Occult osteomalacia in American (U.S.A.) patients with fracture of the hip

Quantitative 31P magnetic resonance imaging on pathologic rat bones by ZTE at 7T

BACKGROUND

Osteoporosis is characterized by low bone mineral density (BMD), which predisposes individuals to frequent fragility fractures. Quantitative BMD measurements can potentially help distinguish bone pathologies and allow clinicians to provide disease-relieving therapies. Our group has developed non-invasive and non-ionizing magnetic resonance imaging (MRI) techniques to measure bone mineral density quantitatively. Dual-energy X-ray Absorptiometry (DXA) is a clinically approved non-invasive modality to diagnose osteoporosis but has associated disadvantages and limitations.

PURPOSE

Evaluate the clinical feasibility of phosphorus (31P) MRI as a non-invasive and non-ionizing medical diagnostic tool to compute bone mineral density to help differentiate between different metabolic bone diseases.

MATERIALS AND METHODS

Fifteen ex-vivo rat bones in three groups [control, ovariectomized (osteoporosis), and vitamin-D deficient (osteomalacia - hypo-mineralized) were scanned to compute BMD. A double-tuned (1H/31P) transmit-receive single RF coil was custom-designed and in-house-built with a better filling factor and strong radiofrequency (B1) field to acquire solid-state 31P MR images from rat femurs with an optimum signal-to-noise ratio (SNR). Micro-computed tomography (μCT) and gold-standard gravimetric analyses were performed to compare and validate MRI-derived bone mineral densities.

RESULTS

Three-dimensional 31P MR images of rat bones were obtained with a zero-echo-time (ZTE) sequence with 468 μm spatial resolution and 12-17 SNR on a Bruker 7 T Biospec having multinuclear capability. BMD was measured quantitatively on cortical and trabecular bones with a known standard reference. A strong positive correlation (R = 0.99) and a slope close to 1 in phantom measurements indicate that the densities measured by 31P ZTE MRI are close to the physical densities in computing quantitative BMD. The 31P NMR properties (resonance linewidth of 4 kHz and T1 of 67 s) of ex-vivo rat bones were measured, and 31P ZTE imaging parameters were optimized. The BMD results obtained from MRI are in good agreement with μCT and gravimetry results.

CONCLUSION

Quantitative measurements of BMD on ex-vivo rat femurs were successfully conducted on a 7 T preclinical scanner. This study suggests that quantitative measurements of BMD are feasible on humans in clinical MRI with suitable hardware, RF coils, and pulse sequences with optimized parameters within an acceptable scan time since human femurs are approximately ten times larger than rat femurs. As MRI provides quantitative in-vivo data, various systemic musculoskeletal conditions can be diagnosed potentially in humans.

Histomorphometric analysis of patients with femoral neck fracture and 25-hydroxyvitamin D deficiency: a cross-sectional study

INTRODUCTION

Vitamin D deficiency causes osteoporosis, bone mineralization disorders, and osteomalacia. Osteomalacia is diagnosed using blood biochemical tests, clinical symptoms, and imaging; however, accurate detection of mineralization disorders requires tissue observation. We investigated the prevalence of bone mineralization disorders and their relationship with serum 25-hydroxyvitamin D (25OHD) levels in patients with untreated osteoporosis with femoral neck fractures.

MATERIALS AND METHODS

A non-demineralized specimen was prepared from the femoral head removed during surgery in 65 patients. Bone histomorphometry of cancerous bone in the femoral head center was conducted. Osteoid volume per bone volume (OV/BV) and osteoid thickness (O.Th) were measured as indicators of mineralization disorder.

RESULTS

The mean serum 25OHD level (11.9 ± 5.7 ng/mL) was in the deficiency range (< 12 ng/mL). There were no clinically diagnosed cases of osteomalacia (OV/BV > 10% and O.Th > 12.5 µm); however, one case of mineralization disorder, considered histologically pre-osteomalacia (OV/BV > 5% and O.Th < 12.5 µm), was observed (OB/BV, 17.6%; O.Th, 12.3 µm). Excluding this case, those with severe (25OHD < 12 ng/mL, at risk of osteomalacia; n = 39) and non-severe deficiency (25OHD ≥ 12 ng/mL; n = 25) did not significantly differ in OV/BV (%; 0.77 ± 0.54 vs. 0.69 ± 0.38, p = 0.484) or O.Th (µm; 5.32 ± 1.04 vs. 5.13 ± 0.78, p = 0.410). Further, 25OHD and OV/BV were not significantly correlated (R = - 0.124, p = 0.327).

CONCLUSION

This is the first study in the twenty-first century to examine serum 25OHD concentrations and bone mineralization disorders in Japanese patients with osteoporosis. The results indicate that vitamin D deficiency does not necessarily cause bone mineralization disorders and rarely leads to osteomalacia.

The complications of male hypogonadism: is it just a matter of low testosterone?

The history of diagnosing hypogonadism and hypotestosteronemia shows us the many steps that were necessary to achieve our current knowledge and the ability to improve these patients' well-being. Moreover, so far, criteria for diagnosing hypotestosteronemia varies according to the underlying condition, and according to the consensus or guideline adopted. Furthermore, besides the many signs and symptoms, there are several complications associated with low testosterone levels such as osteoporosis, metabolic alterations, as well as cardiovascular disorders. However, data are often conflicting regarding the severity, timing or even the real clinical relevance of these complications, although these studies often lack essential information such as gonadotropin levels or the underlying cause of hypogonadism. The present review focus on the complications of male hypogonadism according to the cause of testosterone deficiency, highlighting the lack of information found in many studies investigating its effects. We thereby stress the necessity to always perform a complete evaluation of the type of hypogonadism (including at least gonadotropins and secondary causes) when investigating the effects of low testosterone levels.

Bone metabolism subgroups identified as hip fracture patients via clustering

PURPOSE

The aim of the study was to describe the bone metabolism status that underlies a hip fracture.

METHODS

Estimated glomerular filtration rate (e-GFR), calcium (Ca), phosphorus (P), total (ALP) and bone specific alkaline phosphatase (b-ALP), intact parathyroid hormone (i-PTH), 25-hydroxy-vitamin D (25OHD), total procollagen type I amino-terminal propeptide (PINP), and N-terminal peptide of collagen I (NTx), measured at admission in 272 hip fracture patients, were ex post analyzed by K-means clustering and principal component analysis and were evaluated by a clinician.

RESULTS

Four components, mainly consisting of b-ALP, PINP, ALP, and NTx; e-GFR and P; i-PTH and 25OHD; and Ca explained about 70% of the variability. A total of 184 patients clustered around a centroid (A) with low 25OHD (13.2 ng/ml), well-preserved kidney function (e-GFR=67.19 ml/min/1.73m²), normal Ca, P, i-PTH and bone markers, with the exception of slightly increased NTx (24.82nMBCE). Cluster B (n=70) had increased i-PTH (93.38 pg/ml), moderately decreased e-GFR, very low 25OHD (8.68 ng/dl), and high bone turnover (b-ALP 28.46 U/L, PINP 69.87 ng/ml, NTx 31.3nMBCE). Cluster C (n=17) also had hyperparathyroidism (80.35 pg/ml) and hypovitaminosis D (9.15 ng/ml), low e-GFR(48.89 ml/min/1.73m²), and notably high ALP (173 U/L) and bone markers (b-ALP 44.64 U/L, PINP 186.98 ng/ml, NTx 38.28nMBCE). According to the clinician, 62 cases clearly had secondary hyperparathyroidism.

CONCLUSIONS

Based on serum measurements, the dominant patterns of bone metabolism were normal bone turnover with high normal NTx, and secondary hyperparathyroidism related to chronic kidney disease and hypovitaminosis D. The bone formation markers, e-GFR, NTx, and P composed the most important factors.

Hypogonadism, Type-2 Diabetes Mellitus, and Bone Health: A Narrative Review

One of the complications from chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men is the high prevalence of hypogonadotropic hypogonadism (HH). Both T2DM and hypogonadism are associated with impaired bone health and increased fracture risk but whether the combination results in even worse bone disease than either one alone is not well-studied. It is possible that having both conditions predisposes men to an even greater risk for fracture than either one alone. Given the common occurrence of HH or hypogonadism in general in T2DM, a significant number of men could be at risk. To date, there is very little information on the bone health men with both hypogonadism and T2DM. Insulin resistance, which is the primary defect in T2DM, is associated with low testosterone (T) levels in men and may play a role in the bidirectional relationship between these two conditions, which together may portend a worse outcome for bone. The present manuscript aims to review the available evidences on the effect of the combination of hypogonadism and T2DM on bone health and metabolic profile, highlights the possible metabolic role of the skeleton, and examines the pathways involved in the interplay between bone, insulin resistance, and gonadal steroids.

Microstructural, densitometric and metabolic variations in bones from rats with normal or altered skeletal states

Background

High resolution μCT, and combined μPET/CT have emerged as non-invasive techniques to enhance or even replace dual energy X-ray absorptiometry (DXA) as the current preferred approach for fragility fracture risk assessment. The aim of this study was to assess the ability of µPET/CT imaging to differentiate changes in rat bone tissue density and microstructure induced by metabolic bone diseases more accurately than current available methods.

Methods

Thirty three rats were divided into three groups of control, ovariectomy and vitamin-D deficiency. At the conclusion of the study, animals were subjected to glucose (¹⁸FDG) and sodium fluoride (Na¹⁸F) PET/CT scanning. Then, specimens were subjected to µCT imaging and tensile mechanical testing.

Results

Compared to control, those allocated to ovariectomy and vitamin D deficiency groups showed 4% and 22% (significant) increase in ¹⁸FDG uptake values, respectively. DXA-based bone mineral density was higher in the vitamin D deficiency group when compared to the other groups (cortical bone), yet μCT-based apparent and mineral density results were not different between groups. DXA-based bone mineral density was lower in the ovariectomy group when compared to the other groups (cancellous bone); yet μCT-based mineral density results were not different between groups, and the μCT-based apparent density results were lower in the ovariectomy group compared to the other groups.

Conclusion

PET and micro-CT provide an accurate three-dimensional measurement of the changes in bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. As osteomalacia is characterized by impaired bone mineralization, the use of densitometric analyses may lead to misinterpretation of the condition as osteoporosis. In contrast, µCT alone and in combination with the PET component certainly provides an accurate three-dimensional measurement of the changes in both bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity.

Assessment of axial bone rigidity in rats with metabolic diseases using CT-based structural rigidity analysis

Objectives

This study aims to assess the correlation of CT-based structural rigidity analysis with mechanically determined axial rigidity in normal and metabolically diseased rat bone.

Methods

A total of 30 rats were divided equally into normal, ovariectomized, and partially nephrectomized groups. Cortical and trabecular bone segments from each animal underwent micro-CT to assess their average and minimum axial rigidities using structural rigidity analysis. Following imaging, all specimens were subjected to uniaxial compression and assessment of mechanically-derived axial rigidity.

Results

The average structural rigidity-based axial rigidity was well correlated with the average mechanically-derived axial rigidity results (R2 = 0.74). This correlation improved significantly (p < 0.0001) when the CT-based Structural Rigidity Analysis (CTRA) minimum axial rigidity was correlated to the mechanically-derived minimum axial rigidity results (R2 = 0.84). Tests of slopes in the mixed model regression analysis indicated a significantly steeper slope for the average axial rigidity compared with the minimum axial rigidity (p = 0.028) and a significant difference in the intercepts (p = 0.022). The CTRA average and minimum axial rigidities were correlated with the mechanically-derived average and minimum axial rigidities using paired t-test analysis (p = 0.37 and p = 0.18, respectively).

Conclusions

In summary, the results of this study suggest that structural rigidity analysis of micro-CT data can be used to accurately and quantitatively measure the axial rigidity of bones with metabolic pathologies in an experimental rat model. It appears that minimum axial rigidity is a better model for measuring bone rigidity than average axial rigidity.

Assessment of axial bone rigidity in rats with metabolic diseases using CT-based structural rigidity analysis

Objectives

This study aims to assess the correlation of CT-based structural rigidity analysis with mechanically determined axial rigidity in normal and metabolically diseased rat bone.

Methods

A total of 30 rats were divided equally into normal, ovariectomized, and partially nephrectomized groups. Cortical and trabecular bone segments from each animal underwent micro-CT to assess their average and minimum axial rigidities using structural rigidity analysis. Following imaging, all specimens were subjected to uniaxial compression and assessment of mechanically-derived axial rigidity.

Results

The average structural rigidity-based axial rigidity was well correlated with the average mechanically-derived axial rigidity results (R² = 0.74). This correlation improved significantly (p < 0.0001) when the CT-based Structural Rigidity Analysis (CTRA) minimum axial rigidity was correlated to the mechanically-derived minimum axial rigidity results (R² = 0.84). Tests of slopes in the mixed model regression analysis indicated a significantly steeper slope for the average axial rigidity compared with the minimum axial rigidity (p = 0.028) and a significant difference in the intercepts (p = 0.022). The CTRA average and minimum axial rigidities were correlated with the mechanically-derived average and minimum axial rigidities using paired t-test analysis (p = 0.37 and p = 0.18, respectively).

Conclusions

In summary, the results of this study suggest that structural rigidity analysis of micro-CT data can be used to accurately and quantitatively measure the axial rigidity of bones with metabolic pathologies in an experimental rat model. It appears that minimum axial rigidity is a better model for measuring bone rigidity than average axial rigidity.

Shortcomings of DXA to assess changes in bone tissue density and microstructure induced by metabolic bone diseases in rat models

The aim of this study is to demonstrate the deficiencies of dual-energy X-ray absorptiometry (DXA), compared with quantitative computed tomography, to reflect and differentiate between changes in bone mineral density and microstructure that contribute to a well-defined finding of altered skeletal state for both osteoporosis and renal osteodystrophy induced by chronic renal insufficiency.

INTRODUCTION

The aim of this study is to demonstrate the deficiencies of dual-energy X-ray absorptiometry (DXA), compared with quantitative CT, to reflect and differentiate between changes in bone mineral density and microstructure that contribute to a well-defined finding of altered skeletal state for both osteoporosis and renal osteodystrophy induced by chronic renal insufficiency.

METHODS

Forty-five female Sprague-Dawley rats were divided into three equal groups: control, ovariectomy, and nephrectomy. Following euthanasia, femurs were excised, divided into diaphyseal and distal metaphyseal sections, and subjected to DXA and micro-CT imaging and mechanical testing.

RESULTS

Ovariectomy does not affect the structural and mechanical properties of cortical bone material, but partial nephrectomy does adversely affect these properties. Both are verified by DXA and micro-CT imaging and mechanical testing. Meanwhile, nephrectomy does not affect trabecular bone microstructure or equivalent density, yet ovariectomy affects the trabecular microstructure. DXA is unable to detect changes in trabecular bone microstructure in relation to changes in their mechanical properties.

DISCUSSION

Dual energy X-ray absorptiometry measures the average bone mineral content in a 2D projected area and cannot differentiate whether the changes occur in the bone microstructure or equivalent bone tissue density. In contrast, micro-CT provides an accurate measurement of the changes in both equivalent bone tissue mineral density and microstructure for cancellous and cortical bone.

Seasonal change in osteoid thickness and mineralization lag time in ambulant patients

Low vitamin D levels are common. Bone biopsies taken from 121 ambulant patients were therefore reviewed. Seasonal changes in mineralization correlated inversely with serum 25-hydroxyvitamin D but not the more active metabolite, 1,25-dihydroxyvitamin D. This implies that the latter is produced in bone.

INTRODUCTION

It has been 30 yr since a seasonal variation in osteoid surfaces and calcification fronts was noted in bone biopsies from hip fracture patients in Leeds and attributed to vitamin D status. It was suggested at that time that mild vitamin D deficiency might cause osteoporosis from malabsorption of calcium and more severe deficiency osteomalacia, but little has been published on this subject since.

MATERIALS AND METHODS

We examined bone biopsies, calcium absorption data, and serum vitamin D metabolites in 121 patients attending our osteoporosis clinics in Adelaide. Biopsies were collected from the anterior iliac crest with a Jamshidi needle after two stat oral doses of 1 g of tetracycline 10 days apart, processed into plastic without demineralization, and all parameters were measured by point counting using a Weibel II graticule. Calcium absorption was measured after an oral dose of 5 microCi of (45)Ca in 250 ml of water with 20 mg of calcium carrier. Serum 25-hydroxyvitamin D [25(OH)D] was measured by radioimmunoassay and 1,25-dihydroxyvitamin D [1,25(OH)(2)D] by radioimmunoassay after high-performance liquid chromatography (HPLC).

RESULTS

25(OH)D levels were lower from late autumn to early spring (April to September) than from late spring to early autumn (October to March) (51 +/- 23 versus 61 +/- 27 [SD] nM; p=0.040). None of the biopsies yielded a diagnosis of osteomalacia, but osteoid thickness (O.Th.) was greater in the winter than the summer months (8.5 +/- 3.6 versus 7.1 +/- 2.8 microm; p=0.015) as was mineralization lag time (MLT; 11.9 +/- 5.2 versus 9.5 +/- 3.6; p=0.005). O.Th and log MLT were both inversely related to serum 25(OH)D (p=0.014 and 0.036) but not serum 1,25(OH)(2)D. Calcium absorption was related to serum 1,25(OH)(2)D but not serum 25(OH)D.

CONCLUSIONS

We conclude that circulating 25(OH)D affects the mineralization process, whereas circulating 1,25(OH)(2)D affects bone indirectly through its effect on calcium absorption.

Factors that influence the cutaneous synthesis and dietary sources of vitamin D

The major sources of vitamin D for most humans are casual exposure of the skin to solar ultraviolet B (UVB; 290-315 nm) radiation and from dietary intake. The cutaneous synthesis of vitamin D is a function of skin pigmentation and of the solar zenith angle which depends on latitude, season, and time of day. In order to mimic the natural environment of skin to sunlight exposure, we therefore measured serum 25-hydroxyvitamin D levels in volunteers with different skin types following repeated UV irradiation. Because melanin pigment in human skin competes for and absorbs the UVB photons responsible for the photolysis of 7-dehydrocholesterol to previtamin D3, we also studied the effect of skin pigmentation on previtamin D3 production in a human skin model by exposing type II and type V skin samples to noon sunlight in June when the solar zenith angle is most acute. Vitamin D is rare in food. Among the vitamin D-rich food, oily fish are considered to be one of the best sources. Therefore, we analyzed the vitamin D content in several commonly consumed oily and non-oily fish. The data showed that farmed salmon had a mean content of vitamin D that was approximately 25% of the mean content found in wild caught salmon from Alaska, and that vitamin D2 was found in farmed salmon, but not in wild caught salmon. The results provide useful global guidelines for obtaining sufficient vitamin D3 by cutaneous synthesis and from dietary intake to prevent vitamin D deficiency and its health consequences, ensuing illness, especially, bone fractures in the elderly.

Vitamin D Status in Inpatients Admitted to an Internal Medicine Department

BACKGROUND/AIMS

A role of hypovitaminosis D has been advocated in several medical conditions. We investigated vitamin D status in medical inpatients, compared to a blood donors' group from the same area.

METHODS

Fifty-nine consecutive medical patients were recruited at hospital admission, concomitantly to 207 blood donors of both genders. Serum calcium, albumin, phosphate, creatinine, alkaline phosphatase total activity, 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) were assessed from April to May 2005.

RESULTS

In patients, 25(OH)D values were lower (13.1 +/- 9.2 vs. 16.3 +/- 8.5 ng/ml; p < 0.02) and PTH values higher (73.9 +/- 77.7 vs. 53.4 +/- 24.3 pg/ml; p < 0.01) than in controls, whose mean age was lower (62.5 +/- 14.5 vs. 45.8 +/- 15.6 years, p < 0.01). Such differences were not confirmed when comparing patients to a subgroup of age and sex-matched controls drawn from the whole sample of blood donors. In both patients and controls there was a trend towards a negative correlation between 25(OH)D and age and a positive correlation between PTH and age. The prevalence of 25(OH)D <12 ng/ml was higher in patients than in controls as a whole (58 vs. 34%; chi(2) = 9.95; p < 0.002), but not in respect to the subgroup of matched controls (58 vs. 44%; chi(2) = 2.09; p = 0.14). The prevalence of severe vitamin D deficiency, 25(OH)D <5 ng/ml, was significantly higher in patients than in matched controls (17 vs. 4%; chi(2) = 6.75; p < 0.01).

CONCLUSION

Hypovitaminosis D, defined as 25(OH)D <12 ng/ml, is frequent among inpatients, as in the general population of comparable age. A severe vitamin D deficiency is more common in hospitalized patients.

Histological evaluation of biopsies obtained from vertebral compression fractures: unsuspected myeloma and osteomalacia

STUDY DESIGN

A histological evaluation of biopsies obtained from presumed osteoporotic vertebral compression fractures (VCF) to confirm possible osteomalacia after tetracycline labeling.

OBJECTIVE

To describe the results of a series of biopsies obtained at the time of vertebral augmentation in presumed osteoporotic VCF, with special reference to the presence of unmineralized bone (osteomalacia) and occult or unconfirmed plasma cell dyscrasia.

SUMMARY OF BACKGROUND DATA

Vertebral augmentation is now widely performed as a method to treat osteoporotic or osteolytic VCF. However, the influence of underlying pathology on the effect of treatment is unclear.

METHODS

As of October 2003, 178 biopsies were obtained from 142 patients with VCF during 246 kyphoplasty procedures. There were 110 one-level, 28 two-level, and 4 three-level biopsies. Patients included 41 men and 101 women, with an average age of 72 years (range 40-90). The patients consented to this procedure, and 25 received tetracycline (1g/day, in 2 doses separated by 6 days). Vertebral body biopsies were taken using a trephine just before the kyphoplasty procedure. The biopsies were fixed, embedded, and stained with toluidine blue and hematoxylin eosin, and were viewed with transmitted light. Unstained sections were viewed under fluorescent light to detect tetracycline labels.

RESULTS

The 178 biopsy levels included: T4 (3), T5 (1), T6 (4), T7 (13), T8 (12), T9 (8), T10 (11), T11 (17), T12 (28), L1 (25), L2 (14), L3 (13), L4 (17), and L5 (12). All specimens showed fragmented bone with variable amounts of unmineralized bone (osteoid), suggesting bone remodeling and/or fracture healing. Woven bone and cartilaginous tissue were often present, representing fracture callus formation. The biopsies obtained from 30 patients (21%), including 4 who received tetracycline, showed significantly increased osteoid, suggesting either increased bone remodeling activity or mineralization defect (osteomalacia). One sample from these 4 patients who received tetracycline showed no tetracycline labels, essentially diagnostic of osteomalacia. The biopsies also provided definitive diagnoses for one case of unsuspected and 3 cases of unconfirmed plasma cell dyscrasia.

CONCLUSIONS

The majority of biopsies from this series of patients revealed findings consistent with various stages of fracture healing. Osteoid seams were increased in 30 patients, representing either increased bone remodeling or osteomalacia. More cases with tetracycline labeling will help elucidate the true incidence of osteomalacia in this population. As we confirmed 4 cases of plasma cell dyscrasia, we advocate a biopsy during each first-time vertebral augmentation procedure.

Vitamin D deficiency and secondary hyperparathyroidism in the elderly: consequences for bone loss and fractures and therapeutic implications

Vitamin D deficiency is common in the elderly, especially in the housebound and in geriatric patients. The establishment of strict diagnostic criteria is hampered by differences in assay methods for 25-hydroxyvitamin D. The synthesis of vitamin D3 in the skin under influence of UV light decreases with aging due to insufficient sunlight exposure, and a decreased functional capacity of the skin. The diet contains a minor part of the vitamin D requirement. Vitamin D deficiency in the elderly is less common in the United States than elsewhere due to the fortification of milk and use of supplements. Deficiency in vitamin D causes secondary hyperparathyroidism, high bone turnover, bone loss, mineralization defects, and hip and other fractures. Less certain consequences include myopathy and falls. A diet low in calcium may cause an increased turnover of vitamin D metabolites and thereby aggravate vitamin D deficiency. Prevention is feasible by UV light exposure, food fortification, and supplements. Vitamin D3 supplementation causes a decrease of the serum PTH concentration, a decrease of bone turnover, and an increase of bone mineral density. Vitamin D3 and calcium may decrease the incidence of hip and other peripheral fractures in nursing home residents. Vitamin D3 is recommended in housebound elderly, and it may be cost-effective in hip fracture prevention in selected risk groups.

A survey of vitamin A and D contents of fortified fluid milk in Ontario

High performance liquid chromatographic methods for measuring the concentration of vitamins A and D in fluid milk were validated and used to assess the level of these nutrients in Ontario retail milk samples. Thirteen and fifteen fortified milk samples were tested for vitamins A and D, respectively. Repeatability relative standard deviation values for vitamins A and D in milk were generally less than 10%. Recoveries varied from 87 to 107%. Vitamin D results indicated that only 20% of skim, 40% of 2% fat milk, and 20% of whole milk contained the recommended levels, whereas 46% of skim, and 77% of 2% fat milk had the required levels of vitamin A. The results indicate that vitamin level varies widely in Ontario retail milk.

Osteoporosis in men

Osteoporosis in men has become better recognized as an important health problem, particularly in the aged. Nevertheless, the knowledge available remains limited and fragmentary. Many clinical decisions must be based on extrapolations from the more complete understanding of osteoporosis in women. Gender differences in the causation and manifestation of the disease are probable, and the following issues clearly require better definition: Pathomechanisms. What are the determinants of age-related bone loss and fractures? What is the nature of idiopathic osteoporosis? How do other medical conditions result in osteoporosis? Cost-effective strategies for disease detection. Strategies for the prevention and treatment of bone loss and for the prevention of fractures.

Seasonal prevalence of vitamin D deficiency in institutionalized older adults

OBJECTIVE

To determine the prevalence and seasonal variation of vitamin D deficiency among older residents of long-term care facilities.

DESIGN

Cross-sectional survey with 6-month follow-up.

SETTING

Three long-term care facilities in Toronto.

PATIENTS

Persons more than 65 years old, medically stable, who had resided in the facility for at least 6 months and had no conditions known to interfere with vitamin D metabolism.

MEASUREMENTS

Information regarding demographics, past health, and medication use was collected. Mental and functional status were assessed by questionnaire. Venous blood samples were analyzed for alkaline phosphatase, calcium profile, albumin, intact parathyroid hormone, 25 hydroxyvitamin D (25OHD), and vitamin D binding protein in September 1994 and March 1995. In a subgroup of patients, bone specific alkaline phosphatase was measured, and dietary intake of vitamin D was assessed.

RESULTS

A total of 155 subjects completed the study. The mean age of the subjects was 83.2 years (SD 7.1), and 47% were female. The mean 25OHD level in the March sample (39.9 nmol/L, SD 19.7) was significantly lower than the mean 25OHD level in the September sample (44.9 nmol/L, SD 16.9) (P = .001). The prevalence of vitamin D deficiency in the osteomalacic range (25OHD < 25 nmol/L) increased from 9% in the fall sample to 18% after the winter (chi 2 = 4.65, P = .03). The prevalence of borderline deficiency or hypovitaminosis D (25OHD < 40 nmol/L) increased from 38% in the fall sample to 60% in the spring sample (chi 2 = 14.9, P < .001). Dependence in transfers was associated with an increased risk of hypovitaminosis D, odds ratio 2.08 (95% confidence interval 1.08-4.01), dependence in ambulation 2.57 (1.26-5.23), and regular use of a wheelchair 2.17 (1.09-4.31). When entered into a forward conditional logistic regression model, only dependence in ambulation remained significant, with an adjusted odds ratio of 2.57 (95% CI: 1.26-5.18).

CONCLUSIONS

Vitamin D deficiency and borderline vitamin D status are common among older residents of long-term care facilities in Canada. Even though this population has limited outdoor exposure, seasonal variation in the prevalence of deficiency remains significant. Evaluation of interventions to improve the status of vitamin D nutrition in this population is needed.

Vitamin D stores of urban women in Taipei: effect on bone density and bone turnover, and seasonal variation

This study was performed to survey the vitamin D nutritional status of urban Chinese women, and to define its role in determining bone metabolic rate and bone mineral density (BMD). We measured serum 25-hydroxyvitamin D (25-OHD), the major storage form of vitamin D, and BMD, at the spine, hip, and total body skeleton, of 262 healthy Chinese women aged from 40 to 72 years, residing in Taipei city. Bone turnover markers, including serum osteocalcin, bone alkaline phosphatase isozyme, and C-terminal propeptide of type I procollagen, and a urinary bone resorption marker, N-terminal crosslinked fragment of type I collagen, were also measured. We found generally adequate vitamin D nutritional stores. The mean concentration of serum 25-OHD was 30.7 (SD = 8.2) ng/mL for all 262 subjects and there were no significant age-related changes. Those who had serum sampled during the summer showed higher serum 25-OHD levels (N = 138; mean +/- SD: 32.7 +/- 7.6 ng/mL) than those who had serum sampled during winter (N = 124; mean +/- SD: 28.5 +/- 8.3 ng/mL; Student's t-test, p < 0.001), but these two groups showed similar BMD and bone marker values. Those with serum 25-OHD concentration in the lowest or highest tertile did not show different BMD or bone marker values than those in the other tertiles. Multiple regression demonstrated no correlation between 25-OHD and any bone marker or BMD at any site. Thus, in this free-living urban Chinese population, in a subtropical region, we could not demonstrate a role of vitamin D stores in determining bone turnover rate or BMD in women aged 40-70 years.

Seasonal diminution of vitamin D stores in the United States. Can darker winters lead to lighter bones?

Recent reports indicate that many older Americans have inadequate vitamin D sources and little to no seasonal increase in their body stores. The attendant secondary hyperparathyroidism of incipient and subtle osteomalacia could weaken cortical bone and aggravate the osteoporotic process linked to aging. Increased awareness, by physicians and our elderly, of the importance of avoiding mild, seasonal or perennial vitamin D deficiency could lead to better implementation of vitamin D supplementation schedules.

Calcium homeostasis of an elderly population upon admission to a nursing home

OBJECTIVE

To evaluate the skeletal health, calcium, and vitamin D homeostasis of patients upon their entry to a long-term-care facility. Factors that could contribute to the risk of future osteoporotic fractures were also evaluated.

DESIGN

Cross-sectional study.

PATIENTS

Two hundred eighty-seven consecutive admissions were invited to participate; 109 patients were recruited into the study.

MEASUREMENTS

A high prevalence of low to low-normal circulating levels of 25(OH)D was found in nursing home residents upon their admission to the nursing home, with 86% of the patients having circulating 25(OH)D levels of less than 50 nmol/L and 41% having levels below 25 nmol/L. Frankly elevated parathyroid hormone levels were found in 16% of the patients. Additionally, alkaline phosphatase and osteocalcin levels were elevated in 23% and 13% of the patients, respectively. Bone mineral measurements were in the osteoporotic range for 85% of the nursing home residents. Bone density results for females with a history of any classic osteoporotic fracture were significantly lower than for those with no fracture history (68.5 arbitrary units (AU) for those with no fracture history, 58.8 AU in those with history of hip fracture; P < 0.05). The bone mineral measurements were higher in women with adequate 25(OH)D compared with women with deficient or borderline 25(OH)D with and without fracture history. Levels of 25(OH)D were positively correlated with urine calcium/creatinine (r = .24; P = 0.03) and 1,25(OH)2D (r = .28; P = 0.01) and were negatively correlated with 1-84 PTH (r = -.24; P = 0.02).

CONCLUSION

Hypovitaminosis D is prevalent among elderly patients entering a nursing home with secondary hyperparathyroidism and apparently increased bone turnover present in patients with circulating 25(OH)D levels below 50 nmol/L. Bone density measurements showed that a majority of the individuals entering a nursing home are osteoporotic. There is a positive association between 25(OH)D levels and bone mass and a negative association between 25(OH)D levels and a history of fracture.

The vitamin D content of fortified milk and infant formula

BACKGROUND

The fortification of milk and infant formula with vitamin D has had an important role in eliminating rickets in children and osteomalacia in adults. A recent outbreak of vitamin D intoxication caused by drinking milk fortified with excess vitamin D has led to questions about the level of vitamin D in milk from other producers.

METHODS

We used high-performance liquid chromatography to measure vitamin D in samples of 13 brands of milk with various fat contents and 5 brands of infant formula purchased at random from local supermarkets in five Eastern states.

RESULTS

Only 12 (29 percent) of the 42 samples of the 13 brands of milk and none of the 10 samples of the 5 brands of infant formula contained 80 to 120 percent of the amount of vitamin D stated on the label. Twenty-six of the 42 milk samples (62 percent) contained less than 80 percent of the amount claimed on the label. No vitamin D was detected in 3 of the 14 samples of skim milk tested (lower limit of assay, 4.7 IU per quart [5.0 IU per liter]). One milk sample labeled as containing vitamin D2 (ergocalciferol) contained vitamin D3 (cholecalciferol). Seven of the 10 samples of infant formula contained more than 200 percent of the amount stated on the label; the sample with the highest concentration contained 419 percent of the stated amount. None of the samples of infant formula contained less than the amount stated.

CONCLUSIONS

Milk and infant-formula preparations rarely contain the amount of vitamin D stated on the label and may be either underfortified or overfortified. Since both underfortification and overfortification are hazardous, better monitoring of the fortification process is needed.

Mild vitamin D deficiency and secondary hyperparathyroidism in nursing home patients receiving adequate dietary vitamin D

OBJECTIVE

To compare the vitamin D metabolite and nutritional status of institutionalized elderly males with a noninstitutionalized control group.

DESIGN

Case-control study.

SETTING

Veterans Administration Medical Center Nursing Home (NH) in Richmond, Virginia.

PATIENTS

Fifty-seven consecutive nursing home subjects were screened. After excluding blacks, those receiving anticonvulsants, glucocorticoids, or vitamin supplements, and those with liver or renal failure (creatinine greater than 1.5 mg/dL), 35 subjects were enrolled, and 22 completed the study. The noninstitutionalized control group (n = 18) consisted of consecutive volunteers, meeting the above criteria, from either a senior citizen group or a geriatric clinic.

MEASUREMENTS AND MAIN RESULTS

The serum 25-hydroxy-vitamin D level in the NH residents was significantly lower than in community dwellers (17.4 +/- 5.2 ng/mL vs 31.2 pg/mL +/- 8.0 ng/mL, P less than 0.0001). No significant difference was demonstrated in 1,25-dihydroxyvitamin D levels (36.5 pg/mL +/- 10.5 in NH residents vs 42.0 pg/mL +/- 11.1 in controls). In the NH group PTH levels were inversely correlated with 25 OHD levels (P less than 0.008) and positively correlated with length of stay in the NH (P less than 0.016). There was no significant seasonal variation in vitamin D metabolite levels in the NH group. In the NH patients, the mean dietary intake of vitamin D was 232 +/- 378 mg/day and of calories was 1811 +/- 447 kcal/day.

CONCLUSION

Despite apparently adequate calories, calcium, and vitamin D intake, hypovitaminosis D with compensatory PTH elevations occurs, regardless of season, in the nursing home population.

Osteomalacia and osteoporosis in femoral neck fracture

Iliac crest bone histomorphometry, plasma and urine biochemistry and clinical history were examined in 78 unselected patients (68 women, 10 men) at the time of femoral fracture. Histological abnormalities occurred in 56 of the 78 biopsies. The commonest of these was a low bone volume of less than 15% which, irrespective of other abnormal histological features, was present in 37 of the biopsies. On the basis of the histomorphometry, patients could be classified into four main groups. Normal histomorphometry (bone volume greater than 15%, osteoid surfaces less than 24%, mineralising surface greater than 60%) was present in 22 patients, 23 had osteoporosis as the only abnormality (bone volume less than 15%, osteoid surface less than 24%, mineralising surface greater than 60%), nine had osteomalacia (osteoid surfaces greater than 24%, mineralising surface less than 60%, osteoid width greater than 13 microns) and 13 had decreased mineralising surfaces. Of the remainder, five had increased osteoid surface and six had insufficient osteoid to assess mineralising surface. Plasma and urine biochemistry in the four groups showed that, compared to age-matched controls, all groups had reduced plasma albumin. In comparison to the group with normal histomorphometry, patients with osteoporosis had a higher plasma calcium (P less than 0.01), tubular reabsorption of calcium (P less than 0.05) and plasma vitamin D binding protein (P less than 0.01); patients with osteomalacia had a higher plasma creatinine (P less than 0.02) and parathyroid hormone (P less than 0.02) and lower plasma 24,25-dihydroxyvitamin D (P less than 0.02), urinary calcium/creatinine ratio (P less than 0.02) and tubular reabsorption of phosphate (P less than 0.02). The biochemistry in patients with decreased mineralising surface was no different from patients with a normal biopsy. The prevalence of both osteoporosis and osteomalacia increased with age and, in subjects over the age of 90, osteoporosis occurred in 71% of patients and osteomalacia occurred in 29% of patients. The osteomalacic group were significantly older than the other three groups (P less than 0.05). The histomorphometry did not relate to the site of fracture (subcapital or intertrochanteric). A history of stroke, gastrectomy, rheumatoid arthritis, steroid treatment, thyroid disease, alcohol abuse and anti-convulsant therapy was present in patients with femoral fracture but did not relate to any particular histomorphometric classification.

Photoaging/photodamage and photoprotection

Exposure to sunlight can produce both acute and long-term effects. Acute changes include erythema, photosensitivity, and immunologic alterations. Long-term consequences include carcinogenesis and photoaging. All effects can be minimized by photoprotection. This article reviews the adverse effects of sun exposure and strategies to reduce photodamage.

Osteoporosis and the elderly

Osteoporosis causes significant morbidity and some mortality among the elderly. Although increasing bone content should reduce the rate of osteoporotic fracture, attention should also be paid to other factors (such as falling). Loss of bone mass is a universal phenomenon with aging, and currently we are not able to use risk factor analysis to accurately predict which people are likely to suffer osteoporotic fracture. Bone densitometry cannot be recommended as a useful screening test in elderly patients. When deciding about treatment of osteoporosis in the elderly, it should be noted that few studies have included patients over 75 years of age and that prevention of bone loss is more effective than restoration of lost bone. Although high-dose calcium appears ineffective, patients ingesting low amounts of calcium should be counselled to increase their daily intake to at least 800 mg. Estrogens are very effective at preserving bone mass at least up to age 70 years, and their use is associated with a reduction in hip fractures. Vitamin D at a dose of 600 to 800 IU per day should be given to elderly subjects who do not get significant exposure of their skin to sunlight. Other specific recommendations regarding the prevention and treatment of osteoporosis await the results of further investigation.

Effect of aging on vitamin D stores and bone density in women

It has been suggested that the decrease in vitamin D stores with aging is a contributory cause of age-related osteoporosis. We studied this question by measuring bone mineral density (BMD) of the mid-radius, distal radius, and lumbar spine assessed by single and dual photon absorptiometry in 122 women, aged 33-94 years, selected from a random sample of Rochester, MN residents. We measured serum 25-hydroxyvitamin D (25OHD), the major storage form of vitamin D, as well as 25OHD3 (representing both endogenous and exogenous sources of vitamin D), and 25OHD2 (representing only exogenous sources). Both baseline serum total 25OHD (r = -0.29, P less than 0.001) and the metabolite 25OHD3 (r = -0.41, P less than 0.001), were negatively associated with age at baseline. After adjusting for the effect of age by multiple regression analysis, there was no association between serum levels of 25OHD2, 25OHD3, or total 25OHD and BMD for any of the three skeletal scanning sites. Thus, in a northern American population we cannot demonstrate that reduced bioavailability of vitamin D plays a major role in age-related bone loss.

Postmenopausal osteoporosis--intervention and prophylaxis. A review

Postmenopausal osteoporosis is a common disorder associated with significant morbidity and mortality through fractures of the femoral neck, vertebrae and distal forearm. The national cost of this illness is measured in billions of dollars annually. Although the etiology of postmenopausal osteoporosis is unclear, specific effective therapies are available if initiated early in the course of the disease. A large body of information concerning this illness has been generated but many questions remain. The epidemiology, etiology, diagnosis and therapy of postmenopausal osteoporosis are discussed in this review with emphasis on prophylactic and interventional therapy as related to subpopulations of women at risk for osteoporosis.

Structural and functional changes of normal aging skin

Solar-induced cutaneous changes are more prevalent and profound in older persons and, thus, are often inappropriately attributed to the aging process, per se. Structural and functional alterations caused by intrinsic aging and independent of environmental insults are now recognized in the skin of elderly individuals. Structurally the aged epidermis likely becomes thinner, the corneocytes become less adherent to one another, and there is flattening of the dermoepidermal interface. The number of melanocytes and Langerhans cells is decreased. The dermis becomes atrophic and it is relatively acellular and avascular. Dermal collagen, elastin, and glycosaminoglycans are altered. The subcutaneous tissue is diminished in some areas, especially the face, shins, hands, and feet, while in others, particularly the abdomen in men and the thighs in women, it is increased. The number of eccrine glands is reduced and both the eccrine and apocrine glands undergo attenuation. Sebaceous glands tend to increase in size but paradoxically their secretory output is lessened. The nail plate is generally thinned, the surface ridged and lusterless, and the lunula decreased in size. There is a progressive reduction in the density of hair follicles per unit area on the face and scalp, independent of male-pattern alopecia. The hair shaft diameter is generally reduced but in some areas, especially the ears, nose, and eyebrows of men and the upper lip and chin in women, it is increased as vellus hairs convert to cosmetically compromising terminal hairs. Functional alterations noted in the skin of elderly persons include a decreased growth rate of the epidermis, hair, and nails, delayed wound healing, reduced dermal clearance of fluids and foreign materials, and compromised vascular responsiveness. Eccrine and apocrine secretions are diminished. The cutaneous immune and inflammatory responses are impaired, particularly cell-mediated immunity. Clinical correlates of these intrinsic aging changes of the skin include alopecia, pallor, xerosis, an increased number of benign and malignant epidermal neoplasms, increased susceptibility to blister formation, predisposition to injury of the dermis and underlying tissues, delayed onset and resolution of blisters and wheals, persistent contact dermatitis, impaired tanning response to ultraviolet light, increased risk for wound infections, prolongation of therapy necessary for onychomycosis, and thermoregulatory disturbances.

Fractured neck of femur and contralateral intracerebral lesions

Ten cases of fractured neck of femur studied at necropsy were found to have established contralateral intracerebral lesions. These were mainly infarcts, and it suggested that the presence of hemiparesis predisposes to a fall on to the affected side and that the body weight acts through the hip joint in such a way as to fracture the femoral neck. This may happen irrespective of the magnitude of the patient's trabecular bone volume, but in osteoporotic subjects the fracture will probably be intertrochanteric, whereas in non-osteoporotic patients it will probably be subcapital.

Aging decreases the capacity of human skin to produce vitamin D3

An evaluation of surgically obtained skin (age range, 8-92 yr) revealed that there is an age-dependent decrease in the epidermal concentrations of provitamin D3 (7-dehydrocholesterol). To ascertain that aging indeed decreased the capacity of human skin to produce vitamin D3, some of the skin samples were exposed to ultraviolet radiation and the content of previtamin D3 was determined in the epidermis and dermis. The epidermis in the young and older subjects was the major site for the formation of previtamin D3, accounting for greater than 80% of the total previtamin D3 that was produced in the skin. A comparison of the amount of previtamin D3 produced in the skin from the 8- and 18-yr-old subjects with the amount produced in the skin from the 77- and 82-yr-old subjects revealed that aging can decrease by greater than twofold the capacity of the skin to produce previtamin D3. Recognition of this difference may be extremely important for the elderly, who infrequently expose a small area of skin to sunlight and who depend on this exposure for their vitamin D nutritional needs.

Pathologic features of the femoral head in Mseleni disease

Severe but atypical osteoarthritic deformities were found in each of 12 femoral heads removed during total hip arthroplasty for Mseleni disease. Although degenerative and regenerative changes were present throughout the cartilage, there was a paucity of eburnation. Histomorphometric analysis of bone at the line of excision indicated that mild osteomalacia was present in four of the 12 specimens. The percentage of the endosteum occupied by osteoid was 9.7 +/- 7.96 (SD) in the patients with Mseleni disease, compared with 5.6 +/- 4.33 in seven African black and 4.1 +/- 2.13 in 13 American white control subjects. The mean thickness of the osteoid seams was not increased. The findings suggest that osteomalacia is not a major pathogenetic factor in Mseleni disease.

Biochemical findings in blood of aged patients with femoral neck fractures: a contribution to the detection of occult osteomalacia

A study was made in Geneva of 44 patients with femoral neck fractures and no risk factor of osteomalacia to determine concentrations of 25OHD3, calcium, phosphorus, alkaline phosphatase, albumin, and globulins in blood. The results were compared with those obtained for control groups of adult and aged subjects, as well as of 21 subjects operated on for hip osteoarthritis. For the detection of occult osteomalacia, femoral head bone tissue from 14 patients with fractures was examined by histomorphometric methods. In more than a third of the cases, 25OHD3 and serum albumin values were lower than those found for adult and even aged control subjects. Some slight histological signs of osteomalacia were observed in 1 patient with a femoral neck fracture, but there was no correlation between the histologic and the blood data. In practice, when dealing with aged people with no obvious risk of osteomalacia, it is important that a systematic antiosteomalacia treatment consisting of large supplements of vitamin D be avoided and that the conditions of diet and living be carefully controlled.