Combined Effects of Vitamin D Status, Renal Function and Age on Serum Parathyroid Hormone Levels.

Background: Vitamin D status and renal function are well-known independent predictors of serum parathyroid hormone (PTH) levels. We aimed to describe the combined effects of 25-hydroxy vitamin D (25(OH)D), glomerular filtration rate (GFR) and age on serum PTH levels across the whole clinical spectrum. Methods: We retrieved from our endocrinology center database all PTH measurement between 2012 and 2020 for which a simultaneous measurement of serum 25(OH)D, calcium and creatinine was available. Age, sex and diagnosis were available for all subjects. Intact PTH was measured using the same electrochemiluminescence assay. Results: There were 6,444 adults and 701 children without a diagnosis of hyper- or hypoparathyroidism or abnormal serum calcium levels. In adults with 25(OH)D≥12 ng/mL multiple regression models showed that serum PTH was negatively correlated with both 25(OH)D and GFR. Regression (-0.68 and -1.59 vs. -0.45 and -0.22 respectively), partial correlation (-0.16 and -0.35 vs. -0.12 and -0.10 respectively) and determination coefficients (0.14 vs. 0.031) were higher in CKD than in normal renal function. In subjects with 25(OH)D<12 ng/mL, GFR was the only significant predictor in those with CKD (ß-coefficient=-2.5, r=-0.55) and 25(OH)D was the only significant predictor in those with normal renal function (ß-coefficient=-2.05, r=-0.11). Increasing age was associated with higher PTH levels only in those with normal renal function and 25(OH)D≥12 ng/mL. Conclusions: We showed that declining vitamin D and renal function have additive effects on serum PTH in subjects without vitamin D deficiency. In vitamin D deficient subjects this dependency is stronger but is not additive anymore.

Thyroglobulin in lymph node fine-needle aspiration biopsy washout fluid. A tertiary center experience.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Most PTC secretes thyroglobulin, a useful marker in monitoring preoperative staging and postoperative progression; in addition to serum thyroglobulin, fine needle aspiration washout thyroglobulin (FNA-Tg) is also used. Our aim was to determine the cut-off value for FNA-Tg in our center and to describe major discrepancies between FNA-Tg, cytology and pathology results of the lymph nodes. METHODS: We retrospectively retrieved from the electronic database of our endocrinology center all the FNA-Tg measurements between December 10, 2019 and September 2021. For each measurement we also retrieved the corresponding sex, FNAB results and the pathology reports. FNA-Tg was measured by ECLIA immunoelectro-chemiluminescent method. RESULTS: There were 58 FNAB and FNA-Tg of suspect cervical lymph nodes in 40 patients. There were 17 cytologically benign lymph nodes of which 13 had low and 4 had high FNA-Tg; 3 non-diagnostic cytology results of which one had high FNA-Tg; 38 PTC metastases of which 6 had low and 32 had high FNA-Tg titers. The cut-off value of FNA-Tg in our center is 10 ng/ml, with a sensitivity of 86.6% (in those with pathology reports available after surgery). CONCLUSIONS: Washout TG is useful in suspicious lymph nodes and has added value to cytology in selected cases. The cut-off value of FNA-Tg in our center is 10 ng/ml, with a sensitivity of 86.6%. However, we must consider the possible false negative results that may occur in some histological types of PTC.

Seasonal periodicity of serum parathyroid hormone and its relation with vitamin D in Romania.

We measured serum parathyroid hormone in 8409 Romanian subjects and found a mild seasonal variation with highest levels in March and lowest levels in September. PTH was dependent on serum vitamin D, particularly below 12.82 ng/mL. Together, these suggest that vitamin D supplementation is warranted only in at-risk groups. PURPOSE: Seasonal variation of parathyroid hormone (PTH) and its dependency on serum 25-hydroxy vitamin D (25(OH)D) levels are well-described. However, there are few studies from Europe, and genetic, nutritional, and cultural differences are important. We describe the seasonal variation of serum PTH and its relation with serum 25(OH)D levels in Romania. METHODS: We retrieved from our endocrinology center database all PTH measurements between 2011 and 2019 together with age, sex, diagnosis, and date of blood sampling. Simultaneous serum 25(OH)D levels were partially available. Intact PTH was measured using the same electrochemiluminescence assay. RESULTS: There were 8409 subjects (median age 49 (36, 60) years; 20.5% men) without a diagnosis of hyperparathyroidism (primary or secondary to chronic kidney disease), hypoparathyroidism, or low bone mass. Serum PTH showed a mild seasonal variation with highest levels at the end of March (47.61 pg/mL) and lowest levels at the end of September (43.15 pg/mL). All sex and age subgroups showed highest levels in the spring and lowest levels in the fall. Males had significantly lower PTH levels than females irrespective of season. PTH correlated inversely with serum 25(OH)D with a breakpoint of 12.82 ng/mL in 2800 subjects who had a simultaneous measurement of 25(OH)D. Increasing age was associated with increasing PTH levels independently of serum 25(OH)D. CONCLUSIONS: We showed a mild seasonal variation of serum PTH in Romania, at an inverse sinusoidal pattern than serum 25(OH)D. The breakpoint on the PTH-25(OH)D correlation suggests that vitamin D supplementation is warranted only in at-risk groups.