Bariatric Surgery Outcomes Affected by Vitamin D Status

A new study demonstrates a graded relationship between proxy measures of vitamin D (VitD) status and adverse outcomes following bariatric surgery.

Researchers at Johns Hopkins University (JHU; Baltimore, MD, USA) conducted a retrospective cohort study to investigate the association between adverse surgical outcomes following bariatric surgery when compared by season (Summer, Winter, and Fall/Spring), and latitude (Northern United States vs. Southern) as proxy measures of VitD status, based on the US nationwide inpatient sample (NIS). In all, 932,091 bariatric surgeries were identified (median age 43 years, 81.2% female, and 74.4% white), with most surgeries occurring in the North.

The results showed that most adverse postoperative complications occurred in colder seasons with less sunshine. Adverse outcome rates ranged from wound infections (0.01%) to prolonged length of stay (LOS, 39.4%). Season was inversely associated with wound infection and dehiscence, and extended LOS was inversely correlated with season; the relationships held after adjustment for latitude. For example, around 16% of delayed wound healing cases occurred in summer, compared with 0.07% in winter. The study was published on December 14, 2015, in Obesity Science & Practice.

“Sun exposure is critical in the synthesis of vitamin D, so the notion that people living in less sunny northern states may suffer from vitamin D deficiency is not surprising. What is remarkable is how closely sun exposure, vitamin D, and surgical outcomes were linked,” said lead author nutritionist Leigh Peterson, PhD, MHS, of the JHU Centers for Bariatric Surgery. “The growing rates of obesity and increased popularity of bariatric surgeries mean that primary care clinicians and bariatric surgeons should consider screening their patients and correcting any confirmed vitamin D deficiency.”

VitD is a group of fat-soluble secosteroids that the human body can synthesize with adequate sun exposure. VitD prevents rickets in children and osteomalacia in adults, and together with calcium, helps protect older adults from osteoporosis. It also affects neuromuscular function, inflammation, and the action of many genes that regulate the proliferation, differentiation and apoptosis of cells. Epidemiology has long used season and latitude as proxies for group VitD.

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