Vitamin D deficiency and lifestyle risk factors in a Norwegian adolescent population
Sammanfattning
Aim: The aim was to study vitamin D status in a healthy adolescent Norwegian population at
69°N. Methods: The data presented come from The Tromsø Study: Fit Futures, during the school year
2010/2011 (not including the summer months), where 1,038 (92% of those invited) participated.
Physical examinations, questionnaires and blood samples were collected, and serum 25-
hydroxyvitamin D (25(OH)D) were analyzed using LC-MS/MS. Results: Results are presented from
475 boys and 415 girls (15-18 years old) with available blood samples. A total of 60.2% had vitamin D
deficiency or insufficiency (serum 25(OH)D <50 nmol/l), 16.5% were deficient (<25 nmol/l) and 1.6%
had severe vitamin D deficiency (<12.5 nmol/l). Only 12.4% had levels >75 nmol/l. A significant
gender difference with a mean (SD) serum 25(OH)D level of 40.5 (20.5) nmol/l in boys and 54.2 (23.2)
nmol/l in girls (p <0.01) was present. Furthermore, 51.3% of girls had levels >50 nmol/l in comparison
to 29.7% of boys (p <0.01). There was an inverse correlation between parathyroid hormone levels and
25(OH)D, rs= -0.30 (p<0.01). Explanatory factors that were significantly associated with serum 25
(OH)D levels in multivariate models were use of snuff, consumption of vitamin D fortified milk, cod
liver oil and vitamin/mineral supplements, physical activity, sunbathing holiday and use of solarium
in boys, and vitamin/mineral supplements, physical activity, sunbathing holiday and use of solarium
in girls . Conclusions: Vitamin D deficiency is prevalent during the school year among adolescents in
northern Norway, particularly among boys.