[Bone mineral density disminution post Roux-Y bypass surgery].

INTRODUCTION: Bariatric surgery has important metabolic complications such as bone mass loss.

GOAL: To assess bone mineral density (BMD) after Roux-en-Y gastric by-pass (RYGB) in patients under standard calcium and vitamin D supplementation.

METHOD: In patients with morbid obesity submitted to RYGB, 76 women and 22 men of diverse age, all with standard nutritional instruction including vitamin D and calcium, we measured BMD with a dual X-ray densitometer. They had lumbar spine and hips measurement 2-3 years post-surgery. Twenty females were followed up with BMD until of a mean of 54 months. Using World Health Organization (WHO) criteria's, values were compared with young controls and same age and sex population, evaluating osteopenia and osteoporosis.

RESULTS: Inverse correlation was observed between BMD and age; positive between BMD and body mass index as well as with preoperative weight excess. In women younger than 45 years, we observed a diminished BMD in 26.8% of them, with no cases of osteoporosis. In older females, BMD was decreased in 65.7% (p = 0.0011); corresponding to 45.7% of osteopenia and 20% osteoporosis, more frequent in lumbar spine. In the female's subgroup followed longer, BMD diminished progressively mainly in left hip. In men, there was 36% of osteopenia and 14% of osteoporosis.

CONCLUSION: Patients from both genders and diverse ages after BPYR presented osteopenia and osteoporosis, despite early supplement prescription of calcium and vitamin D. We consider important to perform serial BMD measurements and also to individualize therapy with risk factors control.