Department of Natural Sciences, University of Houston-Downtown, Houston, Texas, USA.
The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
BMJ Open. 2023 Mar 1;13(3):e068974. doi: 10.1136/bmjopen-2022-068974.
This study sought to examine the relationship between seropositivity for toxocariasis and cognitive functioning in a nationally representative sample of US older adults.
A cross-sectional study.
National Health and Nutrition Examination Survey (NHANES) data collection took place in the US at participants' homes and mobile examination centres with specialised equipment.
The study population consisted of 3188 community-dwelling US older adults aged 60 and above from the NHANES 2011 to 2014.
IgG antibody against spp was tested by a Luminex assay using recombinant rTc-CTL-1 antigen. A value >23.1 mean fluorescence intensity (MFI) indicated positive for toxocariasis and a value ≤23.1 MFI as negative for toxocariasis. The Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest immediate and delayed memory, the Animal Fluency test and the Digit Symbol Substitution Test (DSST) were used to assess cognitive functioning. Cognitive test-specific and global cognitive z scores were computed using sample means and SD.
The study population consisted of 3188 participants who represented a total of 111 896 309 civilian citizens in the USA. The mean age of the participants was 69.6 years (standard deviation 6.8). The prevalence of toxocariasis in this population was 7.3% (95% confidence interval [CI] 6.1% to 8.5%). The survey-weighted linear regression model showed that compared with participants who were toxocariasis seronegative, those who were seropositive had lower DSST z score (beta [β] = -0.12, 95% CI -0.22 to -0.01) and global cognition z score (β=-0.11, 95% CI -0.22 to -0.01), after controlling for age, sex, race/ethnicity, education, depressive symptoms, smoking status, body mass index, prevalent coronary heart disease, prevalent stroke, and systolic blood pressure, physical activity, and total cholesterol.
In our study, seropositive toxocariasis was independently and significantly associated with worse working memory, sustained attention, processing speed and global cognition in older adults. If this association is causal, public health measures to prevent human toxocariasis might help protect older adults' cognitive function.
本研究旨在探讨美国老年人群中，弓形虫血清阳性与认知功能之间的关系。
横断面研究。
美国国家健康与营养调查（NHANES）数据采集在参与者家中和配备专业设备的移动体检中心进行。
研究人群为来自 NHANES 2011 至 2014 年的 3188 名 60 岁及以上的社区居住的美国老年人。
使用 Luminex 检测试剂盒（采用重组 rTc-CTL-1 抗原）检测针对 spp 的 IgG 抗体。阳性结果定义为 >23.1 平均荧光强度（MFI），阴性结果定义为 ≤23.1 MFI。使用认知测试特定的和总体认知 z 分数，计算 Consortium to Establish a Registry for Alzheimer's Disease Word Learning 即时记忆和延迟记忆、动物流畅性测试和数字符号替换测试（DSST）的结果。
研究人群由 3188 名参与者组成，代表了美国共 111896309 名平民。参与者的平均年龄为 69.6 岁（标准差为 6.8）。该人群中弓形虫的患病率为 7.3%（95%置信区间[CI]：6.1%至 8.5%）。经过加权线性回归模型校正后，与血清阴性的参与者相比，血清阳性的参与者的 DSST z 分数（β=-0.12，95%CI：-0.22 至 -0.01）和总体认知 z 分数（β=-0.11，95%CI：-0.22 至 -0.01）均较低，校正年龄、性别、种族/民族、教育、抑郁症状、吸烟状况、体重指数、冠心病、中风、收缩压、身体活动和总胆固醇等因素后。
在我们的研究中，血清阳性的弓形虫感染与老年人的工作记忆、持续注意力、处理速度和总体认知能力下降独立相关。如果这种关联是因果关系，预防人类弓形虫病的公共卫生措施可能有助于保护老年人的认知功能。
