Risk Factors for Vitamin D Deficiency
There is little consensus regarding what constitutes vitamin D deficiency in children and adolescents. Different authors have used different definitions of deficiency, including less than 10 ng/ml,[22–24] less than 15 ng/ml[11,25–27] and less than 20 ng/ml.[10,13,28] Most experts agree that whatever level one defines as deficiency, any 25(OH)D levels between the deficiency cut-off and 30 ng/ml constitutes vitamin D 'insufficiency'. Levels above 30 ng/ml are considered, at least in adults, to be associated with the best outcomes.
Common risk factors for 25(OH)D deficiency include those outlined above, non-White ethnicity and obesity, as well as other risk factors outlined in Box 1. Risk factors can be divided into non-modifiable risk factors such as age and skin color, modifiable risk factors such as sunscreen use and low vitamin D intake, and non-patient factors such as living at high latitude and low altitude (further away from the sun). In our analysis of NHANES 2001–2004, we found that older age, female sex, non-White ethnicity, obesity, less frequent milk drinking, and watching over 4 h of television, video or computer per day were associated with 25(OH)D levels below 15 ng/ml. Vitamin D supplement use was associated with a lower risk for deficiency. A study from Japan revealed that limited exposure to sunlight and a limited diet were the primary causes amongst 31 confirmed cases of rickets. Children with inflammatory bowel disease have also been shown to have a high prevalence of 25(OH)D deficiency with almost 35% of 130 patients having 25(OH)D levels below 15 ng/ml. Children with cystic fibrosis also have a high prevalence of inadequate vitamin D levels, in one recent study, 95% had levels below 30 ng/ml. Another study recently demonstrated that the prevalence of vitamin D deficiency has increased over the past 10 years in patients with chronic kidney disease. In summary, certain patient groups are at higher risk of vitamin D deficiency.
Pediatr Health. 2010;4(1):89-97. © 2010 Future Medicine Ltd.
Cite this: Low Levels of 25-hydroxyvitamin D in the Pediatric Populations: Prevalence and Clinical Outcomes - Medscape - Feb 01, 2010.