The effects of season (spring versus autumn) on diagnosis of normocalcemic primary hyperparathyroidism

Abstract

BackgroundRaised parathormone (PTH) and normal calcium concentrations can be observed both in normocalcemic primary hyperparathyroidism (nPHPT) and in secondary hyperparathyroidism, e.g. due to vitamin D deficiency. We assessed the impact of season on the validity of diagnosis of nPHPT in terms of screening investigations to be performed in the primary care settings.Material and methodsOn two occasions (March/April & September/October) we measured vitamin D (25OHD), PTH and total calcium in 125 healthy subjects, age range 6-50, not taking any vitamin D supplements.ResultsIn autumn there was an increase in 25OHD concentrations (from 18.1 ± 7.37ng/ml to 24.58 ± 7.72ng/ml, p<0.0001), a decline in PTH from 44.40 ± 17.76pg/ml to 36.63 ± 14.84pg/ml, p<0.001), without change in calcium levels. Only 45 subjects (36%) were vitamin D sufficient (25OHD>20/ml) in spring versus 83 (66.4%) in autumn, p<0.001. Elevated PTH concentrations were noted in 10 subjects in spring (8%) and in six subjects (4.8%) (p<0.05) in autumn. In spring, however, eight out of ten of these subjects (80%) had 25OHD<20 ng/ml, versus one in six (16.7%) in autumn (p<0.01). Normalization of PTH was observed in seven out ten subjects (70%), and all of them had 25-OHD<20 ng/ml in spring.ConclusionsIn spring elevated PTH concentrations in the setting of normocalcemia are more likely to be caused by 25OHD deficiency rather by nPHPT. In contrast, in autumn, increased PTH concentrations are more likely to reflect nPHPT. We postulate that screening for nPHPT should be done in 25OHD replete subjects, i.e. in autumn rather than in spring.

Editorial: Osteoporosis secondary to endocrine disorders

“…Multiple endocrinopathies lead to osteoporosis development ( 1 , 2 ). Some of them are common - like diabetes mellitus (DM), one of major chronic illness ( 3 ).…”

Letter to the Editor: Parathyroidectomy for Normocalcemic Primary Hyperparathyroidism (nPHPT) is Associated with Improved Bone Mineral Density Regardless of Postoperative Parathyroid Hormone Levels

“…We congratulate the authors on their study on bone mineral density (BMD) changes in Normocalcemic Hyperparathyroidism which is a new kid on the block, even in developing Countries now which are showing increasing trends. In this context Normocalcemic Hyperparathyroidism has been a difficult entity for the endocrine surgeons to understand in terms of the physiology involved, the reset of calcium switch pre‐ and post‐surgery, increased incidence of multi glandular disease, decreased PTH normalization after surgery, seasonal variation and also the reversal of end organ changes [2, 3].…”