Ilda Shizue Kunii

The effect of sun exposure on 25-hydroxyvitamin D concentrations in young healthy subjects living in the city of São Paulo, Brazil

The range of 25-hydroxyvitamin D (25OHD) concentration was determined in a young healthy population based on bone metabolism parameters and environmental and behavioral aspects. We studied 121 healthy young volunteers (49 men, 72 women) living in São Paulo (23 masculine 34 south latitude) belonging to three occupational categories: indoor workers (N = 28), medical school students (N = 44), and resident physicians (N = 49). Fasting morning blood samples were collected once from each volunteer from August 2002 to February 2004, and 25OHD, total calcium, albumin, alkaline phosphatase, phosphorus, creatinine, intact parathyroid hormone, osteocalcin, and type I collagen carboxyterminal telopeptide were measured. Data are reported as means +/- SD. Mean subject age was 24.7 +/- 2.68 years and mean 25OHD level for the entire group was 78.7 +/- 33.1 nM. 25OHD levels were lower (P < 0.05) among resident physicians (67.1 +/- 27.0 nM) than among students (81.5 +/- 35.8 nM) and workers (94.0 +/- 32.6 nM), with the last two categories displaying no difference. Parathyroid hormone was higher (P < 0.05) and osteocalcin was lower (P < 0.05) among resident physicians compared to non-physicians. Solar exposure and frequency of beach outings showed a positive association with 25OHD (P < 0.001), and summer samples presented higher results than winter ones (97.8 +/- 33.5 and 62.9 +/- 23.5 nM, respectively). To define normal levels, parameters such as occupational activity, seasonality and habits related to solar exposure should be taken into account. Based on these data, we considered concentrations above 74.5 nM to be desired optimal 25OHD levels, which were obtained during the summer for 75% of the non-physicians.

Vitamin D Receptor Gene Polymorphism: Correlation with Bone Mineral Density in a Brazilian Population with Insulin-Dependent Diabetes Mellitus

Abstract: Patients with insulin-dependent diabetes mellitus (IDDM) are at higher risk of developing osteoporosis. Among the genetic factors related to the development of osteoporosis, a possible association between vitamin D receptor (VDR) gene polymorphism and bone mineral density (BMD) has been described in some populations. We characterized the VDR gene polymorphism in a healthy adult Brazilian population and in a group of patients with IDDM and correlated these findings with densitometric values in both groups. The Brazilian population is characterized by an important racial heterogeneity and therefore is considered an ethnically heterogeneous population. We recruited 94 healthy adult Brazilian volunteers (63 women and 31 men), mean (+ SD) age 32.4 + 6.5 years (range 18–49 years), and 78 patients with IDDM (33 women and 45 men) diagnosed before 18 years of age, mean (+ SD) age 23.3 + 5.5 years (range 18–39 years). VDR genotype was assessed by polymerase chain reaction amplification followed by BsmI digestion on DNA isolated from peripheral blood leukocytes. Statistical analysis included Bonferroni t-test to compare densitometric values within different genotypes in both groups and multiple regression analysis of bone density adjusted for potential confounding factors. The IDDM group had a lower BMD compared with the control group. The VDR genotype distribution in the control group was 43 Bb (45.7%), 39 bb (41.5%) and 12 BB (12.8%). This distribution did not differ from that observed in the IDDM group: 39 Bb (50%), 26 bb (33.3%) and 13 BB (16.7%). In the IDDM group, patients with the Bb genotype had a higher body weight when compared with the BB genotype (p= 0.02). However, when diabetic patients were controlled for age, sex and body mass index, BB genotype was associated with a lower mean BMD at lumbar spine and femoral neck than in Bb and bb patients. BB patients had a shorter duration of IDDM than bb and Bb patients. These findings suggest a small influence of VDR gene polymorphism on BMD of a racially heterogeneous population with IDDM.

Body fat and cholecalciferol supplementation in elderly homebound individuals

Vitamin D deficiency, observed mainly in the geriatric population, is responsible for loss of bone mass and increased risk of bone fractures. Currently, recommended doses of cholecalciferol are advised, but since there are few studies evaluating the factors that influence the serum levels of 25-hydroxyvitamin D (25(OH)D) following supplementation, we analyzed the relationship between the increase in serum 25(OH)D after supplementation and body fat. We studied a group of 42 homebound elderly subjects over 65 years old (31 women) in order to assess whether there is a need for adjustment of the doses of cholecalciferol administered to this group according to their adipose mass. Baseline measurements of 25(OH)D, intact parathyroid hormone and bone remodeling markers (osteocalcin and carboxy-terminal fraction of type 1 collagen) were performed. Percent body fat was measured by dual-energy X-ray absorptiometry. The patients were divided into three groups according to their percent body fat index and were treated with cholecalciferol, 7,000 IU a week, for 12 weeks. The increases in serum levels of 25(OH)D were similar for all groups, averaging 7.46 ng/mL (P < 0.05). It is noteworthy that this increase only shifted these patients from the insufficiency category to hypovitaminosis. Peak levels of 25(OH)D were attained after only 6 weeks of treatment. This study demonstrated that adipose tissue mass does not influence the elevation of 25(OH)D levels following vitamin D supplementation, suggesting that there is no need to adjust vitamin D dose according to body fat in elderly homebound individuals.

A novel mutation in the LRP5 gene is associated with osteoporosis-pseudoglioma syndrome

Dear Editor, Osteoporosis-pseudoglioma syndrome (OPPG) is an autosomal recessive disorder characterized by low bone mass and ocular globe alterations, with frequent fractures as a consequence of high skeletal fragility and severe visual deficiency [1]. Recently, Gong et al. identified mutations in the low-density lipoprotein receptor-related protein 5 gene (LRP5) that cause OPPG [2]. The LRP5 gene is located on the long arm of chromosome 11 at 11q13.4, has 23 exons, and encodes a transmembrane protein with 1,615 amino acids. This protein is a member of the low-density lipoprotein receptor (LDLR) family, the members of which have very well conserved characteristics. We had the opportunity to follow-up two brothers with clinical characteristics of OPPG, and we decided to investigate the LRP5 gene to identify any mutation that could explain the clinical features of low bone mass, fractures, and blindness. The older brother came to the hospital when he was 12 years old, (53 kg; 157 cm). At that time, lumbar bone mineral density (BMD, Hologic 4,500 A) was 0.512 g/cm (Z score −3.99). He was born blind, had a normal development until the age of 7 years, when he had lumbar pain due to the fracture of a vertebral body. At the age of 11, pain in the left leg led to the diagnosis of a tibial fracture. One month later, the same occurred in the right tibia and 2 months after that, a fracture in the right femur was detected, and he was referred to our hospital. The younger brother was 4 years old at that time and was born blind. At 2.5 years, he had a fracture of the right femur after a small fall. He was eutrophic (13 kg and 97 cm), with a lumbar BMD of 0.277 g/cm2 (Z score −5.4). Both of them had normal biochemical and hormonal parameters. Their parents were consanguineous, had normal BMD and no history of fractures or blindness, and there were no similar cases in the family. The 23 exons were analyzed and we identified an LPR5 missense mutation in the third codon of exon 8, in which an asparagine is replaced by isoleucine (N531I) in two siblings with OPPG and their consanguineous parents. The patients were found to be homozygous for this mutation, while their parents are heterozygous. This amino acid is located at the second propeller domain (YWTD repeat) in the extracellular domain of the receptor. Fifty normal participants underwent analysis of this exon, and the mutation was not present in any of them, but a polymorphism C→T (rs545382 NCBI, F549F) was found at a frequency of 1:5. According to Sidow’s program [3] of multivariate analysis of protein polymorphism (MAPP), we observed that the N531I mutant scored higher (yielding a bad amino acid substitution) and this mutation is located in the group of deleterious variants because of its high degree of evolutionary conservation. Based on these facts, we believe that this mutation is responsible for the clinical features presented in our patients and thereby define a novel mutation that causes OPPG in humans. Osteoporos Int DOI 10.1007/s00198-007-0360-x

Changes in clinical and laboratory findings at the time of diagnosis of primary hyperparathyroidism in a University Hospital in São Paulo from 1985 to 2002

In contrast to most developed countries, most patients with primary hyperparathyroidism in Brazil are still symptomatic at diagnosis. However, we have been observing a change in this pattern, especially in the last few years. We evaluated 104 patients, 77 females and 27 males aged 11-79 years (mean: 54.4 years), diagnosed between 1985 and 2002 at a University Hospital. Diagnosis was made on the basis of clinical findings and of high total and/or ionized calcium levels, high or inappropriate levels of intact parathyroid hormone and of surgical findings in 80 patients. Patients were divided into three groups, i.e., patients diagnosed from 1985 to 1989, patients diagnosed from 1990 to 1994, and patients diagnosed from 1995 to 2002. The number of new cases diagnosed/year increased from 1.8/year in the first group to 6.0/year in the second group and 8.1/year in the third group. The first group comprised 9 patients (mean serum calcium +/- SD, 13.6 +/- 1.6 mg/dl), 8 of them (88.8%) defined as symptomatic. The second group comprised 30 patients (mean calcium +/- SD, 12.2 +/- 1.63 mg/dl), 22 of them defined as symptomatic (73.3%). The third group contained 65 patients (mean calcium 11.7 +/- 1.1 mg/dl), 34 of them symptomatic (52.3%). Patients from the first group tended to be younger (mean +/- SD, 43.0 +/- 15 vs 55.1 +/- 14.4 and 55.7 +/- 17.3 years, respectively) and their mean serum calcium was significantly higher (P < 0.05). All of symptomatic patients independent of group had higher serum calcium levels (12.4 +/- 1.53 mg/dl, N = 64) than asymptomatic patients (11.4 +/- 1.0 mg/dl, N = 40). Our data showed an increase in the percentage of asymptomatic patients over the years in the number of primary hyperparathyroidism cases diagnosed. This finding may be due to an increased availability of diagnostic methods and/or to an increased awareness about the disease.

Factors affecting vitamin D status in different populations in the city of São Paulo, Brazil: the São PAulo vitamin D Evaluation Study (SPADES)

BackgroundHypovitaminosis D is a common condition among elderly individuals in temperate-climate countries, with a clear seasonal variation on 25 hydroxyvitamin D [(25(OH)D] levels, increasing after summer and decreasing after winter, but there are few data from sunny countries such as Brazil. We aimed to evaluate 25-hydroxyvitamin D concentrations and its determining factors, in individuals in the city of São Paulo belonging to different age groups and presenting different sun exposure habits.Methods591 people were included as follows: 177 were living in institutions (NURSING HOMES, NH, 76.2u2009±u20099.0xa0years), 243 were individuals from the community (COMMUNITY DWELLINGS, CD, 79.6u2009±u20095.3xa0years), 99 were enrolled in physical activity program designed for the elderly (PHYSICAL ACTIVITY, PA, 67.6u2009±u20095.4xa0years) and 72 were young (YOUNG, 23.9u2009±u20092.8xa0years). Ionized calcium, PTH, 25(OH)D, creatinine and albumin were evaluated. ANOVA, Mann–Whitney and Kruskal Wallis tests, Pearson Linear Correlation and Multiple Regression were used in the statistical analysis.Results25(OH)D mean values during winter for the different groups were 36.1u2009±u200921.2xa0nmol/L (NH), 44.1u2009±u200924.0xa0nmol/L (CD), 78.9u2009±u200930.9xa0nmol/L (PA) and 69.6u2009±u200926.2xa0nmol/L (YOUNG) (pu2009<u20090.001) while during summer they were 42.1u2009±u200925.9xa0nmol/L, 59.1u2009±u200929.6xa0nmol/L, 91.6u2009±u200931.7xa0nmol/L and 103.6u2009±u200929.3xa0nmol/L, respectively (pu2009<u20090.001). The equation which predicts PTH values based on 25(OH)D concentration is PTHu2009=u200910u2009+u2009104.24.e-(vitD-12.5)/62.36 and the 25(OH)D value above which correlation with PTH is lost is 75.0xa0nmol/L. In a multiple regression analysis having 25(OH)D concentration as the depending variable, the determining factors were PTH, ionized calcium and month of the year (pu2009<u20090.05).ConclusionsMuch lower 25(OH)D values were found for the older individuals when compared to younger individuals. This finding is possibly due to age and habit-related differences in sunlight exposure. The existence of seasonal effects on 25(OH)D concentration throughout the year was evident for all the groups studied, except for the nursing home group. According to our data, PTH values tend to plateau above 75xa0nmol/L.

Total Parathyroidectomy with Presternal Intramuscular Autotransplantation in Renal Patients: A Prospective Study of 66 Patients

Surgical treatment of secondary (SHPT) and tertiary hyperparathyroidism (THPT) may involve various surgical approaches. The aim of this paper was to evaluate presternal intramuscular autotransplantation of parathyroid tissue as a surgical option in SHPT and THPT treatment. 66 patients with renal chronic disease underwent surgery from April 2000 to April 2005 at Universidade Federal São Paulo, Brazil. There were 38 SHPT patients (24 women/14 men), mean age of 39.yrs (range: 14–58), and 28 THPT patients (14 women/14 men), mean age of 43.4 yrs (range: 24–62). Postoperative average followup was 42.9 months (range: 12–96). Postoperative intact PTH increased throughout followup from 73.5 pg/mL to 133u2009pg/mL on average from 1st to the 5th year, respectively, in SHPT and from 54.9u2009pg/mL to 94.7u2009pg/mL on average from 1st to 5th year, respectively, in THPT group. Definitive hypoparathyroidism was observed in 4 (6.06%) patients and graft-dependent recurrence in 6 (9.09%). Presternal intramuscular autotransplantation of parathyroid tissue is a feasible and safe surgical option in SHPT and THPT treatment.

Utilidade da medida de PTH intra-operatório no tratamento cirúrgico do hiperparatiroidismo primário e secundário: análise de 109 casos

INTRODUCAO: A medida de PTH intra-operatorio (PTH-IO) foi inicialmente descrita em 1988, sendo potencialmente util na definicao de sucesso apos a paratiroidectomia. OBJETIVOS: Avaliar prospectivamente perfil de decaimento do PTH-IO e sua capacidade de prever sucesso cirurgico no hiperparatiroidismo primario (HPP) e secundario a insuficiencia renal (HPS). PACIENTES E METODOS: 109 pacientes operados entre 06/2000 e 12/2004, sendo 33 HPP, 76 HPS (52 em dialise, 24 transplantados renais). PTH-IO: metodo imunometrico rapido (Elecsys-PTH/Immunoassay-Roche); tempo para resultado: 10 minutos. Coletas de sangue periferico nos tempos basal, 10 e 20 minutos pos-paratiroidectomia. RESULTADOS: HPP: queda media de PTH de 79,2% aos 10 minutos. HPS: queda media de PTH de 85,8% e 87,6% aos 10 minutos nos pacientes dialise e transplantados respectivamente. A cirurgia foi bem sucedida em todos, exceto em 2 pacientes (1 HPP, 1 HPS). Em ambos nao houve queda PTH-IO, sendo constatado adenoma duplo no HPP e paratiroide ectopica no HPS. CONCLUSAO: Medida PTH-IO fornece resultados confiaveis em tempo rapido, sendo capaz de discriminar persistencia da doenca se mantidos niveis elevados.

Usefulness of a rapid immunometric assay for intraoperative parathyroid hormone measurements

Intraoperative parathyroid hormone (IO-PTH) measurements have been proposed to improve operative success rates in primary, secondary and tertiary hyperparathyroidism (PHP, SHP and THP). Thirty-one patients requiring parathyroidectomy were evaluated retrospectively from June 2000 to January 2002. Sixteen had PHP, 7 SHP and 8 THP. Serum samples were taken at times 0 (before resection), 10, 20 and 30 min after resection of each abnormal parathyroid gland. Samples from 28 patients were frozen at -70 C for subsequent tests, whereas samples from three patients were tested while surgery was being performed. IO-PTH was measured using the Elecsys immunochemiluminometric assay (Roche, Mannheim, Germany). The time necessary to perform the assay was 9 min. All samples had a second measurement taken by a conventional immunofluorimetric method. We considered as cured patients who presented normocalcemia in PHP and THP, and normal levels of PTH in SHP one month after surgery and who remained in this condition throughout the follow-up of 1 to 20 months. When rapid PTH assay was compared with a routine immunofluorimetric assay, excellent correlation was observed (r = 0.959, P < 0.0001). IO-PTH measurement showed a rapid average decline of 78.8% in PTH 10 min after adenoma resection in PHP and all patients were cured. SHP patients had an average IO-PTH decrease of 89% 30 min after total parathyroidectomy and cure was observed in 85.7%. THP showed an average IO-PTH decrease of 91.9%, and cure was obtained in 87.5% of patients. IO-PTH can be a useful tool that might improve the rate of successful treatment of PHP, SHP and THP.

Circulating forms of parathyroid hormone detected with an immunofluorometric assay in patients with primary hyperparathyroidism and in hyperparathyroidism secondary to chronic renal failure

In patients with uremia, intact parathyroid hormone (PTH) measurement appears to overestimate the biologically active hormone in circulation. The recent description of the accumulation in these patients of a non-intact PTH form measured by the standard immunometric assays, re-opened the question. In this study we submitted serum samples from 7 patients with primary hyperparathyroidism (PHP) and from 10 patients with hyperparathyroidism secondary to chronic renal failure (SHP) to preparative HPLC in order to discriminate the molecular forms measured by our currently used immunofluorometric assay for intact PTH. The elution profile obtained with the HPLC system showed two clearly defined peaks, the first one corresponding to a lower molecular weight form, and the second to the intact PTH (1-84) form. In patients with SHP the area under the curve for the first peak (mean 29.5%, range 20.6 to 40.4%) was significantly greater than that observed for patients with PHP (mean 15.6%, range 5.6 to 21.9%). This confirms previous studies showing accumulation of molecular forms of slightly lower molecular weight, presumably PTH (7-84), in patients with SHP and, to a lesser extent, in patients with PHP. The real necessity of assays that discriminate between these two molecular forms is debatable.