Prevalence of vitamin D defiency, its determinants and associations with health factors in infants and toddlers in the Netherlands

In 2009 TNO stated the importance of an investigation on the vitamin D status
in infants and toddlers in the Netherlands. In a previous investigation we
showed a severe vitamin D deficiency (25(OH)D < 20 nmol/l) in 72% of neonates
of non-western origin and in 24% of neonates of western origin born in a Dutch
hospital. After 16 months, over 40% of these severely deficient neonates was
still deficient. This is the first study investigating the vitamin D status in
infants and toddlers in the Netherlands.

We aim to measure the vitamin D status (25(OH)D) and prevalence of vitamin D
deficiency in Western and non-Western infants and toddlers aged six months to
four years in the Netherlands. We will assess the cross sectional association
between vitamin D status and various health aspects. Also determinants of
vitamin D status, such as exposure to sunlight, color of the skin, and vitamin
D intake via the diet or supplements.

Observational design. The main investigation consists of questionnaires,
physical examination and capillary blood drawing. For severely vitamin D
deficient children (25(OH)D < 30 nmol/l) and a matched group of children with a
sufficient vitamin D status (25(OH)D > 50 nmol/l) an extended physical
examination including measurement of hypotonia will be performed. Measurements
will be performed from mid-July to mid-September and from mid-February to
mid-April. At the end of summer 2014, a pilot will be performed in 50-100
children. These children are part of the total population.
In an amendment (18th June 2015) we request approval to measure hypotonia and
the shape of the skull also in the group of children with moderate vitamin D
deficiency (30-50 nmol/l). This is additional to the group of children with
severe vitamin D deficiency and sufficient vitamin D status who already had
these measurements.

By capillary blood drawing we draw only a micro-volume of blood. It is
minimally invasive and less unpleasant than a venapunction. The risks of a
well-performed capillary blood drawing is minimal.

The physical examination and capillary blood drawing will take 20 minutes at
most. Also, filling out the questionnaires will take 20 minutes at most.