Cryptosporidium spp. is an important cause of gastrointestinal disease worldwide, responsible for 69 million cases of illness in 2016. Information on the sources and transmission pathways of human cryptosporidiosis results mainly from outbreak investigations.

A systematic review and a meta-analysis of case-control and cohort studies were performed to determine the main risk factors associated with sporadic cryptosporidiosis. Suitable scientific articles were identified through a systematic literature search and subjected to a methodological quality assessment. From each study, odds ratio (OR) measures were extracted or calculated, as well as study characteristics such as population type, design, type of model and risk factor hierarchy. Mixed-effects meta-analysis models were adjusted by population type to appropriate data partitions.

From 1985 identified references, the quality assessment stage was passed by 57 cohort and case-control studies focusing on sporadic cryptosporidiosis. The eligible studies were conducted between 1983 and 2016 and provided 568 OR categorized for meta-analysis.

This meta-analysis identified travel, immunocompromising conditions, contact with infected humans, waterborne transmission (contact with recreational waters, wastewater, and consumption of untreated drinking water), contact with animals and food consumption as the relevant risk factors for sporadic cryptosporidiosis. With regards to food exposures, consumption of meat, dairy products (raw milk) and dishes consumed outside home were found significantly associated with cryptosporidiosis. The consumption of poorly washed fruits and vegetables significantly increases ORs. This meta-analysis reveals that some potential sources of Cryptosporidium such as shellfish or vegetables are under-investigated.

Future case-control studies for sporadic cryptosporidiosis should include population at risk, and investigate other potential sources in relation to the genotype and the subtype of Cryptosporidium spp.

隐孢子虫属。隐孢子虫病是全球胃肠道疾病的重要原因，2016年造成6900万例疾病。有关人类隐孢子虫病的来源和传播途径的信息主要来自暴发调查。

进行了病例对照研究和队列研究的系统评价和荟萃分析，以确定与散发性隐孢子虫病相关的主要危险因素。通过系统的文献检索确定合适的科学文章，并进行方法学质量评估。从每项研究中，都提取或计算了优势比（OR）测度以及研究特征，例如人口类型，设计，模型类型和风险因素层次。根据人群类型将混合效应荟萃分析模型调整为适当的数据分区。

从1985年确定的参考文献开始，质量评估阶段通过了57个针对散发性隐孢子虫病的队列研究和病例对照研究。符合条件的研究在1983年至2016年之间进行，并提供568个OR分类进行荟萃分析。

这项荟萃分析将旅行，免疫功能低下的条件，与受感染人类的​​接触，水传播（与娱乐用水，废水和未经处理的饮用水的接触），与动物和食物的接触作为散发性隐孢子虫病的相关危险因素。关于食物暴露，发现肉类，奶制品（生乳）和在家庭外食用的食物的消费与隐孢子虫病显着相关。食用水洗不良的水果和蔬菜会大大增加OR。这项荟萃分析表明，对隐孢子虫的某些潜在来源（例如贝类或蔬菜）的研究不足。

未来针对散发性隐孢子虫病的病例对照研究应包括处于危险中的人群，并研究与隐孢子虫属的基因型和亚型有关的其他潜在来源。