Indoor Tanning and the Risk of Overall and Early-Onset Melanoma and Non-Melanoma Skin Cancer: Systematic Review and Meta-Analysis

The aim of this study was to examine the association between indoor tanning use and the risk of overall and early-onset (age < 50) melanoma and non-melanoma skin cancer (NMSC). To evaluate the association between indoor tanning and skin cancer, a systematic review of the literature published until July 2021 was performed using PubMed, EMBASE, and MEDLINE. Summary relative risk (RR) from 18 studies with 10,406 NMSC cases and 36 studies with 14,583 melanoma cases showed significant association between skin cancer and indoor tanning (melanoma, RR= 1.27, 95% CI 1.16–1.39; NMSC, RR = 1.40, 95% CI 1.18–1.65; squamous cell carcinoma (SCC), RR = 1.58, 95% CI 1.38–1.81; basal cell carcinoma (BCC), RR = 1.24, 95% CI 1.00–1.55). The risk was more pronounced in early-onset skin cancer (melanoma, RR = 1.75, 95% CI 1.14–2.69; NMSC, RR = 1.99, 95% CI 1.48–2.68; SCC, RR = 1.81, 95% CI 1.38–2.37; BCC, RR = 1.75, 95% CI 1.15–2.77). Moreover, first exposure at an early age (age ≤ 20 years) and higher exposure (annual frequency ≥ 10 times) to indoor tanning showed increasing risk for melanoma (RR = 1.47, 95% CI 1.16–1.85; RR = 1.52, 1.22–1.89) and NMSC (RR = 2.02, 95% CI 1.44–2.83; RR = 1.56, 95% CI 1.31–1.86). These findings provide evidence supporting primary prevention policies regulating modifiable behaviors to reduce the additional risk of skin cancer among younger adults.

Dietary intake of linoleic acid, its concentrations and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of prospective cohort studies

<b>Background: </b>Earlier evidence on the association between dietary PUFAs and risk of diabetes has been conflicting.<b> </b><b></b> <p><b>Purpose:</b> To quantitatively summarize previous studies on the association between dietary LA intake, its biomarkers, and the risk of type 2 diabetes mellitus (T2DM) in the general population.</p> <p><b>Data source:</b> PubMed/Medline, Scopus, and ISI Web of Science until 24 October 2020, and reference lists of all related articles, and key journals.</p> <p><b>Study selection: </b>Prospective cohort studies that examined the associations of LA with the risk of T2DM in adults.</p> <p><b>Data synthesis:</b> The inverse variance method was applied to calculate summary relative risk (RR) of LA intake and its biomarkers, and dose-response associations was modeled using restricted cubic splines. Twenty-three publications, covering a total of 31 prospective cohorts, were included; these studies included 297,685 participants (22,639 incident diabetes cases) with dietary intake assessment and 84,171 participants (18,458 incident diabetes cases) with biomarker measurements. High intake of LA was associated with a 6% lower risk of T2DM (summary relative risk (RR): 0.94, 95% confidence interval (CI): 0.90, 0.99;<i> I²</i>=48.5%). In the dose-response analysis, each 5% increment in energy from LA intake was associated with a 10% lower risk of T2DM. There was also evidence of a linear association between LA intake and diabetes, with the lowest risk at highest intakes. The summary RR for diabetes per SD increment in LA concentrations in adipose tissue/blood compartments was 0.85 (95%CI: 0.80, 0.90; <i>I²</i>=66.2%). The certainty of the evidence was assessed as moderate.</p> <p><b>Limitation:</b> Observational design of studies included in the analyses.</p> <p><b>Conclusions:</b> We found that a high intake of dietary LA and elevated concentrations of LA in the body were both significantly associated with a lower risk of T2DM. These findings support dietary recommendations to consume dietary LA.</p>

Dietary intake of linoleic acid, its concentrations and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of prospective cohort studies

<b>Background: </b>Earlier evidence on the association between dietary PUFAs and risk of diabetes has been conflicting.<b> </b><b></b> <p><b>Purpose:</b> To quantitatively summarize previous studies on the association between dietary LA intake, its biomarkers, and the risk of type 2 diabetes mellitus (T2DM) in the general population.</p> <p><b>Data source:</b> PubMed/Medline, Scopus, and ISI Web of Science until 24 October 2020, and reference lists of all related articles, and key journals.</p> <p><b>Study selection: </b>Prospective cohort studies that examined the associations of LA with the risk of T2DM in adults.</p> <p><b>Data synthesis:</b> The inverse variance method was applied to calculate summary relative risk (RR) of LA intake and its biomarkers, and dose-response associations was modeled using restricted cubic splines. Twenty-three publications, covering a total of 31 prospective cohorts, were included; these studies included 297,685 participants (22,639 incident diabetes cases) with dietary intake assessment and 84,171 participants (18,458 incident diabetes cases) with biomarker measurements. High intake of LA was associated with a 6% lower risk of T2DM (summary relative risk (RR): 0.94, 95% confidence interval (CI): 0.90, 0.99;<i> I²</i>=48.5%). In the dose-response analysis, each 5% increment in energy from LA intake was associated with a 10% lower risk of T2DM. There was also evidence of a linear association between LA intake and diabetes, with the lowest risk at highest intakes. The summary RR for diabetes per SD increment in LA concentrations in adipose tissue/blood compartments was 0.85 (95%CI: 0.80, 0.90; <i>I²</i>=66.2%). The certainty of the evidence was assessed as moderate.</p> <p><b>Limitation:</b> Observational design of studies included in the analyses.</p> <p><b>Conclusions:</b> We found that a high intake of dietary LA and elevated concentrations of LA in the body were both significantly associated with a lower risk of T2DM. These findings support dietary recommendations to consume dietary LA.</p>

Association of Dietary Carrot Intake With Bladder Cancer Risk in a Prospective Cohort of 99,650 Individuals With 12.5 Years of Follow-Up

Previous studies have provided limited evidence for the effect of carrot intake on bladder cancer incidence. This study aimed to evaluate the association between carrot consumption and bladder cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening cohort. PLCO enrolled 154,897 participants between November 1993 and July 2001 from 10 clinical screening centers throughout the United States. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression model adjusting for confounders. A meta-analysis was also performed based on all available prospective studies with DerSimonian and Laird random-effects model to calculate summary relative risk (RR) and 95% CI. After a median of 12.5 years of follow-up, 762 incident bladder cancer cases occurred. We found no statistically significant association between dietary carrot intake and bladder cancer risk. The multivariate-adjusted HR of bladder cancer for participants in the highest category of total carrot intake compared with those in the lowest category was 0.96 (95% CI: 0.76–1.22; P for trend = 0.436). Corresponding adjusted HR was 0.98 (95% CI 0.90–1.06) per 1 SD increment of carrot intake. A meta-analysis based on two previous cohort studies and our study also found no significant association between carrot intake and bladder cancer risk (Summary HR 1.02, 95% CI 0.95–1.10) without obvious heterogeneity between studies (P = 0.859, I2 = 0.0%). In summary, analysis of the PLCO cohort did not provide evidence that dietary consumption of carrot was associated with the risk of bladder cancer.

Bidirectional association between periodontal disease and diabetes mellitus: a systematic review and meta-analysis of cohort studies

Periodontal disease has been reported to be associated with diabetes mellitus. However, the direction of the association and the influence of bias are not clear. Thus, the aim of this systematic review and meta-analysis was to summarize the existing evidence on the bidirectional prospective association between periodontal disease and diabetes mellitus by accounting for the risk of bias of the original studies. The literature search was conducted on the electronic data sources PubMed and Web of Science up to February 9th, 2021. We included observational studies, which investigated the prospective association between diabetes mellitus and periodontal disease or vice versa. The risk of bias of the primary studies was evaluated by applying the Quality in Prognosis Studies (QUIPS) tool. Random effects models were used to calculate summary relative risk (SRR) with 95% CI. Subgroup analyses were applied to investigate heterogeneity and the robustness of the finding. In total, 15 studies were included . The SRR for incident diabetes mellitus was 1.26 (95% CI 1.12, 1.41; I2: 71%, n = 10; participants = 427,620; identified cases = 114,361), when comparing individuals with periodontitis to individuals without periodontitis. The SRR for incident periodontitis was 1.24 (95% CI 1.13, 1.37; I2: 92%, n = 7; participants = 295,804; identified cases: > 22,500), comparing individuals with diabetes to individuals without diabetes. There were no significant differences between subgroups after stratification for risk of bias. The findings show a positive bidirectional association between periodontal disease and diabetes mellitus, and thus, underline the need for screening of patients with periodontitis regarding diabetes mellitus and vice versa. The main limitation of the study is the high unexplained heterogeneity between the studies including the different assessment methods of the disease diagnosis.

Physical activity and the risk of rheumatoid arthritis: evidence from meta-analysis and Mendelian randomization

Background There is very little information about the association between physical activity (PA) and the risk of rheumatoid arthritis (RA). The purpose of this study is to understand the effect of PA on subsequent risk of developing RA. Methods A literature search was performed in PubMed and Web of Science up to 19 September 2020. Observational studies examining associations between PA and the RA development were identified. Categorical and dose–response meta-analyses were both performed. Then two-sample Mendelian randomization (MR) analysis was conducted to interrogate the causal relationship by utilizing genetic instruments identified from a genome-wide association study of self-reported and accelerometer-based PA traits. Results Four eligible studies were included in the meta-analyses, involving 4213 RA cases among 255 365 participants. The summary relative risk (RR) of RA risk was 0.79 [95% confidence interval (CI): 0.72, 0.87] for the highest vs the lowest PA, and 0.85 (95% CI: 0.79, 0.92) for PA vs inactivity/occasional PA. However, we found no convincing evidence supporting a causal role of genetically predicted accelerometer-measured PA [odds ratio (OR): 0.97; 95% CI: 0.88, 1.08 per 1-SD unit increment], genetically predicted moderate-to-vigorous PA (OR: 1.08; 95% CI: 0.49, 2.39 per 1-SD unit increment) or genetically predicted vigorous PA ≥3 days/week (OR: 2.63; 95% CI: 0.05, 130.96) with RA risk. Conclusions The meta-analyses of the observational studies indicated that higher PA levels correlate with reduced risk of RA. In contrast to meta-analyses, the MR analyses reported here suggested PA may not help to prevent RA.

Vasectomy and prostate cancer risk: a meta-analysis of prospective studies

Epidemiological cohort studies investigating the association between vasectomy and prostate cancer risk have yielded inconsistent results. The aim of the present meta-analysis is to update the evidence on the association between vasectomy and prostate cancer. A comprehensively literature search of relevant studies was performed in December 2019 using PubMed. A DerSimonian and Laird random-effects model was used to calculate the summary relative risk (RR) and its 95% confidence interval (CI). A total of 15 eligible cohort studies (16 data sets) with more than four million of participants were eventually included in this meta-analysis. There was a statistically significant higher risk of prostate cancer among men who underwent vasectomy (RR: 1.09, 95% CI: 1.04–1.13) with obvious heterogeneity among included studies (P &lt; 0.001, I2 = 64.2%). Vasectomy was also associated with the risk of advanced prostate cancer (RR: 1.07, 95% CI: 1.02–1.13), which is less likely to be affected from detection bias. In conclusion, findings from this meta-analysis of prospective studies indicate that vasectomy may be positively associated with the risk of prostate cancer. Further large prospective studies with long follow-up are warranted to verify the findings from this meta-analysis. In addition, the potential underlying molecular mechanism needed further exploration with in vitro and animal studies.

LO92: The effect of prehospital intravenous fluids on mortality in trauma: a systematic review and meta-analysis

Introduction: Hemorrhage is the primary cause of death in 39% of trauma patients. In prehospital trauma management, there is debate over pursuing a ‘scoop-and-run’ approach versus early intravenous (IV) fluid therapy. We evaluated the literature regarding the effect of prehospital IV fluid therapy on mortality in adult trauma patients. Methods: A librarian-assisted search was conducted in PubMed, Medline and Embase. The population was adults with blunt and/or penetrating trauma. The intervention was total prehospital IV fluid volume 0-500 mL, and the control was prehospital fluid volume >500 mL. The outcome of interest was in-hospital mortality. Randomized controlled trials (RCTs), cohort and case-matched studies were included. Two reviewers used the Cochrane Risk of Bias (RoB) and Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tools to evaluate biases, and kappa was calculated for inter-rater agreement. A summary relative risk (RR) of in-hospital mortality was calculated and heterogeneity (I2) analysis performed using RevMan 5 software. Results: Four RCT's and eleven observational studies were identified, with n = 15,448 patients. Two RCTs and four observational studies were excluded due to non-English language, and the location or volume of IV fluid administered, leaving eight studies with n = 4,568 patients. Inter-rater agreement was high with the ROBINS-I (unweighted κ=0.8841) and RoB tool (unweighted κ=0.8276). Two studies found decreased mortality, one found increased mortality, and five found no significant relationship to mortality with 0-500 mL prehospital IV fluid. The summary relative risk of mortality with 0-500 mL IV fluid compared to >500 mL IV fluid was not significant (RR = 0.98 [0.87, 1.11]). The heterogeneity for all studies was high (I2 = 84%), but was low (I2 = 0%) with removal of two studies. Conclusion: The majority of studies did not find a relationship between the volume of prehospital IV fluids and in-hospital mortality. Study heterogeneity was low except for two studies: this may be explained by mortality only being recorded at emergency department discharge in one study, and the high rate of penetrating gunshot and stabbing wounds in the other. There is a paucity of high-quality RCTs on the topic, and many studies are at significant risk of bias. Further research is needed to delineate the best approach to IV fluid therapy in adult trauma patients.

Occupational exposure to formaldehyde and risk of non hodgkin lymphoma: a meta-analysis

Background Formaldehyde, a widely used chemical, is considered a human carcinogen. We report the results of a meta-analyses of studies on the relationship between occupational exposure to formaldehyde and risk of non-Hodgkin lymphoma (NHL). Methods We performed a systematic review and meta-analysis according to international guidelines and we identified 12 reports of occupational populations exposed to formaldehyde. We evaluated inter-study heterogeneity and we applied a random effects model. We conducted a cumulative meta-analysis and a meta-analysis according to estimated average exposure of each study population. Results The meta-analysis resulted in a summary relative risk (RR) for NHL of 0.93 (95% confidence interval 0.83–1.04). The cumulative meta-analysis suggests that higher RRs were detected in studies published before 1986, while studies available after 1986 did not show an association. No differences were found between different levels of occupational exposure. Conclusions Notwithstanding some limitations, the results of this meta-analysis do not support the hypothesis of an association between occupational exposure to formaldehyde and risk of NHL.

Daylight saving time and acute myocardial infarction: a meta-analysis

Background The current evidence on the effects of daylight saving time (DST) transitions on major cardiovascular diseases is limited, and available results are conflicting. We carried out the first meta-analysis aimed at evaluating the risk of acute myocardial infarction (AMI) following DST transitions. Methods We searched MedLine and Scopus up to December 31, 2018, with no language restriction, to retrieve cohort or case-control studies evaluating AMI incidence among adults (≥18y) in the week following spring and/or autumn DST shifts versus control periods. A summary relative risk of AMI was computed after: (1) spring, (2) autumn, (3) both transitions considered together versus control weeks. Stratified analyses were performed by gender and age. Data were combined using a generic inverse-variance approach. Results Seven studies (&gt;115,000 subjects) were included in the analyses. A significantly higher risk of AMI (Odds Ratio: 1.03; 95% CI: 1.01-1.06) was observed in the two weeks following spring or winter DST transitions. The risk increase was however significant only after the spring shift (OR: 1.05; 1.02-1.07), while AMI incidence in the week after winter DST transition was comparable to control periods (OR 1.01; 0.98-1.04). No substantial differences by age or gender emerged. Conclusions The risk of AMI increases modestly but significantly following DST transitions, supporting the proposal of DST shifts discontinuation. Additional studies fully adjusting for potential confounders are required to confirm the present findings. Key messages The risk of acute myocardial infarction increases modestly but significantly following DST transitions. Although preliminary, our findings support the proposal of DST shifts discontinuation.