Associations of birth weight, plasma metabolome in adulthood and risk of type 2 diabetes.

AIMS: We aimed to examine the longitudinal associations of birth weight with plasma metabolites in adulthood, and further quantify the proportions of the links between birth weight and incident adult type 2 diabetes (T2D) that were mediated by plasma metabolites. MATERIALS AND METHODS: A total of 62,033 participants with complete nuclear magnetic resonance metabolomics and birth weight data from the UK Biobank were included in this study. Linear regression was used to assess the associations between birth weight and metabolites. Cox regression was used to estimate hazard ratios for T2D associated with metabolites. We further performed mediation analyses to estimate the extent to which metabolites might mediate the association between birth weight and T2D risk. RESULTS: Low birth weight was associated with the adverse metabolic responses across multiple metabolic pathways, including lipoprotein subclasses, amino acids, fatty acids (FA), and inflammation. Metabolites associated with higher birth weight tended to be associated with a lower risk of T2D (Pearson correlation coefficient: -0.85). A total of 62 metabolites showed statistically significant mediation effects in the protective association of higher birth weight and T2D risk, including large-sized very low-density lipoprotein particles and triglyceride concentrations as well as saturated, and monounsaturated FA and glycoprotein acetyls. CONCLUSIONS: We identified a range of metabolites that reflect the adult metabolic response to birth weight, some of which might lie on the pathway between birth weight and adult T2D risk.

Effects of genetically proxied lipid-lowering drugs on acute myocardial infarction: a drug-target mendelian randomization study.

OBJECTIVE: High low-density-lipoprotein (LDL) cholesterol has been associated with an increased risk of coronary artery diseases (CAD) including acute myocardial infarction (AMI). However, whether lipids lowering drug treatment is causally associated with decreased risk of AMI remains largely unknown. We used Mendelian randomization (MR) to evaluate the influence of genetic variation affecting the function of lipid-lowering drug targets on AMI. METHODS: Single-nucleotide polymorphisms (SNPs) associated with lipids as instruments were extracted from the Global Lipids Genetics Consortium (GLGC). The genome-wide association study (GWAS) data for AMI were obtained from UK Biobank. Two sample MR analysis was used to study the associations between high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides (TG) with AMI (n = 3,927). Genetic variants associated with LDL cholesterol at or near drug target gene were used to mimic drug effects on the AMI events in drug target MR. RESULTS: Genetically predicted higher LDL-C (per one SD increase in LDL-C of 38.67 mg/dL, OR 1.006, 95% CI 1.004-1.007) and TG (per one SD increase in TG of 90.72 mg/dL, 1.004, 1.002-1.006) was associated with increased risk of AMI, but decreased risk for higher HDL-C (per one SD increase in HDL-C of 15.51 mg/dL, 0.997, 0.995-0.999) in univariable MR. Association remained significant for LDL-C, but attenuated toward the null for HDL-C and TG in multivariable MR. Genetically proxied lower LDL-C with genetic variants at or near the PCSK9 region (drug target of evolocumab) and NPC1L1 (drug target of ezetimibe) were associated with decreased risk of AMI (0.997, 0.994-0.999 and 0.986, 0.975-0.998, respectively), whereas genetic variants at HMGCR region (drug target of statin) showed marginal association with AMI (0.995, 0.990-1.000). After excluding drug target-related SNPs, LDL-C related SNPs outside the drug target region remained a causal effect on AMI (0.994, 0.993-0.996). CONCLUSIONS: The findings suggest that genetically predicted LDL-C may play a predominant role in the development of AMI. The drug MR results imply that ezetimibe and evolocumab may decrease the risk of AMI due to their LDL-C lowering effect, and there are other non-drug related lipid lowering pathways that may be causally linked to AMI.

Low-carbohydrate diets, low-fat diets, and mortality in middle-aged and older people: A prospective cohort study.

BACKGROUND: Short-term clinical trials have shown the effectiveness of low-carbohydrate diets (LCDs) and low-fat diets (LFDs) for weight loss and cardiovascular benefits. We aimed to study the long-term associations among LCDs, LFDs, and mortality among middle-aged and older people. METHODS: This study included 371,159 eligible participants aged 50-71 years. Overall, healthy and unhealthy LCD and LFD scores, as indicators of adherence to each dietary pattern, were calculated based on the energy intake of carbohydrates, fat, and protein and their subtypes. RESULTS: During a median follow-up of 23.5 years, 165,698 deaths were recorded. Participants in the highest quintiles of overall LCD scores and unhealthy LCD scores had significantly higher risks of total and cause-specific mortality (hazard ratios [HRs]: 1.12-1.18). Conversely, a healthy LCD was associated with marginally lower total mortality (HR: 0.95; 95% confidence interval: 0.94, 0.97). Moreover, the highest quintile of a healthy LFD was associated with significantly lower total mortality by 18%, cardiovascular mortality by 16%, and cancer mortality by 18%, respectively, versus the lowest. Notably, isocaloric replacement of 3% energy from saturated fat with other macronutrient subtypes was associated with significantly lower total and cause-specific mortality. For low-quality carbohydrates, mortality was significantly reduced after replacement with plant protein and unsaturated fat. CONCLUSIONS: Higher mortality was observed for overall LCD and unhealthy LCD, but slightly lower risks for healthy LCD. Our results support the importance of maintaining a healthy LFD with less saturated fat in preventing all-cause and cause-specific mortality among middle-aged and older people.

Leisure-Time Television Viewing and Computer Use, Family History, and Incidence of Dementia.

INTRODUCTION: Time spent on screen-based sedentary activities is significantly associated with dementia risk, however, whether the associations vary by family history (FHx) of dementia is currently unknown. We aimed to examine independent associations of two prevalent types of screen-based sedentary activities (television [TV] viewing and computer use) with dementia and assess the modifying effect of FHx. METHODS: We included 415,048 individuals free of dementia from the UK Biobank. Associations of TV viewing, computer use, and FHx with dementia risk were determined using Cox regression models. We estimated both multiplicative- and additive-scale interactions between TV viewing and computer use and FHx. RESULTS: During a median follow-up of 12.6 years, 5,549 participants developed dementia. After adjusting for potential confounding factors, we observed that moderate (2-3 h/day; hazard ratio [HR] 1.13, 95% confidence interval 0.03-1.23) and high (>3 h/day; 1.33, 1.21-1.46) TV viewing was associated with a higher dementia risk, compared with low (0-1 h/day) TV viewing. Using restricted cubic spline models, the relationship of TV viewing with dementia was nonlinear (relative to 0 h/day; p for nonlinear = 0.005). We found that >3 h/day of TV viewing was associated with a 42% (1.42, 1.18-1.71) higher dementia risk in participants with FHx while a 30% (1.30, 1.17-1.45) in those without FHx. For computer use, both low (0 h/day; 1.41, 1.33-1.50) and high (>2 h/day; 1.17, 1.05-1.29) computer use were associated with elevated dementia risk, compared with moderate (1-2 h/day) computer use. We observed a J-shaped relationship with dementia (relative to 2 h/day; p for nonlinear <0.001). Compared with 1-2 h/day of computer use, the HRs of dementia were 1.46 (1.29-1.65) and 1.10 (0.90-1.36) for 0 h/day and >2 h/day of computer use in participants with FHx, respectively, while the corresponding HRs were 1.40 (1.30-1.50) and 1.19 (1.06-1.33) in those without FHx. We observed a positive additive interaction (RERI 0.29, 0.06-0.53) between computer use and FHx, while little evidence of interaction between TV viewing and FHx. CONCLUSIONS: The time spent on TV viewing and computer use were independent risk factors for dementia, and the adverse effects of computer use and FHx were additive. Our findings point to new behavioral targets for intervention on preventing an early onset of dementia, especially for those with FHx.

The effects of blood pressure and antihypertensive drugs on heart failure: A Mendelian randomization study.

BACKGROUND AND AIMS: Heart failure (HF) is often triggered by hypertension and can benefit from antihypertensive treatment. We aimed to investigate whether pulse pressure (PP) could independently raise the risk of HF beyond systolic blood pressure (SBP) and diastolic blood pressure (DBP), as well as explore the potential mechanisms of antihypertensives in HF prevention. METHODS AND RESULTS: We generated genetic proxies for SBP, DBP, PP, and five drug classes based on a massive genome-wide association study. We applied two-sample Mendelian randomization (MR) using summary statistics derived from European individuals and conducted summary data-based MR (SMR) with gene expression data. In univariate analysis, PP showed an obvious association with HF risk (OR, 1.24 per 10 mm Hg increment; 95% CI, 1.16 to 1.32), which was largely attenuated in multivariable analysis when adjusted for SBP (0.89; 0.77 to 1.04). A significant decrease in HF risk was obtained with genetically proxied ß-blockers (equivalent to a 10 mm Hg reduction in SBP, 0.71; 0.62 to 0.82) and calcium channel blockers (0.71; 0.65 to 0.78), but not with genetically proxied angiotensin-converting enzyme inhibitors (0.69; 0.40 to 1.19) and thiazide diuretics (0.80; 0.47 to 1.37). Additionally, the enrichment of expression for the KCNH2 gene, a target gene of ß-blockers, in blood vessels and nerves was significantly associated with HF risk. CONCLUSION: Our findings suggest that PP may not be an independent risk factor for HF. ß-blockers and calcium channel blockers have a protective effect against HF, which at least partly depends on their blood pressure-lowering effect.

Effects of three medical nutrition therapies on nutritional metabolism and intestinal flora in overweight/obese with polycystic ovary syndrome (PCOS): Study protocol for a randomised controlled trial.

BACKGROUND AND OBJECTIVES: Observational studies have shown that energy restriction could be beneficial for controlling bodyweight in patients with polycystic ovary syndrome (PCOS). We aim to compare the effects of a high-protein diet (HPD), a high-protein and high-dietary fiber diet (HPHFD), and a calorie-restricted diet (CRD) on metabolic health and gut microbiota in overweight/obese PCOS patients. METHODS AND STUDY DESIGN: We will enroll a total of 90 overweight/obese PCOS patients into this eight-week open-label randomised controlled trial. Participants will be randomly assigned to three groups: CRD group (energy coefficient 20 kcal/kg.day, water ≥1500 mL, 0.8-1.2 g/kg protein, carbohydrate energize 55-60%, and fat energize 25-30%), HDP group (energy coefficient 20 kcal/kg.day, water ≥1500 mL, and 1.5-2.0 g/kg protein) and HPHFD group (based on the high protein diet with 15 g more dietary fiber supplement). The primary outcome is body weight, body fat percentage, and lean body mass. The secondary outcomes will include changes in blood lipids, inflammation, glucose tolerance, blood pressure, and gut microbiota compositions. Between-group differences in adiposity measurements at baseline will be compared using one-way analysis of variance (ANOVA) or Kruskal-Wallis test when appropriate. Within-group difference after 8-week intervention will be compared using paired t-test or Wilcoxon signed rank test. Between-group differences in adiposity measurements after 8-week diet intervention will be compared using linear mixed model and ANCOVA. The gut microbiota will be analyzed using 16S amplicon sequencing and the sequencing data will be analyzed using the standardized QIIME2 piperline.

Associations of reproductive risk score and joint exposure to ambient air pollutants with chronic obstructive pulmonary disease: a cohort study in UK Biobank.

BACKGROUND: Reproductive risk factors and air pollution for developing chronic obstructive pulmonary disease (COPD) have been documented separately. However, the combined effects of overall reproductive risk status on COPD and the extent to which this can be impacted by air pollution are unknown. The aim of this study was to construct a reproductive risk score (RRS) and an air pollution score (APS) and assess independent and joint associations between the two with incident COPD risk. METHODS: 78,027 female participants aged 40-69 years without baseline COPD from UK Biobank recruited between 2006 to 2010 were included in this study. RRS was constructed by 17 women's reproductive health-related items, and APS incorporating PM2.5, PM2.5-10, PM10, NO2, and NOx was calculated to assess the joint exposure level. The outcome of the incident COPD was identified through the in-patient hospital register. The associations of RRS and APS with COPD were examined by Cox proportional hazards regression. RESULTS: The risk of COPD reached its highest in the fourth quartile of the RRS (adjusted HR: 2.23, 95% CI: 1.76-2.82, P for trend < 0.001). A dose-response manner can also be observed between higher tertile APS with increased COPD risk and the highest risk was found in the third tertile of the APS (adjusted HR: 1.37, 95% CI: 1.19-1.58, P for trend < 0.001). The relative excess risk due to interaction (RERI) of 0.030 (95% CI: 0.012-0.048) showed additive interaction between RRS and APS on COPD was significant. In the joint analysis, the combinations of both higher RRS and APS signified higher incident COPD risk. CONCLUSION: High RRS and high APS were jointly associated with increased COPD risks in a dose-response pattern. Using comprehensive indicators to identify women's reproductive risk factors, together with the control of air pollution, is effective for COPD prevention.

Associations of polysocial risk score, lifestyle and genetic factors with incident type 2 diabetes: a prospective cohort study.

AIM/HYPOTHESIS: We aimed to investigate the association between polysocial risk score (PsRS), an estimator of individual-level exposure to cumulative social risks, and incident type 2 diabetes in the UK Biobank study. METHODS: This study includes 319,832 participants who were free of diabetes, cardiovascular disease and cancer at baseline in the UK Biobank study. The PsRS was calculated by counting the 12 social determinants of health from three social risk domains (namely socioeconomic status, psychosocial factors, and neighbourhood and living environment) that had a statistically significant association with incident type 2 diabetes after Bonferroni correction. A healthy lifestyle score was calculated using information on smoking status, alcohol intake, physical activity, diet quality and sleep quality. A genetic risk score was calculated using 403 SNPs that showed significant genome-wide associations with type 2 diabetes in people of European descent. The Cox proportional hazards model was used to analyse the association between the PsRS and incident type 2 diabetes. RESULTS: During a median follow-up period of 8.7 years, 4427 participants were diagnosed with type 2 diabetes. After adjustment for major confounders, an intermediate PsRS (4-6) and high PsRS (≥7) was associated with higher risks of developing type 2 diabetes with the HRs being 1.38 (95% CI 1.26, 1.52) and 2.02 (95% CI 1.83, 2.22), respectively, compared with those with a low PsRS (≤3). In addition, an intermediate to high PsRS accounted for approximately 34% (95% CI 29, 39) of new-onset type 2 diabetes cases. A healthy lifestyle slightly, but significantly, mitigated PsRS-related risks of type 2 diabetes (pinteraction=0.030). In addition, the additive interactions between PsRS and genetic predisposition led to 15% (95% CI 13, 17; p<0.001) of new-onset type 2 diabetes cases (pinteraction<0.001). CONCLUSIONS/INTERPRETATION: A higher PsRS was related to increased risks of type 2 diabetes. Adherence to a healthy lifestyle may attenuate elevated diabetes risks due to social vulnerability. Genetic susceptibility and disadvantaged social status may act synergistically, resulting in additional risks for type 2 diabetes.

Assessment of bidirectional relationships between 98 genera of the human gut microbiota and amyotrophic lateral sclerosis: a 2-sample Mendelian randomization study.

BACKGROUND: Growing evidence suggests a mutual interaction between gut microbiome alterations and ALS pathogenesis. However, previous studies were susceptible to potential confounding factors and reverse causation bias, likely leading to inconsistent and biased results. OBJECTIVES: To decipher the potentially mutual relationship between gut microbiota and ALS, we used a bidirectional two-sample MR approach to examine the associations between the gut microbiome and ALS. RESULTS: Using the inverse variance-weighted method, OTU10032 unclassified Enterobacteriaceae species-level OTU and unclassified Acidaminococcaceae were associated with a higher risk of ALS (per relative abundance: OR, 1.04; 95% CI, 1.01-1.07; P = 0.011 and OR, 1.02; 95% CI, 1.01-1.04; P = 0.009, respectively). Importantly, Gamma-Glu-Phe was showed potential deleterious effects on the risk of ALS (genetically predicted per a 1-standard deviation increase in the level of Gamma-Glu-Phe: OR, 1.96; 95% CI, 1.50-2.55; P = 0.012). Sensitivity analysis of the two candidate genera and metabolites using the MR-Egger and weighted-median methods produced similar estimates, and no horizontal pleiotropy or outliers were observed. Intriguingly, genetically predicted ALS was associated with an increase in the relative abundance of OTU4607_Sutterella (per 1-unit higher log odds: ß, 2.23; 95% CI, 1.27-3.18; P = 0.020) and Lactobacillales_ORDER (per 1-unit higher log odds: ß, 0.51; 95% CI, 0.09-0.94; P = 0.019). CONCLUSIONS: Our findings provide novel evidence supporting the bidirectional relationship between the gut microbiota and ALS. These results may contribute to designing microbiome- and microbiome-dependent metabolite interventions in future ALS clinical trials.

Shared genetic etiology and causality between body fat percentage and cardiovascular diseases: a large-scale genome-wide cross-trait analysis.

BACKGROUND: Accumulating evidences have suggested that high body fat percentage (BF%) often occurs in parallel with cardiovascular diseases (CVDs), implying a common etiology between them. However, the shared genetic etiology underlying BF% and CVDs remains unclear. METHODS: Using large-scale genome-wide association study (GWAS) data, we investigated shared genetics between BF% (N = 100,716) and 10 CVD-related traits (n = 6968-977,323) with linkage disequilibrium score regression, multi-trait analysis of GWAS, and transcriptome-wide association analysis, and evaluated causal associations using Mendelian randomization. RESULTS: We found strong positive genetic correlations between BF% and heart failure (HF) (Rg = 0.47, P = 1.27 × 10- 22) and coronary artery disease (CAD) (Rg = 0.22, P = 3.26 × 10- 07). We identified 5 loci and 32 gene-tissue pairs shared between BF% and HF, as well as 16 loci and 28 gene-tissue pairs shared between BF% and CAD. The loci were enriched in blood vessels and brain tissues, while the gene-tissue pairs were enriched in the nervous, cardiovascular, and exo-/endocrine system. In addition, we observed that BF% was causally related with a higher risk of HF (odds ratio 1.63 per 1-SD increase in BF%, P = 4.16 × 10-04) using a MR approach. CONCLUSIONS: Our findings suggest that BF% and CVDs have shared genetic etiology and targeted reduction of BF% may improve cardiovascular outcomes. This work advances our understanding of the genetic basis underlying co-morbid obesity and CVDs and opens up a new way for early prevention of CVDs.

Association of healthy lifestyle including a healthy sleep pattern with incident type 2 diabetes mellitus among individuals with hypertension.

BACKGROUND: Evidence is limited regarding the association of healthy lifestyle including sleep pattern with the risk of complicated type 2 diabetes mellitus (T2DM) among patients with hypertension. We aimed to investigate the associations of an overall healthy lifestyle including a healthy sleep pattern with subsequent development of T2DM among participants with hypertension compared to normotension, and to estimate how much of that risk could be prevented. METHODS: This study examined six lifestyle factors with T2DM cases among hypertension (227,966) and normotension (203,005) and their interaction in the UK Biobank. Low-risk lifestyle factors were defined as standard body mass index (BMI), drinking alcohol in moderation, nonsmoking, engaging in moderate- to vigorous-intensity physical activity, eating a high-quality diet, and maintaining a healthy sleep pattern. RESULTS: There were 12,403 incident T2DM cases during an average of 8.63 years of follow-up. Compared to those with 0 low-risk lifestyle factors, HRs for those with 5-6 were 0.14 (95% CI 0.10 to 0.19) for hypertensive participants, 0.13 (95% CI 0.08 to 0.19) for normotensive participants, respectively (ptrend < 0.001). 76.93% of hypertensive participants were considerably less likely to develop T2DM if they adhered to five healthy lifestyle practices, increased to 81.14% if they followed 6-factors (with a healthy sleep pattern). Compared with hypertension adults, normotensive people gain more benefits if they stick to six healthy lifestyles [Population attributable risk (PAR%) 83.66%, 95% CI 79.45 to 87.00%, p for interaction = 0.0011]. CONCLUSIONS: Adherence to a healthy lifestyle pattern including a healthy sleep pattern is associated with lower risk of T2DM in hypertensives, and this benefit is even further in normotensives.

Associations of toothbrushing behaviour with risks of vascular and nonvascular diseases in Chinese adults.

Accumulating evidence has shown that poor oral hygiene is associated with increased risk of cardiometabolic diseases in Western populations. However, its relevance about the relationships in Chinese adults remains unclear. The China Kadoorie Biobank enrolled 512 715 adults aged 30-79 years in China during 2004-2008. Cox regression was used to estimate adjusted hazard ratios (HRs) for each disease associated with measures of oral hygiene. Overall 9.3% of the participants reported rarely or never brushing teeth at baseline. Participants who rarely or never brushed teeth had adjusted HR of 1.12 (95% CI: 1.09, 1.15) for MVE, with similar HRs for stroke (1.08, 1.05-1.12), intracerebral haemorrhage (1.18, 1.11-1.26) and pulmonary heart disease (1.22, 1.13-1.32) compared with those who brushed teeth regularly. Those who did not brush teeth also had increased risk of cancer (1.09, 1.04-1.14), chronic obstructive pulmonary disease (COPD) (1.12, 1.05-1.20), liver cirrhosis (1.25, 1.09-1.44) and all-cause death (1.25, 1.21-1.28) but not type 2 diabetes (0.94, 0.86-1.03) and chronic kidney disease (0.98, 0.81-1.18). Among Chinese adults, we found that poor oral hygiene is associated with higher risks of major vascular disease, cancer, COPD, liver cirrhosis and all-cause deaths, but not type 2 diabetes and chronic kidney disease.

Difference in diet quality trends between children and adults in the United States: A serial cross-sectional study from 1999 to 2018.

BACKGROUND AND OBJECTIVES: Previous studies had shown that trends in diet quality between children and adults may vary but lack quantitative comparisons. We aimed to compare diet quality and its trends between US children and adults in this research. METHODS AND STUDY DESIGN: Children aged 2 to 18 and adults aged 19 to 59 years old in the US were enrolled the serial cross-sectional analysis of National Health and Nutrition Examination Survey (NHANES) cycles from 1999 to 2018. Diet quality was assessed using the Healthy Eating Index-2015 (HEI-2015), and trends were analyzed by joinpoint regression model. RESULTS: This study included 31988 children and 34317 adults. From 1999 to 2018, there was a trend-change among 5 children's components trends (including total fruits in 2011-2012, whole fruits in 2005-2006, greens and beans in 2013-2014, dairy in 2013-2014, and total protein foods in 2013-2014, p for joinpoint <0.05 for each) and overall trend in 2013-2014, whereas no significant trend-change in adults' trend. The trends of overall HEI-2015 between children (average annual percent change 0.3%; 95% CI: -0.1% to 0.8%) and adults (0.3%; 95%CI: 0.0% to 0.6%) showed no significant difference in parallelism (p for parallelism=0.60), but a significant difference in coincidence (intercept -7.7±3.7 among children; -2.3±2.5 among adults; p for coincidence <0.05). CONCLUSIONS: Children had a different trend with more trend-changes in diet quality compared with adults, and the diet quality of children was worse than that of adults during 1999-2018 in the US.

Assessment of causality between modifiable factors and heart failure: A Mendelian randomization analysis.

BACKGROUND AND OBJECTIVES: Observational studies have associated lifestyle, dietary, adiposity, biochemical and clinical measures with heart failure. Whether the associations are causal remains unclear. We aimed to determine the causal associations between modifiable risk factors and incidence or mortality of heart failure. METHODS AND STUDY DESIGN: Using single-nucleotide polymorphism (SNP) as genetic instruments, we conducted a two-sample Mendelian randomization (MR) analysis to estimate the causal effects of 27 modifiable risk factors on incident heart failure (2526 cases; 20926 participants) and mortality of heart failure (1798 deaths; 2828 patients). RESULTS: None of 27 modifiable risk factors were significantly associated with incidence or mortality of heart failure after the Bonferroni correction (p<0.0019). However, there was suggestive evidence for genetically predicted educational attainment (odds ratio [OR] per educational year increase: 0.57, 95% CI 0.33-0.99, p=0.049), circulating mono-unsaturated fatty acid concentrations (OR per 1-SD increase [ORSD] : 1.50, 1.10-2.04, p=0.011), C-reactive protein (CRP) (1.53, 1.04-2.25, p=0.031), high-density lipoprotein (HDL) (0.84, 0.72-0.99, p=0.036), triglycerides (1.24, 1.00-1.52, p=0.045), and systolic blood pressure (SBP) (1.06, 1.01-1.11, p=0.017) with incident heart failure. CONCLUSIONS: Our findings provide supporting evidence for prioritizing certain modifiable risk factors such as education, lipids, and blood pressure for primary prevention of heart failure, suggesting important clues for further mechanism research.

Associations between gut microbiota and Alzheimer's disease, major depressive disorder, and schizophrenia.

BACKGROUND: Growing evidence has shown that alterations in the gut microbiota composition were associated with a variety of neuropsychiatric conditions. However, whether such associations reflect causality remains unknown. We aimed to reveal the causal relationships among gut microbiota, metabolites, and neuropsychiatric disorders including Alzheimer's disease (AD), major depressive disorder (MDD), and schizophrenia (SCZ). METHODS: A two-sample bi-directional Mendelian randomization analysis was performed by using genetic variants from genome-wide association studies as instrumental variables for gut microbiota, metabolites, AD, MDD, and SCZ, respectively. RESULTS: We found suggestive associations of host-genetic-driven increase in Blautia (OR, 0.88; 95%CI, 0.79-0.99; P = 0.028) and elevated γ-aminobutyric acid (GABA) (0.96; 0.92-1.00; P = 0.034), a downstream product of Blautia-dependent arginine metabolism, with a lower risk of AD. Genetically increased Enterobacteriaceae family and Enterobacteriales order were potentially associated with a higher risk of SCZ (1.09; 1.00-1.18; P = 0.048), while Gammaproteobacteria class (0.90; 0.83-0.98; P = 0.011) was related to a lower risk for SCZ. Gut production of serotonin was potentially associated with an increased risk of SCZ (1.07; 1.00-1.15; P = 0.047). Furthermore, genetically increased Bacilli class was related to a higher risk of MDD (1.07; 1.02-1.12; P = 0.010). In the other direction, neuropsychiatric disorders altered gut microbiota composition. CONCLUSIONS: These data for the first time provide evidence of potential causal links between gut microbiome and AD, MDD, and SCZ. GABA and serotonin may play an important role in gut microbiota-host crosstalk in AD and SCZ, respectively. Further investigations in understanding the underlying mechanisms of associations between gut microbiota and AD, MDD, and SCZ are required.

Association of physical activity, sedentary behaviours and sleep duration with cardiovascular diseases and lipid profiles: a Mendelian randomization analysis.

BACKGROUND: Observational studies have shown that moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA), sedentary behaviours, and sleep duration were associated with cardiovascular diseases (CVDs) and lipid levels. However, whether such observations reflect causality remain largely unknown. We aimed to investigate the causal associations of physical activity, sedentary behaviours, and sleep duration with coronary artery disease (CAD), myocardial infarction (MI), stroke and lipid levels. METHODS: We conducted a Mendelian randomization (MR) study using genetic variants as instruments which are associated with physical activity, sedentary behaviours, and sleep duration to examine the causal effects on CVDs and lipid levels. This study included analyses of 4 potentially modifiable factors and 7 outcomes. Thus, the threshold of statistical significance is P = 1.8 × 10- 3 (0.05/4 × 7) after Bonferroni correction. RESULTS: In the present study, there was suggestive evidence for associations of genetically predicted VPA with CAD (odds ratio, 0.65; 95% confidence intervals, 0.47-0.90; P = 0.009) and MI (0.74; 0.59-0.93; P = 0.010). However, genetically predicted VPA, MVPA, sleep duration and sedentary behaviours did not show significant associations with stroke and any lipid levels. CONCLUSIONS: Our findings from the MR approach provided suggestive evidence that vigorous exercise decreased risk of CAD and MI, but not stroke. However, there was no evidence to support causal associations of MVPA,sleep duration or sedentary behaviours with cardiovascular risk and lipid levels. TRANSLATIONAL PERSPECTIVE: The findings of this study did not point out specific recommendations on increasing physical activity required to deliver significant health benefits. Nevertheless, the findings allowed clinicians and public health practitioners to provide advice about increasing the total amount of excising time by demonstrating that such advice can be effective. Reliable assessment of the association of physical activity levels with different subtypes of CVDs is needed to provide the basis for a comprehensive clinical approach on CVDs prevention, which can be achieved through lifestyle interventions in addition to drug therapy.

Frequency of Adding Salt to Foods, Genetic Susceptibility, and Incident Type 2 Diabetes: A Prospective Cohort Study.

CONTEXT: Excessive salt consumption is known to increase the risk of hypertension and cardiovascular disease, but the association between salt intake and incident type 2 diabetes has not been extensively researched. OBJECTIVE: In this study, we aimed to investigate the relationships between the frequency of adding salt to foods and incident type 2 diabetes, as well as any potential interactions with genetic predisposition. METHODS: We included 368 137 eligible participants, aged 37 to 73 years, from the UK Biobank. The frequency of adding salt to foods was assessed via a food frequency questionnaire. RESULTS: During a median follow-up of 12.6 years, we documented 10 981 incident type 2 diabetes cases. After adjustment for major confounders, participants who sometimes, usually, and always added salt to foods had 7% (hazard ratio [HR]: 1.07; 95% CI, 1.03-1.12), 9% (HR: 1.09; 95% CI, 1.03-1.16), 28% (HR: 1.28; 95% CI, 1.19-1.38) higher risks of developing type 2 diabetes, respectively, than those that never/rarely added salt to foods (P for trend < .001). We found these associations to be consistent across stratified and sensitivity analyses. However, we did not observe any statistically significant multiplicative or additive interactions between the frequency of adding salt to foods and genetic predisposition regarding incident type 2 diabetes. CONCLUSION: Our findings suggest that consuming salt regularly, regardless of genetic susceptibility, may increase the risk of type 2 diabetes. Therefore, public health interventions aimed at reducing excessive salt consumption may help prevent the onset of type 2 diabetes.

Sleep patterns, genetic predisposition, and risk of chronic liver disease: A prospective study of 408,560 UK Biobank participants.

BACKGROUND: Little is known about the role that combined sleep behaviors play in the association with chronic liver disease (CLD) risk. METHODS: We included 408,560 participants initially free of CLD from the UK Biobank. A healthy sleep pattern was defined by early chronotype, sleep duration of 7-8 h/day, no insomnia, no snoring, and no excessive daytime sleepiness. Cox regression models were used to examine the association of healthy sleep pattern with incident CLD and their interaction with PNPLA3 genetic risk. RESULTS: During a median 12.5 years of follow-up, we documented 10,915 incident all-cause CLD cases, including 388 viral hepatitis, 4782 non-alcoholic fatty liver disease (NAFLD), 1356 cirrhosis, 973 alcoholic liver disease, and 725 liver cancer cases. Compared to participants with a healthy sleep score of 0-1, the hazard ratio (HR) (95 % confidence interval [CI]) for those with a sleep score of 5 was 0.54 (0.49, 0.60) for CLD, 0.52 (0.30, 0.90) for viral hepatitis, 0.47 (0.41, 0.55) for NAFLD, 0.57 (0.43, 0.75) for cirrhosis, 0.32 (0.23, 0.44) for alcoholic liver disease, and 0.53 (0.37, 0.77) for liver cancer. Healthy sleep pattern and PNPLA3 genetic risk exerted significant additive effects on CLD risk (relative excess risk due to the interaction: 0.05; attributable proportion due to the interaction: 13 %). LIMITATIONS: Measurement error was unavoidable for self-reported data on sleep behaviors. CONCLUSIONS: Our analyses provide evidence that healthy sleep pattern was inversely associated with the development of CLD, and participants with higher genetic risk were more likely to develop CLD when exposed to the unhealthy sleep pattern.

Fetal/maternal-determined birth weight and adulthood type 2 diabetes and its subtypes: a Mendelian randomization study.

BACKGROUND: Lower birth weight (BW) might increase the risk of adulthood type 2 diabetes, but its associations with the highly heterogeneous type 2 diabetes subtypes remain to be studied. In addition, whether the associations between lower BW and adulthood type 2 diabetes risks depend on fetal or maternal effect is largely unknown. METHODS: In this study, we performed a two-sample Mendelian Randomization analysis to study the associations between overall, fetal-determined, and maternal-determined BW and the risks of type 2 diabetes and its subtypes, namely mild age-related diabetes (MARD), mild obesity-related diabetes (MOD), severe insulin-deficient diabetes (SIDD), and severe insulin-resistant diabetes (SIRD). RESULTS: Lower BW was genetically associated with increased risks of type 2 diabetes (odds ratio (OR): 1.86; 95% confidence interval (CI): 1.53, 2.26), MARD (OR: 2.15; 95%CI: 1.43, 3.23), MOD (OR: 1.75; 95%CI: 1.10, 2.77), SIDD (OR: 1.86; 95%CI: 1.11, 3.10), and SIRD (OR: 1.66; 95%CI: 1.06, 2.60). When examining the fetal-determined genetic effects independently, lower BW remained associated with type 2 diabetes and its subtypes, except for MOD. Using maternal-determined BW-lowering genotypes to proxy for an adverse intrauterine environment provided no evidence that it raised offspring risks of type 2 diabetes. CONCLUSIONS: Fetal-determined but not maternal-determined lower BW were associated with increased risks of adulthood type 2 diabetes and its subtypes. Our results underscored the importance of early targeted management among people with a low BW in the prevention of type 2 diabetes.

Causal Associations of Cognitive Reserve and Hierarchical Aging-Related Outcomes: A Two-Sample Mendelian Randomization Study.

PURPOSE: Two-sample Mendelian randomization methods were used to explore the causal effects of cognitive reserve proxies, such as educational attainment, occupational attainment, and physical activity (PA), on biological (leukocyte telomere length), phenotypic (sarcopenia-related features), and functional (frailty index and cognitive performance) aging levels. RESULTS: Educational attainment had a potential protective effect on the telomere length (ß = 0.10, 95% CI: 0.08-0.11), sarcopenia-related features (ß = 0.04-0.24, 95% CI: 0.02-0.27), frailty risk (ß = -0.31, 95% CI: -0.33 to -0.28), cognitive performance (ß = 0.77, 95% CI: 0.75-0.80). Occupational attainment was causally related with sarcopenia-related features (ß = 0.07-0.10, 95% CI: 0.05-0.14), and cognitive performance (ß = 0.30, 95% CI: 0.24-0.36). Device-measured PA was potentially associated with one sarcopenia-related feature (ß = 0.14, 95% CI: 0.03-0.25). CONCLUSIONS: Our findings support the potential causality of educational attainment on biological, phenotypic, and functional aging outcomes, of occupational attainment on phenotypic and functional aging-related outcomes, and of PA on phenotypic aging-related outcomes.