Risk factors for sporadic salmonellosis: a systematic review and meta-analysis

Non-typhoidal Salmonella is an important causative agent of diarrheal illness worldwide. A systematic review and meta-analysis of case-control studies were performed to determine the main risk factors associated with sporadic salmonellosis. Suitable scientific articles published up to 2017 were identified through a systematic literature search and subject to methodological quality assessment. From each study, odds ratios (OR) were extracted or calculated, as well as study characteristics such as population type, design, type of model used and risk factor categorization. Mixed-effects meta-analytical models were adjusted by population type to appropriate data partitions. From 3858 identified references, the quality assessment stage was passed by 62 case-control studies focusing on sporadic salmonellosis which provided 1154 ORs for meta-analysis. The meta-analysis identified host-specifics factors, travel, environmental, animal and food exposures as significant risk factors of salmonellosis in the mixed population. For the mixed population, foods significantly associated with salmonellosis were eggs and egg products, composite foods, and meat (pork, red meats other than beef and poultry meats). In the child population, the main risk factors were found for person-to-person transmission, recent use of gastric anti-acids or antibiotics, contact with pets and farm animals, environmental, and food vehicles. Breastfeeding was found to be a protective factor for children. The food vehicles identified in children comprised dairy (milk formula), produce, meat and eggs products. Untreated drinking water was a risk factor for the children and mixed population. The result of the meta-analysis conducted at the international level is very important in the context of increasing international trade in foodstuffs and changes in food consumption patterns.