A prospective analysis of plasma 25-hydroxyvitamin D concentrations in white and black prepubertal females in the southeastern United States

Vitamin D Deficiency and Associated Factors in Children: A Multicenter Study of 21,811 Samples in Southern China

Objective

To investigate the prevalence of vitamin D deficiency (VDD) in children/adolescents in extreme southern China.

Methods

This multicenter, cross-sectional study included 21,811 children aged 0-18 years from 18 districts in Hainan Province, using a multistage stratified random sampling method from January 2021 to March 2022.

Results

Serum 25(OH)D levels decreased with age (p trend <0.001). VDD prevalence increased significantly from 3.7% (95% CI: 3.2, 4.3) in children aged 0-3 years to 43.5% (95% CI: 42.1, 45.0) in those aged 13-18 years. Girls and urban residents showed higher deficiency rates. Adolescents (13-18 years) had the highest prevalence of VDD (43.5%), while toddlers (0-3 years) had the lowest (3.7%). Factors influencing vitamin D status included gender, urban residency, and breastfeeding duration. Seasonal variations showed higher deficiency rates in autumn, particularly among preschoolers. Regional differences were noted, with the highest deficiency in semiarid and subhumid zones for various age groups.

Conclusion

A significant increase in VDD with age, particularly among adolescents, urban girls, and during autumn, emphasizing the need for targeted strategies.

Assessment of Serum Vitamin D Levels in Patients with Vitiligo in Jordan: A Case-Control Study

Background

Low vitamin D serum levels have been associated with many autoimmune disorders and several other skin diseases. Vitiligo is an autoimmune disease characterized by destruction of melanocytes by immune mechanisms. Melanocytes express vitamin D receptors, and their function can be affected by vitamin D status.

Objectives

The main objective of this study is to compare vitamin D levels in patients with vitiligo vs normal population and whether vitamin D deficiency is associated with vitiligo.

Methods

A case-control study was conducted. 100 vitiligo patients and 100 as controls were included in this study. Serum vitamin D level was measured for both vitiligo patients and controls, results were compared, and statistical analysis was done to compare the results.

Results

The median age of vitiligo cases was 23 years (ranges, 2–80). 58% of vitiligo patients were females. The median vitamin D level was not significantly different between the two groups (vitiligo = 14.1 (IQR 9.9–20.4) vs control = 16.5 (IQR 10.3–25.3) (P=0.28)). Most vitiligo cases and controls were found to have low levels of vitamin D (either insufficient 20–30 ng/mL or low <20 ng/mL).

Conclusions

There was no significant difference in vitamin D levels in vitiligo patients compared to controls. However, vitamin D levels were generally low in both groups.

Evidence of a significant vitamin D deficiency among 9-13-year-old Polish children: results of a multicentre study

PURPOSE

To evaluate the extent to which the population of Polish preadolescents is vitamin D deficient and to assess seasonal variations in vitamin D status.

PARTICIPANTS AND METHODS

A total of 720 healthy children aged 9-13 years (409 girls, 311 boys) residing in 6 representative geographical locations in Poland were studied. A parental-assisted questionnaire provided data on nutritional habits, vitamin D supplements and sun exposure. Serum concentration of 25-hydroxyvitamin was determined twice, after the winter in March and after the summer in October.

RESULTS

In March, vitamin D deficiency (25-50 nmol/L) was found in 64%, and severe deficiency (< 25 nmol/L) in 20.2% of children. In October, the deficiency and severe deficiency were still noticed in 25.9 and 0.1% of children, respectively. The mean serum concentration of 25-OHD was 52% higher in October (55.4 ± 14.0 nmol/L) than in March (36.4 ± 13.5 nmol/L), (p < 0.01). In children with 25-OHD < 50 nmol/L in March, their 25-OHD concentration increased by 64% through March to October (32.5 ± 8.2 vs. 53.2 ± 7.9 nmol/L, p < 0.01). An association was found between 25-OHD concentration and regular consumption of vitamin D supplements, cod-liver oil and fish.

CONCLUSIONS

The majority of preadolescent Polish boys and girls show vitamin D deficiency after the winter period, although a distinct amelioration over summertime is found in this age group. There is a need to implement effective prevention and intervention strategies in the management of vitamin D deficiency among schoolchildren in Poland, with the supplementation throughout the entire year.

Prevalence of hypovitaminosis D and associated factors in obese Spanish children

Background/Objectives:

Vitamin D deficiency may contribute to endocrine health and disease (diabetes, autoimmune thyroid diseases, polycystic ovarian syndrome, etc.). The aim of this study was to determine the prevalence and specific factors for hypovitaminosis D among children stratified by body mass index (BMI) in Northern Spain.

Subjects/Methods:

A cross-sectional clinical (sex, age, season of study visit, place of residence and BMI) and blood testing (calcium, phosphorous, calcidiol and parathyroid hormone (PTH)) were accomplished in 546 Caucasian individuals (aged 3.2–15.8 years). The BMI (Z-score) allowed establishing four groups: normal, overweight, obesity and severe obesity. The criteria of the US Endocrine Society were used for the definition of hypovitaminosis D.

Results:

Calcidiol levels were significantly higher in normal and overweight groups (P=0.001), whereas PTH levels were significantly higher in obesity and severe obesity groups (P=0.001). Hypovitaminosis D prevalence was significantly higher in severe obesity (81.1%) and obesity (68.2%) groups, whereas was lowest in overweight (55%) and normal (58.1%) groups (P=0.001). There was a negative correlation between calcidiol and PTH levels (P<0.01). Female (90.9%), adolescent group (88,2%), winter (100%) and autumn (82.4%) time and urban residence (94.1%) imply a higher prevalence of hypovitaminosis D in subjects with severe obesity (P<0.001). Female, puberal age, autumn, winter and spring time, urban residence and severe obesity were found to be independent predictors for hypovitaminosis D.

Conclusions:

Severe obesity could be considered as an associated factor for vitamin D deficiency, and, owing to its high prevalence, the implementation of systematic screening and hypovitaminosis treatment programs would be particularly useful.

Clinical Trial of Vitamin D2 vs D3 Supplementation in Critically Ill Pediatric Burn Patients

BACKGROUND

Hypovitaminosis D exists postburn. However, evidence-based guidelines for vitamin D repletion are unknown. This investigation examined differences between D₂ and D₃ supplementation on outcome in children with burn injuries.

METHODS

Fifty patients with total body surface area burn of 55.7% ± 2.6% and full-thickness injury of 40.8% ± 3.8% were enrolled, ranging in age from 0.7-18.4 years. All participants received multivitamin supplementation per standardized clinical protocol. In addition, 100 IU/kg D₂, D₃, or placebo was administered daily during hospitalization using a randomized, double-blinded study design. Assay of total 25-hydroxyvitamin D (D25), 1,25-dihydroxyvitamin D (D1,25), 25-hydroxyvitamin D₂ (25-OH-D₂), 25-hydroxyvitamin D₃ (25-OH-D₃), and parathyroid hormone (PTH) was performed at 4 preplanned time intervals (baseline, midpoint, discharge, and 1 year postburn). Differences in vitamin D status were compared over time and at each specific study interval.

RESULTS

There were no significant differences in serum vitamin D levels between groups, but >10% of patients had low D25 at discharge, and percent deficiency worsened by the 1-year follow up for the placebo (75%), D₂ (56%), and D₃ (25%) groups. There were no statistical differences in PTH or clinical outcomes between treatment groups, although vitamin D supplementation demonstrated nonsignificant but clinically relevant decreases in exogenous insulin requirements, sepsis, and scar formation.

CONCLUSIONS

The high incidence of low serum D25 levels 1 year following serious thermal injury indicates prolonged compromise. Continued treatment with vitamin D₃ beyond the acute phase postburn is recommended to counteract the trajectory of abnormal serum levels and associated morbidity.

Seasonal variations in calcidiol and parathyroid hormone levels in healthy children and adolescents in Navarre, Spain: a cross-sectional study

Objective

To analyze the seasonal variations in calcidiol and parathyroid hormone serum levels along a natural year in a paediatric population living in a region of the north of Spain considering a normal nutrition status.

Design

A cross-sectional study.

Setting

Navarra Hospital Complex, Pamplona, Spain.

Participants

A total of 413 Caucasian individuals (aged 3.1 to 15.4 years): 227 school children (96 males and 131 females) and 186 adolescents (94 males and 92 females), with normal nutritional status.

Main outcome measures

Clinical examination (sex, age, weight, height and body mass index) and blood testing (calcium, phosphate, alkaline phosphatase, calcidiol and parathyroid hormone) during the year 2014.

Results

Calcidiol levels were lower during spring (25.96 ± 6.64 ng/mL) and reached its maximum level in summer (35.33 ± 7.51 ng/mL); parathyroid hormone levels were lower in summer (27.13 ± 7.89 pg/mL) and reached maximum level in autumn (34.73 ± 15.38 pg/mL). Hypovitaminosis D prevalence was 14.3% in summer and 75.3% in spring. Parathyroid hormone levels were compatible with secondary hyperparathyroidism in eight individuals (1.9%). There is a correlation (p < 0.01) between calcidiol and parathyroid hormone (r = −0.336). Logistic regression showed significant increased risk of hypovitaminosis in females (OR:1.63) and adolescents (OR:1.77), and when blood samples taken in autumn (OR:12.22), winter (OR:8.54) and spring (OR:19.72).

Conclusions

There is a high prevalence of hypovitaminosis D in the paediatric population with a healthy nutrition situation in Navarre, mainly during the months of autumn and winter, and, especially, in spring time. Given the difficulties in maintaining a sufficient amount of body vitamin D content along the year, it should be considered to give vitamin supplements and/or increase the intake of its natural dietary sources or vitamin D fortified foods.

Vitamin D, muscle and bone: Integrating effects in development, aging and injury

Beyond the established effects of muscle loading on bone, a complex network of hormones and growth factors integrates these adjacent tissues. One such hormone, vitamin D, exerts broad-ranging effects in muscle and bone calcium handling, differentiation and development. Vitamin D also modulates muscle and bone-derived hormones, potentially facilitating cross-talk between these tissues. In the clinical setting, vitamin D deficiency or mutations of the vitamin D receptor result in generalized atrophy of muscle and bone, suggesting coordinated effects of vitamin D at these sites. In this review, we discuss emerging evidence that vitamin D exerts specific effects throughout the life of the musculoskeletal system - in development, aging and injury. From this holistic viewpoint, we offer new insights into an old debate: whether vitamin D's effects in the musculoskeletal system are direct via local VDR signals or indirect via its systemic effects in calcium and phosphate homeostasis.

Conflicting reports on vitamin D supplementation: Evidence from randomized controlled trials

A significant number of children and adolescents worldwide have low serum 25(OH)D values relative to the 2010 Institute of Medicine criteria. Since approximately 90% of adult bone mineral content (BMC) is accrued by the end of adolescence, and approximately 40% of adult BMC accumulated during the 4 years surrounding peak BMC velocity, low circulating 25(OH)D during this time may attenuate gains in adolescent bone strength. Reduced bone mineralization and strength during pubertal growth tracks into adulthood and could lead to an increased risk of skeletal fractures. Observational studies examining the relationships between vitamin D and bone are conflicting and few randomized controlled trials (RCTs) have been conducted in children and adolescents. Four of these RCTs, however, provide moderate support for the role of vitamin D supplementation on BMC accrual in adolescent females with baseline serum concentrations <50 nmol/L. Though the daily vitamin D doses employed in these trials ranged from 200 to 3000 IU per day, it is not clear if a dose-response effect exists. Specific maturational stages were associated with optimal bone responses in each of these trials, but they were not consistent across studies. Furthermore, data on male children and among ethnicities other than white and Asian youth were limited in these studies and therefore reduce the generalizability of the findings. Finally, the evidence linking vitamin D supplementation to improved muscle gains and function, important variables to consider in bone health investigations during growth, might imply indirect effects of supplementation on bone. In conclusion, future RCTs are warranted that address the mechanisms by which vitamin D improves bone mineralization in adolescents, including trials that address the impact of vitamin D on muscle function.

Vitamin D deficiency and its associated risk factors in children and adolescents in southern Iran

OBJECTIVES

To evaluate prevalence of vitamin D deficiency and its associated factors in southern Iranian children.

DESIGN

Cross-sectional study. Anthropometric and pubertal characteristics were assessed by a trained physician. Physical activity and sun exposure were evaluated using standard questionnaires. Body composition measurements were performed using dual-energy X-ray absorptiometry. Serum Ca, P alkaline phosphatase and 25-hydroxyvitamin D (25(OH)D) were assessed in all children. Statistical analysis was done using the statistical software package IBM SPSS Statistics 18·0.

SUBJECTS

Iranian children (n 477) aged 9-18 years.

SETTING

Fars Province, Iran, 2011.

RESULTS

Of the children, 81·3 % were 25(OH)D deficient. There was no significant difference in 25(OH)D concentration between boys and girls (P=0·3). 25(OH)D concentration was associated with BMI (r=-0·1, P=0·02), pubertal status (r=-0·08, P=0·04) and sun exposure (r=0·10, P=0·04). Fat mass index was associated with 25(OH)D concentration (r=-0·13, P=0·03), but not lean mass index (P=0·86). In multiple regression analysis with adjustment for confounding factors, age and puberty were found to be independently associated with 25(OH)D concentration (P=0·008 and P=0·006); there was a significant correlation between exercise and 25(OH)D concentration after adjustment for either BMI (P=0·01) or fat mass index (P=0·02).

CONCLUSIONS

25(OH)D deficiency is highly prevalent among children in the south of Iran. It is related to insufficient sun exposure, low physical activity, advancing age and pubertal stage. Measures should be taken to improve the health of southern Iranian children in this critical age group by preventing 25(OH)D deficiency.

Can vitamin D status be assessed by serum 25OHD in children?

BACKGROUND

To examine the relationship of serum 25-hydroxyvitamin D (25OHD) concentrations with serum parathyroid hormone (PTH) levels, body mass index (BMI), and environmental factors in a population of Caucasian children living at latitude 43°N.

METHODS

Cross-sectional study on 288 children aged 1 month to 13 years who presented to a pediatric emergency unit during a 21-month period.

RESULTS

Mean (SD) serum 25OHD concentrations were 40.6 (17.6), 30.9 (12.0), and 26.4 (9.9) ng/ml (1 ng/ml = 2.5 nmol/l), in children aged 0-1, 2-5, and ≥ 6 years, respectively. Serum PTH levels were 26.6 (13.6), 24.3 (11.9), and 32.7 (12.1) pg/ml in the same groups. Infants had 25OHD concentrations significantly higher. PTH levels were significantly higher in children aged ≥ 6 years. There was no significant correlation between serum 25OHD and PTH concentrations. Totals of 15.6 % and 2.1 % of children had 25OHD values less than 20 and 10 ng/ml, respectively, but none had elevated serum PTH or clinical manifestations related with vitamin D deficiency. Age (inverse correlation) and season (higher values in summer), but not BMI, sex, and time spent outdoors, influenced serum 25OHD concentrations.

CONCLUSIONS

Our results raise doubt on the assumption of only a serum 25OHD threshold as indicative of vitamin D deficiency in children.

The effectiveness of a short food frequency questionnaire in determining vitamin D intake in children

Previous studies have found a high prevalence of vitamin D deficiency in children, yet few validated dietary vitamin D assessment tools are available for use in children. Our objective was to determine whether a short food frequency questionnaire (SFFQ) can effectively assess vitamin D intake in children. Vitamin D intake ascertained by a SFFQ was compared with assessments by a previously validated long food frequency questionnaire (LFFQ) in a population of 296 healthy 6- to 14-y-old children (54% male, 60% African American) from Pittsburgh, PA. The questionnaires were completed at two points 6 mo apart. Median reported daily vitamin D intake from the SFFQ (baseline: 380 IU, follow-up: 363 IU) was higher than the LFFQ (255 IU and 254 IU, respectively). Reported median dairy intake, including milk, cheese, and yogurt, was 3.7 cups/day, which meets the USDA recommendation for children. Vitamin D intake reported by the 2 questionnaires was modestly correlated at baseline and follow-up (r = 0.35 and r = 0.37, respectively; p < 0.001). These associations were stronger in Caucasians (r = 0.48 and r = 0.49, p < 0.001) than in African Americans (r = 0.27 and r = 0.31; p = 0.001). The sensitivity of the SFFQ for predicting daily vitamin D intake, defined as intake of ≥ 400 IU on both the SFFQ and LFFQ, was 65%. Specificity, defined as intake of < 400 IU on both questionnaires, was 42%. Vitamin D requirements may not be met despite adequate consumption of dairy products. The SFFQ was found to be a modestly valid and sensitive tool for dietary assessment of vitamin D intake in children.

Does serum 25-hydroxyvitamin D influence muscle development during puberty in girls? A 7-year longitudinal study

Vitamin D is well known for its regulatory role in calcium and phosphate homeostasis, but its role in muscle mass and strength during growth remains inconclusive. We explored the association of serum 25-hydroxyvitamin D (25(OH)D) with muscle development in girls from 11 to 18-years old. Whole body lean tissue mass (LMWB), appendicular lean mass (aLM), muscle cross-sectional area at the lower leg (mCSA), maximal voluntary contraction of elbow flexors (MVC elbow) and knee extensors (MVC knee) were assessed in 217 girls aged 10-13 years (at baseline), 215 in 2-year and 226 in 7.5-year follow-up. Serum concentration of 25(OH)D and intact parathyroid hormone (PTH) were analyzed retrospectively and girls were categorized according to their 25(OH)D levels (consistently insufficient 25(OH)D GLL <50 nmol/l and consistently sufficient GHH >50 nmol/l from baseline to 7-year follow-up). We found that 25(OH)D level declined until menarche (p<0.05) while LMWB, aLM, mCSA, MVC elbow and MVC knee continued to increase (p<0.001 for all) post menarche. At pre-menarche, the GLL (n = 34) had higher LMWB and aLM than the GHH (n = 21, p<0.05), while post-menarche the GHH (n = 15) had a greater catch-up gain in LMWB (p = 0.004), aLM (p = 0.001) and mCSA (p = 0.027) compared to the GLL (n = 65) over the first 2-year period. At the age of 18, no differences in muscle mass/strength between the low (n = 151) and high (n = 77) levels of 25(OH)D groups were found. This finding was independent of vitamin D receptor genotype and other confounders. In conclusion, our results showed that levels of 25(OH)D have no significant negative influence on the development of muscle mass and strength during pubertal growth both with longitudinal and cross-sectional comparison. On the contrary, our results suggest that the temporary negative association between 25(OH)D and muscle mass arises as a consequence of fast growth prior to menarche, and this negative association is diminished through catch-up growth after menarche.

[Vitamin D and breast cancer: physiopathology, biological and clinical implications]

There is a recent increase in interest of vitamin D and breast cancer, facing the number of publications on the subject. This increase have several reasons, on the one hand, vitamin D deficiency is more and more prevalent and, on the other hand, there are new data that highlights the extra-bone effects of vitamin D, especially in breast cancer, the vitamin D is involved in the breast cancer risk factor, the prognosis, and the interaction with breast cancer treatments. This combination between vitamin D deficiency and breast cancer is extremely usual, and combined with all cancer clinical parameters: the incidence, the tumour biology, the clinical presentation, the prognosis, and the antineoplastic treatment tolerance. This vitamin D deficiency is increased after adjuvant cancer treatments. And yet, this problem increases bone metabolism disruptions in breast cancer patients, inducing osteoporotic risk at long time, even though this population is curable. This problem is therefore serious in the adjuvant breast cancer treatment. Unfortunately, in this population, the current recommendations are clearly insufficient, and the current randomized clinical trial results would contribute to define the best way to correct the vitamin D deficiency, quickly and secure.

Racial differences in cortical bone and their relationship to biochemical variables in Black and White children in the early stages of puberty

Osteoporotic fracture rates differ according to race with Blacks having up to half the rate of Whites. The current study demonstrates that racial divergence in cortical bone properties develops in early childhood despite lower serum 25-hydroxyvitamin D in Blacks.

INTRODUCTION

Racial differences in bone structure likely have roots in childhood as bone size develops predominantly during growth. This study aimed to compare cortical bone health within the tibial diaphysis of Black and White children in the early stages of puberty and explore the contributions of biochemical variables in explaining racial variation in cortical bone properties.

METHODS

A cross-sectional study was performed comparing peripheral quantitative computed tomography-derived cortical bone measures of the tibial diaphysis and biochemical variables in 314 participants (n = 155 males; n = 164 Blacks) in the early stages of puberty.

RESULTS

Blacks had greater cortical volumetric bone mineral density, mass, and size compared to Whites (all p < 0.01), contributing to Blacks having 17.0 % greater tibial strength (polar strength-strain index (SSIP)) (p < 0.001). Turnover markers indicated that Blacks had higher bone formation (osteocalcin (OC) and bone-specific alkaline phosphatase) and lower bone resorption (N-terminal telopeptide) than Whites (all p < 0.01). Blacks also had lower 25-hydroxyvitamin D (25(OH)D) and higher 1,25-dihydroxyvitamin D (1,25(OH)2D) and parathyroid hormone (PTH) (all p < 0.05). There were no correlations between tibial bone properties and 25(OH)D and PTH in Whites (all p ≥ 0.10); however, SSIP was negatively and positively correlated with 25(OH)D and PTH in Blacks, respectively (all p ≤ 0.02). Variation in bone cross-sectional area and SSIP attributable to race was partially explained by tibial length, 25(OH)D/PTH, and OC.

CONCLUSIONS

Divergence in tibial cortical bone properties between Blacks and Whites is established by the early stages of puberty with the enhanced cortical bone properties in Black children possibly being explained by higher PTH and OC.

Magnesium retention from metabolic-balance studies in female adolescents: impact of race, dietary salt, and calcium

BACKGROUND

Previously, we showed that black girls retained more calcium than white girls did and that salt loading negatively affected calcium retention. Racial differences likely exist in other bone minerals also, such as magnesium, in response to salt loading during growth.

OBJECTIVE

We studied racial differences in magnesium metabolism in response to dietary sodium and calcium during rapid bone growth.

DESIGN

Twenty-seven white and 40 black girls (11-15 y old) were studied for 3 wk while they consumed low-sodium (1.3 g/d) and high-sodium (3.8 g/d) diets by using a randomized-order, crossover metabolic study with 3 dietary calcium intakes; the magnesium dietary intake was fixed at 230 mg/d. Urine and feces were collected during each 3-wk period in 24-h pools and analyzed for magnesium. A mixed-model ANOVA was used to determine the effect of race and dietary sodium with calcium intake as a covariate.

RESULTS

Salt loading or calcium intake had no significant effect on urinary magnesium excretion. Blacks excreted significantly less urinary magnesium (mean ± SD: 83.8 ± 25.6 mg/d) than did whites (94.9 ± 27.3 mg/d; P < 0.05). No effects were observed in fecal magnesium excretion. Magnesium retention was higher with the low-sodium diet (50.1 ± 44.0 mg/d) than with the high-sodium diet (39.3 ± 49.8 mg/d) (P < 0.05), with no effects of race or calcium intake. Salt loading had no effect on biomarkers. Whites had higher 25-hydroxyvitamin D and insulin-like growth factor binding protein 3 but lower 1,25-dihydroxyvitamin D and parathyroid hormone concentrations.

CONCLUSIONS

Blacks excreted less urinary magnesium than did whites. Magnesium retention was similar between races but higher with the low-sodium diet. Kinetic studies are needed to fully explain magnesium homeostasis. This trial was registered at clinicaltrials.gov as NCT01564238.

The roles of vitamin D in skeletal muscle: form, function, and metabolism

Beyond its established role in bone and mineral homeostasis, there is emerging evidence that vitamin D exerts a range of effects in skeletal muscle. Reports of profound muscle weakness and changes in the muscle morphology of adults with vitamin D deficiency have long been described. These reports have been supplemented by numerous trials assessing the impact of vitamin D on muscle strength and mass and falls in predominantly elderly and deficient populations. At a basic level, animal models have confirmed that vitamin D deficiency and congenital aberrations in the vitamin D endocrine system may result in muscle weakness. To explain these effects, some molecular mechanisms by which vitamin D impacts on muscle cell differentiation, intracellular calcium handling, and genomic activity have been elucidated. There are also suggestions that vitamin D alters muscle metabolism, specifically its sensitivity to insulin, which is a pertinent feature in the pathophysiology of insulin resistance and type 2 diabetes. We will review the range of human clinical, animal, and cell studies that address the impact of vitamin D in skeletal muscle, and discuss the controversial issues. This is a vibrant field of research and one that continues to extend the frontiers of knowledge of vitamin D's broad functional repertoire.

Status of vitamin D in children with sickle cell disease living in Madrid, Spain

Patients with sickle cell disease have vitamin D deficiency and poor bone health which makes them prone to have an increased risk of fractures and osteoporosis in adulthood. We performed a prospective, cross-sectional study in children diagnosed with sickle cell disease living in Madrid, Spain. The purpose of this study was to evaluate the status of vitamin D of these children. Patients 0-16 years old were enrolled between 2008 and 2011. We studied demographics, calcium metabolism, and bone health, especially by measuring levels of 25-hydroxyvitamin D (25(OH)D), during different seasons of the year, and bone densitometry (beyond 4 years of age). Seventy-eight children were included in the study. Mean age was 4.8 ± 4.3 years, and mean serum 25(OH)D level was 21.50 ± 13.14 ng/ml, with no differences in 25(OH)D levels within different seasons. Fifty-six percent of children had levels of 25(OH) vitamin D of <20 ng/ml, whereas 79 and 18 % of them had levels of <30 and <11 ng/ml, respectively. Secondary hyperparathyroidism was observed in 25 % of children. Densitometry was performed in 33 children, and an abnormal z-score was seen in 15.2 % of them with no correlation with levels of 25(OH)D.

CONCLUSIONS

Vitamin D deficiency is highly prevalent in children with sickle cell disease, who are residing in Madrid, Spain, and it is detected at a young age. We propose that early intervention may increase the possibility of an adequate bone density later in life.

Risk factors for vitamin D deficiency in HIV-infected patients in the south central United States

We evaluated the prevalence of serum 25-hydroxyvitamin D [25(OH)D] deficiency and the risk factors for vitamin D deficiency in HIV-infected patients in the South-Central United States. The study consisted of a cross-sectional assessment of vitamin D levels in HIV-infected patients receiving routine clinical care from a private practice in Houston, Texas (latitude 29°N). Vitamin D deficiency was defined as 25(OH)D less than 20 ng/ml (<50 nmol/liter). Two-hundred enrolled patients were surveyed with a vitamin D questionnaire to determine daily supplemental vitamin D intake, dietary vitamin D intake, and average sunlight exposure (minutes/day). Multivariate logistic regression analysis was used to determine significant risk factors for vitamin D deficiency. Median 25(OH)D was 15.5 ng/ml (interquartile range 10.9-24.6) for the total population (n=200). Approximately, two-thirds (64%) of patients had vitamin D deficiency and 20.5% had severe vitamin D deficiency [25(OH)D <10 ng/ml or <25 nmol/liter]. In univariate analysis, African-American race, current tobacco use, increased body mass index (BMI), lower serum calcium level, no supplemental vitamin D use, and low daily supplemental and total daily vitamin D intake were significantly associated with vitamin D deficiency. In multivariate analysis, African-American race [adjusted odds ratio (AOR) 3.53 (95% confidence interval (CI) 1.83-6.82)], higher BMI [AOR 1.07 (95% CI 1.002-1.139)], and low daily vitamin D supplemental intake [AOR 0.997 (95% CI 0.996-0.999)] were significantly associated with vitamin D deficiency. No HIV factors including antiretroviral class use were significantly associated with either vitamin D deficiency or severe vitamin D deficiency. Vitamin D deficiency and severe vitamin D deficiency were highly prevalent in this HIV population. In the HIV population, African-Americans or patients with a high BMI may benefit from vitamin D supplementation.

Demographic, dietary, and biochemical determinants of vitamin D status in inner-city children

BACKGROUND

Reports of clinical rickets are particularly evident in minority infants and children, but only limited analyses of vitamin D are available in this demographic group.

OBJECTIVE

We sought to characterize circulating 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and their determinants, including circulating parathyroid hormone (PTH), total alkaline phosphatase activity (ALP), calcium, and phosphorus, in minority infants and children.

DESIGN

We obtained demographic information and blood samples for measurement of PTH, ALP, 25(OH)D, and 1,25(OH)(2)D in >750 6-mo- to 3-y-old children. Dietary intake data were obtained and analyzed.

RESULTS

The mean (±SD) 25(OH)D concentration was 66 ± 22 nmol/L (26.3 ± 8.7 ng/dL). A total of 15% of children had 25(OH)D concentrations less than the recommended target threshold of 50 nmol/L. Combined elevations of PTH and ALP occurred in only 2.5% of children. Determinants of 25(OH)D included vitamin D intake, age (decreasing with age), skin type (greater concentrations in lighter-skinned children than in darker-skinned children), formula use (higher intakes), season (greater concentrations in the summer and fall than in the winter and spring), and, inversely, PTH. The mean 1,25(OH)(2)D concentration was 158 ± 58 pmol/L (60.6 ± 22.5 pg/mL), which was consistent with a reference range of 41-274 pmol/L or 15.7-105.5 pg/mL. Determinants for 1,25(OH)(2)D were age (decreasing with age), sex (greater concentrations in girls than in boys), skin type (greater concentrations in lighter-skinned children than in darker-skinned children), and, inversely, serum calcium and phosphorus.

CONCLUSIONS

Although 15% of subjects were vitamin D insufficient, only 2.5% of subjects had elevations of both PTH and ALP. The greater 25(OH)D concentrations observed with formula use confirm that dietary vitamin D fortification is effective in this demographic group. Circulating 1,25(OH)(2)D is higher in infants than in older children and adults and, in contrast to 25(OH)D, is not directly correlated with nutrient intakes.

Vitamin D-fortified milk achieves the targeted serum 25-hydroxyvitamin D concentration without affecting that of parathyroid hormone in New Zealand toddlers

For young children, the level of vitamin D required to ensure that most achieve targeted serum 25-hydroxyvitamin D [25(OH)D] ≥50 nmol/L has not been studied. We aimed to investigate the effect of vitamin D-fortified milk on serum 25(OH)D and parathyroid hormone (PTH) concentrations and to examine the dose-response relationship between vitamin D intake from study milks and serum 25(OH)D concentrations in healthy toddlers aged 12-20 mo living in Dunedin, New Zealand (latitude 46°S). Data from a 20-wk, partially blinded, randomized trial that investigated the effect of providing red meat or fortified toddler milk on the iron, zinc, iodine, and vitamin D status in young New Zealand children (n = 181; mean age 17 mo) were used. Adherence to the intervention was assessed by 7-d weighed diaries at wk 2, 7, 11, 15, and 19. Serum 25(OH)D concentration was measured at baseline and wk 20. Mean vitamin D intake provided by fortified milk was 3.7 μg/d (range, 0-10.4 μg/d). After 20 wk, serum 25(OH)D concentrations but not PTH were significantly different in the milk groups. The prevalence of having a serum 25(OH)D <50 nmol/L remained relatively unchanged at 43% in the meat group, whereas it significantly decreased to between 11 and 15% in those consuming fortified study milk. In New Zealand, vitamin D intake in young children is minimal. Our findings indicate that habitual consumption of vitamin D-fortified milk providing a mean intake of nearly 4 μg/d was effective in achieving adequate year-round serum 25(OH)D for most children.

Vitamin D and parathormone levels of late-preterm formula fed infants during the first year of life

BACKGROUND/OBJECTIVES

Preterm infants are at risk for low vitamin D but documentation on late-preterm infants is sparse. This prospective study monitored longitudinally vitamin D and parathormone (PTH) levels in late-preterm formula fed infants during the first year of life, taking into consideration in utero and postnatal growth, and season and diet.

SUBJECTS/METHODS

The study population comprised 128 infants of gestational age (GA) 32-36 weeks, of which 102 were appropriate (AGA) and the remaining 26 were small for GA (SGA). Serum levels of vitamin D (25(OH)D), PTH calcium, phosphate (P) and alkaline phosphate were estimated at 2 and 6 weeks, and at 3, 6, 9 and 12 months of age.

RESULTS

The 25(OH)D levels were relatively low at 2 and 6 weeks in both AGA and SGA infants (21±11, 20±7 ng/ml and 25±16, 23±8 ng/ml, respectively), but increased at 6 months (45±14, 47±10 ng/ml) and remained stable thereafter. SGA infants had lower 25(OH)D levels at 9 and 12 months (AGA 45±14, 47±18 ng/ml vs SGA 38±13, 37±13 ng/ml, P<0.05). Deficiency of 25(OH)D (<20 ng/ml) was found in 18.5% of measurements in 92 (72%) infants, and its insufficiency (20-32 ng/ml) was found in 29.2% of measurements in 99 (77.3%) infants. Most measurements with vitamin D <32 ng/ml were observed at the first three study points, where PTH showed an inverse association with 25(OH)D, reaching a plateau thereafter.

CONCLUSIONS

Late-preterm, formula fed infants may have suboptimal vitamin D levels and elevated PTH, especially, during the first 3 months. Those born SGA may have lower vitamin D levels up to the end of the first year of life.

25-hydroxyvitamin D, insulin-like growth factor-I, and bone mineral accrual during growth

CONTEXT

The extent to which 25-hydroxyvitamin D [25(OH)D] and IGF-I influence bone mineral content (BMC) accrual from early to mid-puberty is unclear. OBJECTIVE, SETTING, AND PARTICIPANTS: This study sought to determine relationships among 25(OH)D, IGF-I, and BMC in community-dwelling prepubertal females (n = 76; aged 4-8 yr at baseline) over a period of up to 9 yr.

DESIGN

The hypothesis that changes in IGF-I vs. 25(OH)D are more strongly associated with BMC accrual was formulated after data collection. 25(OH)D and IGF-I were log-transformed and further adjusted using two-way ANOVA for differences in season and race. Linear mixed modeling (including a random subject-specific intercept and a random subject-specific slope on age) was employed to analyze the proportion of variance the transformed 25(OH)D and IGF-I variables explained for the bone outcomes.

RESULTS

IGF-I was more strongly associated with BMC accrual than 25(OH)D at the total body (R(2) = 0.874 vs. 0.809), proximal femur (R(2) = 0.847 vs. 0.771), radius (R(2) = 0.812 vs. 0.759), and lumbar spine (R(2) = 0.759 vs. 0.698). The rate of BMC accrual was positively associated with changes in IGF-I but negatively associated with 25(OH)D. When IGF-I and 25(OH)D were included in the same regression equation, 25(OH)D did not have a significant predictive effect on BMC accrual above and beyond that of IGF-I.

CONCLUSIONS

These prospective data in early adolescent females indicate that both 25(OH)D and IGF-I have a significant impact on bone mineral accrual; however, the positive association of IGF-I and BMC accrual is greater than the negative association of 25(OH)D and BMC accrual.

Predictors of vitamin D status and its association with parathyroid hormone in young New Zealand children

BACKGROUND

Despite increased awareness of the adverse health effects of low vitamin D status, few studies have evaluated 25-hydroxyvitamin D [25(OH)D] status in young children.

OBJECTIVES

We aimed to assess vitamin D status on the basis of 25(OH)D and its relation with parathyroid hormone (PTH) and to identify possible predictors of 25(OH)D status in young children living in a country with minimal vitamin D fortification.

DESIGN

Serum 25(OH)D and PTH concentrations were measured in a cross-sectional sample of children aged 12-22 mo [n = 193 for 25(OH)D, n = 144 for PTH] living in Dunedin, New Zealand (latitude: 45 degrees S). Anthropometric, dietary, and sociodemographic data were collected.

RESULTS

The majority of children sampled in the summer (94%; 47 of 50) had 25(OH)D >50 nmol/L; however, nearly 80% of children sampled in the winter (43 of 55) had serum concentrations < or =50 nmol/L. In season-adjusted multivariate analysis, breastfeeding and higher levels of education were independently associated with lower 25(OH)D concentrations, whereas male sex and cigarette-smoke exposure were positively associated with 25(OH)D (all P < 0.05). Fractional polynomial regression was used to describe the nonlinear relation between serum PTH and 25(OH)D (P < 0.001). When 25(OH)D concentrations were >60-65 nmol/L, a plateau in PTH was evident.

CONCLUSIONS

Seasonal variation in 25(OH)D concentration implies that postsummer vitamin D stores were insufficient to maintain status >50 nmol/L year-round. Examination of the predictors of 25(OH)D in our model shows few modifiable risk factors, and thus effective dietary strategies may be required if future research determines that children with 25(OH)D concentrations <50 nmol/L are at significant health risk. This trial was registered at www.actr.org.au as ACTRN12605000487617.

Low 25-hydroxyvitamin D levels in adolescents: race, season, adiposity, physical activity, and fitness

OBJECTIVES

The objectives were to characterize the vitamin D status of black and white adolescents residing in the southeastern United States (latitude: approximately 33 degrees N) and to investigate relationships with adiposity.

METHODS

Plasma 25-hydroxyvitamin D levels were measured with liquid chromatography-tandem mass spectroscopy for 559 adolescents 14 to 18 years of age (45% black and 49% female). Fat tissues, physical activity, and cardiovascular fitness also were measured.

RESULTS

The overall prevalences of vitamin D insufficiency (<75 nmol/L) and deficiency (< or = 50 nmol/L) were 56.4% and 28.8%, respectively. Black versus white subjects had significantly lower plasma 25-hydroxyvitamin D levels in every season (winter, 35.9 + or - 2.5 vs 77.4 + or - 2.7 nmol/L; spring, 46.4 + or - 3.5 vs 101.3 + or - 3.5 nmol/L; summer, 50.7 + or - 4.0 vs 104.3 + or - 4.0 nmol/L; autumn, 54.4 + or - 4.0 vs 96.8 + or - 2.7 nmol/L). With adjustment for age, gender, race, season, height, and sexual maturation, there were significant inverse correlations between 25-hydroxyvitamin D levels and all adiposity measurements, including BMI percentile (P = .02), waist circumference (P < .01), total fat mass (P < .01), percentage of body fat (P < .01), visceral adipose tissue (P = .015), and subcutaneous abdominal adipose tissue (P = .039). There were significant positive associations between 25-hydroxyvitamin D levels and vigorous physical activity (P < .01) and cardiovascular fitness (P = .025).

CONCLUSIONS

Low vitamin D status is prevalent among adolescents living in a year-round sunny climate, particularly among black youths. The relationships between 25-hydroxyvitamin D levels, adiposity, physical activity, and fitness seem to be present in adolescence.

A pilot study assessing the role of 25 hydroxy vitamin D levels in patients with vitiligo vulgaris

BACKGROUND

Very low vitamin D levels have been noted in patients with a variety of autoimmune diseases.

OBJECTIVE

To determine whether low vitamin D levels are associated with autoimmunity in the setting of vitiligo vulgaris.

METHODS

A prospective cohort study was conducted on 45 consecutive patients with vitiligo vulgaris. 25-Hydroxyvitamin D levels were determined from sera collected at the time of study enrollment. Logistic regression analysis of the relationship of 25-hydroxyvitamin D levels to disease state was performed, including surface area, recent-onset vitiligo, Fitzpatrick skin type and ethnicity, dairy intake, and both personal and family history of autoimmunity. Multiple univariate and multivariate logistic regression models were developed to assess the interrelationship of these parameters.

RESULTS

25-Hydroxyvitamin D levels were divided into 3 groups: 31.1% were normal (>30 ng/mL), 55.6% were insufficient (<30 ng/mL), and 13.3% were very low (<15 ng/mL). Insufficient 25-hydroxyvitamin D levels were associated with increasing Fitzpatrick phototypes (odds ratio [OR] = 1.76, 95% confidence interval [CI] = 1.12-2.77). Very low 25-hydroxyvitamin D levels were associated with comorbid autoimmune illness (OR = 10.00, 95% CI = 1.06-94.7), but not with age, gender, race/ethnicity, family history of vitiligo or autoimmune disease, new-onset disease, or body surface area affected. None of the surveyed patients reported daily vitamin D intake of greater than 200 IU.

LIMITATIONS

This study consists of a small cohort that assesses point prevalence without assessing seasonal variation in vitamin D levels.

CONCLUSIONS

Very low 25-hydroxyvitamin D levels (<15 ng/mL) appear to be a reasonable screening tool for the presence of comorbid autoimmunity. Furthermore, we demonstrate that Fitzpatrick phototype, rather than ethnicity, is specifically associated with 25-hydroxyvitamin D levels that are insufficient (<30 ng/mL).

Influence of obesity on vitamin D-binding protein and 25-hydroxy vitamin D levels in African American and white women

25-Hydroxy vitamin D (25OHD) is lipophilic and highly bound to vitamin D-binding protein (VDBP) in plasma. In the present study, we examined VDBP and 25OHD levels by race and body mass index (BMI) in young adult women to determine whether circulating VDBP plays a role in the low levels of 25OHD with obesity and among African Americans. In agreement with previous studies, mean 25OHD levels were lower in African American women than in whites (P < .01). In a hierarchical multiple regression model, BMI was associated with 25OHD after adjustment for age in white women (P = .02, R(2) = .10) but not in African American women. The VDBP levels, by contrast, were similar in African Americans and whites, and were unrelated to BMI in either racial group. Furthermore, VDBP was unrelated to the plasma level of 25OHD. These data confirm an interaction between race and obesity in vitamin D metabolism, and imply that the carrier protein is not an important determinant of circulating 25OHD in women, nor is it affected by race or adiposity.

Vitamin D status and calcium metabolism in adolescent black and white girls on a range of controlled calcium intakes

BACKGROUND

There are limited data in adolescents on racial differences in relationships between dietary calcium intake, absorption, and retention and serum levels of calcium-regulating hormones.

OBJECTIVES

The aim of this study was to investigate these relationships cross-sectionally in American White and Black adolescent girls.

METHODS

Calcium balance studies were conducted in 105 girls, aged 11-15 yr, on daily calcium intakes ranging from 760-2195 mg for 3-wk controlled feeding periods; 158 observations from 52 Black and 53 White girls were analyzed.

RESULTS

Black girls had lower serum 25-hydroxyvitamin D [25(OH)D], higher serum 1,25-dihydroxyvitamin D, and higher calcium absorption and retention than White girls. Calcium intake and race, but not serum 25(OH)D, predicted net calcium absorption and retention with Black girls absorbing calcium more efficiently at low calcium intakes than White girls. The relationship between serum 25(OH)D and serum PTH was negative only in White girls. Calcium intake, race, and postmenarcheal age explained 21% of the variation in calcium retention, and serum 25(OH)D did not contribute further to the variance.

CONCLUSIONS

These results suggest that serum 25(OH)D does not contribute to the racial differences in calcium absorption and retention during puberty.

Vitamin D: a growing perspective

Vitamin D deficiency has been widely reported in all age groups in recent years. Rickets has never been eradicated in developed countries, and it most commonly affects children from recent immigrant groups. There is much evidence that current vitamin D guidelines for the neonatal period, 5-10 microg (200-400 IU)/day, prevent rickets at the typical calcium intakes in developed countries. The annual incidence of vitamin D-deficiency rickets in developed countries ranges between 2.9 and 7.5 cases per 100,000 children. The prevalence of vitamin D deficiency in mothers and their neonates is remarkable, and the results of one study suggest that third-trimester 25-hydroxyvitamin D (25(OH)D) is associated with fetal bone mineral accrual that may affect prepubertal bone mass accumulation. Beyond infancy, the evidence indicates that 5 microg (200 IU)/day of vitamin D has little effect on vitamin D status as measured by the serum 25(OH)D concentration. Two randomized clinical trials show that higher vitamin D intake improves one-year gain in bone density in adolescent girls. The functions of vitamin D extend beyond bone to include immune system regulation and anti-proliferative effects on cells. Early life vitamin D inadequacy is implicated in the risk of bone disease, autoimmune disease, and certain cancers later in life; however, long-term interventional studies do not exist to validate the widespread implementation of greater vitamin D consumption. Here we review the available data concerning vitamin D status and health effects of vitamin D in pregnancy through to and including adolescence.

Diagnosis and treatment of vitamin D deficiency

The recent discovery--in a randomised, controlled trial--that daily ingestion of 1100 IU of colecalciferol (vitamin D) over a 4-year period dramatically reduced the incidence of non-skin cancers makes it difficult to overstate the potential medical, social and economic implications of treating vitamin D deficiency. Not only are such deficiencies common, probably the rule, vitamin D deficiency stands implicated in a host of diseases other than cancer. The metabolic product of vitamin D is a potent, pleiotropic, repair and maintenance, secosteroid hormone that targets > 200 human genes in a wide variety of tissues, meaning it has as many mechanisms of action as genes it targets. A common misconception is that government agencies designed present intake recommendations to prevent or treat vitamin D deficiency. They did not. Instead, they are guidelines to prevent particular metabolic bone diseases. Official recommendations were never designed and are not effective in preventing or treating vitamin D deficiency and in no way limit the freedom of the physician--or responsibility--to do so. At this time, assessing serum 25-hydroxy-vitamin D is the only way to make the diagnosis and to assure that treatment is adequate and safe. The authors believe that treatment should be sufficient to maintain levels found in humans living naturally in a sun-rich environment, that is, > 40 ng/ml, year around. Three treatment modalities exist: sunlight, artificial ultraviolet B radiation or supplementation. All treatment modalities have their potential risks and benefits. Benefits of all treatment modalities outweigh potential risks and greatly outweigh the risk of no treatment. As a prolonged 'vitamin D winter', centred on the winter solstice, occurs at many temperate latitudes, < or = 5000 IU (125 microg) of vitamin D/day may be required in obese, aged and/or dark-skinned patients to maintain adequate levels during the winter, a dose that makes many physicians uncomfortable.

Hypovitaminosis D in obese children and adolescents: relationship with adiposity, insulin sensitivity, ethnicity, and season

Low 25-hydroxyvitamin D (25[OH] D) results in hyperparathyroidism and is among the endocrine derangements of adult obesity. There are differing recommendations on defining low 25(OH) D: hypovitaminosis D (serum 25[OH] D concentration <75 nmol/L) and vitamin D deficiency (serum 25[OH] D concentration <50 nmol/L). We sought to evaluate the prevalence of low levels of 25(OH) D by examining hypovitaminosis D (<75 nmol/L), vitamin D sufficiency (> or =75 nmol/L), vitamin D insufficiency (50-74.9 nmol/L), and vitamin D deficiency (<50 nmol/L) in pediatric obesity and the relationship to other calciotropic hormones and adiposity. Serum 25(OH) D, intact parathyroid hormone (iPTH), ionized calcium, glucose, and insulin levels along with hemoglobin A(1c) (HbA(1c)) and quantitative insulin sensitivity check index (QUICKI) were determined in 127 subjects aged 13.0 +/- 3.0 years (49 Caucasian [C], 39 Hispanic [H], and 39 African American [AA]; 61.2% female; body mass index 36.4 +/- 8.1 kg/m(2)) during fall/winter (F/W) and spring/summer (S/S). Body composition was determined by bioelectrical impedance. Hypovitaminosis D was present in 74% of the cohort, but was more prevalent in the H (76.9%, P < .05) and AA (87.2%, P < .05) groups than in the C group (59.1%). Hypovitaminosis D corresponded to decreased vitamin D intake (P < .005) and was more prevalent in F/W than S/S (98.4% vs 49.2, P < .01). Vitamin D deficiency was identified in 32.3% of the entire cohort and was more prevalent in the H (43.6%, P < .0001) and AA (48.7%, P < .0001) groups than in the C group (10.2%) associated with decreased vitamin D intake (P < .0001). Vitamin D insufficiency was present in 41.7% of the cohort, with similar prevalence among C (48.9%), H (33.3%), and AA (38.5%). Vitamin D insufficiency corresponded to decreased vitamin D intake (P < .005), with similar prevalence in F/W and S/S (45.3% vs 38.1%), whereas vitamin D deficiency was not only accompanied by decreased vitamin D intake (P < .0001) but was more prevalent in F/W than S/S (53.1% vs 11.1%, P < .0001). Serum 25(OH) D and iPTH (r = -0.41, P < .0001) levels were negatively correlated without seasonal and ethnic/racial influences. Hypovitaminosis D and vitamin D-deficient groups had higher body mass index, fat mass (FM), and iPTH, but had lower QUICKI than vitamin D-sufficient group (P < .01). Whereas FM was negatively correlated with 25(OH) D (r = -0.40, P < .0001), it was positively correlated with iPTH (r = 0.46, P < .0001) without seasonal and racial/ethnic influences. Serum 25(OH) D was also positively correlated with QUICKI (r = 0.24, P < .01), but was inversely correlated with HbA(1c) (r = -0.23, P < .01). Hypovitaminosis D was identified in 74% of obese subjects, whereas vitamin D deficiency was observed in 32.3% of our cohort. Vitamin D status was influenced by vitamin D intake, season, ethnicity/race, and adiposity. Interrelationships between 25(OH) D, iPTH, and FM were not influenced by season and race/ethnicity. Furthermore, serum 25(OH) D was positively correlated with insulin sensitivity, which was FM mediated, but negatively correlated with HbA(1c), implying that obese children and adolescents with low vitamin D status may be at increased risk of developing impaired glucose metabolism independent of body adiposity. Additional studies are needed to evaluate the underlying mechanisms.

First Homo erectus from Turkey and implications for migrations into temperate Eurasia

Remains of fossil hominins from temperate regions of the Old World are rare across both time and space, but such specimens are necessary for understanding basic issues in human evolution including linkages between their adaptations and early migration patterns. We report here the remarkable circumstances surrounding the discovery of the first fossil hominin calvaria from Turkey. The specimen was found in the Denizli province of western Turkey and recovered from within a solid block of travertine stone as it was being sawed into tile-sized slabs for the commercial natural stone building market. The new specimen fills an important geographical and temporal gap and displays several anatomical features that are shared with other Middle Pleistocene hominins from both Africa and Asia attributed to Homo erectus. It also preserves an unusual pathology on the endocranial surface of the frontal bone that is consistent with a diagnosis of Leptomeningitis tuberculosa (TB), and this evidence represents the most ancient example of this disease known for a fossil human. TB is exacerbated in dark-skinned peoples living in northern latitudes by a vitamin D deficiency because of reduced levels of ultraviolet radiation (UVR). Evidence for TB in the new specimen supports the thesis that reduced UVR was one of the many climatic variables presenting an adaptive challenge to ancient hominins during their migration into the temperate regions of Europe and Asia.

Vitamin D, calcium homeostasis, and skeleton accretion in children

Overt vitamin D deficiency early in life has classically been associated with the etiology of rickets. Recent interest has focused on vitamin D insufficiency and calcium homeostasis and bone health. A review of the literature suggests that the relationship between vitamin D status and calcium utilization has some important differences with life stage and race. In contrast to adults, serum 1,25-dihydroxyvitamin D, but not serum 25-hydroxyvitamin D, predicts calcium absorption in growing children. PTH suppression with increasing serum 25-hydroxyvitamin D varies with race in adolescents. A limitation of our understanding of vitamin D status on calcium homeostasis in children relates to the cross-sectional nature of the evidence and interventions that typically use too little vitamin D supplementation to affect status. Vitamin D status has predicted changes in BMD during growth, and higher doses have been associated with increased bone area and BMC of the hip in pubertal girls with low baseline vitamin D status. Bone accretion is related to calcium status, sexual maturity, race, and genetics. Current cross-sectional studies in children suggest that vitamin D status is less important for bone accrual than for bone health in adults. Intervention studies are needed to identify responsive groups.