Each year 6,800 bariatric operations are performed in Sweden. Bariatric surgery involves both a reduced intake and a reduced absorption of vitamins and minerals. There has been debate about whose responsibility long-term follow-up is, particularly regarding monitoring vitamin and mineral status. The Swedish Society for Bariatric Surgery and the Norwegian Association for Bariatric Surgery, who oversee their respective national quality registers, have appointed an expert group to develop guidelines for postoperative supplementation and nutritional monitoring of vitamins and minerals, along with a schedule for routine follow-up. Several existing international guidelines have served as the basis for the development of this guidance. The Finnish Association for Metabolic Surgery and The Danish Association for the Study of Obesity have also decided to adopt the recommendations. The care of the patient group with severe obesity is a common responsibility of primary care and hospitals, as patients are heavily affected by obesity-related morbidity, which, even without surgery, requires major health care efforts, not least from primary care. After surgery, a large proportion of these efforts can be reduced, but focus changes.

OBJECTIVE: Accumulation of visceral adipose tissue (VAT) is strongly linked to insulin resistance. Variations in the size of any adipose depot are determined by alterations in adipocyte volume and/or number. The individual contribution of each of the latter factors was determined in the major omentum, a fully resectable VAT depot.

SUBJECTS: Total removal of the major omentum (omentectomy) was performed in conjunction with bariatric surgery in 55 obese patients. Tissue weight as well as mean adipocyte size and number in the omentum were determined. In subgroups, total VAT was estimated by computerized tomography (n = 17) or dual-energy x-ray absorptiometry (n = 34).

RESULTS: The weight of the major omentum (on average 0.6 kg) correlated significantly with total VAT mass estimated by computerized tomography or dual-energy x-ray absorptiometry (r = 0.48-0.7; P < .01). Omental weight in relation to total body fat correlated with several features of the metabolic syndrome and inversely with serum-leptin (P < .001). Mean adipocyte size and total adipocyte number correlated strongly with omental weight (r = 0.6-0.8; P < .0001), irrespective of body mass index and total body fat mass, and accounted almost in total for interindividual variations in omental size. However, stepwise regression analysis demonstrated that adipocyte number was significantly (P < .0001) more important (62%) than adipocyte size (35%).

CONCLUSION: The size of the major omentum is representative for VAT mass and correlates with a pernicious metabolic profile. Variations in omental weight are primarily determined by adipocyte number and to a lesser degree by adipocyte size, suggesting that increased VAT mass in obesity is predominantly dependent on adipocyte proliferation.