Within-pair analysis of monozygotic twins after bariatric surgery: a systematic review

Obesity is an increasingly widespread illness currently affecting more than 890 million adults worldwide. Excess body weight is a multifactorial challenge, driven by complex interaction between genetic predisposition and environmental influences rendering the underlying causes of obesity difficult to identify. Monozygotic twin (MZT) studies provide great value in medical research analyzing external exposures within twin pairs with fixed genetic or environmental factors that normally tend to confound results in general population studies. Metabolic-bariatric surgery (MBS) is considered an effective durable therapy in terms of body weight loss (BWL) and the control of cardiometabolic risk factors in obese patients. Body mass index (BMI) is known to be strongly related in MZ twins but whether this relation is stable between MZ twins after MBS is still to be determined. The results of this study support the importance of genetics over BWL after MBS with high correlation amongst MZ twin pairs.