of flavones, flavanones, polymeric flavanols or anthocyanidins were also not associated (Q5 versus Q1 comparison p-values ≥0.05 and p-trend ≥0.09). Higher intakes of flavonols and monomeric flavanols were nominally associated with lower POAG risk, based on the Q5 versus Q1 comparisons or p-trends. The Q5 versus Q1 comparison RRs were: for flavonols, 0.82 (95% CI = 0.69, 0.97; p-trend = 0.05; ~28 versus ~8 mg/day), and for monomeric flavanols, 0.86 (95% CI = 0.72, 1.02; p-trend=0.04; ~110 versus 10 mg/day). The food/beverage that contributed most to both the variation of flavonols and monomeric flavanols was tea; consuming ~2 cups/day was associated with 18% lower POAG risk (RR=0.82; 95% CI = 0.68, 0.99; p-trend = 0.02).

CONCLUSION

Total flavonoid intake was not associated with POAG risk. Greater intakes of flavonols and monomeric flavanols and of tea showed suggestive modest associations with lower risk; these results need confirmation.

Stability of the human faecal microbiome in a cohort of adult men

Characterizing the stability of the gut microbiome is important to exploit it as a therapeutic target and diagnostic biomarker. We metagenomically and metatranscriptomically sequenced the faecal microbiomes of 308 participants in the Health Professionals Follow-Up Study. Participants provided four stool samples-one pair collected 24-72 h apart and a second pair ~6 months later. Within-person taxonomic and functional variation was consistently lower than between-person variation over time. In contrast, metatranscriptomic profiles were comparably variable within and between subjects due to higher within-subject longitudinal variation. Metagenomic instability accounted for ~74% of corresponding metatranscriptomic instability. The rest was probably attributable to sources such as regulation. Among the pathways that were differentially regulated, most were consistently over- or under-transcribed at each time point. Together, these results suggest that a single measurement of the faecal microbiome can provide long-term information regarding organismal composition and functional potential, but repeated or short-term measures may be necessary for dynamic features identified by metatranscriptomics.

Metatranscriptome of human faecal microbial communities in a cohort of adult men

The gut microbiome is intimately related to human health, but it is not yet known which functional activities are driven by specific microbes’ ecological configurations or transcription. We report a large-scale investigation of 372 human fecal metatranscriptomes and 929 metagenomes from a subset of 308 men in the Health Professionals Follow-up Study. We identified a metatranscriptomic “core” universally transcribed over time and across participants, often by different microbes. In contrast to the housekeeping functions enriched in this core, a “variable” metatranscriptome included specialized pathways that were differentially expressed both across participants and among microbes. Finally, longitudinal metagenomic profiles allowed ecological interaction network reconstruction, which remained stable over the six-month timespan, as did strain tracking within and between participants. These results provide an initial characterization of human fecal microbial ecology into core, subject-specific, microbe-specific, and temporally-variable transcription, and they differentiate metagenomically versus metatranscriptomically informative aspects of the human fecal microbiome.

Association of Vegetable Nitrate Intake With Carotid Atherosclerosis and Ischemic Cerebrovascular Disease in Older Women

BACKGROUND AND PURPOSE

A short-term increase in dietary nitrate (NO₃^-) improves markers of vascular health via formation of nitric oxide and other bioactive nitrogen oxides. Whether this translates into long-term vascular disease risk reduction has yet to be examined. We investigated the association of vegetable-derived nitrate intake with common carotid artery intima-media thickness (CCA-IMT), plaque severity, and ischemic cerebrovascular disease events in elderly women (n=1226).

METHODS

Vegetable nitrate intake, lifestyle factors, and cardiovascular disease risk factors were determined at baseline (1998). CCA-IMT and plaque severity were measured using B-mode carotid ultrasound (2001). Complete ischemic cerebrovascular disease hospitalizations or deaths (events) over 14.5 years (15 032 person-years of follow-up) were obtained from the West Australian Data Linkage System.

RESULTS

Higher vegetable nitrate intake was associated with a lower maximum CCA-IMT (B=-0.015, P=0.002) and lower mean CCA-IMT (B=-0.012, P=0.006). This relationship remained significant after adjustment for lifestyle and cardiovascular risk factors (P≤0.01). Vegetable nitrate intake was not a predictor of plaque severity. In total 186 (15%) women experienced an ischemic cerebrovascular disease event. For every 1 SD (29 mg/d) higher intake of vegetable nitrate, there was an associated 17% lower risk of 14.5-year ischemic cerebrovascular disease events in both unadjusted and fully adjusted models (P=0.02).

CONCLUSIONS

Independent of other risk factors, higher vegetable nitrate was associated with a lower CCA-IMT and a lower risk of an ischemic cerebrovascular disease event.

Comparison of flavonoid intake assessment methods

BACKGROUND

Flavonoids are a diverse group of polyphenolic compounds found in high concentrations in many plant foods and beverages. High flavonoid intake has been associated with reduced risk of chronic disease. To date, population based studies have used the United States Department of Agriculture (USDA) food content database to determine habitual flavonoid intake. More recently, a new flavonoid food content database, Phenol-Explorer (PE), has been developed. However, the level of agreement between the two databases is yet to be explored.

AIM

To compare the methods used to create each database, and to explore the level of agreement between the flavonoid intake estimates derived from USDA and PE data.

DESIGN

The study population included 1063 randomly selected women aged over 75 years. Two separate intake estimates were determined using food composition data from the USDA and the PE databases.

RESULTS

There were many similarities in methods used to create each database; however, there are several methodological differences that manifest themselves in differences in flavonoid intake estimates between the 2 databases. Despite differences in net estimates, there was a strong level of agreement between total-flavonoid, flavanol, flavanone and anthocyanidin intake estimates derived from each database. Intake estimates for flavanol monomers showed greater agreement than flavanol polymers. The level of agreement between the two databases was the weakest for the flavonol and flavone intake estimates.

CONCLUSION

In this population, the application of USDA and PE source data yielded highly correlated intake estimates for total-flavonoids, flavanols, flavanones and anthocyanidins. For these sub-classes, the USDA and PE databases may be used interchangeably in epidemiological investigations. There was poorer correlation between intake estimates for flavonols and flavones due to differences in USDA and PE methodologies. Individual flavonoid compound groups that comprise flavonoid sub-classes had varying levels of agreement. As such, when determining the appropriate database to calculate flavonoid intake variables, it is important to consider methodologies underpinning database creation and which foods are important contributors to dietary intake in the population of interest.

Flavonoid intake and all-cause mortality

BACKGROUND

Flavonoids are bioactive compounds found in foods such as tea, chocolate, red wine, fruit, and vegetables. Higher intakes of specific flavonoids and flavonoid-rich foods have been linked to reduced mortality from specific vascular diseases and cancers. However, the importance of flavonoids in preventing all-cause mortality remains uncertain.

OBJECTIVE

The objective was to explore the association between flavonoid intake and risk of 5-y mortality from all causes by using 2 comprehensive food composition databases to assess flavonoid intake.

DESIGN

The study population included 1063 randomly selected women aged >75 y. All-cause, cancer, and cardiovascular mortalities were assessed over 5 y of follow-up through the Western Australia Data Linkage System. Two estimates of flavonoid intake (total flavonoidUSDA and total flavonoidPE) were determined by using food composition data from the USDA and the Phenol-Explorer (PE) databases, respectively.

RESULTS

During the 5-y follow-up period, 129 (12%) deaths were documented. Participants with high total flavonoid intake were at lower risk [multivariate-adjusted HR (95% CI)] of 5-y all-cause mortality than those with low total flavonoid consumption [total flavonoidUSDA: 0.37 (0.22, 0.58); total flavonoidPE: 0.36 (0.22, 0.60)]. Similar beneficial relations were observed for both cardiovascular disease mortality [total flavonoidUSDA: 0.34 (0.17, 0.69); flavonoidPE: 0.32 (0.16, 0.61)] and cancer mortality [total flavonoidUSDA: 0.25 (0.10, 0.62); flavonoidPE: 0.26 (0.11, 0.62)].

CONCLUSIONS

Using the most comprehensive flavonoid databases, we provide evidence that high consumption of flavonoids is associated with reduced risk of mortality in older women. The benefits of flavonoids may extend to the etiology of cancer and cardiovascular disease.

The effect of yoghurt and its probiotics on blood pressure and serum lipid profile; a randomised controlled trial

BACKGROUND AND AIMS

Despite strong mechanistic data, and promising results from in vitro and animal studies, the ability of probiotic bacteria to improve blood pressure and serum lipid concentrations in humans remains uncertain. The aim of this study was to determine the effect of Lactobacillus acidophilus La5 and Bifidobacterium animalis subsp lactis Bb12, provided in either yoghurt or capsule form, on home blood pressure and serum lipid profile.

METHODS AND RESULTS

Following a 3-week washout period, 156 overweight men and women over 55 y were randomized to a 6-week double-blinded, factorial, parallel study. The four intervention groups were: A) probiotic yoghurt plus probiotic capsules; B) probiotic yoghurt plus placebo capsules; C) control milk plus probiotic capsules; and D) control milk plus placebo capsules. Each probiotic test article provided a minimum L. acidophilus La5 and B. animalis subsp. lactis Bb12 dose of 3.0 × 10⁹ CFU/d. Home blood pressure monitoring, consisting of 7-day bi-daily repeat measurements, were collected at baseline and week 6. Fasting total cholesterol, low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), and serum triglyceride were performed at baseline and week 6. When compared to control milk, probiotic yoghurt did not significantly alter blood pressure, heart rate or serum lipid concentrations (P > 0.05). Similarly, when compared to placebo capsules, supplementation with probiotic capsules did not alter blood pressure or concentrations of total cholesterol LDLC, HDLC, or triglycerides (P > 0.05).

CONCLUSIONS

The probiotic strains L. acidophilus La5 and B. animalis subsp. lactis Bb12 did not improve cardiovascular risk factors.

Long-term proton pump inhibitor therapy and falls and fractures in elderly women: a prospective cohort study

Proton pump inhibitors (PPIs) are widely used in the elderly. Recent studies have suggested that long-term PPI therapy is associated with fractures in the elderly, however the mechanism remains unknown. We investigated the association between long-term PPI therapy ≥1 year and fracture risk factors including bone structure, falls, and balance-related function in a post hoc analysis of a longitudinal population-based prospective cohort of elderly postmenopausal women and replicated the findings in a second prospective study of falling in elderly postmenopausal women. Long-term PPI therapy was associated with increased risk of falls and fracture-related hospitalizations; adjusted odds ratio (AOR) 2.17; 95% CI, 1.25-3.77; p = 0.006 and 1.95; 95% CI, 1.20-3.16; p = 0.007, respectively. In the replication study, long-term PPI use was associated with an increased risk of self-reported falling; AOR, 1.51; 95% CI, 1.00-2.27; p = 0.049. No association of long-term PPI therapy with bone structure was observed; however, questionnaire-assessed falls-associated metrics such as limiting outdoor activity (p = 0.002) and indoor activity (p = 0.001) due to fear of falling, dizziness (p < 0.001) and numbness of feet (p = 0.017) and objective clinical measurement such as Timed Up and Go (p = 0.002) and Romberg eyes closed (p = 0.025) tests were all significantly impaired in long-term PPI users. Long-term PPI users were also more likely to have low vitamin B12 levels than non-users (50% versus 21%, p = 0.003). In conclusion, similar to previous studies, we identified an increased fracture risk in subjects on long-term PPI therapy. This increase in fracture risk in elderly women, already at high risk of fracture, appears to be mediated via increased falls risk and falling rather than impaired bone structure and should be carefully considered when prescribing long-term PPI therapy.

Associations of proanthocyanidin intake with renal function and clinical outcomes in elderly women

Background

Progression to chronic renal failure involves accelerated atherosclerosis and vascular calcification. Oxidative stress and endothelial dysfunction play a role in renal failure pathophysiology. In addition to improving vascular health and function, proanthocyanidins have been shown to exert renoprotective effects in animal models. Thus we hypothesize that proanthocyanidins may contribute to the maintenance of healthy renal function.

Objective

Determine the association of habitual proanthocyanidin intake with renal function and the risk of clinical renal outcomes in a population of elderly women.

Design

948 women aged over 75 y, free of prevalent renal disease at baseline, were randomly selected from ambulant Caucasian women. Proanthocyanidin consumption was determined using a validated food frequency questionnaire and the United States Department of Agriculture proanthocyanidin food content database. Fasting serum cystatin C and creatinine were assessed at baseline. Renal failure hospitalisations and deaths were assessed over 5 years of follow-up through the Western Australia Data Linkage System.

Results

Compared to participants with low consumption, participants in the highest tertile of proanthocyanidin intake had a 9% lower cystatin C concentration (P<0.001). High proanthocyanidin consumers were at 50% lower risk of moderate chronic kidney insufficiency, and 65% lower risk of experiencing a 5-year renal disease event (P<0.05). These relationships remained significant following adjustment for renal disease risk factors and diet-related potential confounders.

Conclusion

Increased consumption of proanthocyanidins was associated with better renal function and substantially reduced renal associated events, which has been supported by mechanistic and animal model data. Proanthocyanidin intake should be further examined as a dietary contributor to better renal health.

Association between yogurt, milk, and cheese consumption and common carotid artery intima-media thickness and cardiovascular disease risk factors in elderly women

BACKGROUND

Despite the contribution of dairy foods to total dietary saturated fat intake, available data indicate that dairy consumption may lower the risk of cardiovascular disease.

OBJECTIVE

The objective of this study was to investigate the relation between consumption of milk, cheese, and yogurt and common carotid artery intima-media thickness (CCA-IMT) in a cohort of elderly women.

DESIGN

Dairy consumption was assessed with a validated food-frequency questionnaire in 1080 participants randomly selected from ambulant white women aged >70 y living in Perth, Western Australia. CCA-IMT was assessed by using B-mode carotid ultrasound 3 y later. Cardiovascular disease risk factors, including serum lipids and blood pressure, were assessed at baseline.

RESULTS

Total dairy product, milk, and cheese consumption was not associated with CCA-IMT (P > 0.05), whereas yogurt consumption was negatively associated with CCA-IMT (unadjusted standardized β = -0.081, P = 0.008; baseline risk factor-adjusted standardized β = -0.075, P = 0.015). Participants who consumed >100 g yogurt/d had a significantly lower CCA-IMT than did participants with lower consumption (unadjusted = -0.024 mm, P = 0.002). This relation remained significant after adjustment for baseline, dietary, and lifestyle risk factors (multivariable analysis = -0.023 mm, P = 0.003).

CONCLUSION

Increased consumption of yogurt, but not of other dairy products, is associated with a lower CCA-IMT, independent of other risk factors.