Metformin and risk of hematological cancers in patients with diabetes: a systematic review and meta-analysis

FUNDING

No external funding.

Adipocytokines in obstructive sleep apnea: A systematic review and meta-analysis

BACKGROUND AND AIM

Adipocytokines play an important role in obstructive sleep apnea (OSA) by mediating inflammatory responses. Previous studies have reported that OSA is related to a change in the serum levels of adipocytokines; however, the results are still controversial. This meta-analysis aimed to assess the relationship between OSA and circulating level of adipocytokines in adults and children.

METHODS

A comprehensive search was conducted in databases of Medline/PubMed and Scopus for pertinent articles published since their inception to July 2022. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were used to assess the strength of the relationship between the concentrations of adipocytokines with OSA.

RESULTS

In the overall analysis, contrary to IL-10, which showed a significant reduction, IL-1β, IL-4, IL-8, IL-17, and IFN- gamma showed higher levels in OSA patients in comparison with control groups (p <0.05). For adults, IL-1β, IL-8, IL-17, IL-18, vaspin, visfatin, and chemerin were linked to a greater serum levels in patients with OSA, while, IL-5 and IL-10 were detected significantly lower in adults with OSA in comparison with healthy adults (p <0.05). In children with OSA, the serum levels of IL-4, IL-8, IL-12, IL-17, IL-23, and IFN-gamma were significantly higher than healthy children (p <0.05).

CONCLUSION

The levels of inflammatory markers were found to be higher in OSA patients compared with control individuals, suggesting that adipocytokines may contribute to the pathology of OSA.

The negative impact of obesity on the occurrence and prognosis of the 2019 novel coronavirus (COVID-19) disease: a systematic review and meta-analysis

PURPOSE

The 2019 novel coronavirus (COVID-19) is an emerging pandemic, with a disease course varying from asymptomatic infection to critical disease resulting to death. Recognition of prognostic factors is essential because of its growing prevalence and high clinical costs. This meta-analysis aimed to evaluate the global prevalence of obesity in COVID-19 patients and to investigate whether obesity is a risk factor for the COVID-19, COVID-19 severity, and its poor clinical outcomes including hospitalization, intensive care unit (ICU) admission, need for mechanical ventilation, and mortality.

METHODS

The study protocol was registered in PROSPERO (CRD42020203386). A systematic search of Scopus, Medline, and Web of Sciences was conducted from 31 December 2019 to 1 June 2020 to find pertinent studies. After selection, 54 studies from 10 different countries were included in the quantitative analyses. Pooled odds ratios (OR) with 95% confidence intervals (CIs) were calculated to assess the associations.

RESULTS

The prevalence of obesity was 33% (95% CI 30.0%-35.0%) among patients with COVID-19. Obesity was significantly associated with susceptibility to COVID-19 (OR = 2.42, 95% CI 1.58-3.70; moderate certainty) and COVID-19 severity (OR = 1.62, 95% CI 1.48-1.76; low certainty). Furthermore, obesity was a significant risk factor for hospitalization (OR = 1.75, 95% CI 1.47-2.09; very low certainty), mechanical ventilation (OR = 2.24, 95% CI 1.70-2.94; low certainty), intensive care unit (ICU) admission (OR = 1.75, 95% CI 1.38-2.22; low certainty), and death (OR = 1.23, 95% CI 1.06-1.41; low certainty) in COVID-19 patients. In the subgroup analyses, these associations were supported by the majority of subgroups.

CONCLUSION

Obesity is associated with COVID-19, need for hospitalization, mechanical ventilation, ICU admission, and death due to COVID-19.

LEVEL OF EVIDENCE

Level I, systematic reviews and meta-analyses.

Metabolic phenotypes and risk of colorectal cancer: a systematic review and meta-analysis of cohort studies

BACKGROUND

The association of obesity with colorectal cancer (CRC) may vary depending on metabolic status.

OBJECTIVE

This meta-analysis aimed to investigate the combined impacts of obesity and metabolic status on CRC risk.

METHODS

The Scopus, PubMed, and web of sciences databases were systematically searched up to Jun 2021 to find all eligible publications examining CRC risk in individuals with metabolically unhealthy normal-weight (MUHNW), metabolically healthy obesity (MHO), and metabolically unhealthy obesity (MUHO) phenotypes.

RESULTS

A total of 7 cohort studies with a total of 759,066 participants were included in this meta-analysis. Compared with healthy normal-weight people, MUHNW, MHO, and MUHO individuals indicated an increased risk for CRC with a pooled odds ratio of 1.19 (95% CI = 1.09-1.31) in MUHNW, 1.14 (95% CI = 1.06-1.22) in MHO, and 1.24 (95% CI = 1.19-1.29) in MUHO subjects. When analyses were stratified based on gender, associations remained significant for males. However, the elevated risk of CRC associated with MHO and MUHO was not significant in female participants.

CONCLUSIONS

The individuals with metabolic abnormality, although at a normal weight, have an increased risk for CRC. Moreover, obesity is associated with CRC irrespective of metabolic status.

Mercury Exposure and Risk of Type 2 Diabetes: A Systematic Review and Meta-Analysis

METHODS

Scopus and PubMed databases were systematically searched from their inception to November 2021 to obtain pertinent studies. Standardized mean differences (SMDs) with corresponding 95% confidence intervals (CIs) were calculated to evaluate the difference in Hg levels between people with and without T2DM. The association of the Hg exposure with T2DM was assessed using a random-effects model by pooling the odds ratios (ORs) and 95% CIs.

RESULTS

A total of 17 studies, with 42,917 participants, aged ≥18 years, were analyzed. Overall, Hg levels were significantly higher in T2DM patients compared with non-T2DM controls (SMD = 1.07; 95%CI = 0.59 to 1.55, P ≤ 0.001), with significant heterogeneity across studies (I² = 96.1%; P=≤0.001). No significant association was found between Hg exposure and risk of T2DM in the overall analysis and subgroup analysis based on the source of sample and study design. However, higher exposure to Hg was related to reduced risk of T2DM in men (OR = 0.71; 95%CI = 0.57 to 0.88), but not in women. No significant evidence for publication bias was detected.

CONCLUSIONS

Although the Hg level in T2DM is significantly higher than that of nondiabetics, there was no association between Hg exposure and the overall risk of T2DM. Nevertheless, our study shows that higher exposure to Hg might reduce the risk of T2DM in men.

Effects of Pre/Probiotic Supplementation on Breast Milk Levels of TGF-b1, TGF-b2, and IgA: A Systematic Review and Meta-Analysis of Randomized-Controlled Trial

Background: Previous studies have proposed that the maternal intake of pre/probiotics may affect the immune composition of breast milk. Nevertheless, the available findings are contradictory. This meta-analysis aimed to examine the impact of maternal supplementation with pre/probiotics on the levels of total immunoglobulin A (IgA), secretory IgA (SIgA), transforming growth factor beta 1 (TGF-β1), and TGF-2 in breast milk. Methods: PubMed and Scopus were systematically searched using a comprehensive search strategy for eligible randomized-controlled trials published up to February 2021. A random-effects model was applied to pool weighted mean difference and 95% confidence interval (CI) as effect size. Cochran's Q statistic and the I2 statistic were used to measure the between-study variance. Egger's regression test was used to assess publication bias. Results: A total of 12 different studies, with a total sample size of 1722 individuals (probiotic group: 858, placebo group: 864), were included in this meta-analysis. In the overall analysis, compared with placebo, maternal supplementation with pre/probiotics had no significant effect on concentrations of total IgA, SIgA, TGF-β1, and TGF-β2 in the breast milk. In the subgroup analysis, pre/probiotics did not affect total IgA, TGF-β1, and TGF-β2 in both colostrum/transitional and mature milk. However, a significant increase in SIgA was found in colostrum/transitional milk following pre/probiotic administration (WMD = 19.33, 95% CI: 0.83-37.83; p = 0.04), without evidence for remarkable heterogeneity (I² = 0.0, p = 0.57). Conclusions: Maternal supplementation with pre/probiotics may increase SIgA in colostrum/transitional milk, without any effect on total IgA, TGF-β1, and TGF-β2.

The association between psoriasis and psoriatic arthritis with the risk of osteoporosis, osteopenia and bone fractures: A systematic review and meta-analysis

BACKGROUND AND AIMS

The possible association between psoriatic/psoriatic arthritis (PsA) and bone loss has been observed; however, studies have yielded inconclusive results. This meta-analysis aimed to assess whether there is an increase in the risk of osteoporosis, osteopenia and fractures in patients with psoriasis/PsA, compared with healthy individuals.

METHODS

PubMed and Scopus were systematically searched from their inception to September 2020 to identify relevant studies. Relative risk, hazard ratio or odds ratio (OR), with their corresponding 95% confidence intervals (95% CI) were calculated and pooled using a random-effects model.

RESULTS

A total of 12 different studies, with a total of 199 389 296 participants, were included. Overall, no significant relationship was observed between psoriasis/PsA and the risk of osteoporosis (psoriasis: OR = 1.28, 95%CI = 0.86-1.90; PsA: OR = 1.32, 95%CI = 0.79-2.19) and osteopenia (psoriasis: OR = 1.50, 95%CI = 0.75-3.02; PsA: OR = 1.61, 95%CI = 0.67-3.85). However, in the subgroup analysis, psoriasis was significantly associated with an increased risk of osteoporosis in men (OR = 1.27, 95%CI = 1.02-1.59) and studies with cohort design (OR = 1.04, 95%CI = 1.003-1.09). Psoriasis was also related to the risk of osteopenia in studies on a combination of both genders (OR = 2.86, 95%CI = 2.70-3.02). The pooled analysis demonstrated a significantly higher risk of fractures among patients with psoriasis (OR = 1.29, 95%CI = 1.02-1.63) and PsA (OR = 2.88, 95%CI = 1.51-5.48), compared with participants without psoriasis/PsA.

CONCLUSIONS

Patients with psoriasis/PsA have an increased risk of fractures. There is little evidence supporting the relation of psoriasis to osteoporosis/osteopenia.

Glycemic index, but not glycemic load, is associated with an increased risk of metabolic syndrome: Meta-analysis of observational studies

BACKGROUND

Diets with high glycemic index (GI) or high glycemic load (GL) have been linked to important risk factors associated with the development of metabolic syndrome (MetS), such as dyslipidemia, higher blood glucose, and insulin concentrations. However, the role of GI and GL in relation to Mets is still understudied and controversial. This review, therefore, assessed whether high GI or GL contribute to development of Mets.

METHODS

A systematic search of four bibliographic databases was conducted (MEDLINE/PubMed, EMBASE, Web of Sciences, and Scopus) from inception to January 2020 for observational studies assessing GI/GL in relation to MetS. Risk estimates were pooled using random-effect models for the highest versus lowest intake categories, and assessed for heterogeneity using subgroup analysis. The dose-response nature of the relationship was also investigated. Sensitivity analysis and Egger test were used to check the robustness of findings and the possibility of publication bias, respectively.

RESULTS

Data from 12 publications (one cohort study and eleven cross-sectional studies) with a total sample size of 36,295 subjects are included. The pooled effect sizes from the nine studies indicated high versus low dietary GI was associated with increased risk of MetS (OR = 1.05, 95% CI: 1.01 to 1.09) (I²  = 58.1, P = .004). This finding was supported by all subgroup analyses except where studies used 24-h recalls for dietary assessment. Additionally, a linear dose-response investigation revealed that each 5-point increment in GI was associated with 2% increase in the risk of MetS (OR = 1.02, 95% CI: 1.01 to 1.02); non-linear pattern was insignificant, however (p-nonlinearity = 0.63). Moreover, pooled effect sizes from ten studies suggested that no association was found between the GL and MetS with results remaining consistent in all subgroup analyses.

CONCLUSION

A diet with lower GI may protect against MetS. Nutrition policy and clinical practices should encourage a diet with low GI. Future studies should include both GI and GL and different criteria of MetS to provide a better comparison.