# Association of Low Vitamin D and Intact Parathyroid Hormone (iPTH) in Nepalese Population: When Does iPTH Exactly Rise?

## TL;DR

This study finds that in Nepal, parathyroid hormone levels rise at specific vitamin D thresholds, suggesting a need to maintain higher vitamin D levels for health.

## Contribution

The study identifies specific vitamin D thresholds (18.5 and 42.0 ng/mL) where parathyroid hormone levels change in the Nepalese population.

## Key findings

- 30.2% of participants had vitamin D levels below 20 ng/mL.
- Two inflection points in PTH levels were observed at 18.5 and 42.0 ng/mL of vitamin D.
- Maintaining vitamin D above 42.0 ng/mL is recommended to prevent health issues.

## Abstract

Vitamin D deficiency is a global public health concern that provokes bone demineralization and weakening. In response to the decreased vitamin D level, calcium stores wear out. The homeostatic effect of compensatory hyperparathyroidism in vitamin D deficiency incites variable discrepancies in different populations. This study intends to decipher the transition point of PTH in relation to levels of vitamin D in a Nepalese population. A cross-sectional study was carried out at Tribhuvan University Teaching Hospital, Nepal. Serum calcium, phosphorus, intact PTH, and 25-hydroxy vitamin D levels were assayed in an Abbott ARCHITECT Integrated System. A correlation plot of PTH and vitamin D was analyzed in Statistical Package for Social Sciences version 22.0. Using a locally weighted scatter plot smoothing method, the relation between these variables was presented graphically. Among 281 individuals, 30.2% had vitamin D levels below 20 ng/mL. There was an archetypical transition in the PTH levels in concert with the decrease in vitamin D level marked by 2 inflection points (ie, 18.5 and 42.0 ng/mL). Our findings suggest that to augment overall health and avert weakness due to vitamin D deficiency, the levels of vitamin D should be maintained above 42.0 ng/mL in our population.