Table 3.

Key points of vitamin D supplementation in childhood [115].

First Year of Life	1–18 Years
Vitamin D supplementation is recommended in all newborns, independently of the type of feeding.	Vitamin D supplementation is recommended in children and adolescents with risk factors for vitamin D deficiency.
Vitamin D supplementation should be started within the first days of life and continued throughout the first year.	Vitamin D supplementation is recommended from the end of fall to the beginning of spring (November–April) in children and adolescents with reduced sun exposure during summer. Continuous vitamin D supplementation is recommended in cases of permanent risk factors for vitamin D deficiency.
Infants born at term without risk factors for vitamin D deficiency should receive 400 IU/day of vitamin D. In the presence of risk factors for vitamin D deficiency up to 1000 IU/day of vitamin D can be given.	At-risk children should receive daily vitamin D supplementation ranging from 600 IU/day (i.e., in presence of reduced sun exposure) up to 1000 IU/day (i.e., in presence of multiple risk factors for vitamin D deficiency).
Daily administration of vitamin D is recommended.	In cases of poor compliance, supplementation with intermittent dosing (weekly or monthly doses for a cumulative monthly dose of 18,000–30,000 IU of vitamin D) can be considered, starting from children aged 5–6 years and particularly during adolescence.
Individuals on anticonvulsants, oral corticosteroids, antimycotics and antiretroviral drugs should receive at least 2–3 times more vitamin D than the daily requirement recommended for age.
Vitamin D metabolites and their analogs (calcifediol, alfacalcidol, calcitriol, and dihydrotachysterol) are not recommended for the routine vitamin D supplementation.
25(OH)D testing in children and adolescents is not recommended. Evaluation of serum 25(OH)D levels can be considered in presence of multiple risk factors for vitamin D deficiency. Vitamin D status should be monitored at least yearly in subjects that require continuous supplementation.