Most physicians can recall the impressive x-ray of the rickets rosary or the flared radial head seen in medical school. On almost every exam, there was an a reference to the infant who was solely breastfed which led to seizures and abnormal finding on physical exam, but in practice, most of us would be hard pressed to recall an infant that presented with any of those symptoms.
With recent guideline changes to require that all infants be supplemented with vitamin D from birth, extreme presentations of vitamin D deficiency such as rickets are rare, but has vitamin D deficiency really gone away?
Dr. Francine Pearce
It is hard to pin down the prevalence of vitamin D deficiency in adolescents; it depends on the cut-off you use. In one study of 307 healthy Boston adolescents presenting for primary care, 24% were vitamin D deficient (serum 25[OH]D level, ≤15 ng/mL); of these 4.6% were severely vitamin D deficient (25[OH]D level, ≤8 ng/mL) (Arch. Pediatr. Adolesc. Med. 2004;158:531-7). Broader studies have demonstrated the prevalence of vitamin D deficiency to be 7% for adolescent males aged 14-18 years and 10% for females that age (National Center for Health Statistics Data Brief No. 59, March 2011). This makes sense given that the natural sources of vitamin D are oily fishes such as salmon and sardines, cod liver oil, liver, egg yolk, and organ meat, none of which are big favorites in the adolescent population.
Other factors that contribute to the rise in D deficiency are the promotion of sunscreen use to block UV rays which are essential for cutaneous synthesis. Skin cancer prevention and the promotion of the use of sunscreen and a direct correlation of lower vitamin D levels have been identified(Am. J. Clin. Nutr. 2008;88:1519-27).
Obesity plays a unique role, in that it causes sequestration of the vitamin D into the fat cells. With the dramatic rise in adolescent obesity plus poor nutritional intake, vitamin D deficiency is the natural result.