A systematic review of vitamin D status in southern European countries.

PURPOSE: Despite an acknowledged dearth of data on serum 25-hydroxyvitamin D (25(OH)D) concentrations from Southern European countries, inter-country comparison is hampered by inconsistent data reporting. The purpose of the current study was to conduct a systematic literature review of available data on serum 25(OH)D concentrations and estimate vitamin D status in Southern European and Eastern Mediterranean countries, both at a population level and within key population subgroups, stratified by age, sex, season and country. METHODS: A systematic review of the literature was conducted to identify and retrieve scientific articles reporting data on serum 25(OH)D concentration and/or vitamin D status following standard procedures. RESULTS: Data were extracted from 107 studies, stratified by sex and age group, representing 630,093 individuals. More than one-third of the studies reported mean 25(OH)D concentrations below 50 nmol/L and ~ 10% reported mean serum 25(OH)D concentrations below 25 nmol/L. Overall, females, neonates/ infants and adolescents had the higher prevalence of poor vitamin D status. As expected, there was considerable variability between studies. Specifically, mean 25(OH)D ranged from 6.0 (in Italian centenarians) to 158 nmol/L (in elderly Turkish men); the prevalence of serum 25(OH)D < 50 nmol/L ranged from 6.8 to 97.9% (in Italian neonates). CONCLUSIONS: Contrary to expectations, there was a high prevalence of low vitamin D status in the Southern Europe and the Eastern Mediterranean regions, despite abundant sunshine. These data further emphasize the need for strategies, such as fortification of foods with vitamin D and/or vitamin D supplementation, which will be tailored to the needs of specific population groups with higher risk of insufficiency or deficiency, to efficiently tackle the pandemic of hypovitaminosis D in Europe.

25-hydroxyvitamin D is differentially associated with calcium intakes of Northern, Central, and Southern European adolescents: Results from the HELENA study.

OBJECTIVES: Adolescents in the European Union (EU) exhibit a higher prevalence of vitamin D (VitD) deficiency than other age groups. The degree to which sunlight exposure 25-hydroxyvitamin D [25(OH)D] concentrations depends on a variety of factors, including diet. Nevertheless, the relationship between calcium and VitD intake and 25(OH)D concentrations has not been previously studied among adolescents living in different EU countries and consequently in different latitudes. Therefore, the aim of this study was to examine whether calcium and VitD intakes are differentially associated with 25(OH)D in adolescents from northern, central and southern EU countries. METHODS: The present analysis included 178 adolescents from northern EU countries, 251 from central EU countries, and 212 from southern EU countries (ages 12.5-17.5 y). Mixed model linear regression analyses stratified by geographic location were used to verify associations between calcium and VitD intake and 25(OH)D concentrations. Age, Tanner stage, seasonality, energy intake, and supplement use were entered as covariates. RESULTS: Only the calcium intake of central EU adolescents was positively associated with 25(OH)D (α = 0.005; 95% confidence interval, 0.007-0.028). CONCLUSIONS: Further longitudinal studies should confirm these observations, as this could be important for future public health interventions aiming to increase 25(OH)D concentrations in adolescents.

The n-3 long-chain PUFAs modulate the impact of the GCKR Pro446Leu polymorphism on triglycerides in adolescents.

Dietary n-3 long-chain PUFAs (LC-PUFAs) are associated with improvement in the parameters of the metabolic syndrome (MetS). Glucokinase regulatory protein (GCKR) is a key protein regulating intracellular glucose disposal. Our aim was to investigate: i) the relationship between the GCKR rs1260326 (Pro446Leu) polymorphism and parameters of the MetS; and ii) a potential influence of n-3 and n-6 LC-PUFA levels on this relationship in the HELENA study (1,155 European adolescents). Linear regression analyses were performed to study the association between rs1260326 and the outcomes of interest. Interactions between rs1260326 and LC-PUFA levels on outcomes were explored. The T allele of rs1260326 was associated with higher serum TG concentrations compared with the C allele. In contrast to n-6 LC-PUFA levels, a significant interaction (P = 0.01) between rs1260326 and total n-3 LC-PUFA levels on serum TG concentrations was observed. After stratification on the n-3 LC-PUFA median values, the association between rs1260326 and TG concentration was significant only in the group with high n-3 LC-PUFA levels. In conclusion, this is the first evidence that n-3 LC-PUFAs may modulate the impact of the GCKR rs1260326 polymorphism on TG concentrations in adolescents. Several molecular mechanisms, in link with glucose uptake, could explain these findings.

Impact of physical activity and cardiovascular fitness on total homocysteine concentrations in European adolescents: The HELENA study.

We examined the association of physical activity (PA), cardiovascular fitness (CVF) and fatness with total homocysteine (tHcy) concentrations in European adolescents. The present study comprised 713 European adolescents aged 14.8 ± 1.2 y (females 55.3%) from the multicenter HELENA cross-sectional study. PA was assessed through accelerometry, CVF by the 20-m shuttle run test, and body fat by skinfold thicknesses with the Slaughter equation. Plasma folate, cobalamin, and tHcy concentrations were measured. To examine the association of tHcy with PA, CVF, and fatness after controlling for a set of confounders including age, maturity, folate, cobalamin, creatinine, smoking, supplement use, and methylenetetrahydrofolate reductase 677 genotype (CC 47%, CT 43%, TT 10%), bivariate correlations followed by multiple regression models were performed. In the bivariate correlation analysis, tHcy concentrations were slightly negatively correlated (p<0.05) with CVF in females (measured both by stages: r=-0.118 and by VO2max: r=-0.102) and positively with body mass index (r=0.100). However, daily time spent with moderate and vigorous PA showed a weak positive association with tHcy in females (p<0.05). tHcy concentrations showed a tendency to decrease with increasing CVF and increase with increasing BMI in female European adolescents. However, tHcy concentrations were positively associated with moderate and vigorous PA in female European adolescents.

Factors associated with vitamin D deficiency in European adolescents: the HELENA study.

Evidence indicates low 25-hydroxyvitamin D [(25(OH)D] concentrations in European adolescents. Identification of potential determinants is therefore essential to guide public health initiatives aiming at optimizing vitamin D status across Europe. The aim of the study was to identify potential influencing factors of 25(OH)D concentrations in European adolescents aged 12.5 to 17.5 y, participating in the multi-centre cross-sectional Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. A subset of 1,006 participants (46.8% males) was drawn from the main study. Measures of body composition, biochemical markers, socioeconomic status, dietary intake, physical activity, fitness, sleep time and vitamin D genetic polymorphism (rs1544410) were assessed. Stepwise multivariate linear regression analysis was conducted stratified by gender. In males, linear regression of 25(OH)D, suggested that (1) winter season (ß=-0.364; p<0.01), (2) higher latitudes (ß=-0.246; p<0.01), (3) BMI z-score (ß=-0.198; p<0.05) and (4) retinol concentration (ß=0.171; p<0.05) independently influenced 25(OH)D concentrations. In females, (1) winter season (ß=-0.370; p<0.01), (2) sleep time (ß=-0.231; p<0.01), (3) supplement intake (ß=0.221; p<0.05), (4) flexibility (ß=0.184; p<0.05), (5) body fat % (ß=0.201; p<0.05) (6), BMI z-score (ß=-0.272; p<0.05), (7) higher latitudes (ß=-0.219; p<0.01) and (8) handgrip strength (ß=0.206; p<0.05) independently influenced 25(OH)D concentrations. Season, latitude, fitness, adiposity, sleep time and micronutrient supplementation were highly related to 25(OH)D concentrations found in European adolescents.

Polymorphisms in the CD36/FAT gene are associated with plasma vitamin E concentrations in humans.

BACKGROUND: Blood vitamin E concentrations are modulated by dietary, metabolic, and genetic factors. CD36 (cluster of differentiation 36), a class B scavenger receptor, might be involved in tissue vitamin E uptake and thus would influence blood vitamin E concentrations. OBJECTIVE: The goal of the study was to assess the association between CD36 single nucleotide polymorphisms (SNPs) and plasma α-tocopherol concentrations in humans. DESIGN: A subsample from the adult SU.VI.MAX (SUpplementation en VItamines et Minéraux AntioXydants) cohort (n = 621) and the adolescent cross-sectional HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study (n = 993) were genotyped for CD36 SNPs (4 and 10 SNPs, respectively). Fasting plasma α-tocopherol concentrations were assayed by using HPLC. Associations were determined by haplotype analyses and by general linear regression models. RESULTS: In the SU.VI.MAX subsample, haplotype analyses showed that some haplotypes of SNPs rs1984112, rs1527479, rs7755, and rs1527483 tended to be associated with plasma α-tocopherol concentrations (P = 0.08 and P = 0.09 for haplotypes 1222 and 1122, respectively). We then investigated the whole known common genetic variability (10 SNPs) of CD36 in the HELENA Study. Three SNPs were associated with lower plasma α-tocopherol concentrations (rs1984112: -3.2%, P = 0.053; rs1761667: -2.9%, P = 0.046; rs1527479: -3.7%, P = 0.0061). After correction for multiple testing, the association between rs1527479 and α-tocopherol concentrations remained significant. This association was modulated by concentrations of fasting serum triglycerides (P for interaction = 0.006) and long-chain polyunsaturated fatty acids (P for interaction = 0.005). CONCLUSION: Our results suggest that CD36 can modulate blood α-tocopherol concentrations and may therefore be involved in the intestinal absorption or tissue uptake of vitamin E.