Impact of bariatric surgery, lifestyle change, and pharmacotherapy on fertility in men with obesity: a systematic review protocol.

Objective: This review will determine whether various health interventions designed to reduce weight (lifestyle change, bariatric surgery, pharmacotherapy) in men with obesity are associated with improved fertility markers. The review will also establish whether the degree of weight loss achieved through these methods is associated with improvement.

Introduction: Current preconception guidelines provide limited information for men with obesity. Small studies implementing lifestyle changes in men are associated with improvement in sperm quality, whereas bariatric surgery has not been associated with improvements in sperm quality. Determining the benefit of different interventions and the relationship to weight lost is necessary to optimize male fertility.

Inclusion criteria: The population will be men younger than 50 years with overweight (BMI >25 kg/m 2 ) or obesity (BMI >30 kg/m 2 ). The exposure of interest will be an intervention undertaken to improve health or reduce weight, categorized as lifestyle change, bariatric surgery, or pharmacotherapy. Outcomes will include time to conception, fecundity rate, assisted reproduction outcomes, and semen quality measures. Secondary analysis will determine whether degree of weight loss achieved is associated with degree of improvement.

Methods: This review will follow the JBI methodology for systematic reviews of etiology and risk. Databases to be searched will include PubMed, Embase (Ovid), Cochrane Central Register of Controlled Trials, Web of Science Core Collection, and Scopus. Articles not published or translated into English will be excluded. Methodological quality will be assessed using the JBI critical appraisal tools. Data will be extracted using a tool developed by the reviewers. Statistical meta-analysis will be performed where possible to synthesize outcomes of similar methods.

Review registration: PROSPERO CRD42022349665.