Serum iPTH range in a reference population: From an integrated approach to vitamin D prevalence impact evaluation.

BACKGROUND: The iPTH upper reference limit (URL) reported by our laboratory provider (Abbott Laboratories) at Tor Vergata University Hospital was evaluated by internal verification procedures as not representative of our population and resulting as underestimated. In this study, a new reference interval has been investigated and established by comparing a direct and an indirect method based on a statistical reduction from results stored in the laboratory database. METHODS: For reference interval calculation from the healthy population, we analyzed a cohort of 100 blood donors (84% males and 16% females) screened with no bone-related and malabsorption diseases. We analyzed a cohort of 495 patients retrieved from more than 800 iPTH results by excluding subjects with pathological measurement for calcium, phosphorus, and creatinine for the reference interval evaluation. Patients with vitamin D results were included in the analysis. Vitamin D sufficiency status during the period from January to September 2020 was also evaluated by investigating 3,050 patients. RESULTS: The iPTH reference interval of a healthy blood donor population was measured as 25.2-109.1 pg/mL (2.7-11.6 pmol/L) at 2.5 and 97.5 distribution percentile. The iPTH reference interval from data stored in the laboratory database was 19.3-112.5 pg/mL (2.0-11.9 pmol/L). Furthermore, 60% of the whole population had prevalently insufficient vitamin D concentration (<30 ng/dL; <75 nmol/L). The impact of vitamin D concentration on the iPTH reference interval was measured for insufficient vitamin D (<30 ng/dL; <75 nmol/L) as 15.2-127.7 pg/mL (1.6-13.5 pmol/L), desirable vitamin D (30-40 ng/ml; 75-100 nmol/L) as 25.6-105 pg/mL (2.7-10.7 pmol/L) and optimal vitamin D (>40 ng/ml; >100 nmol/L) as 26.2-89.2 pg/mL (2.8-9.4 pmol/L), respectively. CONCLUSIONS: The URL reported in manufacturer datasheets likely refers to a normal population with non-pathological vitamin D levels. On the contrary, the considered population was mostly vitamin D insufficient, resulting in a URL shift. On this basis, we suggest describing in medical reports the iPTH range for vitamin D deficiency for diagnosis of primary hyperparathyroidism even when a specific vitamin D request is lacking. On the other hand, reporting optimal vitamin D-based iPTH reference interval could be clinically relevant in supplemented patients as a marker of treatment efficacy.

Prevalence of major cardiovascular risk factors among oil and gas and energy company workers.

INTRODUCTION: Cardiovascular diseases (CVD) remain the biggest cause of disability and premature death throughout the world. AIM: The aim of this study was to describe and determine the prevalence of major cardiovascular risk factors emerged at the first medical examination carried out by a group of an oil and gas contractor company workers in the observation period 2000-2010. METHODS: An observational cross-sectional study was conducted on 1073 workers (mean age 41 years, SD = 9.5) presenting overweight BMI (body mass index) values, hypertension and cholesterol problems. RESULTS: In particular, we found that workers > 45 years had significant higher risk to have obesity (OR = 3.8, CI 95% = 2.5-5.7), hypertension (OR = 2.7, CI 95% = 2.1-3.6), high blood fasting glucose (OR = 2.6, CI 95% = 1.2-5.5), high cholesterol (OR = 2.7, CI 95% = 2.0-3.6), high triglycerides (OR = 1.8, CI 95% = 1.4-2.4) compared to younger (< 45 years).