Hypovitaminosis D is Associated with Greater Body Mass Index and Disease Activity in Pediatric Systemic Lupus Erythematosus
Received 25 September 2008; received in revised form 30 December 2008; accepted 13 February 2009. published online 18 May 2009.
Objectives
To determine whether pediatric systemic lupus erythematosus (SLE) is associated with alterations in the vitamin D-parathyroid hormone (PTH) axis and to assess the relation between vitamin D deficiency and SLE activity.
Study Design
25-hydroxy vitamin D [25(OH)D], 1,25-dihydroxy vitamin D [1,25(OH)2D], and intact PTH were measured in subjects with SLE (n = 38) and healthy controls (n = 207), ages 5 to 21 years. Vitamin D status and its relation with disease activity were assessed using multivariable logistic and linear regression.
Results
Severe vitamin D deficiency (25(OH)D <10 ng/ml) was observed in a significantly higher proportion of subjects with SLE (36.8% vs 9.2%, P < .001). In SLE, the odds ratio (OR) for severe deficiency was 2.37 (P = .09), adjusting for age, sex, race, and season. However, for each 1 SD greater body mass index (BMI) z-score, 25(OH)D levels were 4.2 ng/mL lower (P = .01) in SLE, compared with controls. Adjusting for 25(OH)D levels, SLE was associated with significantly lower 1,25(OH)2D (P < .001) and intact PTH levels (P = .03). Greater SLE disease activity index scores were observed in those with 25(OH)D <20 ng/mL (P = .01).
Conclusions
SLE was associated with vitamin D deficiency, particularly among those subjects with SLE who were overweight. Future studies should assess the effect of vitamin D supplementation on skeletal and nonskeletal outcomes in SLE.
aDepartment Of Pediatrics, Division of Rheumatology, University of Texas Southwestern Medical Center, Dallas, TX
bDepartment of Pediatrics, Division of Rheumatology, The Children's Hospital of Philadelphia, Philadelphia, PA
cDivision of Nephrology, The Children's Hospital of Philadelphia, Philadelphia, PA
dDivision of Gastroenterology And Nutrition, The Children's Hospital of Philadelphia, Philadelphia, PA
eCenter for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA
fUniversity of Pennsylvania School of Medicine, Philadelphia, PA
Reprint requests: Dr Tracey B. Wright, 5323 Harry Hines Boulevard, MC 9063, Dallas, TX 75390.
Funding for this project was provided by the American College of Rheumatology Research and Education Foundation's Physician Scientist Development Award (TBW), NIH (P60-MD000209 and K23 RR021969), and the Clinical and Translational Research Center (UL1-RR024134). The authors declare no conflicts of interest, real or perceived.
ABSTRACT