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Congenital cryptorchidism is a well-established risk factor of testicular malignancies. However, there is still remarkable variability in the measures of associations between of these two clinical entities. The current meta-analysis investigates the up-to-date risk of testicular cancer in adults with a history of surgically corrected congenital cryptorchidism until adolescence. The meta-analysis was conducted with strict criteria for the identification of the congenital cryptorchidism cases that underwent surgery before adulthood. The study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of the PubMed and the Scopus databases was conducted, using a defined strategy, from inception to February 2023. Two independent authors screened the literature and extracted the data, using inclusion and exclusion criteria. Of the 2176 articles identified, 93 articles were fully retrieved, and 6 articles met all the inclusion criteria. The Newcastle-Ottawa scale was applied for the studies' quality assessment. The random-effects model in RevMan 5.4 program was used for the meta-analysis. Three case-control studies and three cohort studies were selected. They included 371,681 patients and 1786 incidents of testicular cancer. The pooled odds ratio (OR) was 3.99 (95% confidence intervals (CI): 2.80-5.71). The heterogeneity was moderate and estimated at 51% with the I-squared statistic. A forest plot and a funnel plot were produced to evaluate the ORs and the probable publication bias, respectively. The mean Newcastle-Ottawa score was 8/9 for all the included reports.  Conclusion: This systematic review and meta-analysis verifies, with an updated estimate, the increased risk of testicular cancer in adults with an orchidopexy history. New evidence on the maldescent laterality supports that the cancer risk remains increased and for the contralateral, unaffected testicle, although to a lesser extent. The orchidopexy in the first year of life prevents the testicular damage and decreases the overall cancer risk. What is Known: • Congenital cryptorchidism is the commonest genitourinary abnormality and a risk factor for testicular cancer. • The most recent meta-analysis reporting this association was in 2013. What is New: • After reviewing literature until February 2023, the association of congenital cryptorchidism with testicular cancer risk in adulthood was verified: odds ratio=3.99 [2.80-5.71], 95% CI. • The meta-analysis highlights the protective role of early orchidopexy and the controversial data about maldescent and testicular cancer laterality., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Genetic and environmental factors during early development may influence lung growth and impact lung function. We performed a meta-analysis of epidemiological studies examining the association between conception history of assisted reproduction techniques (ART) and childhood asthma. We searched PubMed and Embase up to November 2020 for relevant observational studies and synthesized data data under a fixed or random effects model as appropriate. Heterogeneity was assessed using the I 2 metric. We identified 13 individual studies including 3,226,386 participants. We did not observe a statistically significant association between ART and physician-diagnosed asthma (n = 9, random OR 1.16; 95% CI 0.94-1.43; I 2 61%). We observed a statistically significant association between ART and prescription of asthma medications (n = 6, fixed OR 1.27; 95% CI 1.23-1.32; I 2 0%). Wheezing was also associated with ART (n = 4, fixed OR 1.71; 95% CI 1.08-2.72; I 2 0%). When we combined studies using any asthma definition, a statistically significant association was observed (random OR 1.19; 95% CI 1.05-1.34; I 2 80%).Conclusion: The available observational evidence suggests that the risk of asthma is higher among children born after ART. The mechanism and potential sources of bias behind this association are under scrutiny, and further work is needed to establish causality. What is Known: • "Positive" epidemiological signals for the association between assisted reproduction techniques and asthma stemming from large studies were not replicated by subsequent research. • Any available research synthesis effort so far bears no quantitative aspect. What is New: • The available observational evidence suggests that the risk of asthma is higher among children born after ART. • The mechanism and potential sources of bias behind this association are under scrutiny.

It is not well known whether genetic markers identified through genome-wide association studies (GWAS) confer similar or different risks across people of different ancestry. We screened a regularly updated catalog of all published GWAS curated at the NHGRI website for GWAS-identified associations that had reached genome-wide significance (p ≤ 5 × 10(-8)) in at least one major ancestry group (European, Asian, African) and for which replication data were available for comparison in at least two different major ancestry groups. These groups were compared for the correlation between and differences in risk allele frequencies and genetic effects' estimates. Data on 108 eligible GWAS-identified associations with a total of 900 datasets (European, n = 624; Asian, n = 217; African, n = 60) were analyzed. Risk-allele frequencies were modestly correlated between ancestry groups, with >10% absolute differences in 75-89% of the three pairwise comparisons of ancestry groups. Genetic effect (odds ratio) point estimates between ancestry groups correlated modestly (pairwise comparisons' correlation coefficients: 0.20-0.33) and point estimates of risks were opposite in direction or differed more than twofold in 57%, 79%, and 89% of the European versus Asian, European versus African, and Asian versus African comparisons, respectively. The modest correlations, differing risk estimates, and considerable between-association heterogeneity suggest that differential ancestral effects can be anticipated and genomic risk markers may need separate further evaluation in different ancestry groups.