Adolescents and young adults with severe obesity

Body mass index is calculated as kilograms divided by height in meters squared. Percent change in body mass index from baseline is calculated as: [(Follow-up BMI - Baseline BMI) /Baseline BMI]*100%.

Among those subjects identified with diabetes (DM) at baseline, remission of DM at each post-operative study time point was defined as: no use of medication for DM, and HbA1c < 6.5%, or, if HbA1c was not available, fasting glucose <126mg/dL. DM at baseline was defined by taking into consideration self-report of prior diagnosis, as well as prior medical records from referring physician, use of DM medications, baseline HbA1c ≥6.5%, fasting glucose ≥126 mg/dL, or oral glucose tolerance results in prior 6 months. Participants reporting having polycystic ovarian syndrome who did not meet laboratory criteria for diabetes and were not taking a DM medication other than metformin were not considered to have DM. Participants who were on metformin at baseline for weight management or for insulin resistance, with no other indication of a prior diagnosis of DM documented and no laboratory findings consistent with the diagnosis of DM were not considered to have DM.

Among those subjects identified with hypertension (HTN) at baseline, remission of HTN was defined as that no medications for blood pressure (BP) were being used and systolic BP < 140 mmHg and diastolic BP < 90 mmHg. BP was measured at the time of the study visit and use of medications for control of BP was recorded on medication use form (MED). Hypertension was defined in a manner consistent with that used to clinically define hypertension: use of BP medications or systolic BP>140 mmHg or diastolic BP > 90 mmHg.

Fasting blood specimens were drawn at the preoperative, 6 month, and annual research visits. All laboratory assays were performed by the Northwest Lipid Metabolism and Diabetes Research Laboratories (Seattle, WA). Presence of hypoferritinemia is defined as <10ug/L for females and <20ug/L for males.