Table 1. Epidemiological studies of vitamin D deficiency (25(OH)D < 50 nmol/L) in Polish population.

Study group	n	25(OH)D < 50 nmol /L	References
Mothers/newborns (Winter 1987)	25/25	100%/100%	14
Mothers/newborns (Winter 2012)	116/116	78%/78%	11
Mothers/newborns (Summer 1987)	33/33	90%/100%	14
Mothers/newborns (Summer 2012)	116/116	58%/35%	11
Newborns	40	100%	10
Infants 3 mths old	28	0%	10
Infants 6 mths old	134	7%	13
Children 12 mths old	98	20%	13
Children 2–3 y old	275	17%	12
Children 2–4 y old	45	35%	8
Children 5–9 y old	702	84%	5
Children 5–11yrs old	69	80%	8
Children 12–19 y old	38	85%	8
Adults 19–86 y old	448	79%	15
Women > 61 y	274	83%	16