ABSTRACT
Purpose/Aim: To evaluate the association between the Bsm1 vitamin D receptor polymorphism and the calcium-vitamin D-parathormone axis following bariatric surgery. Materials and Methods: This cross-sectional study included 86 morbidly obese patients, who underwent either gastric bypass or sleeve gastrectomy, with a mean follow-up of four years. Calcium metabolism indices and bone turnover markers were assessed according to the presence of secondary hyperparathyroidism and the Bsm1 vitamin D receptor genotypes. Results: Secondary hyperparathyroidism (42.2% of sample) was associated with lower levels of 25hydroxyvitamin D and elevated markers of bone turnover. In subjects without secondary hyperparathyroidism, presence of the unfavorable B allele resulted in higher levels of parathormone (Bb and BB vs. bb genotype: 50.3 ± 8.2 pg/dl vs. 44.4 ± 10.7 pg/dl, p = .011, adjusted for weight loss, baseline body mass index, 25hydroxyvitamin D, surgical procedure, and duration after surgery). In the whole sample, patients bearing the unfavorable B allele exhibited lower weight loss, a parameter that was negatively associated with markers of bone resorption. Conclusions: Secondary hyperparathyroidism is highly prevalent after bariatric surgery. Bsm1 vitamin D receptor polymorphism may have an effect in early stages of calcium metabolism imbalance, while no association is detected in patients who have already developed secondary hyperparathyroidism. Moreover, vitamin D receptor polymorphism is associated with post-surgery weight loss, a process related to bone turnover.
SUPPLEMENTARY MATERIAL
Questionnaire
Evaluation of demographic and lifestyle parameters.
Race
(0: Caucasian, 1: Non-Caucasian)
Ethnicity
(0: Greek, 1: Other)
Type of surgery
(0: Roux-En-Y-Gastric Bypass, 1: Sleeve Gastrectomy)
Gender (0: male, 1: female)
Date of birth
Marital status
(0: married, 1: single/divorced/widowed)
Highest degree obtained
(0: no education, 1: primary education, 2: secondary education, 3: university degree)
Physical exercise
(0: not at all, 1: ≤ 1 hr weekly, 2: 1–4 hr weekly,
3: > 3 hr per week)
Alcohol consumption
(0: never, 1: occasionally, 2: daily)
Smoking habits
(0: never or past smoker, 1: current smoker)
Medical history:
(0: no, 1: yes)
• Diabetes mellitus?
• Hypertension?
• Coronary heart disease?
• Dyslipidemia
• Arterial thrombosis
• Thromboembolism
• Thyroid dysfunction
• Other (specify)
12. Medication administration (0: no, 1: yes)
• Oral hypoglycemic drugs (metformin, sulfonylureas, a-glycosidase inhibitors, DPP4, GLP-1)
• Insulin (glargine, levemir, or human isophane insulin)
• Angiotensin II receptor antagonist
• Calcium channel blocker
• Diuretic
• B-Blocker
• Digoxin
• Hypolipidemic drugs: statins, fibrates, nicotinic acid
• Acenocoumarol
• Heparin
• Levothyroxine
• Antithyroid drugs: carbimazole, thiamazole
• NSAIDs
13. vitamin and micronutrient supplementation (0: no, 1: yes)
• Calcium and vitamin D
• Ferrum
• Folic acid
• Vitamin B12
• Multivitamins
14. Menopausal status (for women)
(0: premenopausal, 1: postmenopausal)
15. For women: Years since menopause