Normal vitamin D and low free estradiol levels in women on enzyme-inducing antiepileptic drugs

Epilepsy Behav. 2011 Aug;21(4):453-8. doi: 10.1016/j.yebeh.2011.05.001. Epub 2011 Jun 25.

Abstract

Relationships between reproductive hormone levels, bone turnover marker levels, bone mineral density, and rates of bone loss were evaluated in premenopausal women with epilepsy taking enzyme-inducing antiepileptic drugs (EIAEDs: phenytoin or carbamazepine) or lamotrigine. Calciotropic and reproductive hormone levels, bone turnover marker levels, and bone mineral density were measured at baseline and 1 year. Bone mineral density did not differ between groups. Serum calcium (P<0.001) and estrone (P<0.001) levels were lower in the EIAED group. Sex hormone-binding globulin levels were higher (P<0.001) and percentage free estradiol levels were lower (P<0.001) in the EIAED group. We detected no relationship between bone mineral density change and calciotropic hormone or bone turnover marker levels. Women with higher sex hormone-binding globulin and lower free estradiol levels sustained more bone loss at the total hip (P=0.04 and P=0.02) and a trend toward more bone loss at the lumbar spine (P=0.07 and P=0.08). These findings suggest that lower estrogen levels may contribute to bone loss in premenopausal women with epilepsy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Anticonvulsants / pharmacology
  • Anticonvulsants / therapeutic use*
  • Bone Density / drug effects
  • Carbamazepine / pharmacology
  • Carbamazepine / therapeutic use*
  • Epilepsy / blood*
  • Epilepsy / drug therapy
  • Estradiol / blood*
  • Female
  • Humans
  • Lamotrigine
  • Phenytoin / pharmacology
  • Phenytoin / therapeutic use*
  • Triazines / pharmacology
  • Triazines / therapeutic use
  • Vitamin D / blood*

Substances

  • Anticonvulsants
  • Triazines
  • Vitamin D
  • Carbamazepine
  • Estradiol
  • Phenytoin
  • Lamotrigine