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Lifestyle-, environmental-, and additional health factors associated with an increased sperm DNA fragmentation: a systematic review and meta-analysis.
Szabó, A, Váncsa, S, Hegyi, P, Váradi, A, Forintos, A, Filipov, T, Ács, J, Ács, N, Szarvas, T, Nyirády, P, et al
Reproductive biology and endocrinology : RB&E. 2023;21(1):5
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The World Health Organization defines infertility as regular unprotected sexual intercourse without achieving conception within a year. In recent years, there has been a growing demand for functional, objective parameters reflecting fertility status more clearly than classical parameters. Of these, sperm DNA fragmentation (SDF) and the DNA fragmentation index – denoting the percentage of sperm with damaged DNA – seem to be of utmost importance. The aim of this study was to investigate all risk factors that may potentially be increasing SDF. This study is a systematic review and meta-analysis of one hundred and ninety articles. The earliest studies were published in 2003, and the latest in 2021. Results show that several modifiable risk factors negatively affect SDF, namely; a. health conditions: varicocele [when veins become enlarged inside the pouch of skin that holds the testicles] and impaired glucose tolerance, b. infections: Chlamydia, c. malignancies: testicular tumours, and d. lifestyle factors: smoking, alcohol consumption and body mass index. Authors conclude that several lifestyle-, environmental-, and additional health factors are associated with increased SDF.
Abstract
INTRODUCTION Infertility affects one in every six couples in developed countries, and approximately 50% is of male origin. In 2021, sperm DNA fragmentation (SDF) testing became an evidence-based test for fertility evaluations depicting fertility more clearly than standard semen parameters. Therefore, we aimed to summarize the potential prognostic factors of a higher SDF. METHODS We conducted a systematic search in three medical databases and included studies investigating any risk factors for SDF values. We calculated mean differences (MD) in SDF with 95% confidence interval (CI) for exposed and non-exposed individuals. RESULTS We included 190 studies in our analysis. In the group of associated health conditions, varicocele (MD = 13.62%, CI: 9.39-17.84) and impaired glucose tolerance (MD = 13.75%, CI: 6.99-20.51) had the most significant increase in SDF. Among malignancies, testicular tumors had the highest impact, with a maximum of MD = 11.3% (CI: 7.84-14.76). Among infections, the overall effects of both Chlamydia and HPV were negligible. Of lifestyle factors, smoking had the most disruptive effect on SDF - an increase of 9.19% (CI: 4.33-14.06). Different periods of sexual abstinence did not show significant variations in SDF values. Age seemed to have a more drastic effect on SDF from age 50 onwards, with a mean difference of 12.58% (CI: 7.31-17.86). Pollution also had a detrimental effect - 9.68% (CI: 6.85-12.52). CONCLUSION Of the above risk factors, varicocele, impaired glucose tolerance, testicular tumors, smoking, pollution, and paternal age of over 50 were associated with the highest SDF. TRIAL REGISTRATION CRD42021282533.
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Causal relationship between obesity, lifestyle factors and risk of benign prostatic hyperplasia: a univariable and multivariable Mendelian randomization study.
Wang, YB, Yang, L, Deng, YQ, Yan, SY, Luo, LS, Chen, P, Zeng, XT
Journal of translational medicine. 2022;20(1):495
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Benign prostatic hyperplasia (BPH) is a common benign disease in middle-aged and elderly men which is often underestimated and underdiagnosed. If patients are not treated in time, it may lead to serious complications, such as urinary retention, renal insufficiency and renal failure. The aim of this study was to evaluate the possible causal associations of abdominal obesity (measured as waist circumference), overall obesity (measured as body mass index), lifestyle factors (dietary habits, smoking, alcohol drinking, and sedentary behaviour) with risk of BPH. This study is a univariable and multivariable mendelian randomised study. Results show that genetic predisposition to higher waist circumference and sedentary behaviour are independently and causally associated with the risk of BPH. However, there isn’t conclusive evidence that genetic predisposition to relative carbohydrate, fat, protein, and sugar intake, smoking and alcohol drinking are causally associated with the risk of BPH. Authors conclude that further studies are needed to identify comprehensive risk factors on BPH and develop freely accessible prediction models for the BPH. These will help to identify individuals at particular risk and provide decision-making supports for individualised intervention.
Abstract
BACKGROUND Obesity (waist circumference, body mass index (BMI)) and lifestyle factors (dietary habits, smoking, alcohol drinking, Sedentary behavior) have been associated with risk of benign prostatic hyperplasia (BPH) in observational studies, but whether these associations are causal is unclear. METHODS We performed a univariable and multivariable Mendelian randomization study to evaluate these associations. Genetic instruments associated with exposures at the genome-wide significance level (P < 5 × 10-8) were selected from corresponding genome-wide associations studies (n = 216,590 to 1,232,091 individuals). Summary-level data for BPH were obtained from the UK Biobank (14,126 cases and 169,762 non-cases) and FinnGen consortium (13,118 cases and 72,799 non-cases). Results from UK Biobank and FinnGen consortium were combined using fixed-effect meta-analysis. RESULTS The combined odds ratios (ORs) of BPH were 1.24 (95% confidence interval (CI), 1.07-1.43, P = 0.0045), 1.08 (95% CI 1.01-1.17, P = 0.0175), 0.94 (95% CI 0.67-1.30, P = 0.6891), 1.29 (95% CI 0.88-1.89, P = 0.1922), 1.23 (95% CI 0.85-1.78, P = 0.2623), and 1.04 (95% CI 0.76-1.42, P = 0.8165) for one standard deviation (SD) increase in waist circumference, BMI, and relative carbohydrate, fat, protein and sugar intake, 1.05 (95% CI 0.92-1.20, P = 0.4581) for one SD increase in prevalence of smoking initiation, 1.10 (95% CI 0.96-1.26, P = 0.1725) and 0.84 (95% CI 0.69-1.02, P = 0.0741) for one SD increase of log-transformed smoking per day and drinks per week, and 1.31 (95% CI 1.08-1.58, P = 0.0051) for one SD increase in sedentary behavior. Genetically predicted waist circumference (OR = 1.26, 95% CI 1.11-1.43, P = 0.0004) and sedentary behavior (OR = 1.14, 95% CI 1.05-1.23, P = 0.0021) were associated with BPH after the adjustment of BMI. CONCLUSION This study supports independent causal roles of high waist circumference, BMI and sedentary behavior in BPH.
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SARS-CoV-2 effects on sperm parameters: a meta-analysis study.
Xie, Y, Mirzaei, M, Kahrizi, MS, Shabestari, AM, Riahi, SM, Farsimadan, M, Roviello, G
Journal of assisted reproduction and genetics. 2022;39(7):1555-1563
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Infertility is a reproductive system disorder. Viruses as a major cause of fertility problems can potentially interfere with reproductive function in men. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was found to be the causing viral pathogen of COVID-19 and capable of affecting human health. The aim of this study was to evaluate the effects of SARS-CoV-2 on different semen parameters including sperm count, sperm concentration, volume, motility, and progressive motility. This study is a meta-analysis of twelve studies of which seven were case control studies and five were retrospective cohort studies. Results show that SARS-CoV-2 infection could lead to significant impairments of male reproductive function through exerting negative influences on different semen parameters namely semen volume, sperm concentration, sperm count, and sperm motility. Authors conclude that their findings revealed the vulnerability of semen quality to SARS-CoV-2 infection.
Abstract
AIM: The rapid outbreak of the coronavirus disease 2019 (COVID-19) pandemic posed challenges across different medical fields, especially reproductive health, and gave rise to concerns regarding the effects of SARS-CoV-2 on male infertility, owing to the fact that the male reproductive system indicated to be extremely vulnerable to SARS-CoV-2 infection. Only a small number of studies have investigated the effects of SARS-CoV-2 on male reproduction, but the results are not consistent. So, we performed this meta-analysis to draw a clearer picture and evaluate the impacts of COVID-19 on male reproductive system. METHOD We searched Embase, Web of Science, PubMed, and Google Scholar databases to identify the potentially relevant studies. Standardized mean difference (SMD) with 95% confidence interval (CI) was applied to assess the relationship. Heterogeneity testing, sensitivity analysis, and publication bias testing were also performed. RESULTS A total of twelve studies including 7 case control investigations and 5 retrospective cohort studies were found relevant and chosen for our research. Our result showed that different sperm parameters including semen volume [SMD = - 0.27 (- 0.46, - 1.48) (p = 0.00)], sperm concentration [SMD = - 0.41 (- 0.67, - 0.15) (p = 0.002)], sperm count [SMD = - 0.30 (- 0.44, - 0.17) (p = 0.00)], sperm motility [SMD = - 0.66 (- 0.98, - 0.33) (p = 0.00)], and progressive motility [SMD = - 0.35 (- 0.61, - 0.08) (p = 0.01)] were negatively influenced by SARS-CoV-2 infection. However, sperm concentration (p = 0.07) and progressive motility (p = 0.61) were not found to be significantly associated with SARS-CoV-2 infection in case control studies. No publication bias was detected. CONCLUSION The present study revealed the vulnerability of semen quality to SARS-CoV-2 infection. Our data showed a strong association of different sperm parameters with SARS-CoV-2 infection. The results suggested that SARS-CoV-2 infection in patients may negatively influence their fertility potential in a short-term period, but more studies are needed to decide about the long-term effects.
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Effect of vitamin E on Semen Quality Parameters: A Meta-Analysis of a Randomized Controlled Trial.
Wang, R, Wang, S, Song, Y, Zhou, H, Pan, Y, Liu, L, Niu, S, Liu, X
Urology journal. 2022;19(5):343-351
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The incidence of male infertility is increasing year by year. The mechanism of male infertility is complex. One of the important causes of male infertility is the decline in semen quality. The aim of this study was to evaluate the effectiveness of oral vitamin E in improving semen quality. This study is a meta-analysis of eight articles with a total of 459 patients, including 238 cases in the experimental group and 221 cases in the control group. Results show that oral vitamin E treatment could significantly increase the total sperm count and reduce the volume of semen. It was further found that oral vitamin E treatment for up to 6 months could improve the forward motility of sperm but not for 3 months. Authors conclude that vitamin E could increase the total sperm count and reduce the volume of semen in male infertility patients.
Abstract
PURPOSE To explore the effectiveness of vitamin E in male infertility, a systematic review and meta-analysis was conducted. MATERIALS AND METHODS The retrieval time was from January 1947 to May 2021, without language restriction. Stata 12.0 was used for the meta-analysis. RESULTS A total of 8 randomized controlled trials involving 459 patients were included. The results showed that after vitamin E treatment, semen volume was reduced (95% CI: - 0.55 to - 0.06, SMD = - 0.30, p = 0.015), total sperm count was increased (95% CI: 0.02-0.45, SMD = 0.23, p = 0.035), and the differences were statistically significant. There were no statistically significant differences in increasing sperm concentration (95% CI: -0.21-0.29, SMD = 0.04, p = 0.769), total sperm motility (95% CI: -0.01-0.42, SMD = 0.20, p = 0.061) or sperm forward motility rate (95% CI: -0.06-0.65, SMD = 0.29, p = 0.106). Subgroup analysis showed that vitamin E treatment for six months could improve sperm forward motility (95% CI: 0.46-1.14, SMD = 0.80, p <0.001). CONCLUSION Vitamin E could increase the total sperm count and reduce the volume of semen in male infertility patients, and long-term treatment could improve the forward motility rate of sperm. The decrease of semen volume may be the result of different abstinence time before and after the test.
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Psoriasis and cardiovascular disease risk in European and East Asian populations: evidence from meta-analysis and Mendelian randomization analysis.
Zhang, L, Wang, Y, Qiu, L, Wu, J
BMC medicine. 2022;20(1):421
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Psoriasis constitutes a chronic, inflammatory skin disease with an immune-genetic basis that has been linked to numerous diseases, including metabolic syndrome, cancer, as well as cardiovascular disease (CVD). The aim of this study was to determine if the relationship of psoriasis with CV events (CVE) risk is congruent with causal associations. This study is a report employing a meta-analysis of observational studies and a two-sample mendelian randomised trial (MR). Results from the meta-analysis show that psoriasis was remarkably associated with a higher risk of incident coronary artery disease (CAD) and myocardial infarction (MI) and was not associated with heart failure risk. Furthermore, the MR approach showed that psoriasis was linked with a higher risk of CAD in both European and East Asian populations. Additionally, psoriasis was also causally linked to an elevated risk of MI in European population. Authors conclude that their findings indicate a causal association of psoriasis with CAD and MI. However, further studies are needed to establish the mechanisms of the causal relationship of psoriasis with CAD and MI.
Abstract
BACKGROUND Psoriasis has been linked to cardiovascular disease (CVD), including coronary artery disease (CAD), myocardial infarction (MI), and heart failure (HF). However, available studies regarding this relationship have shown inconsistent results. Therefore, in this report, we performed a comprehensive review of the literature to assess the effects of psoriasis on risk of these CVDs. METHODS A search of literature until 24 December 2021 was done in PubMed, the Cochrane Library, Web of Science, Google Scholar, and Embase. Within European and East Asian populations, meta-analyses of observational studies assessing correlations between psoriasis and various CVD risk factors were conducted. Mendelian randomization (MR) was then employed to assess the causative impact of genetic pre-disposition for psoriasis on these CVD risk factors. RESULTS The results of the meta-analyses indicated that, in both the European and East Asian populations, psoriasis was significantly linked to an elevated risk in the incidence of CAD (RR = 1.51, 95% confidence interval (CI): 1.04-2.18, p = 0.028 and RR = 1.91, 95% CI: 1.62-2.25, p < 0.001) and MI (RR = 1.23, 95% CI: 1.04-1.46, p = 0.017 and RR = 2.17, 95% CI: 1.44-3.28, p < 0.001). A positive genetic relationship of psoriasis with CAD was found in European individuals (IVW OR1.03; 95% CI: 1.01-1.06, p = 0.005) and in East Asian individuals (IVW OR1.18; 95% CI: 1.03-1.32, p = 0.031). We also established that psoriasis was causally linked with an elevated risk of MI (IVW OR1.05; 95% CI: 1.01-1.09, p = 0.026) in the European population as determined using an MR approach. Moreover, our MR results were congruent with the null findings from the meta-analysis assessing associations of psoriasis with HF risk. CONCLUSIONS This research work provides preliminary evidence that psoriasis and CVD have a common genetic origin and that targeted psoriasis treatment might improve cardiovascular outcomes. These results not only increase our knowledge of the genetic underpinnings linking a comorbidity of psoriasis with CVD but also suggests a novel approach for CVD prevention.
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Cadmium exposure and risk of diabetes and prediabetes: A systematic review and dose-response meta-analysis.
Filippini, T, Wise, LA, Vinceti, M
Environment international. 2022;158:106920
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Cadmium is a toxic metal released in the environment after both natural and anthropogenic activities, particularly in contaminated and industrial areas devoted to smelting and refining of metals, and the manufacturing of batteries, coatings, or plastics. Exposure to cadmium may occur through occupational activities, smoking, food, and air pollution. The aim of this study was to provide updated literature on cadmium exposure and the risk of both type 2 diabetes and prediabetes, and to model the shape of these associations using a dose response approach. This study is a systematic review and meta-analysis of forty-two studies. Diabetes was investigated as an outcome in thirty-one studies, prediabetes in four studies, and both diabetes and prediabetes in seven studies. Results show that higher cadmium exposure was associated with increased risks of both diabetes and prediabetes. Diabetes risk increased linearly in studies using urinary cadmium concentrations, while disease risk increased only at the highest exposure levels when assessed using blood concentrations. The analysis for prediabetes also showed a linear increase in risk from low exposure, with a flattening effect at higher urinary cadmium concentrations. Authors conclude that their findings add to the available evidence on potential adverse health effects of environmental exposure to cadmium.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Cadmium exposure through diet, occupational exposure and smoking may increase the risk of type 2 diabetes in affected individuals.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Background
Cadmium exposure might occur through occupational activities, food, air pollution, and smoking. Smokers, in particular, have higher blood cadmium concentrations than non-smokers. Food is the main transmission route for non-smokers, particularly cereals, vegetables, mollusks, and offal. Females and older adults are at a greater risk due to an increased risk of iron deficiency in these population groups, leading to increased absorption, as well as greater age-related bioaccumulation.
Furthermore, cadmium exposure has been associated with an increased risk of diabetes in a number of studies, as referenced in the present manuscript. However, the magnitude and shape of the correlation are uncertain.This systematic review and meta-analysis therefore investigates the relationship between exposure to cadmium and type 2 diabetes and prediabetes risk.
Methods
- The systematic review was conducted and reported in line with the PRISMA 2020 statement. Search strings related to the terms “cadmium” and “diabetes”, or “prediabetes state” in PubMed/MEDLINE, Web of Science and EMBASE databases were employed to search for relevant articles. Latest search date: 1 October 2021.
- Eligibility criteria included: studies evaluating cadmium exposure via biomarker levels with outcomes of interest being type 2 diabetes or prediabetes using WHO criteria and the American Diabetes Association; and reporting of relative risk estimates using the hazard ratio (HR), risk ratio (RR), or odds ratio (OR) with the corresponding 95% confidence interval (CIs). For inclusion in dose-response meta-analysis: reported effect estimates for all exposure categories along with dose in each category.
- Studies were assessed for risk of bias using theROBINS-E tool. Overall certainty of the evidence was assessed using the GRADE approach.
- The meta-analysis involved estimating RRs with corresponding 95% CIs from each study. Generalised least-squares regression with a random effects model and restricted maximum likelihood estimation were used. The highest versus lowest exposure categories were compared. The association between exposure and risk of diabetes or prediabetes was investigated using a one-stage dose-response meta-analysis. Sensitivity analyses were performed and heterogeneity between studies was assessed..
Results
- 42 eligible studies (case-control, cross-sectional, and cohort studies), ranging 65-34, 814 male and female adult participants, were identified investigating the association between cadmium exposure and risk of diabetes or prediabetes. Seven of the included studies were at overall high risk of bias; heterogeneity in the resulting meta-analyses was moderate to substantial. Sensitivity analyses indicated comparable results. Assessment with GRADE found no major inconsistency, indirectness or imprecision for either outcome.
- Comparing the highest versus lowest cadmium exposure concentrations associated with type 2 diabetes resulted in a RR of 1.24 (95% CI 0.96–1.59), RR 1.21 (CI 95% 1.00–1.45), and RR 1.47 (CI 95% 1.01–2.13) for blood, urinary, and toenail matrices, respectively. Concurrently, there was an elevated risk of prediabetes for cadmium levels in urine of RR 1.41 (95% CI: 1.15–1.73) and blood RR 1.38 (95% CI: 1.16–1.63), respectively.
- In the dose-response meta-analysis, a linear positive correlation between increasing urinary cadmium levels and diabetes risk was observed, with a RR 1.25 (95% CI 0.90–1.72) at concentration 2.0 µg/g of creatinine compared with no exposure. Conversely, for blood cadmium concentrations, the diabetes risk seemed to rise above 1 µg/L compared with no exposure. Moreover, prediabetes risk increased up to approximately 2 µg/g creatinine beyond which a plateau was reached with RR 1.40 (95% CI 1.12–1.76) at 2 µg/g creatinine.
- The meta-regression showed a negligible correlation between blood cadmium levels and diabetes risk. However, a positive yet imprecise association was found with increasing urinary cadmium concentrations. Similarly, no association was observed between blood cadmium concentrations and risk of prediabetes, whereas a positive relationship with urinary cadmium levels was observed. However, these findings were based on a limited cohort of studies.
Conclusions
- A positive linear correlation between cadmium concentration (measured in multiple matrices) and risk of both type 2 diabetes and prediabetes with a dose-response relationship (moderate-certainty evidence) were observed in this systematic review and meta-analysis. Diabetes risk increased linearly in studies using urinary cadmium concentrations, whereas disease risk increased only at the highest exposure levels when assessed using blood levels. The analysis for prediabetes also demonstrated a linear increase in risk from low exposure, which plateaued at higher urinary cadmium concentrations.
Clinical practice applications:
- To inform practitioners and clients of the risks of cadmium exposure in the diet, through occupational exposure, and through smoking.
- To motivate practitioners to educate themselves and their clients regarding the foods which may pose a higher risk of cadmium exposure (not reviewed in the present article).
- To advise clients on prediabetes and type 2 diabetes risk from cadmium exposure through smoking.
Considerations for future research:
- As cited by the authors, future studies could incorporate stratified analysis in specific subgroups, e.g., non-smokers, or could be restricted to prospective cohort studies with more sufficient data,
- Large-scale observational studies could be conducted investigating cadmium exposure in smokers versus non-smokers.
- Clinical trials could be performed to evaluate the effect of reduction or cessation of tobacco smoking on total body cadmium concentrations .
- Continuous surveillance of dietary cadmium exposure and other heavy metals should be prioritised to inform public health.
- Dietary interventions could assess the possibility to attenuate the risk of cadmium exposure.
Abstract
BACKGROUND Cadmium exposure has been associated with increased diabetes risk in several studies, though there is still considerable debate about the magnitude and shape of the association. OBJECTIVE To perform a systematic review and meta-analysis of observational studies investigating the relation between cadmium exposure and risk of type 2 diabetes and prediabetes, and to summarize data on the magnitude and shape of the association. DATA SOURCE After conducting an online literature search through October 1, 2021, we identified 42 eligible studies investigating the association between cadmium exposure and risk of diabetes and prediabetes. STUDY ELIGIBILITY CRITERIA We included studies that assessed cadmium exposure through biomarker levels; examined type 2 diabetes or prediabetes among outcomes; and reported effect estimates for cadmium exposure for meta-analysis only. STUDY APPRAISAL AND SYNTHESIS METHODS Studies were evaluated using ROBINS-E risk of bias tool. We quantitively assessed the relation between exposure and study outcomes using one-stage dose-response meta-analysis with a random effects meta-analytical model. RESULTS In the meta-analysis, comparing highest-versus-lowest cadmium exposure levels, summary relative risks (RRs) for type 2 diabetes were 1.24 (95% confidence interval 0.96-1.59), 1.21 (1.00-1.45), and 1.47 (1.01-2.13) for blood, urinary, and toenail matrices, respectively. Similarly, there was an increased risk of prediabetes for cadmium concentrations in both urine (RR = 1.41, 95% CI: 1.15-1.73) and blood (RR = 1.38, 95% CI: 1.16-1.63). In the dose-response meta-analysis, we observed a consistent linear positive association between cadmium exposure and diabetes risk, with RRs of 1.25 (0.90-1.72) at 2.0 µg/g of creatinine. Conversely for blood cadmium, diabetes risk appeared to increase only above 1 µg/L. Prediabetes risk increased up to approximately 2 µg/g creatinine above which it reached a plateau with RR of 1.42 (1.12-1.76) at 2 µg/g creatinine. LIMITATIONS AND CONCLUSIONS This analysis provides moderate-certainty evidence for a positive association between cadmium exposure (measured in multiple matrices) and risk of both diabetes and prediabetes.
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Is Air Pollution Associated with Increased Risk of Dementia? A Meta-Analysis of Epidemiological Research.
Dhiman, V, Trushna, T, Raj, D, Tiwari, RR
Neurology India. 2022;70(3):1004-1019
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Several studies have indicated that there may be a link between exposure to air pollution and the development of dementia. This study aimed to perform a systematic review and meta-analysis to determine the risk of developing dementia, cognitive decline, and/or Alzheimer’s disease (AD) following air pollution exposure. The results showed that exposure to small particulate matter (less than 2.5 micro m) was a risk factor for the development of dementia, AD and dementia caused by blockages in the blood vessels leading to the brain. Exposure to ozone was a risk factor for AD. Carbon monoxide, large particulate matter (10 micro m and less), nitrogen dioxide, nitrous oxides, and sulphur dioxide exposure was not a risk factor for any dementia related diseases. It was concluded that exposure to certain types of pollution may be detrimental to brain health and further research is required in developing countries, where pollution exposure can be particularly high. This study could be used by health care professionals to make informed decisions on the control of air pollution in those who are at risk of developing dementia or who are already suffering from this disease. The introduction of plants and air purifiers may be of benefit to those who are vulnerable.
Abstract
BACKGROUND There are prevailing inconsistencies in epidemiological research about air pollution being a risk factor for dementia. OBJECTIVE We performed meta-analyses to calculate the pooled estimates of the risk of developing dementia due to air pollution exposure. METHODS AND MATERIALS We performed a systematic search in PubMed, Google Scholar, The Cochrane Library, and J-GATEPLUS databases for peer-reviewed epidemiological studies reporting the risk of developing all-cause dementia, cognitive decline, Alzheimer's disease (AD), and vascular dementia (VaD) due to exposure to particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) and less than 10 μm (PM10), ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), nitrogen oxides (NOX) and sulfur dioxide (SO2) from the beginning until December 2020. Meta-analysis was performed by adopting the random-effects model using Meta-XL. RESULTS In all-cause dementia, the pooled hazard ratio (HR) for PM2.5 and NO2 exposure was 1.03 [(95%CI: 1.01-1.06; I2 = 99% (P < 0.001)] and 1.00 [(95%CI: 1.00-1.01; I2 = 96% (P < 0.001)], respectively. The pooled HR for NOX was 1.00 [(95%CI: 1.00-1.01; I2 = 61% (P = 0.05)]. In AD, the pooled HRs for PM2.5 and O3 was 1.08 (95%CI: 1.01-1.15; I2 = 99% (P < 0.001)]) and 1.02 (95%CI: 0.96-1.08; I2 = 100% (P < 0.001)], respectively. In VaD, the pooled HR for PM2.5 exposure was 1.03 (95%CI: 1.01-1.06; I2 = 91% (P < 0.001)]. In NO2/NOX, the results were found to be equivocal. Meta-analysis could not be performed in cognitive decline because of wide variations in assessments methods. CONCLUSIONS The present study showed exposure to PM2.5 as a risk factor for all-cause dementia, AD, and VaD and exposure to O3 as a possible risk factor for AD. These findings can be used for policy measures and further research.
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Chronic urticaria and thyroid autoimmunity: a meta-analysis of case-control studies.
Tienforti, D, Di Giulio, F, Spagnolo, L, Castellini, C, Totaro, M, Muselli, M, Francavilla, S, Baroni, MG, Barbonetti, A
Journal of endocrinological investigation. 2022;45(7):1317-1326
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The term “urticaria” is widely used to define a skin manifestation characterised by the onset of itchy, fleeting wheals of variable size, shape, and distribution. Using a temporal criterion, urticaria can be classified into acute and chronic: in chronic urticaria (CU), manifestations occur daily or nearly daily and last for more than 6 weeks. The aim of this study was to assess the overall risk of thyroid autoimmunity in people with diagnosis of CU. This study is a systematic review and meta-analysis of nineteen case-control studies. The studies provided information on 14,351 patients with CU (cases) and 12,404 subjects without CU (controls). Results show that the diagnosis of CU was associated with an approximately fivefold higher risk of exhibiting positivity for anti-thyroperoxidase antibodies [a marker of chronic autoimmune thyroiditis]. Authors conclude that their findings point to the opportunity to perform a screening for thyroid autoimmunity in the presence of CU.
Abstract
PURPOSE Autoimmunity has been implicated in some patients with idiopathic chronic urticaria (CU). Because of the frequency of autoimmune thyroid diseases, their association with CU deserves special attention. We tested both the existence and the extent of an association between thyroid autoimmunity and CU. METHODS A thorough search of PubMed, Scopus, Web of Science, and Cochrane databases was performed. Studies reporting the positivity rate for anti-thyroperoxidase antibodies (TPOAbs) in people with (cases) and without CU (controls) were included. Quality of the studies was assessed by the Newcastle-Ottawa Scale. Between-study heterogeneity was assessed by Cochrane Q and I2 tests, and the odds ratio (OR) for TPOAbs positivity was combined using random-effects models. RESULTS Nineteen studies provided information about TPOAbs positivity on 14,351 patients with CU and 12,404 controls. The pooled estimate indicated a more than fivefold increased risk of exhibiting TPOAbs positivity in the group with CU (pooled OR 5.18, 95% CI 3.27, 8.22; P < 0.00001). Correction for publication bias had a negligible effect on the overall estimate (pooled adjusted OR: 4.42, 95% CI 2.84, 6.87, P < 0.0001). Between‑study heterogeneity was established (I2 = 62%, Pfor heterogeneity = 0.0002) and when, according to meta‑regression models, a sensitivity analysis was restricted to the 16 studies with the highest quality scores, the OR for TPOAbs positivity rose to 6.72 (95% CI 4.56, 9.89; P < 0.00001) with no significant heterogeneity (I2 = 31%, Pfor heterogeneity = 0.11). CONCLUSIONS Patients with CU have a five-to-nearly sevenfold higher risk of displaying TPOAbs positivity. All patients with CU may well be offered a screening for thyroid autoimmunity.
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Exposure to glyphosate and risk of non-Hodgkin lymphoma: an updated meta-analysis.
Boffetta, P, Ciocan, C, Zunarelli, C, Pira, E
La Medicina del lavoro. 2021;112(3):194-199
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Glyphosate is an herbicide and crop desiccant widely used by professional applicators and consumers. The aim of this study was to update a recent systematic review and meta-analysis of epidemiologic studies to help clarify the association between exposure to glyphosate and risk of non-Hodgkin lymphoma (NHL). Results confirmed the conclusions drawn on the previous systematic review and meta-analysis i.e. that there was no association between exposure to glyphosate and the risk of NHL even though larger better-designed studies were analysed. Authors conclude that an association with risk of diffuse large B-cell lymphoma [happens when healthy B-cells change into fast-growing cancer cells that do not die] cannot be ruled out.
Abstract
OBJECTIVE We updated a recent systematic review and meta-analysis of epidemiologic studies to help clarifying the association between exposure to glyphosate and risk of non-Hodgkin lymphoma (NHL). METHODS We conducted an updated search of the literature, and identified a total of 15 relevant publications, from which we extracted results from six non-overlapping studies. We performed random-effects meta-analyses for ever-exposure to glyphosate, dose-response, and risk of specific NHL subtypes Results: The meta-RR for ever-exposure to glyphosate was 1.05 (95% confidence interval [CI] 0.90-1.24; I2 = 0%). The meta-RR for the highest category of exposure was 1.15 (95% CI 0.72-1.83; 3 studies). The meta-RR for diffuse large B-cell lymphoma (DLBCL) was 1.29 (95% CI 1.02-1.63; 4 studies), that for follicular lymphoma was 0.84 (95% CI 0.61-1.17), and that for chronic lymphocytic leukemia/small lymphocytic lymphoma was 1.33 (95% CI 0.65-2.70). There was indication of publication bias. CONCLUSIONS This updated meta-analysis reinforces our previous conclusion of a lack of an association between exposure to glyphosate and risk of NHL overall, although an association with DLBCL cannot be ruled out.
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Impact of Diabetes Mellitus on Lower Urinary Tract Symptoms in Benign Prostatic Hyperplasia Patients: A Meta-Analysis.
Xin, C, Fan, H, Xie, J, Hu, J, Sun, X, Liu, Q
Frontiers in endocrinology. 2021;12:741748
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Benign prostatic hyperplasia (BPH) is a disease that causes lower urinary tract symptoms (LUTS). Age, sex hormones, diet, diabetes, obesity, and genetic factors are closely related to the occurrence of BPH. The aim of this study was to investigate the impact of diabetes mellitus on LUTS in BPH patients. This study is a systematic review and meta-analysis of eighteen articles consisting of 1685 cases and 4653 controls. Results show that the International Prostate Symptom Score of the diabetic BPH group was significantly higher than that of the non-diabetic BPH group, indicating that diabetes mellitus may aggravate the LUTS of BPH patients. Authors conclude that LUTS in BPH patients is increased in patients with diabetes mellitus compared with controls.
Abstract
BACKGROUND Benign prostatic hyperplasia (BPH) is a disease that causes lower urinary tract symptoms (LUTS), which are the most common urological problem in approximately one-third of the male population aged over 50 years. Some studies have suggested that diabetes may be a risk factor for the development of BPH. However, whether diabetes aggravates the LUTS of BPH patients is still controversial. AIM: To investigate the impact of diabetes mellitus on LUTS in BPH patients. METHODS A literature search was conducted using Web of Science, Embase, PubMed, and China National Knowledge Infrastructure literature databases. This meta-analysis was registered in PROSPERO (registration number: CRD 42020200794). Fixed- or random-effects models were used for analysis according to heterogeneity. The results of the systematic analysis are presented as weighted mean difference (WMD) with the corresponding 95% confidence intervals (CI). RESULTS In total, 1308 studies were retrieved from databases and 18 articles comprising 1685 cases and 4653 controls were selected for meta-analysis. The results of the meta-analysis showed that the International Prostate Symptom Score (IPSS) value and prostate volume of BPH patients with diabetes was significantly higher than that of BPH patients without diabetes. CONCLUSIONS This systematic review is the first to evaluate the impact of diabetes mellitus on LUTS in BPH patients. The results of our meta-analysis support the hypothesis that LUTS in BPH patients is increased in patients with diabetes mellitus compared with controls, which suggests that physicians should pay more attention to BPH patients with diabetes mellitus. SYSTEMATIC REVIEW REGISTRATION PROSPERO [https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=200794], identifier CRD 42020200794.