Abstracts

RATIONALE: Chronic use of antiepileptic drugs (AEDs) constitutes a well-recognized cause of secondary osteoporosis, with affected patients showing increased bone turnover. METHODS:Women with epilepsy (WWE) aged 18-40 years on AED monotherapy underwent estimation of lumbar spine and bone mineral density (BMD)by DXA (Hologic QDR 1000). Fasting morning urine and blood were obtained for turnover markers (NTx and osteocalcin) and calciotropic hormones. RESULTS:Data was obtained from 72 WWE; 38 with localization related epilepsy (LRE), 20 with primary generalized epilepsy (PGE), and 14 not definitively classifed. Mean age was 31. AEDs were 30 carbamazepine (CBZ), 18 lamotrigine (LTG), 11 phenytoin (PHT), 13 valproate (VPA). Mean duration of AED exposure was 141 +/- 121 mos. Average spine BMD for age did not differ from normal for the entire group (Z=+0.132), but total hip BMD was signficantly lower than the population norm (Z=-0.308, p<0.05). 13 and 21 WWE met WHO criteria for osteopenia at spine and hip, respectively. 2 WWE met t-scores criteria for osteoporosis. Deficits in hip BMD were significant only in women taking CBZ (Z=-0.563, p=0.003). NTx and osteocalcin values were all within normal limits, although NTx was significantly higher in WWE taking PHT (52.3 +/- 31 nM/mM). No group differences in osteocalcin concentrations. To date, 45 WWE returned for follow-up for BMD measurements at 6 and 12 months. No signficant relationship was observed between bone turnover markers and 1 year change in BMD. CONCLUSIONS:WWE generally have normal spine BMD for age, but may have a greater than expected prevalence of hip osteopenia. Deficits in the hip BMD in this population are generally associated with CBZ treatment. BMD appears to be stable over time in young WWE. Funded by Glaxo Wellcome, Inc.