Helicobacter pylori colonization and obesity - a Mendelian randomization study

Bidirectional Mendelian randomization to explore the causal relationships between the gut microbiota and male reproductive diseases

Gut bacteria might play an important role in male reproductive disorders, such as male infertility and sperm abnormalities; however, their causal role is unclear. Herein, Mendelian randomization (MR)-Egger, weighted median, inverse variance weighting, Simple mode, and Weighted mode were used to test the causal relationship between gut microbes and male reproductive diseases. The MR results were validated using various metrics. The MR results were also consolidated using reverse causality speculation, conducted using two-way MR analysis and Steiger filtering. Biological function was analysed using enrichment analyses. The results suggested that eight intestinal microflorae were causally associated with male infertility. The Eubacterium oxidoreducens group was associated with an increased risk of male infertility, while the family Bacteroidaceae was negatively associated with male reproductive diseases. Eight intestinal microflorae were causally associated with abnormal spermatozoa. The family Streptococcaceae was associated with a high risk of abnormal spermatozoa, whereas the family Porphyromonadaceae was associated with a low risk of abnormal spermatozoa. No pleiotropy was observed, this study identified a high correlation between the gut flora and the likelihood of male reproductive diseases. Future research will attempt to advance microbial-focused treatments for such diseases.

Obesity, abdominal obesity, metabolic obesity phenotypes, and Helicobacter pylori infection: results from NHANES 1999-2000

BACKGROUND

Recent studies on the association between Helicobacter pylori (H. pylori) infection and obesity have reported conflicting results. Therefore, the purpose of our study was to investigate the association of obesity, abdominal obesity, and metabolic obesity phenotypes with H. pylori infection.

METHODS

A cross-sectional study of 1568 participants aged 20 to 85 was conducted using the National Health and Nutrition Examination Survey (NHANES) cycle 1999-2000. Logistic regression models were employed to evaluate the association of general obesity as defined by body mass index (BMI), abdominal obesity as defined by waist circumference (WC) and waist-height ratio (WHtR), and metabolic obesity phenotypes with H. pylori seropositivity. Subgroup analyses stratified by age were conducted to explore age-specific differences in this association.

RESULTS

After grouping individuals according to their WHtR, the prevalence rate of WHtR ≥ 0.5 in H. pylori-seropositive participants was significantly higher than that in H. pylori-seronegative participants (79.75 vs. 68.39, P < 0.001). The prevalence of H. pylori seropositivity in non-abdominal obesity and abdominal obesity defined by WHtR was 24.97% and 31.80%, respectively (P < 0.001). In the subgroup analysis, the adjusted association between abdominal obesity, as defined by the WHtR, and H. pylori seropositivity was significant in subjects aged < 50 years (OR = 2.23; 95% CI, 1.24-4.01; P = 0.01) but not in subjects aged ≥ 50 years (OR = 0.84; 95% CI, 0.35-1.99; P = 0.66). Subjects older than 50 years old had an OR (95% CI) for metabolically healthy obesity of 0.04 (0.01-0.35) compared with the control group. H. pylori seropositivity was consistently not associated with obesity as defined by BMI.

CONCLUSIONS

Abdominal obesity, as defined by the WHtR, was associated with H. pylori infection in subjects aged ≤ 50 years.

The potential bidirectional association between Helicobacter pylori infection and gallstone disease in adults: A two-cohort study

BACKGROUND

Previous studies have suggested that Helicobacter pylori (H. pylori) may act as a precipitating factor in gallstone formation, and the potential association between H. pylori infection and gallstone disease (GD) is still unclear and controversial. This study aimed to clarify the potential bidirectional relationship between H. pylori infection and GD.

METHODS

This retrospective cohort study was performed in a population that underwent health checkups at the hospital between 2013 and 2018. H. pylori infection status was evaluated by urea breath test (UBT), and GD was diagnosed via ultrasound. Cox regression and propensity score matching (PSM) were used.

RESULTS

Among 1011 participants without H. pylori infection at baseline, 134 participants were infected with H. pylori. Among 1192 participants without gallstones or cholecystectomy at baseline, 60 participants developed gallstones or cholecystectomy. The hazard ratio (HR) (95% CI) for incident H. pylori infection comparing the GD versus the no GD group was 1.84 (1.19, 2.85). The age- and sex-adjusted HR (95% CI) for incident GD comparing H. pylori-positive subjects to H. pylori-negative subjects was 1.74 (1.01, 2.98). Consistent results were also found with PSM and multivariate analysis.

CONCLUSIONS

This cohort study demonstrated a potential bidirectional association between H. pylori infection and GD, which provides a basis for indicating the risk of GD and implementing the clinical strategies for GD. For the prevention and treatment of GD, H. pylori infection should be carefully considered and evaluated.

Microbiome Dysbiosis: A Pathological Mechanism at the Intersection of Obesity and Glaucoma

The rate at which obesity is becoming an epidemic in many countries is alarming. Obese individuals have a high risk of developing elevated intraocular pressure and glaucoma. Additionally, glaucoma is a disease of epidemic proportions. It is characterized by neurodegeneration and neuroinflammation with optic neuropathy and the death of retinal ganglion cells (RGC). On the other hand, there is growing interest in microbiome dysbiosis, particularly in the gut, which has been widely acknowledged to play a prominent role in the etiology of metabolic illnesses such as obesity. Recently, studies have begun to highlight the fact that microbiome dysbiosis could play a critical role in the onset and progression of several neurodegenerative diseases, as well as in the development and progression of several ocular disorders. In obese individuals, gut microbiome dysbiosis can induce endotoxemia and systemic inflammation by causing intestinal barrier malfunction. As a result, bacteria and their metabolites could be delivered via the bloodstream or mesenteric lymphatic vessels to ocular regions at the level of the retina and optic nerve, causing tissue degeneration and neuroinflammation. Nowadays, there is preliminary evidence for the existence of brain and intraocular microbiomes. The altered microbiome of the gut could perturb the resident brain-ocular microbiome ecosystem which, in turn, could exacerbate the local inflammation. All these processes, finally, could lead to the death of RGC and neurodegeneration. The purpose of this literature review is to explore the recent evidence on the role of gut microbiome dysbiosis and related inflammation as common mechanisms underlying obesity and glaucoma.

Body mass index is associated with Helicobacter pylori infection and increased oxidative DNA damage in an obese population

Objective

To determine the prevalence of Helicobacter pylori infection in a Saudi Arabian population and its association with the body mass index (BMI) and serum 8-hydroxy deoxyguanine (8-OHdG) levels as biomarker for oxidative stress.

Methods

This cross-sectional study enrolled patients that had experienced epigastric discomfort or dyspepsia for > 1 month and had undergone diagnostic upper endoscopy. Patients with a body mass index (BMI) ≥30 kg/m² were defined as obese. The presence of anti-H. pylori antibodies was confirmed using an H. pylori immunoglobulin G (IgG) antibody enzyme-linked immunosorbent assay. The levels of 8-OHdG were measured using a competitive inhibition enzyme immunoassay.

Results

A total of 298 patients were enrolled in the study. Of these, 186 (62.4%) patients were H. pylori-positive and 112 (37.6%) patients were H. pylori-negative. The mean ± SD age of the overall study cohort was 47.17 ± 9.27 years. The H. pylori-positive patients had significantly higher levels of H. pylori IgG antibodies than H. pylori-negative patients. H. pylori prevalence linearly correlated with BMI quantile. The 8-OHdG levels were strongly associated with the BMI of the patients in the H. pylori-positive group.

Conclusion

Obese individuals exhibited higher H. pylori prevalence than individuals with a lean BMI (BMI < 25.00 kg/m²).

Association between Helicobacter pylori infection and serum thyroid stimulating hormone in the National Health and Nutrition Examination Survey 1999-2000

OBJECTIVE

Current evidence on the associations between plasma thyroid stimulating hormone and Helicobacter pylori infection is conflicting. Therefore, our study aimed to examine TSH in relation to H. pylori infection.

METHODS

Based on the US National Health and Nutrition Examination Survey (NHANES) 1999-2000, a cross-sectional study was conducted with 948 participants aged 30 to 85 years. The associations between H. pylori seropositivity and TSH were evaluated using binary logistic regression models. A subgroup analysis stratified by sex, age, and body mass index was conducted.

RESULTS

A higher serum TSH level was found in subjects with H. pylori seropositive than in subjects with H. pylori seronegative. A significant positive association was found between H. pylori seropositivity and TSH with increasing quartiles of hormonal levels in univariate regression models (Q4 vs Q1: OR = 1.659; 95% CI, 1.152-2.389) and in multivariate regression models (Q4 vs Q1: OR = 1.604; 95% CI, 1.087-2.367). In stratified analyses, the adjusted association of serum TSH with H. pylori seropositivity was statistically significant in male (Q4 vs Q1: OR = 1.894; 95% CI, 1.109-3.235), normal BMI (Q4 vs Q1: OR = 1.894; 95% CI, 1.109-3.235), overweight (Q4 vs Q1: OR = 2.124; 95% CI, 1.047-4.308);, obese (Q4 vs Q1: OR = 0.429; 95% CI, 0.220-0.837), and age over 60 years (Q4 vs Q1: OR = 1.999; 95% CI, 1.118-3.575).

CONCLUSION

High TSH levels were associated with H. pylori infection, especially among male, overweight and elderly adults.

The association between Helicobacter pylori and obesity: a systematic review and meta-analysis of case-control studies

INTRODUCTION

The relationship between H. pylori infection and obesity development has remained controversial among various studies. The aim of this study was to clarify the pooled effect of H. pylori infection on the development of obesity and vice versa.

METHODS

We searched international databases including Medline (PubMed), Web of sciences, Scopus, EMBASE, Cochrane, Ovid, and CINHAL to retrieve all case-control studies reporting the effect of H. pylori on obesity and vice versa, which had been published in English between January 1990 and June 2019. The quality of included studies was assessed by the Modified Newcastle-Ottawa Scale for Case-Control studies. The logarithm of the odds ratio (OR) and its standard error was used for the meta-analysis.

RESULTS

Eight case-control studies with 25,519 participants were included for qualitative and quantitative analyses. The pooled analysis showed that obese participants had a higher risk of H. pylori infection than lean participants with an odds ratio of 1.46 (95%CI: 1.26, 1.68). Also, the pooled analysis revealed that participants infected by H. pylori had a higher risk of obesity than non-infected participants with an odds ratio of 1.01 (95%CI: 1.01, 1.02).

CONCLUSION

The results of this meta-analysis showed that there was a positive correlation between the risk of H. pylori infection and the prevalence of obesity development. Thus, H. pylori positive patients were more likely to be obese, and obese individuals had higher risks of H. pylori infection.

Evaluation of Helicobacter pylori Genotypes in Obese Patients with Gastric Ulcer, Duodenal Ulcer, and Gastric Cancer: An Observational Study

INTRODUCTION

Obesity is a well-known risk factor for a variety of gastrointestinal disorders (GID). Helicobacter pylori is associated with different GID, such as gastric cancer and chronic gastritis. In this study, we investigated the prevalence of dominant genotypes in H. pylori isolated from obese patients diagnosed with gastric ulcer, duodenal ulcer, and gastric cancer.

METHODS

A total of 222 H. pylori-positive samples were collected from patients with obesity. GID and gastric cancer were identified by endoscopy and histopathology, respectively. Three biopsy specimens from the gastric antrum were obtained from each patient for culture tests, histological examination, and identification of vacuolating cytotoxin A (vacA) (vacA s1, vacA s2, vacA m1, vacA m2, vacA s1m1 vacA s1m2, vacA s2m1, and vacA s2m2), cagA, cagE, iceA1, oipA, dupA, and babA2 using polymerase chain reaction.

RESULTS

vacA, cagE, cagA, iceA1, oipA, dupA, and babA2 genes were detected in 222 (100%), 171 (77%), 161 (72.5%), 77 (34.6%), 77 (34.6%), 137 (61%), and 69 (31%) patients with obesity, respectively. Our findings revealed that vacA, iceA1, oipA, and babA2 were significantly associated with a higher risk of GID, while cagE, cagA, and dupA indicated no correlation with the development of GID. Also, in the combination of s- and m-region genotypes, s1m2 (79%) was the most frequently identified genotype in patients with obesity. A significant association was also found between cagA and the presence of vacA genotypes (except for vacA m1 and babA2).

CONCLUSIONS

This study indicated the high prevalence of different virulence genes in H. pylori isolated from obese patients and supported the significant role of H. pylori in the development of GID.

Gut Microbiota: The Missing Link Between Helicobacter pylori Infection and Metabolic Disorders?

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. Although the majority of infected individuals remain asymptomatic, this bacterium colonizes the gastric mucosa causing the development of various clinical conditions as peptic ulcers, chronic gastritis and gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas, but complications are not limited to gastric ones. Extradigestive pathologies, including metabolic disturbances such as diabetes, obesity and nonalcoholic fatty liver disease, have also been associated with H. pylori infection. However, the underlying mechanisms connecting H. pylori with extragastric metabolic diseases needs to be clarified. Notably, the latest studies on the topic have confirmed that H. pylori infection modulates gut microbiota in humans. Damage in the gut bacterial community (dysbiosis) has been widely related to metabolic dysregulation by affecting adiposity, host energy balance, carbohydrate metabolism, and hormonal modulation, among others. Taking into account that Type 2 diabetic patients are more prone to be H. pylori positive, gut microbiota emerges as putative key factor responsible for this interaction. In this regard, the therapy of choice for H. pylori eradication, based on proton pump inhibitor combined with two or more antibiotics, also alters gut microbiota composition, but consequences on metabolic health of the patients has been scarcely explored. Recent studies from our group showed that, despite decreasing gut bacterial diversity, conventional H. pylori eradication therapy is related to positive changes in glucose and lipid profiles. The mechanistic insights explaining these effects should also be addressed in future research. This review will deal with the role of gut microbiota as the linking factor between H. pylori infection and metabolic diseases, and discussed the impact that gut bacterial modulation by H. pylori eradication treatment can also have in host's metabolism. For this purpose, new evidence from the latest human studies published in more recent years will be analyzed.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

The association between Helicobacter pylori infection with overweight/obesity: A protocol for a systematic review and meta-analysis of observational studies

BACKGROUND

Obesity has become a serious public health issue. The role of Helicobacter pylori (H. pylori) infection in overweight or obesity is inconsistent and controversial. It is very necessary to conduct a systematic review and meta-analysis for determining whether H. pylori infection was associated with risk of overweight/obesity.

METHODS

Four databases (PubMed, Web of Science, The Cochrane Library, and EMBASE) will be searched from the inception to January 15, 2019. All observational studies (including cross-sectional, case-control or longitudinal studies) reporting the association between H. pylori infection and overweight/obesity will be included. The primary outcome was the presence and incidence of overweight/obesity in conjunction with H. pylori infection. Study selection, data extraction, and assessment of quality will be conducted independently by 2 reviewers. RevMan 5.3 and STATA 14.0 software will be used for data synthesis.

RESULTS

The results of this study will provide a better understanding of the role of H. pylori infection in overweight/obesity among overall population.

CONCLUSION

This systematic review and meta-analysis will generate evidence of the association between H. pylori infection and overweight/obesity, and the findings of this study will be published in a peer-reviewed journal.PROSPERO registration number: CRD42019121939.

Helicobacter pylori in relation to asthma and allergy modified by abdominal obesity: The HUNT study in Norway

Objective

It is unknown whether the decreasing prevalence of H. pylori infections is associated with the increase in obesity and asthma and allergy. In this study, we assessed if obesity plays an intermediate role between H. pylori infections and allergy.

Design

A population-based, nested case-control study of 10,005 participants within the second Nord-Trøndelag Health Study (HUNT2), Norway, was performed in 1995-1997. The presence of H. pylori was tested by an enzyme immunoassay Pyloriset EIA-IgG, and weight, height, and waist circumference were measured. Body mass index (BMI) and waist circumference were used as measures of general and abdominal obesity, respectively. Self-reported asthma and allergic diseases were collected through questionnaires. The odds ratios of H. pylori relative to asthma and allergic diseases were estimated by logistic regression models stratified by waist circumference categories.

Results

H. pylori infection was present in 31%, ever asthma was reported in 10.4% and allergic rhinitis in 16.2%. The mean BMI was 26.4 ​kg/m² and the mean waist circumference was 86.6 ​cm. H. pylori infection was neither associated with asthma nor allergic diseases. However, when stratified by waist circumference, H. pylori infection was associated with 30-40% reduced odds of asthma and 25% reduced odds of allergic diseases in individuals with abdominal obesity (waist circumference ≥86 ​cm in women and ≥96 ​cm in men).

Conclusion

H. pylori infection is associated with reduced risk of asthma and allergy in individuals with abdominal obesity, suggesting a possible causal pathway from reduced H. pylori infections through obesity to increased risk of asthma and allergy.

First-line Helicobacter pylori eradication rates are significantly lower in patients with than those without type 2 diabetes mellitus

Purpose: To assess the difference of the first-line therapy for Helicobacter pylori in patients with or without type 2 diabetes (DM) and to investigate the clinical factors influencing treatment outcomes. Patients and methods: In total, 719 patients with H. pylori infection were treated with 7-day standard first-line triple therapy, of whom 182 did and 537 did not have DM. Propensity score matched at a 1:2 ratio - for age, sex and body mass index was performed for the two groups, yielding a DM group with 147 patients and a non-DM group with 249 matched controls for analysis. Urea breath test was performed 6-8 weeks after treatment. Clinical and laboratory parameters were collected for identifying factors associated with failed eradication. Results: H. Pylori was eradicated in 74.1% (95% confidence interval [CI] =66.2-81.0) of the DM group and 85.3% (95% CI =80.8-89.4) of the non-DM group (p=0.005). Of 51 gastric biopsy samples cultured for H. pylori, 41 were positive. In the DM group, the rates of resistance to amoxicillin, clarithromycin, levofloxacin, and tetracycline were 0%, 50.0%, 50.0% and 0%, respectively. In the non-DM group, the comparable proportions were 2.9%, 17.1%, 22.9%, and 0%, respectively. Univariate analysis revealed that DM (Odds ratio [OR], 1.771, 95% CI, 1.167-2.668, p=0.006), clarithromycin resistance (OR, 15.273; 95% CI, 1.687-138.269; p=0.015), and amoxicillin resistance (OR, 4.672; 95% CI, 2.431-8.979; p<0.001) were independently associated with failure to eradicate H. pylori. Multivariate analysis showed that clarithromycin resistance was the major factor independently associated with failure of eradication (OR, 25.472; 95% CI, 1.549-418.956; p=0.023). Conclusions: First-line H. pylori eradication rates in patients with DM were significantly lower than in those without DM, although neither group achieved >90% eradication.

The Influences of Visceral Fat Area on the Sites of Esophageal Mucosal Breaks in Subjects with Gastroesophageal Reflux Diseases

Background

Central obesity is suggested as a risk factor for gastroesophageal reflux diseases. The aim of this study was to evaluate the influences of a visceral fat area on the site of mucosal breaks in the esophagogastric junction (EGJ).

Methods

Subjects who underwent abdomen-computerized tomography and esophagogastroduodenoscopy for screening on the same day were evaluated between 2007 and 2016. We enrolled 178 subjects who had erosive esophagitis (LA classifications A-D). Abdominal obesity was evaluated by measuring visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), VAT-to-SAT ratio, total adipose tissue (TAT), body mass index (BMI), and waist circumference (WC).

Results

The lesser curvature (LC) of EGJ was the most frequent site of mucosal breaks (104 cases, 58.4%). BMI, WC, VAT, the VAT-to-SAT ratio, and TAT were higher in the LC group. In multivariate analysis, higher VAT (odds ratio (OR) 2.90, 95% confidence interval (CI) 1.18 to 7.13, 3rd vs. 1st quartile, P = 0.021; OR 3.63, 95% CI 1.44 to 9.10, 4th vs. 1st quartile, P = 0.006) and the VAT/SAT ratio (OR 2.91, 95% CI 1.11 to 7.61, 3rd vs. 1st quartile, P = 0.03; OR 3.02, 95% CI 1.17 to 7.83, 4th vs. 1st quartile, P = 0.023) were significantly associated with mucosal breaks in the LC group. However, BMI, WC, and TAT were not significant in the multivariate analysis.

Conclusion

The VAT and the VAT/SAT ratio were significantly associated with the mucosal breaks in the LC of EGJ. Visceral obesity could influence the location of the mucosal breaks on EGJ.