Bone health in adults with epilepsy and intellectual disability

BONE HEALTH AND EPILEPSY

There has been growing interest in the association between abnormalities of bone health and epilepsy in recent years. PWE who are housebound or institutionalised, avoid sunlight for cultural reasons, or have poor nutrition are at increased risk of vitamin D deficiency. This can predispose to osteopenia/osteoporosis and proximal myopathy leading to weakness and increased fall liability. Associated conditions such as cerebral palsy with inability to weight bear, reduced physical activity, or visual impairment can be contributory factors. Anti-seizure drug (ASD) side-effects like ataxia, sedation, and seizures, especially convulsive ones, can increase the risk of falls and subsequent fractures particularly in those with reduced bone mineral density (BMD).

Attention, however, has focused mainly on ASDs and their role in abnormal bone metabolism. The relationship between abnormalities of bone health and ASDs is commonly thought to be due to the enzyme-inducing properties of many ASDs leading to reduced serum vitamin D levels, but this is not the only mechanism. Sodium valproate, an enzyme inhibitor, is also associated with reduced BMD and increased risk of fractures. Other mechanisms suggested include inhibition of intestinal calcium absorption, osteoclast cell growth, cellular response to parathyroid hormone and calcitonin secretion, and direct effects on bone cells.⁴ Newer …