Proxy measures of vitamin D status - season and latitude - correlate with adverse outcomes after bariatric surgery in the Nationwide Inpatient Sample, 2001-2010: a retrospective cohort study.

Objective: To investigate the association between adverse surgical outcomes following bariatric surgery and proxy measures of vitamin D (VitD) status (season and latitude) in the Nationwide Inpatient Sample (NIS).

Background: Obesity is an independent risk factor for VitD deficiency (25(OH)D < 20 ng ml). VitD deficiency compounds the chronic inflammation of obesity, increasing the risk of adverse outcomes following bariatric surgery.