Rising trend in vitamin D status from 1993 to 2013: dual concerns for the future.

BACKGROUND: The Institute of Medicine 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D specified higher intakes for all age groups compared to the 1997 report, but also cautioned against spurious claims about an epidemic of vitamin D deficiency and against advocates of higher intake requirements. Over 40 years, we have noted marked improvement in vitamin D status but we are concerned about hypervitaminosis D. OBJECTIVE: We sought to evaluate the 25-hydroxyvitamin D (25OHD) trend over 20 years. DESIGN: We retrieved all results of serum 25OHD from 1993 to 2013 (n=69 012) that was trimmed to one sample per person (n=43 782). We conducted a time series analysis of the monthly averages for 25OHD using a simple sequence chart and a running median smoothing function. We modelled the data using univariate auto-regressive integrated moving average (ARIMA) and forecast 25OHD levels up to 2016. RESULTS: The time series sequence chart and smoother function demonstrated a steady upward trend with seasonality. The yearly average 25OHD increased from 36.1 nmol/l in 1993 to 57.3 nmol/l in 2013. The ARIMA model was a good fit for the 25OHD time series; it forecasted monthly average 25OHD up to the end of 2016 with a positive stationary R(2) of 0.377. CONCLUSIONS: Vitamin D status improved over the past 40 years, but there remains a dual problem: there are groups at risk of vitamin D deficiency who need public health preventative measures; on the other hand, random members of the population are taking unnecessarily high vitamin D intakes for unsubstantiated claims.

An association between abnormal bone turnover, systemic inflammation, and osteoporosis in patients with chronic pancreatitis: a case-matched study.

INTRODUCTION: Because of deteriorating exocrine function, malabsorption renders chronic pancreatitis (CP) patients at risk of osteoporosis and fracture. However, the pathogenesis of low bone mineral density (BMD) has not been characterized. We hypothesized that bone turnover is elevated in CP, and we sought to investigate an association between bone metabolism and systemic inflammation. METHODS: Twenty-nine CP patients and twenty-nine matched controls were recruited. Bone-turnover markers procollagen 1 amino-terminal propeptide (P1NP), OC (osteocalcin; bone formation markers), and carboxy-terminal telopeptide of type I collagen (CTX-I; bone resorption marker) were measured along with vitamin D (25-hydroxyvitamin D, 25OHD), parathyroid hormone (PTH), interleukin 6 (IL-6), high-sensitivity (hs) C-reactive protein (CRP), and sex/thyroid hormones. BMD was measured by dual-energy X-ray absorptiometry. Smoking status was noted. RESULTS: Of the CP patients, 31% had osteoporosis and 44.8% osteopenia (controls: 6.9 and 51.7%, respectively; P=0.019). BMD was lower for patients at the lumbar spine (P=0.014) and femoral neck (P=0.029). Patients had elevated bone formation (P1NP (P=0.0068), OC (P=0.033)) and bone resportion (CTX-I (P=0.016)) compared with controls. Patients had lower 25OHD compared with controls (P=0.0126) and higher inflammatory markers (hsCRP, P=0.0013). Sex and thyroid hormone levels were similar. Patients with lowest 25OHD levels had highest P1NP. In a multivariable model, age, PTH, and smoking were predictive of 25OHD. Patients with osteoporosis had higher P1NP, PTH, and IL-6 and lower 25OHD. Using analysis of variance, inflammation (hsCRP) was highest in those with lowest 25OHD and lowest BMD. CONCLUSIONS: For the first time, bone turnover was shown to be abnormal in CP, and importantly, an association between low 25-OHD, smoking, and systematic inflammation was identified. Moreover, those with osteoporosis had the highest systemic inflammation. Together these factors provide an avenue for potential modification of risk factors, which may ultimately reduce bone loss and avert fractures in this group.

Hungry bone syndrome and normalisation of renal phosphorus threshold after total parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia: a case report.

INTRODUCTION: This is the first report of which the authors are aware to describe this c.2166delinsGG mutation in X-linked hypophosphataemia and to describe normalisation of renal threshold for phosphate excretion after parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia. CASE PRESENTATION: We present the case of a 34-year-old Caucasian woman with X-linked hypophosphataemia. She developed tertiary hyperparathyroidism with markedly high bone turnover requiring total parathyroidectomy and had prolonged requirement for intravenous calcium infusion after surgery. She had a novel mutation in her phosphate-regulating gene with homologies to endopeptidases on the X-chromosome and had an unusual degree of dependence on phosphate supplementation. Prior to operative intervention she had a trial of cinacalcet that improved bone turnover markers when used in isolation but which led to a paradoxical rise in parathyroid hormone levels when given with phosphate supplementation. After correction of hungry bone syndrome, the renal phosphorus threshold normalised as a manifestation of hypoparathyroid state despite marked elevation in level of fibroblast growth factor 23. CONCLUSIONS: This case illustrates the risk of tertiary hyperparathyroidism as a complication of treatment for hypophosphataemia; it highlights the morbidity associated with hungry bone syndrome and provides novel insight into renal handling of phosphorus.

Evaluation of three different specimen types (serum, plasma lithium heparin and serum gel separator) for analysis of certain analytes: clinical significance of differences in results and efficiency in use.

BACKGROUND: There is a lack of consensus regarding the most appropriate specimen type for analysis of many biochemistry analytes. The aim of this study was to compare renal and lipid analyte profiles and phenytoin values in plain serum (S), serum gel (G) and plasma (lithium heparin, P) tubes and to investigate the stability of these analytes after prolonged contact with cells or gel at room temperature (RT, 20 degrees C) and as aliquoted and stored at 4 degrees C. METHODS: Primary specimens were centrifuged once, maintained at RT and analysed within 2 h (T(0)) and after 24 h (T(24)) and 48 h (T(48)). For assessment of stability at 4 degrees C, two cell-free aliquots were separated from each of the primary tubes and stored at 4 degrees C and then analysed at T(24) and T(48). Differences in analyte concentrations between tubes at T(0) and following storage (at T(24) and T(48)) were evaluated for both statistical and clinical significance. RESULTS: At T(0) all analytes, except potassium, demonstrated equivalence between serum, gel and plasma tubes. Potassium and creatinine were more stable in gel tubes than in serum/plasma tubes. In contrast, phentytoin was stable in plain serum and plasma up to T(48) at RT, but showed a progressive and clinically significant decrease in concentration in gel tubes at T(24) and T(48) at RT. All analytes except CO(2) were stable up to T(48) when aliquoted and stored at 4 degrees C. CONCLUSIONS: We concluded that the serum gel tube has advantages over plain serum and plasma tubes for measurement of the analytes investigated in this study, with the exception of phenytoin. In practice, the gel tubes demonstrate enhanced analyte stability and reduce the need to aliquot specimens, with greater protection against possible contamination. Further investigation would be required to evaluate a broader range of analytes.