Secondary hyperparathyroidism: Predictors and relationship with vitamin D status, bone turnover markers and bone mineral density.
Level 4 - case-series / case-control
Cross-sectional analysis of an observational cohort
PubMed 38642819 · doi:10.1016/j.bone.2024.117108
What was done
Researchers analyzed 4,139 adults aged 60 and older from the Trinity-Ulster-Department of Agriculture (TUDA) cohort in Ireland. Participants with an eGFR <30 ml/min or serum calcium >2.5 mmol/l were excluded to rule out advanced chronic kidney disease and primary hyperparathyroidism. Determinants of secondary hyperparathyroidism (SHPT) were evaluated, and bone turnover markers alongside dual-energy X-ray absorptiometry (BMD) were assessed in a subsample of 1,488 individuals.
What was found
SHPT prevalence was 30.6% in vitamin D-deficient individuals (<30 nmol/l) compared to 9.8% in those with 25(OH)D ≥50 nmol/l. In non-calcium supplement users, key independent predictors of SHPT included vitamin D deficiency (OR 4.18, 95% CI 3.05–5.73, p < 0.001), eGFR 30–44 ml/min (OR 3.69, 95% CI 2.44–5.57, p < 0.001), loop diuretic use (OR 3.52, 95% CI 2.59–4.79, p < 0.001), eGFR 45–59 ml/min (p < 0.001), BMI (p = 0.001), and 25(OH)D 30–49 nmol/l (p = 0.002). Proton pump inhibitor use was associated with SHPT among calcium supplement users (OR 1.55, 95% CI 1.08–2.22, p = 0.018). Participants with SHPT had higher bone alkaline phosphatase (p = 0.017) and tartrate-resistant acid phosphatase (p = 0.033), along with lower BMD at the femoral neck (0.880 vs. 0.903 g/cm², p = 0.033) and total hip (0.968 vs. 0.995 g/cm², p = 0.017).
Why it matters
This study highlights that SHPT is prevalent in community-dwelling older adults and is linked to medication use (loop diuretics and PPIs) as well as subclinical vitamin D insufficiency, correlating directly with increased bone resorption and reduced hip bone density.
Limits
The cross-sectional design cannot establish causality between medication exposure, vitamin D status, and bone loss. BMD and bone turnover markers were assessed in only a subset (n = 1,488) of the cohort, and the study population was limited to older Irish adults, limiting generalizability to other demographics.
Cited by
- supports Parathyroid hormone levels serve as an indirect test to assess vitamin D absorption and severe deficiency.