Causal roles of circulating adiponectin in osteoporosis and cancers

Metabolic dysfunction-associated fatty liver disease and osteoporosis: the mechanisms and roles of adiposity

Nonalcoholic fatty liver disease (NAFLD) has recently been renamed metabolic dysfunction-associated fatty liver disease (MAFLD) by international consensus. Both MAFLD and osteoporosis are highly prevalent metabolic diseases. Recent evidence indicates that NAFLD increases the risk of low bone mineral density and osteoporosis, likely mediated by obesity. NAFLD has a close association with obesity and other metabolic disorders. Although obesity was previously thought to protect against bone loss, it now heightens osteoporotic fracture risk. This overview summarizes current clinical correlations between obesity, NAFLD, and osteoporosis, with a focus on recent insights into potential mechanisms interconnecting these three conditions. This study reviewed the scientific literature on the relationship between obesity, nonalcoholic fatty liver disease, and osteoporosis as well as the scientific literature that reveals the underlying pathophysiologic mechanisms between the three. Emerging evidence suggests obesity plays a key role in mediating the relationship between NAFLD and osteoporosis. Accumulating laboratory evidence supports plausible pathophysiological links between obesity, NAFLD, and osteoporosis, including inflammatory pathways, insulin resistance, gut microbiota dysbiosis, bone marrow adiposity, and alterations in insulin-like growth factor-1 signaling. Adiposity has important associations with NAFLD and osteoporosis, the underlying pathophysiologic mechanisms between the three may provide new therapeutic targets for this complex patient population.

An atlas on risk factors for gastrointestinal cancers: A systematic review of Mendelian randomization studies

OBJECTIVE

Gastrointestinal cancers are one of the most frequent cancer types and seriously threaten human life and health. Recent studies attribute the occurrence of gastrointestinal cancers to both genetic and environmental factors, yet the intrinsic etiology remains unclear. Mendelian randomization is a powerful well-established statistical method that is based on genome-wide association study (GWAS) to evaluate the causal relationship between exposures and outcomes. In the present study, we aimed to conduct a systematic review of Mendelian randomization studies investigating any causal risk factors for gastrointestinal cancers.

METHODS

We systematically searched Mendelian randomization studies that addressed the associations of genetically predicted exposures with five main gastrointestinal cancers from September 2014 to March 2024, as well as testing the research quality and validity.

RESULTS

Our findings suggested robust and consistent causal effects of body mass index (BMI), basal metabolic rate, fatty acids, total cholesterol, total bilirubin, insulin like growth factor-1, eosinophil counts, interleukin 2, alcohol consumption, coffee consumption, apolipoprotein B on colorectal cancer risks, BMI, waist circumference, low-density lipoprotein (LDL), total testosterone, smoking on gastric cancer risks, BMI, fasting insulin, LDL, waist circumference, visceral adipose tissue (VAT), immune cells, type 2 diabetes mellitus (T2DM) on pancreatic cancer risks, waist circumference, smoking, T2DM on esophageal adenocarcinoma risks, and VAT, ferritin, transferrin, alcohol consumption, hepatitis B virus infection, rheumatoid arthritis on liver cancer risks, respectively.

CONCLUSION

Larger, well-designed Mendelian randomization studies are practical in determining the causal status of risk factors for diseases.

Risk of myocardial infarction and Osteoporosis: Insights from the 2015-2018 NHANES and Mendelian randomization Studies

Background

There are some common pathophysiological risk factors between myocardial infarction and osteoporosis, and the exact relationship between the two is not yet clear. Our study aims to provide evidence on the relationship between myocardial infarction and osteoporosis through the analysis of data from the National Health and Nutrition Examination Survey (NHANES) and Mendelian Randomization (MR) analysis from 2015 to 2018.

Methods

A two-sample MR study using summary statistics from genome-wide association studies (GWAS) was conducted to determine the causal relationship between myocardial infarction and osteoporosis. The Inverse Variance Weighted (IVW) method and other supplementary MR methods were used to validate the causal relationship between myocardial infarction and osteoporosis. Sensitivity analysis was performed to verify the robustness of the results. Weighted multivariable adjusted logistic regression was used on the NHANES 2015-2018 data to evaluate the relationship between HDL, LDL, and BMD factors closely related to myocardial infarction.

Results

An observational study conducted in NHANES included a total of 2516 participants. Weighted multivariable adjusted logistic regression analysis showed that HDL was positively correlated with BMD, with OR and 95 % CI of 0.051 and 0.013-0.088, respectively. LDL was negatively correlated with BMD. The MR analysis also indicated a causal relationship between myocardial infarction and osteoporosis (IVW (OR = 1.16, 95 % CI = 1.02-1.32, P = 0.03)). Sensitivity analysis further confirmed the robustness and reliability of these study results (all P > 0.05).

Conclusion

There is a causal relationship between myocardial infarction and osteoporosis.

EPSTI1 promotes osteoclast differentiation and bone resorption by PKR/NF-κB signaling

BACKGROUND

Epithelial stromal interaction 1 (EPSTI1) plays an important role in M1 macrophages, which induce osteoclastogenesis. One recent genome-wide association study (GWAS) involving 426,824 individuals has shown that EPSTI1 is strongly associated with osteoporosis (P < 5E-8). Therefore, we speculate that EPSTI1 participates in the modulation of osteoporosis through osteoclastogenesis. The roles of EPSTI1 in osteoclastogenesis and bone resorption remain unclear.

METHODS

Femur specimens were collected from osteoporotic patients and control patients. Immunofluorescence staining was used to detect the expression of EPSTI1 and signaling pathways. The osteoclastic potential of RAW264.7 cells with Sh-EPSTI1 lentivirus infection was tested using tartrate-resistant acid phosphatase (TRAP) staining, western blotting, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Western blotting was also used to examine signaling pathways.

RESULTS

In this study, EPSTI1 was found to be significantly increased in tartrate-resistant acid phosphatase positive (ACP5+) osteoclasts of bone sections from osteoporotic patients. Next, we identified EPSTI1 as a positive regulator of osteoclastogenesis and osteoclast differentiation capability. Diminished EPSTI1 expression resulted in reduced osteoclastic resorption. Mechanistically, EPSTI1-driven osteoclastogenesis was regulated by NF-κB pathway, which was mediated by the phosphorylation of protein kinase R (p-PKR). Furthermore, EPSTI1 participating in the modulation of osteoporosis via PKR/NF-κB pathway was also verified in the bone samples of osteoporotic patients.

CONCLUSIONS

Collectively, our findings suggest that EPSTI1 may regulate osteoclast differentiation and bone resorption through PKR/NF-κB pathway and in vivo experiments are needed to further verify EPSTI1 as the therapy target for osteoporosis.

Association of anemia with hyperadiponectinemia in oldest-old Japanese women who resided at home alone without wheelchair use

The association of anemia with hyperadiponectinemia (HAN) (≥ 20 μg/mL) was studied in 95 Japanese women aged 65-74 (young-old), 175 women aged 75-84 (old-old), and 51 women aged over 85 (oldest-old) who resided at home alone without wheelchair use. The prevalence of anemia was 21.5% overall and increased with aging stepwise (9.5, 22.9, and 39.2% in young-olds, old-olds, and oldest-olds, respectively, p < 0.001). Most of the anemia was normocytic and only one woman had hemoglobin < 10 g/dL. Old-olds with anemia had low serum iron, albumin, and cholesterol and a higher prevalence of renal insufficiency (30.0 versus 5.2%, p < 0.001). In contrast, these variables did not differ between anemic and non-anemic young-olds. oldest-olds with anemia had low serum iron and higher adiponectin concentrations (22.8 ± 9.8 vs. 16.0 ± 6.7 μg/mL, p = 0.005) and prevalence of HAN (60.0 vs. 19.4%, p = 0.006) and renal insufficiency (50.0 vs. 0%, p < 0.001). However, inflammatory markers did not differ between anemic and non-anemic oldest-olds. The prevalence of anemia was higher in oldest-olds with versus without HAN (66.7 vs. 24.2%, p = 0.006). In multivariable logistic regression analysis, anemia was associated with HAN (OR: 15.7, 95% CI 1.2-207, p = 0.03) in oldest-olds and with renal insufficiency (OR: 7.1, 95% CI 2.4-21.0, p < 0.001) in old-olds. In conclusion, the association of anemia with HAN was evident in oldest-old Japanese women, suggesting the anti-inflammatory properties of circulating adiponectin.

Risk factors for prostate cancer: An umbrella review of prospective observational studies and mendelian randomization analyses

BACKGROUND

The incidence of prostate cancer is increasing in older males globally. Age, ethnicity, and family history are identified as the well-known risk factors for prostate cancer, but few modifiable factors have been firmly established. The objective of this study was to identify and evaluate various factors modifying the risk of prostate cancer reported in meta-analyses of prospective observational studies and mendelian randomization (MR) analyses.

METHODS AND FINDINGS

We searched PubMed, Embase, and Web of Science from the inception to January 10, 2022, updated on September 9, 2023, to identify meta-analyses and MR studies on prostate cancer. Eligibility criteria for meta-analyses were (1) meta-analyses including prospective observational studies or studies that declared outcome-free at baseline; (2) evaluating the factors of any category associated with prostate cancer incidence; and (3) providing effect estimates for further data synthesis. Similar criteria were applied to MR studies. Meta-analysis was repeated using the random-effects inverse-variance model with DerSimonian-Laird method. Quality assessment was then conducted for included meta-analyses using AMSTAR-2 tool and for MR studies using STROBE-MR and assumption evaluation. Subsequent evidence grading criteria for significant associations in meta-analyses contained sample size, P values and 95% confidence intervals, 95% prediction intervals, heterogeneity, and publication bias, assigning 4 evidence grades (convincing, highly suggestive, suggestive, or weak). Significant associations in MR studies were graded as robust, probable, suggestive, or insufficient considering P values and concordance of effect directions. Finally, 92 selected from 411 meta-analyses and 64 selected from 118 MR studies were included after excluding the overlapping and outdated studies which were published earlier and contained fewer participants or fewer instrument variables for the same exposure. In total, 123 observational associations (45 significant and 78 null) and 145 causal associations (55 significant and 90 null) were categorized into lifestyle; diet and nutrition; anthropometric indices; biomarkers; clinical variables, diseases, and treatments; and environmental factors. Concerning evidence grading on significant associations, there were 5 highly suggestive, 36 suggestive, and 4 weak associations in meta-analyses, and 10 robust, 24 probable, 4 suggestive, and 17 insufficient causal associations in MR studies. Twenty-six overlapping factors between meta-analyses and MR studies were identified, with consistent significant effects found for physical activity (PA) (occupational PA in meta: OR = 0.87, 95% CI: 0.80, 0.94; accelerator-measured PA in MR: OR = 0.49, 95% CI: 0.33, 0.72), height (meta: OR = 1.09, 95% CI: 1.06, 1.12; MR: OR = 1.07, 95% CI: 1.01, 1.15, for aggressive prostate cancer), and smoking (current smoking in meta: OR = 0.74, 95% CI: 0.68, 0.80; smoking initiation in MR: OR = 0.91, 95% CI: 0.86, 0.97). Methodological limitation is that the evidence grading criteria could be expanded by considering more indices.

CONCLUSIONS

In this large-scale study, we summarized the associations of various factors with prostate cancer risk and provided comparisons between observational associations by meta-analysis and genetically estimated causality by MR analyses. In the absence of convincing overlapping evidence based on the existing literature, no robust associations were identified, but some effects were observed for height, physical activity, and smoking.

Efficacy of magnetic therapy for osteoporotic patients: A meta-analysis of randomized controlled studies

BACKGROUND

Magnetic therapy may have some potential in treating osteoporosis, and this meta-analysis aims to study the efficacy of magnetic therapy for osteoporotic patients.

METHODS

We have searched several databases including PubMed, EMbase, Web of Science, EBSCO and Cochrane library databases, and selected the randomized controlled trials comparing the efficacy of magnetic therapy for osteoporotic patients. This meta-analysis was conducted using the random-effect or fixed-effect model based on the heterogeneity.

RESULTS

Five randomized controlled trials were included in this meta-analysis. Compared with sham procedure in osteoporotic patients, magnetic therapy was associated with significantly increased bone mineral density (standard mean difference [SMD] = 2.39; 95% confidence interval [CI] = 0.27-4.51; P = .03), decreased pain scores (mean difference [MD] = -0.86; 95% CI = -1.04 to -0.67; P < .00001), and calcium (MD = -0.61; 95% CI = -0.92 to -0.29; P = .0002), but revealed no influence on phosphate (MD = 0.07; 95% CI = -0.30 to 0.44; P = .71), osteocalcin (SMD = 0.65; 95% CI = -2.87 to 4.17; P = .72), or ALP (SMD = -0.43; 95% CI = -0.92 to 0.07; P = .09).

CONCLUSIONS

Magnetic therapy may be effective for the treatment of osteoporotic patients.

Causal influence of muscle weakness on cardiometabolic diseases and osteoporosis

The causal roles of muscle weakness in cardiometabolic diseases and osteoporosis remain elusive. This two-sample Mendelian randomization (MR) study aims to explore the causal roles of muscle weakness in the risk of cardiometabolic diseases and osteoporosis. 15 single nucleotide polymorphisms (SNPs, P < 5 × 10-8) associated with muscle weakness were used as instrumental variables. Genetic predisposition to muscle weakness led to increased risk of coronary artery disease (inverse variance weighted [IVW] analysis, beta-estimate: 0.095, 95% confidence interval [CI]: 0.023 to 0.166, standard error [SE]:0.036, P-value = 0.009) and reduced risk of heart failure (weight median analysis, beta-estimate: - 0.137, 95% CI - 0.264 to - 0.009, SE:0.065, P-value = 0.036). In addition, muscle weakness may reduce the estimated bone mineral density (eBMD, weight median analysis, beta-estimate: - 0.059, 95% CI - 0.110 to - 0.008, SE:0.026, P-value = 0.023). We found no MR associations between muscle weakness and atrial fibrillation, type 2 diabetes or fracture. This study provides robust evidence that muscle weakness is causally associated with the incidence of coronary artery disease and heart failure, which may provide new insight to prevent and treat these two cardiometabolic diseases.

Exploratory analysis of the effect of a controlled lifestyle intervention on inflammatory markers - the Healthy Lifestyle Community Programme (cohort 2)

BACKGROUND

Chronic low-grade inflammation is associated with an increased risk of chronic disease and mortality. The objective of the study was to test the effect of a healthy lifestyle intervention on biomarkers of inflammation (among other risk markers).

METHODS

We conducted a non-randomized controlled trial with mostly middle-aged and elderly participants from the general population in rural northwest Germany (intervention: n = 114; control: n = 87). The intervention consisted of a 1-year lifestyle programme focusing on diet (largely plant-based; strongest emphasis), physical activity, stress management, and social support. High-sensitivity C-reactive protein (hs-CRP) was assessed at baseline, 10 weeks, 6 months, and 1 year. Homocysteine (Hcy) was assessed at baseline, 10 weeks, and 1 year. Adiponectin (Apn) was assessed at baseline and 10 weeks. An exploratory analysis of these inflammatory markers assessing the between-group differences with ANCOVA was conducted.

RESULTS

The 1-year trajectory of hs-CRP was significantly lower in the intervention group compared to control (between-group difference: -0.8 (95% CI -1.2, -0.3) mg/l; p = 0.001; adjusted for baseline). The 1-year trajectory of Hcy was non-significantly higher in the intervention compared to control (between-group difference: 0.2 (95% CI -0.3, 0.7) µmol/l; p = 0.439; adjusted for baseline). From baseline to 10 weeks, Apn decreased significantly more in the intervention group compared to control (between-group difference: -1.6 (95% CI -2.7, -0.5) µg/ml; p = 0.004; adjusted for baseline).

CONCLUSIONS

Our study shows that healthy lifestyle changes can lower hs-CRP and Apn levels and are unlikely to significantly affect Hcy levels within 1 year.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS; reference: DRKS00018775 , registered 12 Sept 2019; retrospectively registered; www.drks.de ).

Adiponectin in anorexia nervosa and its modifiers: A meta-regression study

OBJECTIVE

Adiponectin, which is secreted from adipose tissue, is a protein hormone. Although a large body of studies have found that circulating adiponectin levels increase in anorexia nervosa (AN) and caloric restriction, the effect of subtypes of AN and modifiers of adiponectin in AN are not yet known.

METHODS

A systematic search of electronic databases was performed using the search terms "adiponectin," "anorexia nervosa," and "eating disorder" up to January 2021. All studies published in peer-reviewed journals, which included cases and control groups, were selected. The main outcome was the pooled standardized mean difference (SMD) in adiponectin levels between cases and controls, using the random-effects model. Modifiers of SMD were tested via meta-regression. Heterogeneity and publication bias were evaluated.

RESULTS

Thirty-four studies met all eligibility criteria. The total sample of AN participants (Hedges' g = .765, p < .0001), and specifically the binge-eating/purging (Hedges' g = 1.211, p < .00001) and restrictive subtypes (Hedges' g = .913, p < .00001) of AN have increased adiponectin plasma levels compared with healthy controls. Meta-regression determined that insulin, IGF-1, BMI, triglyceride, resistin, glucose, IL-6 levels are significant modifiers of adiponectin levels.

DISCUSSION

Compared with controls, adiponectin levels are higher in AN overall, and specifically in the binge-eating/purging and the restrictive AN subtypes. Many of metabolic parameters of glucose metabolism and pro-inflammatory molecules modify the relationship between AN and adiponectin levels. Adipose tissue is important to maintain metabolic stability.

PUBLIC SIGNIFICANCE

Anorexia nervosa is a psychiatric disorder associated with a severe decrease in body weight and multiple metabolic abnormalities, including an increase in the hormone adiponectin. In this paper, we used meta-analysis, a powerful statistical method, to aggregate data from 34 rigorously selected research reports. This enabled us to understand the value of adiponectin to differentiate clinical subtypes of anorexia nervosa and the relations between adiponectin and other important metabolic parameters.

The Positive Association of Plasma Levels of Vitamin C and Inverse Association of VCAM-1 and Total Adiponectin with Bone Mineral Density in Subjects with Diabetes

Context. Population studies have shown a trend in decreasing vitamin C status and increasing prevalence of osteoporosis in patients with diabetes and non-diabetic people. Dietary vitamin C consumption is linked to improvement in bone mineral density (BMD) in epidemiological studies. VCAM-1 and adiponectin are known to activate osteoclasts, which increase bone loss. Aim: This study examined whether there is any association between the circulating level of vitamin C and BMD and whether the beneficial effect of vitamin C on BMD was linked to a simultaneous decrease in circulating levels of adiponectin and VCAM-1 in subjects with diabetes. Methods: Patients with diabetes (T2D, n = 74) and age-matched non-diabetic controls (n = 26) were enrolled in this study. Fasting blood levels of glycemia, adiponectin, VCAM-1, inflammation biomarkers, and vitamin C were determined in both groups. The BMD of the lumbar spine (L1–L4), left femur, and right femur was determined using a DXA scan in subjects with diabetes. Results: Patients with diabetes had lower levels of vitamin C and higher levels of VCAM-1 and inflammatory cytokines. There was a significant positive association between vitamin C blood levels and lumbar spine BMD as well as a significant negative association between total adiponectin and VCAM-1 levels with that of vitamin C and lumbar BMD in patients with diabetes. Total adiponectin and VCAM-1 also showed a negative association with BMD of both the right and left femurs. The inter-relationship among the circulating levels of vitamin C and VCAM-1 and BMD was strong and is a novel finding. Conclusions: This study reports a positive association of circulating vitamin C levels and the BMD and that the beneficial effects of vitamin C on BMD could be linked to a simultaneous lowering in circulating VCAM-1 and total adiponectin levels. Thus, dietary vitamin C consumption has potential to lower inflammation and the risk of osteoporosis in subjects with diabetes.

Causal associations of circulating adiponectin with cardiometabolic diseases and osteoporotic fracture

Circulating adiponectin shows some relationships with the occurrence of cardiometabolic diseases and osteoporotic fracture, but little is known about their causal associations. This two-sample Mendelian randomization (MR) study aims to explore the causal roles of circulating adiponectin in cardiometabolic diseases and osteoporotic fracture. We used 15 single nucleotide polymorphisms associated with circulating adiponectin as the instrumental variables. Inverse variance weighted, weighted median and MR-Egger regression methods were applied to study the causal associations. The results found that high circulating adiponectin was causally associated with reduced risk of type 2 diabetes (beta-estimate: -0.030, 95% CI: -0.048 to -0.011, SE: 0.009, P-value = 0.002) and may be the risk factor of coronary artery disease (beta-estimate: 0.012, 95% CI: 0.001 to 0.023, SE: 0.006, P-value = 0.030). No causal associations were seen between circulating adiponectin and other outcomes including heart failure, atrial fibrillation, cerebral ischemia, intracerebral hemorrhage or osteoporotic fracture. This study found the potential causal roles of high circulating adiponectin in reduced risk of type 2 diabetes and increased risk of coronary artery disease, which may help prevent and treat these two diseases.

Causal Roles of Sleep Duration in Osteoporosis and Cardiometabolic Diseases: A Mendelian Randomization Study

Sleep duration suggests some association with osteoporosis and cardiometabolic diseases, but it is unknown if these associations are causal or confounded. In this two-sample Mendelian randomization (MR) study, we included the largest genome-wide association studies (GWASs) associated with sleep duration and the outcome measures of osteoporosis and cardiometabolic diseases. Finally, 25 single nucleotide polymorphisms (SNPs) associated with short sleep duration and 7 SNPs associated with long sleep duration obtained the genome-wide significance (P < 5 × 10^-8) and were used as instrumental variables. Genetic predisposition to short sleep duration was strongly associated with increased risk of coronary artery disease (beta-estimate: 0.199, 95% confidence interval CI: 0.081 to 0.317, standard error SE:0.060, P value = 0.001) and heart failure (beta-estimate: 0.145, 95% CI: 0.025 to 0.264, SE:0.061, P value = 0.017), which were both confirmed by the sensitivity analyses. Both short and long sleep duration may reduce the estimated bone mineral density (eBMD, beta-estimate: -0.086, 95% CI: -0.141 to -0.031, SE:0.028, P value = 0.002 for short sleep duration; beta-estimate: -0.080, 95% CI: -0.120 to -0.041, SE:0.020, P value < 0.0001 for long sleep duration). There was limited evidence of associations between sleep duration and fracture, type 2 diabetes, atrial fibrillation, fasting glucose, fasting insulin, or HbA1c. This study provides robust evidence that short sleep duration is causally associated with high risk of coronary artery disease and heart failure and suggests that short sleep duration should be avoided to prevent these two cardiovascular diseases. Short and long sleep duration show some MR association with reduced eBMD, which indicates that both short and long sleep duration may be prevented to reduce the incidence of osteoporosis.