Vitamin D status and glucose metabolism in youth.

This study aimed to review and synthesize the available scientific evidence on the relationship between serum 25(OH)D concentrations and glucose metabolism among adolescents. A total of 19 studies were included. Many studies did not find a relation between 25(OH)D concentrations and insulin sensitivity, but most studies have shown that vitamin D status influences glucose dysregulation in youth due to particularities of this life stage. Considering the prevalence of vitamin D deficiency and insufficiency were high among adolescents, the importance for vitamin D status correction in this young group, in which chronic diseases are not expected but getting every day more common, is mandatory.

Crosstalk Between Bone and Fat Tissue: Associations Between Vitamin D, Osteocalcin, Adipokines, and Markers of Glucose Metabolism Among Adolescents.

OBJECTIVES: This study aimed to investigate the relationship between 25-hydroxyvitamin D (25(OH)D), osteocalcin, markers of glucose metabolism, and obesity-related parameters among adolescents. METHODS: This was a cross-sectional study with 198 adolescents age 14-18 years. Weight, height, and waist and hip circumferences were measured, as well as the following biochemical parameters: serum 25(OH)D, parathyroid hormone (PTH), total (tOC) and undercarboxylated (ucOC) osteocalcin, adiponectin, leptin, glucose, and insulin. The homeostasis model of assessment estimate of insulin resistance (HOMA-IR) and ß-cell function (HOMA-ß) and quantitative insulin sensitivity check index (QUICKI) were calculated. Student's t test, analysis of variance (ANOVA), Pearson's correlation, and linear regression models were performed. RESULTS: Overweight was observed in 42.6% of the sample. This group presented significantly higher PTH, leptin, insulin, HOMA-IR, and HOMA-ß and lower 25(OH)D, adiponectin, tOC, ucOC, and QUICKI than normal-weight subjects. 25(OH)D was positively correlated with ucOC and adiponectin and negatively associated with body mass index (BMI), weight, and waist circumference (p < 0.05 for all). The association between 25(OH)D and ucOC was also observed in the multiple regression analysis, adjusted for age, BMI, and season of the year (partial r2 = 0.071, p < 0.0001). 25(OH)D and ucOC were not associated with markers of glucose metabolism. However, leptin was strongly correlated with insulin, HOMA-IR, HOMA-ß, and QUICKI (p < 0.0001 for all). CONCLUSION: The present study demonstrated that undercarboxylated osteocalcin is related to 25(OH)D and adiponectin concentrations. Both ucOC and 25(OH)D were lower in overweight and obese adolescents, reinforcing the importance of fighting obesity. Although a relationship of ucOC and 25(OH)D with markers of glucose metabolism was not observed, leptin has shown to be the hormone most related to energy homeostasis.

Comparison between body mass index and a body shape index with adiponectin/leptin ratio and markers of glucose metabolism among adolescents.

BACKGROUND: Besides body mass index (BMI), new parameters have been developed to classify individual body shape. AIM: To investigate the relationship between BMI, waist circumference (WC), a body shape index (ABSI) and ABSI-adolescents among adolescents and verify which would better predict lower adiponectin/leptin (A/L) ratio and disturbances on glucose metabolism. SUBJECTS AND METHODS: A cross-sectional study with 197 Brazilian adolescents of 14-18 years. Serum leptin, adiponectin, glucose and insulin were measured. A/L ratio, ABSI, ABSI-adolescents, BMI, homeostasis model assessment estimates of insulin resistance (HOMA-IR) and ß-cell function (HOMA-ß) and the quantitative insulin sensitivity check index (QUICKI) were calculated. RESULTS: ABSI-adolescents positively correlated with WC (r = 0.83, p < 0.0001) and BMI (r = 0.66, p < 0.0001), but stronger correlations were observed between WC and BMI (r = 0.95, p < 0.0001). ABSI-adolescents, BMI and WC negatively correlated with A/L ratio (all p < 0.0001). The correlation between BMI and A/L ratio was the strongest (r = -0.63, p < 0.001). A/L ratio, BMI, WC and ABSI-adolescents correlated with markers of glucose metabolism (all p < 0.0001) and the strongest correlation was observed with BMI (QUICKI: r = -0.75; HOMA-IR: r = 0.76; HOMA-ß: r = 0.77; insulin: r = 0.79). Associations were confirmed by linear regression analysis, adjusted for sex and age. CONCLUSIONS: ABSI-adolescents, but not ABSI, was related to A/L ratio and to markers of glucose metabolism, but not more strongly than BMI and WC.

Relationship between Vitamin D Receptor gene polymorphisms and the components of metabolic syndrome.

BACKGROUND: The Vitamin D Receptor gene (VDR) is expressed in many tissues and modulates the expression of several other genes. The purpose of this study was to investigate the association between metabolic syndrome (MetSyn) with the presence of VDR 2228570 C > T and VDR 1544410 A > G polymorphisms in Brazilian adults. METHODS: Two hundred forty three (243) individuals were included in a cross-sectional study. MetSyn was classified using the criteria proposed by National Cholesterol Educational Program--Adult Treatment Panel III. Insulin resistance and ß cell secretion were estimated by the mathematical models of HOMA IR and ß, respectively. The VDR 2228570 C > T and VDR 1544410 A > G polymorphisms were detected by enzymatic digestion and confirmed by allele specific PCR or amplification of refractory mutation. RESULTS: Individuals with MetSyn and heterozygosis for VDR 2228570 C > T have higher concentrations of iPTH and HOMA ß than those without this polymorphism, and subjects with recessive homozygosis for the same polymorphisms presented higher insulin resistance than those with the heterozygous genotype. There is no association among VDR 1544410 A > G and components of MetSyn, HOMA IR and ß, serum vitamin D (25(OH)D3) and intact parathormone (iPTH) levels in patients with MetSyn. A significant lower concentration of 25(OH)D3 was observed only in individuals without MetSyn in the VDR 1544410 A > G genotype. Additionally, individuals without MetSyn and heterozygosis for VDR 2228570 C > T presented higher concentration of triglycerides and lower HDL than those without this polymorphism. CONCLUSIONS: Using two common VDR polymorphism data suggests they may influence insulin secretion, insulin resistance an serum HDL-cholesterol in our highly heterogeneous population. Whether VDR polymorphism may influence the severity of MetSyn component disorder, warrants examination in larger cohorts used for genome-wide association studies.

Antioxidant intake and bone status in a cross-sectional study of Brazilian women with osteoporosis.

This study aimed to investigate the association between antioxidant intake and bone mineral density (BMD) in postmenopausal women with osteoporosis. We conducted a cross-sectional study with 150 women, mean age 68.7 (SD 9.1) years. BMD and body composition were obtained using dual-energy X-ray absorptiometry (DXA). We assessed anthropometric measures and dietary intake and applied an adapted Dietary Antioxidant Quality Score (a-DAQS) to evaluate the antioxidant consumption. 65.3% of women had higher scores on the a-DAQS. We found no relationship between the a-DAQS and BMD; however, we observed an inverse correlation between vitamin A and lumbar spine (LS) BMD in g/cm(2) (r = - 0.201; p = 0.013). An analysis of variance (ANOVA) test also showed that vitamin A was negatively associated with the LS BMD (F = 6.143; p = 0.013, but without significance when a multivariate analysis was applied. The a-DAQS did not have an association with BMD; however, Vitamin A showed a negative correlation with BMD, but such an association disappeared when the other antioxidants were taken together. Our findings encourage an antioxidant-based dietary approach to osteoporosis prevention and treatment, since the negative effect of vitamin A was neutralized by the intake of such nutrients.

Role of food fortification with vitamin D and calcium in the bone remodeling process in postmenopausal women: a systematic review of randomized controlled trials.

CONTEXT: Foods containing vitamin D reduce the deficiency of this vitamin and improve bone turnover. OBJECTIVE: To discuss effects of the intake of vitamin D-fortified foods in isolated form or associated with calcium on bone remodeling in postmenopausal women. DATA SOURCES: PubMed, Lilacs, Scopus, and Bireme databases. OpenThesis and Google Scholar were searched as "grey literature". Medical subject headings or similar terms related to food fortified with vitamin D and bone in postmenopausal women were used. DATA EXTRACTION: Information was collected on study methodology and characteristics of studied populations; dosage; the food matrix used as the fortification vehicle; duration of intervention; dietary intake; 25-hydroxyvitamin D [25(OH)D] levels; serum parathyroid hormone (PTH) concentrations; bone resorption and/or formation markers (ie, carboxy terminal cross-linked telopeptide of type I collagen [CTX], tartrate-resistant acid phosphatase isoform 5b [TRAP5b], and procollagen type 1 N-terminal propeptide [P1NP]); main results; and study limitations. DATA ANALYSIS: Five randomized controlled trials involving postmenopausal women were included. The mean ages of participants ranged from 56.1 to 86.9 years. Daily consumption of soft plain cheese fortified with 2.5 µg of vitamin D3 and 302 mg of calcium for 4 weeks resulted in a mean increase of 0.8 ng/mL in 25(OH)D and 15.9 ng/mL in P1NP levels compared with baseline, and decreased CTX, TRAP5b, and PTH values. A similar intervention for 6 weeks, using fortified cheese, showed a reduction only in TRAP5b values (-0.64 U/L). Yogurt fortified with 10 µg of vitamin D3 and 800 mg of calcium did not change P1NP values after 8 weeks of intervention, but was associated with decreases of 0.0286 ng/mL and 1.06 U/L in PTH and TRAP5b, respectively. After 12 weeks of eating the fortified yogurt, 25(OH)D levels increased by a mean of 8.8 ng/mL and PTH levels decreased in by a mean of 0.0167 ng/mL. CONCLUSIONS: The interventions contributed toward the improvement of the bone resorption process but not to the bone formation process in postmenopausal women. PROSPERO REGISTRATION NUMBER: CRD42019131976.

Official position of the Brazilian Association of Bone Assessment and Metabolism (ABRASSO) on the evaluation of body composition by densitometry: part I (technical aspects)-general concepts, indications, acquisition, and analysis.

OBJECTIVE: To review the technical aspects of body composition assessment by dual-energy X-ray absorptiometry (DXA) and other methods based on the most recent scientific evidence. MATERIALS AND METHODS: This Official Position is a result of efforts by the Scientific Committee of the Brazilian Association of Bone Assessment and Metabolism (Associação Brasileira de Avaliação Óssea e Osteometabolismo, ABRASSO) and health care professionals with expertise in body composition assessment who were invited to contribute to the preparation of this document. The authors searched current databases for relevant publications. In this first part of the Official Position, the authors discuss the different methods and parameters used for body composition assessment, general principles of DXA, and aspects of the acquisition and analysis of DXA scans. CONCLUSION: Considering aspects of accuracy, precision, cost, duration, and ability to evaluate all three compartments, DXA is considered the gold-standard method for body composition assessment, particularly for the evaluation of fat mass. In order to ensure reliable, adequate, and reproducible DXA reports, great attention is required regarding quality control procedures, preparation, removal of external artifacts, imaging acquisition, and data analysis and interpretation.

Associations between markers of glucose metabolism and bone measures among diabetic and non-diabetic adults.

PURPOSE: To investigate the relationships between bone measures, vitamin D status and markers of glucose metabolism among diabetic and non-diabetic adults. METHODS: Cross sectional study with 298 adults (mean age 57.5 years, SD = 14.8; 44.3% male, 16.9% diabetic) participants of the Health Survey-São Paulo (ISA-Capital) 2014-2015. Blood samples were collected to assess serum glucose, insulin and 25 hydroxyvitamin D [25(OH)D] concentrations. Dual-energy x-ray absorptiometry (DXA) was performed to determine total body fat; total lean mass; full body bone mineral density (BMD); lumbar spine BMD and bone mineral content (BMC); and femur BMD and BMC. Fat mass index (FMI), lean mass index (LMI), quantitative insulin sensitivity check index (QUICKI), homeostasis model assessment of insulin resistance (HOMA-IR) and of ß-pancreatic cell function (HOMA-ß) were calculated. Linear regression analysis were performed. RESULTS: Multiple bone measures were associated with markers of glucose metabolism in analyses adjusted by age and sex. However, after additional adjustments by LMI, FMI and serum 25(OH)D, only associations of lumbar spine BMC with HOMA-IR (ß = 0.167; p = 0.035) and QUICKI (ß = -1.879; p = 0.027) persisted, in the subgroup of diabetic participants. Analysis restricted to diabetic subjects revealed stronger correlations between bone parameters and markers of glucose metabolism. CONCLUSIONS: Our study observed positive associations between BMD and markers of insulin resistance among a sample of adults. Correlations were stronger among diabetic subjects, and some associations between bone and glucose metabolism were independent of adiposity. Findings reinforce the need of further research for better understanding the bidirectional and multifactorial crosstalk between glucose homeostasis and bone metabolism.

Effects of calcium supplementation on body weight reduction in overweight calcium stone formers.

A randomized, placebo-controlled trial was conducted in overweight calcium stone-forming (CSF) patients, to evaluate the effect of calcium supplementation associated with a calorie-restricted diet on body weight (BW) and fat reduction and its potential changes upon serum and urinary parameters. Fifteen patients were placed on a hypocaloric diet for 3 months, supplemented with either calcium carbonate (CaCO(3), n = 8) or placebo (n = 7), 500 mg bid. Blood and 24-h urine samples were collected and body composition was assessed at baseline and after the intervention. At the end of the study, final BW was significantly lower vs baseline in both CaCO(3) (74 +/- 14 vs. 80 +/- 14 kg, P = 0.01) and placebo groups (80 +/- 10 vs. 87 +/- 9 kg, P = 0.02) but the mean percentage of loss of body weight and body fat did not differ between CaCO(3) and placebo (7.0 +/- 2.0 vs. 8.0 +/- 3.0%, P = 0.40 and 13.0 +/- 7.0 vs. 13.0 +/- 10.0%; P = 0.81, respectively). After CaCO(3) or placebo, no significant differences versus baseline were observed for urinary parameters in both CaCO(3) and placebo, except for a higher mean urinary citrate in placebo group. These data suggest that increasing calcium intake by calcium carbonate supplementation did not contribute to a further reduction of BW and fat in overweight CSF patients submitted to a hypocaloric diet nor altered urinary lithogenic parameters.

Prevalence of vitamin D insufficiency in Brazilian adolescents.

BACKGROUND/AIMS: Cutaneous sun exposure and dietary vitamin D intake are important determinants of vitamin D status. The objective of the present study was to evaluate the vitamin D status of a group of healthy adolescent students living in Brazil. METHODS: One hundred and thirty-six adolescents, 64 boys and 72 girls, aged 16-20 years old, living in a rural town in the state of São Paulo, Brazil, participated in this study. RESULTS: The mean dietary vitamin D intake was 140 (120-156) IU/day [3.5 (3.0-3.9) microg/day]. Only 14.9% of the students met the daily adequate intake recommendation of vitamin D. Only 27.9% practice physical activity outdoors and 17.6% of the adolescents apply sunscreen daily. The mean 25(OH)D concentration was 73.0 (22.0) nmol/l [29.2 (8.8) ng/ml]. Vitamin D insufficiency was observed in 60% of adolescents. CONCLUSIONS: The present study suggests that even in a sunny climate like Brazil the prevalence of vitamin D insufficiency in adolescents is high. Most likely this is due to low intakes of vitamin D in this group. Due to the limited extent of natural dietary sources of vitamin D, a policy of vitamin D food fortification should be considered in the future, and in the meantime greater use of vitamin D supplements in this population group should be encouraged to provide the increased amounts of this essential nutrient for optimal health.

Lack of association between dietary inflammatory index and low impact fractures in the Brazilian population: the Brazilian Osteoporosis Study (BRAZOS).

INTRODUCTION: Adequate nutrition, including intake of dietary calcium and vitamin D, is important to maintain bone health. Evidence suggests that a deficiency in micronutrients may contribute to bone loss during aging and exert generalized effects on chronic inflammation. Recently, the Dietary Inflammatory Index (DII) was developed to assess the inflammatory potential of individual diets. Our aim was to evaluate the DII in a representative sample and verify its association with low-impact fractures. METHODS: Individuals from The Brazilian Osteoporosis Study (BRAZOS) database had their DII calculated. BRAZOS is an important cross-sectional epidemiological study carried out with a representative sample of men and women ≥40 years old. The research was conducted through in-home interviews administered by a trained team. Nutrition Database System for Research (NDSR) software was used to analyze data on the intake of nutrients, which were employed to calculate the DII using Statistical Analysis Software (SAS®) and Statistical Package for the Social Sciences (SPSS®) to assess its association with low-impact fractures. RESULTS: A total of 2269 subjects had their DII score calculated using information from 24-h recall data. Males had lower DII than females (DII = 1.12 ± 1.04 vs DII = 1.24 ± 0.99, p = 0.012). Women taking statins had lower DII (DII = 0.65 ± 1.14 vs DII + 1.26 ± 0.98, p = 0.002), indicating a greater potential for diet-related anti-inflammatory effects. CONCLUSION: Our findings suggest that women might have a pro-inflammatory diet pattern compared to men. However, we did not find any association between DII scores and low-impact fractures.

Fruit and vegetable intake and bones: A systematic review and meta-analysis.

BACKGROUND: Although intake of fruits and vegetables seemed to have a protective effect on bone metabolism, its effect on fractures remains uncertain. METHODS: A systematic review of randomized controlled trials (RCTs) and cohort studies (PROSPERO: CRD42016041462) was performed. RCTs and cohort studies that evaluated the combined intake of fruits and vegetables in men and women aged over 50 years were included. We considered fractures as a primary outcome measure. Changes in bone markers were considered as secondary outcomes. The search strategy included the following descriptors: fruit, vegetables, vegetable products, bone and bones, bone fractures, postmenopausal osteoporosis, and osteoporosis. PubMed, Embase, and Cochrane Library were the databases used. The appraisal of the studies was performed by two independent reviewers, and discussed and agreed upon by both examiners. The data extracted from the RCTs and cohort studies were summarized separately. The risks of fractures were combined across studies using random models. Bone resorption marker (CTx) was summarized with standardized mean differences. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) method was used to evaluate the strength of recommendations. RESULTS: Of the 1,192 studies screened, 13 articles were included in the systematic review and 10 were included in the pooled analysis (6 cohort studies and 4 RCTs). The six cohort studies included in the meta-analysis included a population of 225,062. The pooled hazard ratio (HR) (95% confidence interval (CI)) of the hip in five studies was 0.92 (0.87, 0.98). Its heterogeneity was moderate (I2 = 55.7%, p = 0.060), GRADE (⊕⊕⊕O). Two cohort studies evaluated the risk of any fracture; the HR was 0.90 (95% CI: 0.86-0.96), with aheterogeneity of 24.9% (p = 0.249, GRADE (⊕⊕⊕O)). There was no association between the bone resorption marker CTx and 3 months of fruit and vegetable intake evaluated by four RCTs, GRADE (⊕⊕O O). CONCLUSION: There was an association between the increase of at least one serving of fruits and vegetables per day and decreases in the risk of fractures. The level of evidence for this association is moderate.

Body trunk fat and insulin resistance in post-pubertal obese adolescents.

CONTEXT AND OBJECTIVE: Insulin resistance is a metabolic disorder commonly associated with excess body fat accumulation that may increase chronic disease risk. The present study was undertaken to evaluate the relationship between body composition and insulin resistance among obese adolescents. DESIGN AND SETTING: Cross-sectional study, at the Adolescence Center, Pediatric Department, Universidade Federal de São Paulo. METHODS: Body composition was assessed using dual-energy X-ray absorptiometry. Dietary intake was evaluated using a three-day dietary record. The biochemical evaluation comprised glucose, insulin, serum lipid, leptin and ghrelin measurements. Insulin resistance was calculated by means of the homeostasis model assessment of insulin resistance (HOMA-IR). RESULTS: Forty-nine post-pubertal obese adolescents participated in the study: 12 boys and 37 girls of mean age 16.6 (1.4) years and mean body mass index (BMI) of 35.0 (3.9) kg/m(2). The mean glucose, insulin and HOMA values were 90.3 (6.4) mg/dl, 16.6 (8.1) microIU/ml and 3.7 (1.9), respectively. Hyperinsulinemia and insulin resistance were observed in 40.2% and 57.1% of the subjects, respectively. Adolescents with insulin resistance had higher BMI and body trunk fat. There was a trend towards higher leptin concentration in obese individuals with insulin resistance. Insulin resistance was positively correlated with body trunk fat, BMI, body fat mass (kg), leptin and body fat percentage. Furthermore, there was a negative correlation between HOMA-IR and lean body mass. The body composition predicted 30% of the HOMA-IR levels, according to linear regression models. CONCLUSION: Body trunk fat was significantly associated with insulin resistance, demonstrating the clinical importance of abdominal obesity during adolescence.

Dairy consumption and inflammatory profile: A cross-sectional population-based study, São Paulo, Brazil.

OBJECTIVES: The aim of this study was to investigate the association between dairy product consumption and plasma inflammatory biomarkers levels among a representative sample of Brazilian adults from São Paulo City. METHODS: Data were acquired from the Health Survey for São Paulo, a cross-sectional population-based study. All individuals 20 to 59 y of age with complete food consumption information (24-h dietary recall and food frequency questionnaire) and blood sample analysis were included (N = 259). The sample was separated into two groups according to systemic inflammatory pattern considering plasma levels of C-reactive protein; tumor necrosis factor-α; soluble intracellular adhesion molecule; soluble vascular cell adhesion molecule, monocyte chemoattractant protein; interleukin-1ß, -6, -8, -10, and -12; adiponectin; leptin; and homocysteine. Multiple logistic regression tests were conducted to estimate the odds ratio for the inflammatory cluster across tertiles of dairy consumption. RESULTS: When adjusted by age, smoking status, and energy intake the odds ratio for the inflammatory cluster group in the highest tertile of yogurt consumption was 0.34 (95% confidence interval [CI], 0.14-0.81) relative to the reference tertile, demonstrating also a linear effect (Ptrend = 0.015). Cheese consumption exhibited an odds ratio of 2.49 (95% CI, 1.09-5.75) relative to the reference. CONCLUSIONS: Increasing yogurt consumption might have a protective effect on inflammation, whereas cheese consumption appears to be associated with a proinflammatory status. The results of the present study aggregate a new perspective on existing evidence demonstrating the importance of assessing the contribution of dairy products on diet and their effect on the development of non-communicable diseases and associated risk factors.

Associations among body composition, inflammatory profile and disease extent in ulcerative colitis patients.

OBJECTIVE: The aim of our study was to assess body composition status and its association with inflammatory profile and extent of intestinal damage in ulcerative colitis patients during clinical remission. METHOD: This is a cross-sectional study in which body composition data (phase angle [PhA], fat mass [FM], triceps skin fold thickness [TSFt], mid-arm circumference [MAC], mid-arm muscle circumference [MAMC], adductor pollicis muscle thickness [APMt]), inflammatory profile (C-reactive protein [CRP], a1-acid glycoprotein, erythrocyte sedimentation rate [ESR]) and disease extent were recorded. RESULTS: The mean age of the 59 patients was 48.1 years; 53.3% were women. Most patients were in clinical remission (94.9%) and 3.4% was malnourished according to body mass index. PhA was inversely correlated with inflammatory markers such as CRP (R=-0.59; p<0.001) and ESR (R=-0.46; p<0.001) and directly correlated with lean mass: MAMC (R=0.31; p=0.01) and APMt (R=0.47; p<0.001). Lean mass was inversely correlated with non-specific inflammation marker (APMt vs. ESR) and directly correlated with hemoglobin values (MAMC vs. hemoglobin). Logistic regression analysis revealed that body cell mass was associated with disease extent (OR 0.92; 95CI 0.87-0.97; p<0.01). CONCLUSION: PhA was inversely correlated with inflammatory markers and directly correlated with lean mass. Acute inflammatory markers were correlated with disease extent. Body cell mass was associated with disease extent.

Relationship between nutrient intake and vitamin D status in osteoporotic women.

Vitamin D is essential for maintaining calcium homeostasis and optimizing bone health. Its inadequacy is related to many factors including dietary intake. The aim of the present study was to evaluate serum 25(OH)D and its relationship with nutrient intakes in postmenopausal Brazilian women with osteoporosis. This cross-sectional study comprised 45 free-living and assisted elderly at São Paulo Hospital. Three-day dietary records were used to assess dietary intakes. Bone mineral density was measured with a dual-energy X-ray absorptiometer (DXA). Blood and urine sample were collected for analysis of biochemical markers of bone and mineral metabolism. Insufficiency of vitamin D was observed in 24.4% of the women and optimal levels (> or = 50 nmol/L) were observed in 75.6%. Parathyroid hormone was above the reference range in 51% of the participants. The mean calcium (724 mg/day) and vitamin D (4.2 microg/day) intakes were lower than the value proposed by The Food and Nutrition Board and sodium intake was more than two-fold above the recommendation. Higher levels of serum 25(OH)D were inversely associated with sodium intake. Dietary strategies to improve serum vitamin D must focus on increasing vitamin D intake and should take a reduction of sodium intake into consideration.

Effects of parathyroidectomy on bone remodeling markers and vitamin D status in patients with chronic kidney disease-mineral and bone disorder.

BACKGROUND/AIMS: Chronic renal failure (CRF) is often associated with bone disorders including chronic kidney disease-mineral and bone disorder (CKD-MBD). Parathyroid hormone (PTH) has a relationship to bone remodeling, and so this study was undertaken to evaluate changes in bone remodeling markers after parathyroidectomy (PTX). METHODS: Twelve adult patients, mean age 43.4 +/- 12.7 years, of both genders, were evaluated, prior to and six months after PTX. Analysis of biochemical markers of bone metabolism, such as total and ionized calcium, phosphorus, 25(OH)D(3), total alkaline phosphatase (TAP), bone-specific alkaline phosphatase (BAP), intact PTH, osteoprotegerin (OPG), and tartrate-resistant acid phosphatase isoform 5b (TRAP), were measured. RESULTS: No changes were observed after PTX in the serum total and ionized calcium, TAP, BAP, and 25(OH)D(3). After surgery there was a significant decrease in serum phosphorus, iPTH, and TRAP (P < 0.001). No significant change was observed in OPG; however there was a positive correlation between OPG and 25(OH)D(3) before and after surgery (r = 0.774, P = 0.014; and r = 0.706, P = 0.01, respectively). The percentage of patients with vitamin D deficiency decreased from 16.7% to 8.3%, while those with sufficient levels increased from 41.7% to 58.3%. CONCLUSION: The small number of patients in the study notwithstanding, the present study is unique because it provides information on bone metabolism and vitamin D status six months after PTX. The removal of parathyroid glands significantly decreased bone resorption and indicated a tendency of 25(OH)D(3) concentration to increase. However, the precise role of OPG and BAP in the improvement in bone remodeling in patients with CKD-MBD requires further study.

Associations among osteocalcin, leptin and metabolic health in children ages 9-13 years in the United States.

BACKGROUND: This study aimed to investigate the relationships among osteocalcin, leptin and metabolic health outcomes in children ages 9-13 years. METHODS: This was a cross-sectional analysis of baseline data from 161 boys and 157 girls (ages 9-13 years) who previously participated in a double-blinded randomized placebo controlled trial of vitamin D supplementation. Relationships among fasting serum total osteocalcin (tOC), undercarboxylated osteocalcin (ucOC), leptin, and metabolic health outcomes were analyzed. RESULTS: Approximately 52% of study participants were obese based on percent body fat cutoffs (>25% for boys and >32% for girls) and about 5% had fasting serum glucose within the prediabetic range (i.e. 100 to 125 mg/dL). Serum tOC was not correlated with leptin, glucose, insulin, HOMA-IR, or HOMA-ß after adjusting for percent body fat. However, serum ucOC negatively correlated with leptin (partial r = -0.16; p = 0.04) and glucose (partial r = -0.16; p = 0.04) after adjustment for percent body fat. Leptin was a positive predictor of insulin, glucose, HOMA-IR, and HOMA-ß after adjusting for age, sex and percent body fat (all p < 0.001). CONCLUSIONS: These data depict an inverse relationship between leptin and various metabolic health outcomes in children. However, the notion that tOC or ucOC link fat with energy metabolism in healthy children was not supported. CLINICAL TRIAL REGISTRATION NUMBER: NCT00931580.

Relationship between calcium intake and body mass index in adolescents.

Epidemiologic and experimental data support thee possibility that dietary calcium intake plays a role in human body weight regulation. The aim of the present study was to evaluate calcium intake and its relationship with body mass index (BMI) in adolescents. Weight, height, 3-day food record and a food frequency questionnaire were collected among all adolescents participants at the Outpatient Clinic for Adolescents at the Federal University of Sao Paulo between 2001 and 2003. The statistical analysis comprised Chi-square, Student's T-test, Pearson correlation and linear regression. One-hundred and twenty-one adolescents were studied (62.8% female), with a mean age of 14.9 +/- 2.2 years old. Mean energy and calcium intakes were 1729.9 +/- 557.8 kcal/day and 598.2 +/- 287.9 mg/day respectively, with no significant statistical differences between sex or age. Almost ninety-eight percent of adolescents presented a mean calcium intake lower than proposed values. Calcium intake adjusted for energy presented a significant negative correlation with body weight (r=-0.194, p=0.03) and BMI (r=-0.185, p=0.04). Furthermore, adolescents in the lowest quartile of calcium intake presented higher BMI (29.7 +/- 7.4 kg/m2) than adolescents in the highest calcium quartile. These results indicated a dietary calcium intake lower than recommendations for this life stage, and a contribution of this mineral in the body mass index.

Secondary hyperparathyroidism and its relationship with sarcopenia in elderly women.

Low dietary intake of calcium and poor vitamin D status during aging can result in mild secondary hyperparathyroidism, which may be associated with low muscle mass and reduced strength in the elderly. The aim of this study was to investigate whether low vitamin D, high parathormone (PTH), or both, are associated with sarcopenia. A total of 105 women, 35 with sarcopenia and 70 without sarcopenia, were enrolled in the present study. Body composition measurements were performed by DXA and sarcopenia was defined as skeletal muscle mass index<5.45 kg/m2 and grip strength lower than 20 kg. Three-day dietary records were taken and adjustments for energy intake made. The estimated average requirement (EAR) method was adopted as a cut-off point for estimating the prevalence of inadequate intake. Serum total calcium, phosphorus, creatinine, intact PTH, and 25(OH)D were measured. Only 1% of the patients met the daily adequate intake for vitamin D and 11% met the daily adequate intake for calcium. Notably, the prevalence of sarcopenia was higher in hyperparathyroidism (25(OH)D<20 ng/mL and PTH>65 pg/dL) than in the absence of hyperparathyroidism (41.2 vs 16.2%, respectively; p=0.046). The odds ratio for sarcopenia in hyperparathyroidism cases was 6.81 (95%CI 1.29-35.9) compared with participants who had low PTH and a high 25(OH)D concentration. The present study showed that vitamin D insufficiency associated with secondary hyperparathyroidism increased the risk of sarcopenia, suggesting that the suppression of hyperparathyroidism by ensuring adequate calcium and vitamin D intake should be considered in interventional studies to confirm potential benefits.