Vitamin D inadequacy is widespread in Tunisian active boys and is related to diet but not to adiposity or insulin resistance.
BACKGROUND
Vitamin D inadequacy is widespread in children and adolescents worldwide. The present study was undertaken to assess the vitamin D status in active children living in a sunny climate and to identify the main determinants of the serum concentration of 25-hydroxyvitamin D (25-OHD).


METHODS
This cross-sectional study included 225 children aged 7-15 years practicing sports in a football academy. Anthropometric measures were performed to calculate body mass index (BMI), fat mass, and maturity status. A nutritional enquiry was performed including 3-day food records and food frequency questionnaire. Plasma 25-OHD and insulin were assessed by immunoenzymatic methods ensuring categorization of vitamin D status and calculation of insulin sensitivity/resistance indexes. A logistic regression model was applied to identify predictors for vitamin D inadequacy.


RESULTS
Vitamin D deficiency (25-OHD<12 µg/L) was observed in 40.9% of children and insufficiency (12<25-OHD<20 µg/L) was observed in 44% of children. In a multivariate analysis, vitamin D deficiency and insufficiency were associated with a lower dietary intake of vitamin D, proteins, milk, red meat, fish, and eggs. However, no significant relationship was observed with maturation status, adiposity, or insulin resistance.


CONCLUSIONS
Tunisian children and adolescents are exposed to a high risk of vitamin D inadequacy despite living in a sunny climate. Circulating 25-OHD concentrations are related to the intake of vitamin D food sources but not to maturation status or body composition. Ensuring sufficient and safe sun exposure and adequate vitamin D intake may prevent vitamin D inadequacy in children from sunny environments.
Rabta Hospital, Laboratory of Biochemistry, UR05/08-08 and LR99ES1, Tunis, Tunisia.|Tunisian Research Laboratory 'Sport Performance Optimization', National Center of Medicine and Sciences in Sports, Tunis, Tunisia.|Faculty of Medicine of Tunis, University Tunis El Manar, Tunis, Tunisia; ikram_cnmss@yahoo.fr.
Ikram
I
Bezrati
Rabta Hospital, Laboratory of Biochemistry, UR05/08-08 and LR99ES1, Tunis, Tunisia.
Mohamed Kacem
MK
Ben Fradj
Rabta Hospital, Laboratory of Biochemistry, UR05/08-08 and LR99ES1, Tunis, Tunisia.
Nejmeddine
N
Ouerghi
Rabta Hospital, Laboratory of Biochemistry, UR05/08-08 and LR99ES1, Tunis, Tunisia.|Faculty of Medicine of Tunis, University Tunis El Manar, Tunis, Tunisia.
Moncef
M
Feki
Tunisian Research Laboratory 'Sport Performance Optimization', National Center of Medicine and Sciences in Sports, Tunis, Tunisia.
Anis
A
Chaouachi
Rabta Hospital, Laboratory of Biochemistry, UR05/08-08 and LR99ES1, Tunis, Tunisia.
Naziha
N
Kaabachi
D050154:Adiposity; D000293:Adolescent; D000886:Anthropometry; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D012044:Regression Analysis; D012307:Risk Factors; D014416:Tunisia / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology* / Q000378:metabolism
D014807:Vitamin D; C104450:25-hydroxyvitamin D
25-hydroxyvitamin D; adiposity; child; insulin resistance; vitamin D deficiency