Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder

Seasonal Affective Disorder (SAD) is prevalent when vitamin D stores are typically low. Broad-spectrum light therapy includes wavelengths between 280-320 nm which allow the skin to produce vitamin D. This study was designed to test the hypothesis that vitamin D deficiency might play a role in SAD. A prospective, randomized controlled trial was conducted in a group of 15 subjects with SAD. Eight subjects received 100,000 I.U. of vitamin D and seven subjects received phototherapy. At the onset of treatment and after 1 month of therapy subjects were administered the Hamilton Depression scale, the SIGH-SAD, and the SAD-8 depression scale. All subjects also had serum levels of 25-hydroxyvitamin D (25-OH D) measured before and 1 week after intervention therapy. All subjects receiving vitamin D improved in all outcome measures. The phototherapy group showed no significant change in depression scale measures. Vitamin D status improved in both groups (74% vitamin D group, p < 0.005 and 36% phototherapy group, p < 0.01). Improvement in 25-OH D was significantly associated with improvement in depression scale scores (r2=0.26; p=0.05). Vitamin D may be an important treatment for SAD. Further studies will be necessary to confirm these findings.     

Assessing the Relationship between Vitamin D3 and Stratum Corneum Hydration for the Treatment of Xerotic Skin

Vitamin D₃ has been called the “sunshine” vitamin since the formation of vitamin D is mediated by exposure to sunlight. Vitamin D₃ is linked to many health benefits, however serum levels of vitamin D₃ have been decreasing over the last few decades and the lower levels of vitamin D₃ may have consequences on normal physiology. We investigated the association between serum 25-hydroxyvitamin D (25(OH)D) levels and stratum corneum conductance as well as the effect of topical application of cholecalciferol (vitamin D₃) on dry skin. Eighty three subjects were recruited and blood serum levels and skin conductance measurements were taken after a one week washout. A correlation was observed between vitamin D levels and skin moisture content, individuals with lower levels of vitamin D had lower average skin moisture. Subsequently, a 3-week split leg, randomized, vehicle controlled clinical study was conducted on a subset of 61 of the above individuals who were identified with non-sufficient vitamin D serum levels. Topical supplementation with cholecalciferol significantly increased measurements of skin moisturization and resulted in improvements in subjective clinical grading of dry skin. Taken together our finding suggest a relationship between serum vitamin D₃ (25(OH)D) levels and hydration of the stratum corneum and further demonstrate the skin moisture benefit from topical application of vitamin D₃.     

Serum levels of vitamin D metabolites in children receiving total parenteral nutrition

Serum levels of 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) were measured on 19 occasions in seven children receiving total parenteral nutrition (TPN). The daily intakes of vitamin D3 ranged from 44 to 540 IU/day, and all serum samples were obtained after the same daily intake of vitamin D3 for more than 1 month. There was a significant positive correlation between serum 25-OHD levels and parenteral vitamin D3 intakes (r = 0.90, p less than 0.01). In this study, serum 25-OHD levels in all cases taking 200 to 360 IU/day of vitamin D3 were within the normal range. On the other hand, no significant correlation was found between serum 1,25-(OH)2D levels and vitamin D3 intakes, and serum 1,25-(OH)2D levels were normal or elevated in all cases.     

Bone marrow and serum concentrations of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1 alpha,25-dihydroxyvitamin D in patients with leukemia and normal subjects

Concentrations of 25-hydroxyvitamin D (25-OH-D), 24,25-dihydroxyvitamin D [24,25(OH)2D], and 1 alpha,25-dihydroxyvitamin D [1,25(OH)2D] in bone marrow and serum of patients with leukemia and normal subjects were assayed. There were highly significant correlations between the bone marrow and serum concentrations of the respective vitamin D metabolites. Especially, the concentrations of 25-OH-D and 1,25(OH)2D in the bone marrow gave very similar values to those in serum. This is a big advantage in controlling the bone marrow levels of vitamin D metabolites in patients with leukemia, because doctors can calculate the bone marrow levels from the serum levels of the respective vitamin D metabolites without bone marrow aspiration. When 1 alpha-hydroxyvitamin D3 (1 alpha-OH-D3) was administered orally to eight patients with leukemia, clinical conditions were improved in seven patients: four complete remissions (CR), one partial response (PR), and two minor responses (MR) without severe hypercalcemia. The results suggest that the therapy with 1 alpha-OH-D3 is fairly effective for curing human leukemia although it is not dramatic.     

Hypovitaminosis D and elevated serum alkaline phosphatase in elderly Irish people

The vitamin D status of 181 elderly Irish community-dwelling and institutionalized subjects was studied during Winter-Spring. The mean serum 25-hydroxyvitamin D level was 10 nmol/L (95% range less than 5.0-59 nmol/L); values were below 25 nmol/L in 79 percent of subjects. A significant seasonal variation of serum 25-hydroxyvitamin D levels was noted in elderly community-dwelling subjects. The previously documented age-related increase in serum alkaline phosphatase activity was significantly less in vitamin D replete subjects than in vitamin D deplete subjects in this study (P less than 0.005). The higher serum alkaline phosphatase values found in the vitamin D deplete subjects may represent mild secondary hyperparathyroidism or osteomalacia. The relationship of vitamin D status to both dietary intake and effective sunlight (latitude) is examined.     

血清25-羟维生素D水平与2型糖尿病的关系

目的 研究血清维生素D水平在2型糖尿病发病过程中的作用。方法采用随机分层抽样,共589例志愿者纳入本研究。根据空腹血糖及口服葡萄糖耐量试验结果将志愿者区分为糖尿病人群及非糖尿病人群。共计249例检测了血清25-羟维生素D水平,应用二元Logistic回归分析糖尿病与相关因素的关系,应用Cox—Staurt趋势检验分析各年龄段血清25-羟维生素D水平,按血清25（OH）D四分位值分层,分别计算糖尿病患病优势比OR值及95％置信区间。结果所有年龄段均存在不同程度的25-羟维生素D缺乏,调节年龄、HOMA．IR、BMI后,血清25．羟维生素D水平与糖尿病发病呈剂量依赖的负相关（r=-0．9271,P〈0．01）,当血清25-羟维生素D水平达到94．6nmol／L以上时,糖尿病发病显著降低[OR=0．52,95％CI（0．23—0．78）,P〈0．01]。结论血清25-羟维生素D水平与2型糖尿病发病呈明显负相关,血清25-羟维生素D水平降低增加糖尿病发病风险。     

Defective photoproduction of cholecalciferol in normal and uremic humans

The initial step in cholecalciferol (vitamin D3) metabolism is the photo-conversion of 7-dehydrocholesterol to previtamin D3. This reaction occurs in the epidermis and requires ultraviolet light. We measured the circulating concentration of vitamin D (ergocalciferol and cholecalciferol), 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in 14 normal white, 9 normal black subjects, and in 9 white and 17 black hemodialysis patients. The mean plasma vitamin D in normal white subjects was greater than in normal black subjects, 4.01 +/- 1.02 ng/ml versus 0.96 +/- 0.30 ng/ml, respectively (P less than 0.05). Plasma 25-hydroxyvitamin D in normal blacks was also less than in normal whites, 17.7 +/- 1.5 ng/ml versus 31.3 +/- 3.0 ng/ml, respectively (P less than 0.01). In uremic white subjects, plasma vitamin D, 6.7 +/- 2.6 ng/ml, was similar to normal white subjects. However, vitamin D was not detectable in 12 of 17 uremic black subjects and was depressed in the remainder of the group. Following exposure to a single minimal erythema dose of ultraviolet-B irradiation, the maximal increase in plasma vitamin D was depressed in white dialysis patients as compared to healthy white subjects, 6.3 +/- 1.9 ng/ml versus 21.3 +/- 2.8 ng/ml, respectively (P less than 0.02). 7-Dehydrocholesterol content was similar in epidermis from site-matched skin of fresh cadavers and white hemodialysis patients, 131 +/- 23 ng/mg versus 124 +/- 14 ng/mg skin, respectively. It is concluded that chronic hemodialysis patients exhibit defective photoproduction of cholecalciferol, despite normal epidermal content of substrate, 7-dehydrocholesterol.     

Hypovitaminosis D in an Italian population of healthy subjects and hospitalized patients.

The present study aimed to investigate the prevalence and seasonal variation of hypovitaminosis D (defined as serum 25-hydroxyvitamin D level below 30 nmol/l) among healthy subjects and hospitalized patients living in central Italy. We studied 297 subjects, 131 in February 1997 and 166 in July 1997, subdivided into four groups: (a) young healthy blood donors; (b) healthy postmenopausal women; (c) inpatients with various medical diseases and (d) inpatients engaged in long-term rehabilitation programmes because of various neurological disorders. In all subjects and patients serum levels of 25-hydroxyvitamin D were measured by radioimmunoassay. We found a significant seasonal variation (P < 0.0001) of serum 25-hydroxyvitamin D levels, mean values being higher in summer in all groups, except in patients with a longer hospitalization time (group (d)). In each group, a significantly higher prevalence of hypovitaminosis D was found in winter compared with summer time (P < 0.001), being unexpectedly high in postmenopausal women (winter 32% and summer 4.5%); furthermore, in both seasons, inpatients were characterized by the highest incidences of hypovitaminosis, particularly those in group (d) (winter 82.3% and summer 57.8%). The results of the present study emphasize the importance of 25-hydroxyvitamin D measurement, and the need to increase vitamin D intake in Italy; foodstuff fortification and supplement use must be considered in order to prevent negative effects of vitamin D deficiency on skeletal integrity.     

Determinants of vitamin D status in patients with hip fracture and in elderly control subjects

The factors that influence vitamin D status were investigated in 125 patients with hip fracture and in 74 elderly control subjects. The serum concentrations of 25-hydroxyvitamin D [25(OH)D] varied with sunshine score and were paralleled by serum 1,25-dihydroxyvitamin D [1,25(OH)2D]. The control subjects showed a higher sunshine score and higher serum 24(OH)D levels than the patients with hip fracture. Dietary vitamin D intake was similar in both groups (mean 115 IU/d). A positive correlation between vitamin D intake and serum 25(OH)D was observed in the patients with low sunshine exposure. It appeared from this relation that dietary vitamin D intake should be approximately 300 IU/d to maintain an adequate serum (25(OH)D concentration. Vitamin D status was very poor in patients who were institutionalized before hip fracture. Multiple regression analysis on serum 25(OH)D confirmed the primary role of sunshine exposure as determinant of vitamin D status. The principal determinants of serum 1,25(OH)2D were serum 25(OH)D, serum creatinine, and serum phosphate.     

Bone mineral density and serum 25-hydroxyvitamin D level: is there any difference according to the dressing style of the female university students

Nutrition plays a role in the etiology of osteoporosis. Two of the most important nutrients for bone health are calcium and vitamin D. Plasma 25-hydroxyvitamin D [25-(OH)D] is the most sensitive clinical index of vitamin D status and has been found to be positively related to bone mineral density (BMD) in middle-aged and elderly women, and positive relations exist between the BMD of adult women and their calcium consumption throughout life.The aim of the present study was to determine relationships between BMD, serum vitamin D levels and dietary calcium intake of female young adult students who dressed in different styles. We studied two groups of volunteer female students (total = 67). Students in the first group dressed in a style that exposed the skin to sunlight, students in the second group wore dresses completely covering the skin except for the face and hands. Serum 25-(OH)D levels were measured by radioimmunoassay, BMDs were determined at the lumbar spine and femoral neck by dual-energy X-ray absorptiometry, and calcium intakes were estimated with a 3-day food recording questionnaire.The serum 25-(OH)D level was significantly lower in the second group. There was no significant difference in BMD between the two groups. The dietary calcium intake of the two groups were lower than the adequate intake of 1000 mg daily for this age. There was a correlation between the serum 25-(OH)D level and BMD at the femoral neck in the first group.Our results indicate that vitamin D and calcium requirements for normal bone mineral accrual in young adults may advance until a certain age, and the covered dressing style causes vitamin D insufficiency and most of the students were under risk for osteoporosis in later life.     

Bone mineral density and serum 25-hydroxyvitamin D level: is there any difference according to the dressing style of the female university students

Nutrition plays a role in the etiology of osteoporosis. Two of the most important nutrients for bone health are calcium and vitamin D. Plasma 25-hydroxyvitamin D [25-(OH)D] is the most sensitive clinical index of vitamin D status and has been found to be positively related to bone mineral density (BMD) in middle-aged and elderly women, and positive relations exist between the BMD of adult women and their calcium consumption throughout life.

The aim of the present study was to determine relationships between BMD, serum vitamin D levels and dietary calcium intake of female young adult students who dressed in different styles. We studied two groups of volunteer female students (total=67). Students in the first group dressed in a style that exposed the skin to sunlight, students in the second group wore dresses completely covering the skin except for the face and hands. Serum 25-(OH)D levels were measured by radioimmunoassay, BMDs were determined at the lumbar spine and femoral neck by dual-energy X-ray absorptiometry, and calcium intakes were estimated with a 3-day food recording questionnaire.

The serum 25-(OH)D level was significantly lower in the second group. There was no significant difference in BMD between the two groups. The dietary calcium intake of the two groups were lower than the adequate intake of 1000 mg daily for this age. There was a correlation between the serum 25-(OH)D level and BMD at the femoral neck in the first group.

Our results indicate that vitamin D and calcium requirements for normal bone mineral accrual in young adults may advance until a certain age, and the covered dressing style causes vitamin D insufficiency and most of the students were under risk for osteoporosis in later life.     

成都市0～6岁儿童25-羟维生素D水平调查

目的:了解成都市儿童维生素D的营养状况。方法:对来医院儿童保健科门诊进行常规体检的0～6岁701例儿童采用酶联免疫法进行血清25-(OH)D检测。结果:25-(OH)D的平均测定值为(68.60±1.29)nmol/L,25-(OH)D缺乏及严重缺乏的为226例,占32.24%;25-(OH)D水平不足的为237例,占33.811%;水平充足(合适水平)的为238例,占33.95%,前两者占总人数的66.05%。男性和女性血清25-(OH)D水平差异无统计学意义(P>0.05),但25-(OH)D水平随着年龄增高而呈下降(P<0.01)。血清25-(OH)D水平夏秋季显著高于春冬季节(P<0.05)。结论:成都市0～6岁儿童25-(OH)D水平低下,应增加该地区儿童的维生素D摄入量及加强户外活动,尤需重视3～6岁的儿童及冬春季节维生素D的补充。     

Serum 25-hydroxyvitamin D concentrations are associated with erythrocyte levels of n-3 PUFA but not risk of CVD

Increasing evidence suggests that the status of vitamin D and n-3 PUFA is associated with the risk of CVD. Major dietary sources of vitamin D include fish and fish products, which are also rich in n-3 PUFA; however, the relationship between serum 25-hydroxyvitamin D levels and tissue contents of n-3 PUFA remains unknown. The present study investigates the hypothesis that serum 25-hydroxyvitamin D and erythrocyte n-3 PUFA levels are positively correlated in patients with CVD. We recruited sixty CVD cases and matched them with sixty healthy controls based on age, sex and season during which blood was drawn for the study. As serum 25-hydroxyvitamin D levels increased, erythrocyte levels of docosapentaenoic acid, DHA, omega-3 index and total n-3 PUFA increased significantly, while erythrocyte levels of stearic acid and total SFA decreased significantly, after adjusting for age, sex, BMI and smoking. Partial correlation analysis also showed that erythrocyte n-3 PUFA levels were positively correlated (r 0·215; P?=?0·021) and total SFA content was negatively correlated (r -?0·263; P?=?0·004) with serum 25-hydroxyvitamin D levels. However, multiple logistic regression analysis showed that serum 25-hydroxyvitamin D levels were not significantly associated with the risk of CVD, after adjusting or not adjusting for age, sex, BMI and smoking. In conclusion, the results of our case-control study suggest that serum 25-hydroxyvitamin D levels are positively related to erythrocyte n-3 PUFA levels, but are not associated with the risk of CVD in this population.     

Diminished and erratic absorption of ergocalciferol in adult cystic fibrosis patients

BACKGROUND: Osteoporosis diminishes the quality of life in adults with cystic fibrosis (CF). Vitamin D deficiency resulting from malabsorption may be a factor in the etiology of low bone mineral density (BMD) in patients with CF. OBJECTIVE: Absorption of oral ergocalciferol (vitamin D2) and the consequent response of 25-hydroxyvitamin D in 10 adults with CF and exocrine pancreatic insufficiency was compared with that of 10 healthy control subjects. DESIGN: In this pharmacokinetic study, CF patients and control subjects were pair-matched on age, sex, and race. Each subject consumed 2500 microg oral vitamin D2 with a meal. The CF group also took pancreatic enzymes that provided > or = 80000 U lipase. Blood samples were obtained at baseline and at 5, 10, 24, 30, and 36 h after vitamin D2 consumption to measure serum vitamin D2 and 25-hydroxyvitamin D concentrations. RESULTS: Vitamin D2 concentrations in all subjects were near zero at baseline. CF patients absorbed less than one-half the amount of oral vitamin D2 that was absorbed by control subjects (P < 0.001). Absorption by the CF patients varied greatly; 2 patients absorbed virtually no vitamin D2. The rise in 25-hydroxyvitamin D in response to vitamin D2 absorption was significantly lower over time in the CF group than in the control group (P = 0.0012). CONCLUSIONS: Vitamin D2 absorption was significantly lower in CF patients than in control subjects. These results may help explain the etiology of vitamin D deficiency in CF patients, which may contribute to their low BMD.     

Adolescent girls in Maine are at risk for vitamin D insufficiency

The objective was to determine the seasonal fluctuations in serum 25-hydroxyvitamin D (25-OHD) in a group of healthy adolescents living in a northern climate. Twenty-three 9- to 11-year-old girls participated in the study from September 2000 to March 2003. Serum 25-OHD and parathyroid hormone levels were measured each September and March. Dietary intake of vitamin D was assessed each summer and winter. Summer-sun exposure was evaluated using reports of time spent outdoors. The mean decrease in serum 25-OHD from September to March was 28%. Vitamin D insufficiency (at least one serum 25-OHD level <50 nmol/L) was observed in 11 of 23 (48%) subjects. Four of 23 subjects (17%) exhibited vitamin D insufficiency in both September and March. Mean parathyroid hormone levels increased 4 pg/mL (15%) from September to March. Vitamin D intakes need to be increased in winter at northern latitudes.     

Serum 25-hydroxyvitamin D3 levels are elevated in South Indian patients with ischemic heart disease

Several lines of evidence point to a possible relationship between vitamin D and cardiovascular disease. Animal experiments and observational studies in humans suggest vitamin D to be arteriotoxic and an association of high intake of vitamin D with increased incidence of ischemic heart disease (IHD). The major source of vitamin D in adults is vitamin D synthesized in the skin through exposure to the sun. In tropical environment there is a possibility of high level of solar exposure and enhanced serum levels of vitamin D in the population. We explored the relation between serum level of 25-hydroxyvitamin D₃ and IHD in a case-control study involving 143 patients with either angiographic evidence of coronary artery disease or patients with acute myocardial infarction and 70 controls, all men in the age group of 45–65 years. Fasting blood samples were collected, serum separated and serum levels of 25-hydroxyvitamin D₃ was measured by protein binding radioligand assay. Serum levels of cholesterol, triglyceride, calcium, magnesium and inorganic phosphate were also determined. Prevalences of diabetes, hypertension and smoking history were noted. Statistical comparisons of variables between cases and controls were done using ²-tests. Multivariate logistic regression analysis was done to examine the association of IHD with serum levels of 25-hydroxyvitamin D₃ controlling for selected variables. Serum levels of 25-hydroxyvitamin D₃, calcium, inorganic phosphate, total cholesterol, low density lipoprotein and triglycerides were elevated in a higher proportion of patients, compared to controls. Serum levels of 25-OH-D₃ above 222.5 nmol/l (89 ng/ml) was observed in 59.4% of cases compared to 22.1% in controls (p < 0.001; unadjusted odds ratio (OR): 5.17; 95% confidence interval (CI): 2.62–10.21). When controlled for age and selected variables using the multivariate logistic regression, the adjusted OR relating elevated serum 25-hydroxyvitamin D₃ levels ( 222.5 nmol/l, 89 ng/ml) and IHD is 3.18 (95% CI: 1.31–7.73). Given the evidences for the arteriotoxicity of vitamin D, further investigations are warranted to probe whether the elevated serum levels of 25-hydroxyvitamin D₃ observed in patients with IHD in a tropical environment has any pathogenic significance.     

High prevalence of low dietary calcium and low vitamin D status in healthy south Indians

Calcium and vitamin D under nutrition can adversely affect the bone mineral metabolism. There is no population-based study from India documenting dietary habits, serum calcium and vitamin D levels. Our study investigated the dietary habits of rural and urban societies in and around Tirupati and their relationship with serum calcium, phosphorous and vitamin D [25(OH)D] levels. Four hundred and seven subjects from 5 villages around Tirupati, (rural population) and 125 asymptomatic staff of our hospital (urban population) were studied. Dietary intakes of calcium, phosphorous and phytates were documented by diet history. Serum calcium, phosphorus and 25 (OH) D levels were estimated in 191 rural subjects and 125 urban subjects. Compared to urban subjects, rural subjects had a significantly lower intake of dietary calcium (P <0.0001) and a significantly higher dietary phytate/calcium ratio and serum calcium and 25 (OH) D levels (P <0.0001). Dietary calcium intake was inadequate in both rural and urban subjects compared to the recommended daily allowances (RDA) for our country. About 31% of the population had normal vitamin D levels, 54% had vitamin D insufficiency and 15% vitamin D deficiency. About two-thirds of the population had low levels of vitamin D. Inadequate dietary calcium intake associated with high phytate/calcium ratio reduces the bioavailable calcium in the gut. Hence, there is a need to fortify food with calcium and to propose new guidelines for 25 (OH) D in Indian subjects. Multicentric studies with large sample populations are required to generate normal standards and nationally relevant guidelines.     

Vitamin D absorption in healthy subjects and in patients with intestinal malabsorption syndromes

We developed a test procedure for the clinical evaluation of the absorption of vitamin D. Serum vitamin D concentrations were evaluated in seven patients with intestinal fat malabsorption syndromes and in seven healthy, normal subjects, after being given a single oral dose of 50,000 IU (1.25 mg) vitamin D2. In the normal subjects, serum vitamin D concentrations rose from a baseline of less than 5 ng/ml to a peak of over 50 ng/ml by 12 h, gradually falling to baseline levels by 3 days. In five of the seven patients with intestinal fat malabsorption, oral administration of 50,000 IU vitamin D2 did not raise serum vitamin D concentrations above 10 ng/ml. Two patients with severe inflammatory bowel disease had a normal absorption pattern, however. These findings suggest that an oral vitamin D absorption test may be of value for determination of patients at risk for development of vitamin D deficiency. They also raise questions about the efficacy of oral vitamin D preparations in patients with intestinal fat malabsorption.     

High risk of vitamin D deficiency in children with sickle cell disease

Vitamin D is a particularly concerning nutrient for children with homozygous SS sickle cell disease (SCD-SS) due to their increased skin melanin concentrations, reduced levels of physical activity, and poor vitamin D intake. The goal of this study was to compare the vitamin D status of children with SCD-SS to healthy African-American children living in the same geographic area. Growth, dietary intake, serum 25-hydroxyvitamin D [25(OH)D], and intact parathyroid hormone (iPTH) concentrations were measured in 61 African-American subjects with SCD-SS and 89 healthy African-American control subjects age 5 to 18 years from the Philadelphia, PA, region (latitude 39.95 degrees N). Median serum 25(OH)D concentrations were 15 ng/mL (95% confidence interval [CI]: 13, 17) in subjects with SCD-SS and 21 ng/mL (95% CI: 18, 22) in healthy control subjects (P<0.0002). Vitamin D deficiency [25(OH)D<11 mg/mL] was found in 33% of subjects with SCD-SS and 9% of healthy control subjects (P<0.001); 25% of subjects with SCD-SS and 17% of healthy control subjects had elevated iPTH [(>59 rhog/mL), P<0.05]. Ninety-three percent of subjects with SCD-SS and 90% of healthy subjects had vitamin D insufficiency [25(OH)D<30 mg/mL]. The risk of vitamin D deficiency among subjects with SCD-SS was 5.3 (95% CI: 2.5, 8.2) times greater than control subjects, adjusted for season and age. Poor vitamin D status was prevalent in children with SCD-SS and healthy African-American children living in the same geographic area. However, children with SCD-SS were at greater risk for vitamin D deficiency than healthy African-American children.     

Low vitamin D status in preschool children in Greece

Vitamin D status in humans depends on the amount of sun exposure and vitamin D intake. Recent reports suggest that hypovitaminosis D (as defined by serum 25-hydroxyvitamin D [25(OH)D] <10 ng/mL) is reemerging in developed countries and in the Middle East, pointing out the significance of dietary and cultural practices. In the line of prevention, we determined vitamin D status in 393 healthy preschool children randomly selected from 7 day care centers in the Municipality of Athens in October. The data for the analysis were collected from a questionnaire regarding their actual dietary practices, voluntary sun exposure, and lifestyle conditions; clinical investigation for the determination of the skin phototype; and blood sampling for the determination of serum 25(OH)D, parathyroid hormone, and osteocalcin levels. Of the 393 children, 49 were immigrants. According to our results, 6.6% of our population had serum 25(OH)D less than 10 ng/mL. Multilinear analysis showed that the amount of sun exposure and vitamin D intake were the direct determinants of vitamin D status. Immigrant children presented lower serum 25(OH)D levels associated with lower vitamin D intake and lower socioeconomic class when compared with the Greek children. No relationship was found between 25(OH)D concentration and skin phototype, whereas 93.3% of children used topical sunscreen. We suggest that abundant sunlight exposure in Athens is not sufficient to prevent hypovitaminosis D in preschool children. The extensive use of topical sunscreens and environmental factors such as air pollution would account for inadequate sunlight exposure and the need for dietary intake of vitamin D.