Bariatric Surgery in Class 1 Obesity

Obesity is still on the rise and remains as the second most common cause of preventable deaths following tobacco smoking. Since only a small portion of obeseObese patients can achieve enough and sustainable weight lossWeight loss by non-surgical methods, bariatric surgeryBariatric surgery became an invaluable option for the treatment of chronic obesity during the last decades. The undisputed evidence that weight reduction surgerySurgical weight reduction extends life-span mainly had come from two sources. The data from the Swedish ObeseObese Subjects (SOS) study (Lissner et al. in Eur J Clin Nutr 52(5):316–322, 1998 [1]; Carlsson et al. in N Engl J Med 383(16):1535–1543, 2020 [2]) and the data from the United States-UTAH (Adams et al. in N Engl J Med 377(12):1143–1155, 2017 [3]; Adams et al. in Obesity (Silver Spring) 31(2):574–585, 2023 [4]), both similarly and repeatedly showed the positive effect of bariatric surgeryBariatric surgery on longevity of life. This effect is mainly due to resolution of metabolic syndromeMetabolic syndrome and cardiovascular risk reduction and to some extent may also be due to cancerCancer risk reduction. However, both the SOS and UTAH data comprised mainly patients with body mass indexBody mass index (BMI) ≥ 35 kg/m2 and class 1 obeseObese patients were vastly excluded during the evolvement of bariatric surgical practice. In a class 1 obeseObese patient, the risk of surgery was apparently similar compared to patients having higher BMIs; however no data on long-term outcome or probable longevity benefit are available; therefore, the risk/benefit ratio of bariatric surgeryBariatric surgery in class 1 obeseObese patients remained unknown.