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Vitamin D, calcium, and bone status in children with developmental delay in relation to anticonvulsant use and
M T Baer1, B W Kozlowski, E M Blyler
1Childrens Hospital Los Angeles, Department of Pediatrics, University of Southern California 90054, USA. mbaer%smtpgate@chlais.usc.edu
Insights
Ambulatory status, not anticonvulsant use, significantly impacts vitamin D, calcium, and bone health in children with developmental delays. Nonambulatory children are at higher risk for low vitamin D and osteopenia.
Area of Science:
- Pediatric Endocrinology
- Nutritional Biochemistry
- Bone Metabolism
Background:
- Inconsistent findings exist regarding anticonvulsant effects on vitamin D, calcium, and bone status.
- Previous studies often lacked detailed analysis of ambulatory status, a key confounding factor.
Purpose of the Study:
- To investigate the independent and interactive effects of anticonvulsant use and ambulatory status on vitamin D, calcium, and bone health in children with developmental delays.
- To clarify the relative importance of mobility versus medication in bone health outcomes.
Main Methods:
- A cohort of 338 children with developmental delays was categorized by ambulatory status (ambulatory vs. nonambulatory) and anticonvulsant use.
- Data collected included dietary records, serum calcium and calcidiol levels, and radiographic bone assessments.
- General Linear Models (GLM) and Analysis of Covariance (ANCOVA) were employed for statistical analysis.
Main Results:
- Dietary intake of calcium and vitamin D was insufficient in a majority of participants, falling below recommended allowances.
- Ambulatory status, rather than anticonvulsant use, was a significant predictor of serum calcium, calcidiol levels, and bone maturation parameters.
- A significant interaction between anticonvulsant use and nonambulatory status was observed for cortical bone area, indicating increased risk in this subgroup.
Conclusions:
- Ambulatory status plays a more critical role in vitamin D, calcium, and bone status than previously recognized.
- Nonambulatory children, irrespective of anticonvulsant use, are at elevated risk for low serum calcidiol and osteopenia.
- Routine monitoring and prophylactic vitamin D supplementation should be considered for nonambulatory children.
Abstract:
Reports of abnormalities in vitamin D, calcium, and bone status associated with anticonvulsant use are inconsistent and difficult to interpret because of widely varying study designs, particularly for ambulatory status. We examined the relative effects of anticonvulsant use and ambulatory status on vitamin D, calcium, and bone status in a large group (n = 338) of children who had either normal motor function (ambulatory) or were nonambulatory and either receiving anticonvulsants or not; all had developmental delays. Data included diet records, serum analyses (calcium and calcidiol), and hand-wrist radiographs evaluated for bone maturation and quality. Data were analyzed by using a general linear models (GLM) procedure. Dietary and biochemical data were compared with those of a group of 34 normal children. There were no differences in calcium or vitamin D intakes among the four study groups; however, a high percentage of intakes was below the recommended dietary allowances for calcium (56%) and vitamin D (70%). Vitamin D intakes were positively associated with serum calcium (P < 0.005) and calcidiol (P < 0.01) concentrations. Analysis of covariance indicated that ambulatory status but neither anticonvulsant use nor their interaction contributed significantly to the prediction of serum calcium (P < 0.009) and calcidiol (P < 0.0001), the Z scores for number of ossified centers (P < 0.008), bone age (P < 0.0001), and bone area (P < 0.003). A strong interaction between anticonvulsant use and ambulatory status was seen for percentage cortical area (P < 0.0008), which was entirely due to anticonvulsant use in nonambulatory children (effect size = 0.98). Results suggest that ambulatory status is more important than was recognized previously in relation to abnormalities in vitamin D, calcium, and bone statuses; that all nonambulatory children may be at risk for low serum calcidiol and osteopenia; and that routine monitoring of risk and consideration of prophylactic vitamin D supplementation are warranted.