Effect of Vitamin D level on bone density after bariatric surgery.

 (Does increase vitamin D level before bariatric surgery decrease risk of losing bone density after bariatric surgery?) Use the Jadad Scale. – Clarify how to measure bone density in studies. It may be one of the criteria to include or exclude the study. – Maximum length of abstract: 350 words. The abstract should be a factual condensation of the entire paper, including a statement of aims and objectives, a clear description of observations and findings, and a concise presentation of conclusions. References to cited literature should not be included.