Hyperparathyroidism and Vitamin D Deficiency after Laparoscopic Gastric Bypass

Abstract

Hyperparathyroidism (HPT) can occur after gastric bypass because of the alteration in vitamin D and calcium absorption. Adequate serum vitamin D concentrations have not been clearly defined in this patient population. Vitamin D (Vit D) and parathyroid hormone (PTH) were assessed 1 year after laparoscopic gastric bypass (LGB). The prevalence of HPT and Vit D deficiency were determined and their association was evaluated using Fisher's exact test. Ninety-three patients (aged 44 ± 1.1 years, 49.6 ± 0.67 kg/m2 body mass index, 79.6% female, 69.6% white) were evaluated. The prevalence of Vit D deficiency (less than 20 ng/mL) and HPT (greater than 65 pg/mL) was 23.6 per cent (n = 22) and 25.7 per cent (n = 28), respectively. Among patients with HPT, only eight of 28 (28.6%) had Vit D deficiency, and of those with Vit D deficiency, only eight of 22 (36.4%) had HPT. There was a weak inverse correlation (r = –0.37) between PTH and Vit D. Blacks are at higher risk for Vit D deficiency. There was no significant association between Vit D deficiency and HPT, Vit D deficiency and Roux limb length, or HPT and Roux limb length. After LGB, Vit D deficiency and hyperparathyroidism occur commonly. Body mass index and Roux limb length are not associated with these two conditions, but racial differences do exist. There is a weak inverse correlation between Vit D and PTH. Further research is needed to elucidate the causes, treatments, and significance of HPT after LGB.

Review article: the nutritional and pharmacological consequences of obesity surgery

“…Secondary hyperparathyroidism (SHPT), vitamin D deficiency and bone loss occur frequently after obesity surgery . Increased post‐surgical serum PTH levels have been reported in up to 53% of patients .…”

Calcium and Vitamin D Status in Morbidly Obese Patients and in Patients After Biliopancretic Diversion/Duodenal Switch

“…It is interesting that in morbidly obese patients there is a direct relationship between the level 25(OH)D and the level of PTH, but in patients who undergo bypass surgery, the correlation between 25(OH)D and PTH cannot be revealed [35][36][37][38]. When patients undergo GBP, the preferential sites for the absorption of calcium, the duodenum, and proximal jejunum are bypassed, so they have a risk of hypocalcaemia that only partially depends on of vitamin D. In the study by Clements R. et al patients were recruited one year after GBP: vitamin D deficiency was found in 23.6% cases, elevated PTH -in 25.7% cases [38]. Only 28.6% patients with SHPT had low 25(OH)D and in patients with vitamin D deficiency, only 36% had PTH elevation.…”

“…Malabsorption is a result of the anatomic changes imposed by bariatric surgery, and most of the patients are predisposed to calcium and vitamin D deficiency. Secondary hyperparathyroidism (SHPT) and osteoporosis may occur in the absence of adequate supplementation [12][13][14][15].…”

Endocrine and metabolic aspects of the management of patients undergoing bariatric surgery. Review of clinical recommendations.

“…При отсутствии должной коррекции дефицит витамина D и гипокальциемия развиваются практически у всех пациентов, перенесших шунтирующие бариатрические операции [16,25,34,64]. Проблема профилактики и лечения нарушений обмена кальция у этой категории больных требует особого внимания, так как назначение стандартной терапии витамином D в дозе 1000 МЕ в сутки в комбинации с 1500-2000 мг кальция не позволяет добиться удовлетворительных показателей [28].…”