Insufficient autumn vitamin D intake and low vitamin D status in 7-year-old Icelandic children.
OBJECTIVE
The aim was to investigate autumn vitamin D intake and status in 7-year-old Icelanders, fitting BMI and cardiorespiratory fitness as predictors.


METHODS
Three-day food records and fasting blood samples were collected evenly from September to November, and cardiorespiratory fitness was measured with an ergometer bike. Food and nutrient intakes were calculated, and serum 25-hydroxyvitamin D (s-25(OH)D) and serum parathyroid hormone were analysed. Suboptimal vitamin D status was defined s-25(OH)D <50 nmol/l, and deficient status as s-25(OH)D <25 nmol/l.


METHODS
School-based study in Reykjavik, Iceland in 2006.


METHODS
Of the 7-year-olds studied (n 265), 165 returned valid intake information (62 %), 158 gave blood samples (60 %) and 120 gave both (45 %).


RESULTS
Recommended vitamin D intake (10 μg/d) was reached by 22·4 % of the children and 65·2 % had s-25(OH)D <50 nmol/l. Median s-25(OH)D was higher for children taking vitamin D supplements (49·2 nmol/l v. 43·2 nmol/l, respectively; P < 0·0 0 1). Median s-25(OH)D was lower in November (36·7 nmol/l) than in September (59·9 nmol/l; P < 0·001). The regression model showed that week of autumn accounted for 18·9 % of the variance in s-25(OH)D (P < 0·001), vitamin D intake 5·2 % (P < 0·004) and cardiorespiratory fitness 4·6 % (P < 0·005).


CONCLUSIONS
A minority of children followed the vitamin D recommendations and 65 % had suboptimal vitamin D status during the autumn. Week of autumn was more strongly associated with vitamin D status than diet or cardiorespiratory fitness, which associated with vitamin D status to a similar extent. These results demonstrate the importance of sunlight exposure during summer to prevent suboptimal vitamin D status in young schoolchildren during autumn in northern countries. An increased effort is needed for enabling adherence to the vitamin D recommendations and increasing outdoor activities for sunlight exposure.
1Unit for Nutrition Research, Landspitali-University Hospital & Faculty of Food Science and Nutrition,School of Health Sciences,University of Iceland,Laeknagardur,Vatnsmyrarvegur 16,101 Reykjavík,Iceland.
Adda
A
Bjarnadottir
1Unit for Nutrition Research, Landspitali-University Hospital & Faculty of Food Science and Nutrition,School of Health Sciences,University of Iceland,Laeknagardur,Vatnsmyrarvegur 16,101 Reykjavík,Iceland.
Asa Gudrun
AG
Kristjansdottir
2Center for Sport and Health Sciences,School of Education,University of Iceland,Reykjavík,Iceland.
Hannes
H
Hrafnkelsson
2Center for Sport and Health Sciences,School of Education,University of Iceland,Reykjavík,Iceland.
Erlingur
E
Johannsson
2Center for Sport and Health Sciences,School of Education,University of Iceland,Reykjavík,Iceland.
Kristjan Thor
KT
Magnusson
1Unit for Nutrition Research, Landspitali-University Hospital & Faculty of Food Science and Nutrition,School of Health Sciences,University of Iceland,Laeknagardur,Vatnsmyrarvegur 16,101 Reykjavík,Iceland.
Inga
I
Thorsdottir
D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D002112:Calcifediol / Q000097:blood; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects*; D015930:Diet Records; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007055:Iceland; D008297:Male; D018673:Nutrition Policy; D009752:Nutritional Status; D010281:Parathyroid Hormone / Q000097:blood; D010349:Patient Compliance; D010809:Physical Fitness; D012574:Schools; D012621:Seasons; D014504:Urban Health; D014807:Vitamin D / Q000008:administration & dosage* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control
C470125:PTH protein, human; D010281:Parathyroid Hormone; D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol
25-Hydroxyvitamin D; Children; Deficiency; Suboptimal levels; Vitamin D