Relationships Between Vitamin D Status and PTH over 5 Years After Roux-en-Y Gastric Bypass: a Longitudinal Cohort...

Area of Science:

• Endocrinology
• Bariatric Surgery
• Nutritional Science

Background:

• Secondary hyperparathyroidism (SHPT) is a potential complication after obesity surgery, impacting bone health.
• Optimal vitamin D levels to prevent postoperative SHPT remain undetermined.

Purpose of the Study:

• To investigate the relationship between serum 25-hydroxyvitamin D (S-25(OH)D) levels and the development of SHPT.
• To determine if SHPT prevalence differs across various S-25(OH)D thresholds post-Roux-en-Y gastric bypass (RYGB).

Main Methods:

• Longitudinal study of 554 patients up to 5 years after RYGB.
• Analysis of serum 25-hydroxyvitamin D (S-25(OH)D), ionized calcium (iCa), and parathyroid hormone (PTH) levels.
• Assessment of SHPT prevalence across different S-25(OH)D concentration thresholds.

Main Results:

• Parathyroid hormone (PTH) and SHPT prevalence increased over 5 years, while S-25(OH)D and iCa decreased.
• SHPT occurred less frequently with S-25(OH)D levels ≥ 50 nmol/l (OR 0.44), ≥ 75 nmol/l (OR 0.38), and ≥ 100 nmol/l (OR 0.19) compared to < 50 nmol/l.
• At 5 years, 38% of patients had SHPT, with prevalence highest in the S-25(OH)D < 50 nmol/l group (50%) and lowest in the S-25(OH)D ≥ 100 nmol/l group (19%).

Conclusions:

• A significant relationship exists between S-25(OH)D levels and the development of PTH and SHPT.
• Higher S-25(OH)D thresholds (≥ 50 nmol/l and ≥ 75 nmol/l) were associated with lower SHPT prevalence over 5 years.
• The lowest SHPT prevalence was observed with S-25(OH)D levels ≥ 100 nmol/l.