The frequency and the risk factors for vitamin D deficiency in preschool children at Split and Dalmatian County

Iako nedostatak vitamina D predstavlja globalni problem, posebno kod djece, postoji manjak informacija o ovoj problematici u odnosu na predškolsku djecu iz jugoistočne Europe. Cilj ove studije ustanoviti je prevalenciju nedostatka vitamina D, te povezanost u odnosu na spol, vrijeme provedeno na otvorenom, tjelesnu aktivnost (TA), indeks tjelesne mase (ITM), omjer opsega struka i visine WHtR, mediteranski tip prehrane (prediktori) i status vitamina D (rezultat/ishod) kod zdrave predškolske djece. Sudionici su bili predškolci (svi u dobi od 5 do 6 godina) iz južne Hrvatske. Svi sudionici su testirani tijekom obveznog sistematskog pregleda, 6-7 mjeseci prije upisa u školu. TA je izračunata uz pomoć Pre-Paq upitnika koji kategorizira TA na pet razina (od sjedilačke do visoke razine tjelesne aktivnosti). Prevalencija nedostatka vitamina D bila je visoka; kod 58% djece razine vitamina D, 25(OH)D bile su <50 nmol/l (VDD), dok je kod ostalih 29% zabilježena nedostatna koncentracija vitamina D, 25(OH)D 50- 75 nmol/l (VDI). Kod dječaka razine vitamina D bile su više nego kod djevojčica (49.61±19.67 i 43.37±20.23 nmol/l, pojedinačno; t-test: 2.52, P < 0.01). Uz pomoć multinomijalne regresije kojom se računao učinak vitamina D i dostatna razina (25(OH)D >75 nmol/l) kao referentna vrijednost, utvrđeno je kako je spol signifikantni prediktor statusa vitamina D, pri čemu su dječaci pod nižim rizikom od razvoja nedostatka vitamina D u odnosu na djevojčice (OR: 0.33; 95%CI: 0.15-0.74). ). Kao značajan čimbenik više razine D vitamina utvrđen je Kidmed indeksa veći od 7 što govori o optimalnom pridržavanju principa mediteranske prehrane. Pomoću Bayesianske selekcije modela, dokazana je pozitivna povezanost razina D vitamina sa konzumacijom više od dva obroka voća dnevno i upotrebom maslinovog ulja, dok je preskakanje obroka imalo negativan utjecaj na razine D vitamina. Model je mogao objasniti samo 5,2% raznolikosti u razinama VD u krvi, ali je statistički značajan. Ovi rezultati pokazali su visoku prevalenciju nedostatka vitamina D kod predškolaca iz južnog dijela Hrvatske, što je posebno alarmantno s obzirom na geografski položaj promatrane regije (42oN) kao i veliki broj sunčanih sati (>2600 sati godišnje). Postoji potreba za daljnjim istraživanjima ostalih potencijalnih poveznica s vitaminom D i utemeljenje javnozdravstvene platforme za nadoknadu vitamina D.The deficiency of the vitamin D is an important global problem, particularly in children. However, in relation to preschool children from Southern Europe there is a lack of information regarding this issue. The aim of this study was to establish the prevalence of vitamin D deficiency and the association in relation to gender, time spent out doors, physical activity (PA), body mass indeks (BMI), waist and height ratio (WhtR), Mediterranean diet (predictors) and vitamin D status (outcome) in healthy preschool children. The participants were preschool children (all aged 5 to 6 years) from South Croatia. All participants were tested during mandatory medical examination, 6-7 months prior to school enrollment. The PA was calculated using Pre-Paq questionnaire categorizing PA in to five levels (from sedentiary to high level of physical activity). The prevalence of vitamin D deficiency was high; 58% of children had vitamin D, 25(OH)D levels <50 nmol/l (VDD), while in the remaining 29% an insufficient concentration of vitamin D, 25(OH)D 50-75 nmol/l (VDI) was reported. The boys had higher levels of vitamin D than girls (49.61±19.67 i 43.37±20.23 nmol/l, respectively; ttest: 2.52, P < 0.01). Using multinomial regression in order to calculate the effectof vitamin D and the sufficient level (25(OH)D >75 nmol/l) as the reference value, the gender was determined as a significant predictor for vitamin D status, with boys being at lower risk for vitamin D deficiency in relation to girls (OR: 0.33; 95%CI: 0.15-0.74). As a significant factor of high vitamin D levels, the KIDMED index higher than 7 points was indicated, which suggested an optimal following of the Mediterranean diet. The implementation of Bayesian model selection enable devidence of the postive correlation between vitamin D and the intake of more than two servings of fruit per day as well as the olive oil consumption, where as skipping meals had negative effect on vitamin D levels. The model could have accounted for only 5.2% of variations in blood levels of VD, but it was statistically significant. These results indicated the high prevalence of the vitamin D deficiency in the preschool children from South Croatia, which is especially alarming given the geographical position of the studied region (42 o N) as well as the high number of sunlight hours(>2600 hours per year). Further investigation for other potential correlations with vitamin D is essential, also the establishment of a public health platform for vitamin D supplementation