Bone mineral density following long-term use of antiepileptic drugs in a tropical Asian country

Abstract

The objective of this study was to investigate bone mineral density (BMD) in Thai epileptics who had been receiving long-term, antiepileptic drugs. Subjects were epileptic patients aged 15 to 50 years who had been taking antiepileptic drugs for longer than six months. All were free of disease and none was taking any medication that might interfere with bone metabolism other than antiepileptic drugs. BMD at the left femoral neck and spine was measured with dual energy X-ray absorptiometry. Demographic data, basic laboratory studies and history of clinical epilepsy were obtained. One hundred and thirty patients (63 males and 67 females) were included. Mean age (+ SD) was 31.9 +/- 9.7 year. There were 79 patients receiving monotherapy and 51 patients receiving polytherapy. All patients had normal serum calcium. Thirteen patients had slightly low serum phosphate levels. The BMD at the femoral neck had a mean Z-score - 0.15 +/- 1.17 and the mean Z-score at the lumbar spine was - 0.56 +/- 1.03. Thirty one patients had osteopenia at the spine and 30 patients at the femoral neck. Three patients had osteoporosis of the spine and 1 patient of the femoral neck. There was found to be no significant correlation between age, sex, body mass index, duration of treatment and type of antiepileptic drug with bone mineral density at the femur and spine. The mean BMD of long-term antiepileptic users was lower than that of the sex and age-adjusted mean.