The relationship between femoral neck bone mineral density (BMD) and antiepileptic drug therapy in ambulatory, young male patients with epilepsy (ages 25 to 54 years, mean 45 yrs) was determined in an outpatient seizure clinic at the University of Washington, Seattle. Dual-energy absorptiometry scans were obtained in 81 consecutive patients and were repeated in 54 patients, 12 to 29 months later (mean, 19 months). Nineteen patients (23%) had suffered 25 fractures. Low BMD values were analyzed for bone loss risk factors. Age and duration of AED therapy were the 2 important risk factors associated with low femoral neck BMD. Only the youngest patients (25-44 yrs) showed significant bone loss. The mean duration of AED therapy was 18 years, and patients with continuing bone loss had received AED the shortest length of time (median 11 yrs). Phenytoin and/or carbamazepine were the most frequently used AED, in 30 and 22 of 54 patients, respectively, but no AED was specific for bone loss. Risk factors previously associated with bone loss, including vitamin D deficiency, hypocalcemia, cigarette and heavy alcohol use, were not of significance as a cause of bone loss, after correcting for age and time on AED. 
COMMENT. Young male patients taking AED therapy for seizures are at risk of significant bone loss at the femoral neck. Almost 50% have osteopenia, a 2.5 fold increased prevalence compared to the healthy male population, and the risk of fractures is increased.