Importance The parasite Toxoplasma gondii has been associated with behavioral alterations and psychiatric disorders. Studies investigating neurocognition in people with T gondii infection have reported varying results. To systematically analyze these findings, a meta-analysis evaluating cognitive function in healthy people with and without T gondii seropositivity is needed. Objective To assess whether and to what extent T gondii seropositivity is associated with cognitive function in otherwise healthy people. Data Sources A systematic search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline. A systematic search of PubMed, MEDLINE, Web of Science, PsycInfo, and Embase was performed to identify studies from database inception to June 7, 2019, that analyzed cognitive function among healthy participants with available data on T gondii seropositivity. Search terms included toxoplasmosis, neurotoxoplasmosis, Toxoplasma gondii, cognition disorder, neuropsychological, and psychomotor performance. Study Selection Studies that performed cognitive assessment and analyzed T gondii seroprevalence among otherwise healthy participants were included. Data Extraction and Synthesis Two researchers independently extracted data from published articles; if needed, authors were contacted to provide additional data. Quantitative syntheses were performed in predefined cognitive domains when 4 independent data sets per domain were available. Study quality, heterogeneity, and publication bias were assessed. Main Outcomes and Measures Performance on neuropsychological tests measuring cognitive function. Results The systematic search yielded 1954 records. After removal of 533 duplicates, an additional 1363 records were excluded based on a review of titles and abstracts. A total of 58 full-text articles were assessed for eligibility (including reference list screening); 45 articles were excluded because they lacked important data or did not meet study inclusion or reference list criteria. The remaining 13 studies comprising 13 289 healthy participants (mean [SD] age, 46.7 [16.0] years; 6586 men [49.6%]) with and without T gondii seropositivity were included in the meta-analysis. Participants without T gondii seropositivity had favorable functioning in 4 cognitive domains: processing speed (standardized mean difference [SMD], 0.12; 95% CI, 0.05-0.19; P = .001), working memory (SMD, 0.16; 95% CI, 0.06-0.26; P = .002), short-term verbal memory (SMD, 0.18; 95% CI, 0.09-0.27; P < .001), and executive functioning (SMD, 0.15; 95% CI, 0.01-0.28; P = .03). A meta-regression analysis found a significant association between older age and executive functioning (Q = 6.17; P = .01). Little suggestion of publication bias was detected. Conclusions and Relevance The study's findings suggested that T gondii seropositivity was associated with mild cognitive impairment in several cognitive domains. Although effect sizes were small, given the ubiquitous prevalence of this infection globally, the association with cognitive impairment could imply a considerable adverse effect at the population level. Further research is warranted to investigate the underlying mechanisms of this association.

中文翻译：

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刚地弓形虫血清阳性与健康人认知功能的关联：系统评价和荟萃分析。

重要性 寄生虫弓形虫与行为改变和精神疾病有关。调查弓形虫感染者的神经认知的研究报告了不同的结果。为了系统地分析这些发现，需要进行一项荟萃分析，评估有和没有弓形虫血清阳性的健康人的认知功能。目的 评估弓形虫血清阳性是否以及在多大程度上与其他健康人群的认知功能相关。数据来源 按照系统评价和荟萃分析的首选报告项目 (PRISMA) 报告指南进行了系统搜索。对 PubMed、MEDLINE、Web of Science、PsycInfo 和 Embase 进行了系统搜索，以确定从数据库开始到 2019 年 6 月 7 日的研究，该研究利用弓形虫血清阳性的可用数据分析了健康参与者的认知功能。搜索词包括弓形虫病、神经弓形虫病、弓形虫、认知障碍、神经心理学和精神运动表现。研究选择 包括在其他健康参与者中进行认知评估和分析弓形虫血清阳性率的研究。数据提取与综合 两名研究人员独立从已发表的文章中提取数据；如果需要，会联系作者以提供更多数据。当每个域有 4 个独立的数据集可用时，在预定义的认知域中进行定量合成。评估了研究质量、异质性和发表偏倚。主要结果和测量 测量认知功能的神经心理学测试的表现。结果 系统检索产生了 1954 条记录。在删除 533 个重复项后，根据对标题和摘要的审查，排除了另外 1363 条记录。共评估了 58 篇全文文章的资格（包括参考列表筛选）；45 篇文章因缺乏重要数据或不符合研究纳入或参考列表标准而被排除。其余 13 项研究包括 13 289 名健康参与者（平均 [SD] 年龄，46.7 [16.0] 岁；6586 名男性 [49.6%]），有和没有 T gondii 血清学阳性的患者被纳入荟萃分析。没有弓形虫血清阳性的参与者在 4 个认知领域有良好的功能：处理速度（标准化平均差 [S​​MD]，0.12；95% CI，0.05-0.19；P = .001），工作记忆（SMD，0.16；95% CI， 0.06-0.26；P = .002），短期言语记忆（SMD，0.18; 95% CI，0.09-0.27；P < .001）和执行功能（SMD，0.15；95% CI，0.01-0.28；P = .03）。元回归分析发现年龄较大与执行功能之间存在显着关联（Q = 6.17；P = .01）。几乎没有发现发表偏倚的迹象。结论和相关性 该研究的结果表明，刚地弓形虫血清阳性与多个认知领域的轻度认知障碍有关。尽管影响很小，但鉴于这种感染在全球范围内普遍存在，与认知障碍的关联可能意味着在人群水平上产生相当大的不利影响。需要进一步研究来调查这种关联的潜在机制。元回归分析发现年龄较大与执行功能之间存在显着关联（Q = 6.17；P = .01）。几乎没有发现发表偏倚的迹象。结论和相关性 该研究的结果表明，刚地弓形虫血清阳性与多个认知领域的轻度认知障碍有关。尽管影响很小，但鉴于这种感染在全球范围内普遍存在，与认知障碍的关联可能意味着在人群水平上产生相当大的不利影响。需要进一步研究来调查这种关联的潜在机制。元回归分析发现年龄较大与执行功能之间存在显着关联（Q = 6.17；P = .01）。几乎没有发现发表偏倚的迹象。结论和相关性 该研究的结果表明，刚地弓形虫血清阳性与多个认知领域的轻度认知障碍有关。尽管影响很小，但鉴于这种感染在全球范围内普遍存在，与认知障碍的关联可能意味着在人群水平上产生相当大的不利影响。需要进一步研究来调查这种关联的潜在机制。的研究结果表明，弓形虫血清阳性与几个认知领域的轻度认知障碍有关。尽管影响很小，但鉴于这种感染在全球范围内普遍存在，与认知障碍的关联可能意味着在人群水平上产生相当大的不利影响。需要进一步研究来调查这种关联的潜在机制。的研究结果表明，弓形虫血清阳性与几个认知领域的轻度认知障碍有关。尽管影响很小，但鉴于这种感染在全球范围内普遍存在，与认知障碍的关联可能意味着在人群水平上产生相当大的不利影响。需要进一步研究来调查这种关联的潜在机制。