OBJECTIVES: To determine the prevalence of 25-hydroxyvitamin D (25[OH]D) deficiency and associations between 25(OH)D deficiency and cardiovascular risk factors in children and adolescents.
METHODS: With a nationally representative sample of children aged 1 to 21 years in the National Health and Nutrition Examination Survey 2001–2004 (n = 6275), we measured serum 25(OH)D deficiency and insufficiency (25[OH]D <15 ng/mL and 15–29 ng/mL, respectively) and cardiovascular risk factors.
RESULTS: Overall, 9% of the pediatric population, representing 7.6 million US children and adolescents, were 25(OH)D deficient and 61%, representing 50.8 million US children and adolescents, were 25(OH)D insufficient. Only 4% had taken 400 IU of vitamin D per day for the past 30 days. After multivariable adjustment, those who were older (odds ratio [OR]: 1.16 [95% confidence interval (CI): 1.12 to 1.20] per year of age), girls (OR: 1.9 [1.6 to 2.4]), non-Hispanic black (OR: 21.9 [13.4 to 35.7]) or Mexican-American (OR: 3.5 [1.9 to 6.4]) compared with non-Hispanic white, obese (OR: 1.9 [1.5 to 2.5]), and those who drank milk less than once a week (OR: 2.9 [2.1 to 3.9]) or used >4 hours of television, video, or computers per day (OR: 1.6 [1.1 to 2.3]) were more likely to be 25(OH)D deficient. Those who used vitamin D supplementation were less likely (OR: 0.4 [0.2 to 0.8]) to be 25(OH)D deficient. Also, after multivariable adjustment, 25(OH)D deficiency was associated with elevated parathyroid hormone levels (OR: 3.6; [1.8 to 7.1]), higher systolic blood pressure (OR: 2.24 mmHg [0.98 to 3.50 mmHg]), and lower serum calcium (OR: −0.10 mg/dL [−0.15 to −0.04 mg/dL]) and high-density lipoprotein cholesterol (OR: −3.03 mg/dL [−5.02 to −1.04]) levels compared with those with 25(OH)D levels ≥30 ng/mL.
CONCLUSIONS: 25(OH)D deficiency is common in the general US pediatric population and is associated with adverse cardiovascular risks.
Comments
Low 25(OH)D Not Consistent Predictor of Nutritional Rickets
Dear Editor,
We read with interest the article recently published in the journal of Pediatrics titled: Prevalence and Associations of 25-OH vitamin D Deficiency in US Children: NHANES 2001-2004. Kumar and colleagues report that 9% of the pediatric population in the U.S. were noted to have circulating levels of 25-OH vitamin D <15 ng/mL. Those at greatest risk were females, African-Americans, obese, older children who drank little milk and who watched a lot of TV. Additionally, those with the lowest levels of vitamin D were noted to have adverse cardiovascular outcomes.
Most pediatricians would agree that there has been a plethora of literature focused on vitamin D in recent years. Vitamin D deficiency rickets, once thought to be eradicated in the US with milk fortification programs, is now showing up in pediatric offices across the country. As such, your journal presented revised vitamin D intake guidelines last year (Wagner CL et al, Pediatrics 2008). However, even in locations of the country which to some might considered relatively sunny, such as Oakland, California (Latitude 38º) nutritional rickets is observed. Between January, 2001 and July, 2006, similar to the time period studied in the Kumar report, we confirmed a total of 59 cases of severe vitamin D deficiency rickets (Bhatia, 2006 abstract). Despite the increased attention vitamin D has received in the press, an additional 23 cases were confirmed in the last 3 years. The majority of cases were diagnosed in the first year of life. We also found these cases to be primarily African American, Arabic or Hispanic who were exclusively breastfed (90%). What is fascinating is that nutritional rickets was diagnosed in all, despite only 75% of these children exhibiting circulating 25-OH vitamin D levels of <15 ng/mL, (Mean 25-OH level was 14 ng/mL, Median: 9.0 ng/mL).
We bring this to your readers’ attention given the often heated debate regarding the absolute cut-off value that is considered for vitamin D deficiency and sufficiency. If vitamin D were used in isolation of other informative laboratory and radiologic findings, one quarter of these nutritional rickets cases could have been missed. Alternatively, a low 25- OH vitamin D value, with no other clinically significant findings could simply reflect assay variability. Citations:
Kumar J, Muntner P, Kaskel FJ, Hailpern SM, Melamed M. Prevalence and associations of 25-OH vitamin D deficiency in US Children: NHANES 2001- 2004.
Wagner CL, Greer FR. Prevention of Rickets and Vitamin D deficiency in infants, children and adolescents. Pediatrics 2008;122:1142-52.
Bhatia S, Umanzor CY, Dwyer WM, Gildengorin G, King JC. Rickets identified among children in Oakland, CA: a chart review. J Bone Mineral Research 2006, abstract.
Conflict of Interest:
None declared