Influence of food matrix delivery system on the bioavailability of vitamin D3: A randomized crossover trial in postmenopausal women.

OBJECTIVES: Vitamin D insufficiency (blood 25-hydroxyvitamin D <50 nmol/L) is a global health problem. Vitamin D food fortification might be a solution, but knowledge is sparse on which food matrices yield the highest bioavailability. The aim of this study was to investigate the influence of different food matrices including complex formations with whey proteins on the human bioavailability of vitamin D. METHODS: In this randomized, multiple crossover trial, we enrolled 30 postmenopausal women 60 to 80 y of age with vitamin D insufficiency. We measured changes in serum concentrations of vitamin D3 (D3) postprandially for 24 h in response to the intake of 500 mL of different food matrices with 200 µg D3 added compared with a control (500 mL of water). Foods included apple juice with whey protein isolate (WPI), apple juice, semi-skim milk, and water (with D3). The food matrices were provided in a randomized order with ≥10-d washout period between them. On each intervention day, blood samples were collected at 0, 2, 4, 6, 8, 10, 12 and 24 h. RESULTS: D3 with WPI in juice did not enhance area under the curve (AUC) of serum D3 compared with juice without WPI (370 nmol ×  24 h/L; 95% confidence interval [CI], 321-419 versus 357 nmol ×  24 h/L; 95% CI, 308-406 nmol ×  24 h/L; P = 0.65). However, compared with juice, the AUC was significantly higher in response to the intake of D3 in milk (452 nmol ×  24 h/L; 95% CI, 402-502 nmol ×  24 h/L) and water with D3 (479 nmol ×  24 h/L; 95% CI, 430-527 nmol ×  24 h/L; P < 0.05). No difference was observed between milk and water (P = 0.34). CONCLUSIONS: The bioavailability of D3 was superior in milk and water compared with juice, regardless of whether WPI was added.

Effects of PTH and PTH Hypersecretion on Bone: a Clinical Perspective.

PURPOSE OF REVIEW: Hyperparathyroidism may be due to an autonomous hypersecretion of parathyroid hormone (PTH) or occurs in response to a number of physiological stimuli. A number of recent findings have provided new insights into the importance of the calcium-parathyroid-vitamin D axis to bone in normal physiology and pathological conditions. RECENT FINDINGS: PTH is known to affect bone microarchitecture with different effects on cortical and trabecular bone compartments. In trabecular bone, PTH may exert anabolic effects, whereas PTH promotes bone resorption in cortical bone. Vertebral fractures are prevalent in primary hyperparathyroidism (PHPT), and patients seem to fracture at higher values of bone mineral density (BMD) than patients with osteoporosis. This may be explained by changes in bone microarchitecture, which cannot be detected by measuring BMD. Even in mild PHPT, bone seems to benefit from parathyroidectomy. In secondary hyperparathyroidism, bone seems much more susceptible to fracture with insufficient levels of vitamin D compared with a replete vitamin status. If elevated PTH levels cannot be explained by conditions known to cause secondary hyperparathyroidism, the condition is termed normocalcemic PHPT, which also has been associated with an increased risk of fractures. Hyperparathyroidism is harmful to bone, which is why it is of importance to normalize PTH levels either by parathyroidectomy in PHPT or by counteracting conditions known to increase PTH in secondary hyperparathyroidism.

Effect of Parathyroidectomy on Cardiovascular Risk Factors in Primary Hyperparathyroidism: A Randomized Clinical Trial.

CONTEXT: It remains unclear whether risk of cardiovascular diseases is increased in patients with mild (<1.45 mmol/L) to moderate (≥1.45 to 1.60 mmol/L) primary hyperparathyroidism (PHPT). OBJECTIVE: We aimed to determine the short-term effect of parathyroidectomy (PTX) on arterial stiffness, cholesterol levels, and blood pressure (BP). DESIGN: This study was a clinical trial randomly allocating patients to either PTX or a control group (no surgery). Follow-up was performed 3 months after surgery in the PTX group and 3 months after baseline in the control group. SETTING: University hospital. PARTICIPANTS: We recruited 79 patients with PHPT; 69 participants completed the study. MAIN OUTCOMES: Office and ambulatory 24-hour BP, pulse wave velocity (PWV), augmentation index, and fasting plasma cholesterol levels. RESULTS: At baseline, participants had a median level of ionized calcium of 1.41 mmol/L (range, 1.33 to 1.60 mmol/L) and PTH of 10.4 pmol/L (4.5 to 30.4 pmol/L). Median age was 64 years (range, 18 to 81) and 72% were females. Following PTX, plasma total cholesterol levels decreased significantly compared with the controls (P = 0.04). Changes in PWV, augmentation index, and ambulatory 24-hour BP did not differ between groups, except for an increase in ambulatory diastolic BP following PTX. However, in patients with baseline levels of ionized calcium ≥1.45 mmol/L, PWV decreased significantly in response to PTX compared with the control group (P = 0.03). CONCLUSION: PTX may decrease risk of cardiovascular diseases in PHPT by lowering total cholesterol levels, although ambulatory diastolic BP increases in response to surgery. Patients with moderate to severe hypercalcemia may benefit from PTX by a decrease in PWV.

Health-related quality of life improves 1 year after parathyroidectomy in primary hyperparathyroidism: A prospective cohort study.

OBJECTIVE: Impaired quality of life (QoL) in primary hyperparathyroidism (PHPT) is commonly present. Patients may complain about nonspecific neurocognitive symptoms which can be difficult to quantify. Two different disease-specific questionnaires have been developed, that is, the parathyroid assessment of symptoms score (PAS) and the primary hyperparathyroidism quality of life (PHPQoL). Using these two questionnaires, we assessed relationship between QoL and biochemical indices in PHPT and effects of parathyroidectomy (PTX). DESIGN: A prospective cohort study. METHODS: Patients with PHPT diagnosed from 2015 to 2017 were asked to answer the questionnaires before and 12 months after PTX. Biochemistry was obtained on both occasions. RESULTS: A total of 104 PHPT patients answered PAS and PHPQoL questionnaires at baseline, with a median age of 64 years (73% females). PHPQoL score correlated inversely with ionized calcium and PTH at baseline (P Ë‚ 0.04). Total PAS and PHPQoL score did not differ between those with and without osteoporosis, renal calcifications and impaired renal function. Based on levels of ionized calcium, PHPQoL differed significantly between patients with mild- and moderate-severe hypercalcemia (P = 0.01). Fifty-three patients answered PAS and PHPQoL 12 months after PTX showing an improved QoL at follow-up (Pall  Ë‚ 0.02). Stratifying patients into groups based on levels of ionized calcium showed a significantly improved PHPQoL score in patients with mild (˂1.45 mmol/L) as well as moderate-severe hypercalcemia (≥1.45 mmol/L) at follow-up (Pall  Ë‚ 0.03). CONCLUSION: Quality of life improved 12 months after PTX in PHPT patients. Impaired QoL seems to be associated with the degree of hypercalcemia rather than organ manifestations attributable to PHPT.

Predictors of Renal Function and Calcifications in Primary Hyperparathyroidism: A Nested Case-Control Study.

Context: Some patients with primary hyperparathyroidism (PHPT) develop renal calcifications. Investigation of urinary and nonurinary risk factors are essential. Objective: We aimed to study the prevalence and potential biochemical predictors of renal calcifications. Design: Nested case-control study. Setting: University hospital. Participants: We identified 792 patients with PHPT from 2005 to 2015. We used biochemical data to validate the diagnosis of PHPT. Main Outcome Measures: The prevalence of renal calcifications defined as nephrolithiasis or nephrocalcinosis assessed by a routine CT scan at the time of diagnosis. Results: A total of 792 patients with PHPT were identified among whom 617 patients (78%) had a CT scan preformed. We found a prevalence of renal calcifications of 23%, equally frequent between sexes. A total of 76 patients (12%) had nephrolithiasis and 75 patients (12%) had nephrocalcinosis where 7 patients (1%) had both nephrolithiasis and nephrocalcinosis. Compared with patients without renal calcifications, patients with renal calcifications had significantly higher levels of ionized calcium, parathyroid hormone, and 24-hour calcium excretion (Pall < 0.01). Patients with nephrocalcinosis had higher plasma levels of phosphate and a higher calcium-phosphate product compared with patients with nephrolithiasis (Pall < 0.05). Impaired renal function (estimated glomerular filtration rate <60 mL/min) was observed in 12% of patients. However, no differences in renal function were observed between those with and without renal calcifications. Conclusion: Renal calcifications are frequent in patients with PHPT and are associated with the severity of the disease. Impaired renal function is also common in PHPT, but renal function was not associated with renal calcifications.

Prevalence and Risk of Vertebral Fractures in Primary Hyperparathyroidism: A Nested Case-Control Study.

Prevalence of vertebral fractures (VFx) in primary hyperparathyroidism (PHPT) remains uncertain. We aimed to estimate the prevalence of VFx, investigate potential risk factors associated with VFx, and whether bone mineral density (BMD) differs between PHPT and osteoporotic patients with VFx. Through the Danish National Patient Register, we identified patients diagnosed with PHPT from 2005 to 2015. The diagnosis was verified by reviewing biochemical findings, and X-ray reports were reviewed by two investigators. Osteoporotic patients with VFx were identified from our outpatient clinic and matched on age and sex with PHPT patients with VFx. We identified 792 PHPT patients among whom spine X-ray was available from 588 patients. VFx were present in 122 (21%) patients and were equally frequent among sexes (77% females). Fractured patients were older (70 versus 63 years) and had lower heights (163 versus 166 cm) compared with nonfractured patients (p all < 0.02). After stratification by age groups, the prevalence of VFx differed significantly between sexes (p < 0.01). Ionized calcium and parathyroid hormone did not differ between groups. BMD at total hip and forearm were lower in fractured compared with nonfractured patients (p < 0.03 for both) after adjusting for age, sex, and body mass index (BMI). Compared with osteoporotic patients with VFx (n = 108), BMD at the lumbar spine was higher in PHPT patients with VFx (n = 108) (p < 0.01). This did not change by excluding patients with lumbar VFx (p < 0.01). The severity of PHPT assessed by biochemistry does not seem to be associated with risk of VFx. Compared with osteoporosis, VFx seems to occur at a higher BMD in PHPT. © 2018 American Society for Bone and Mineral Research.