SUN-359 Preserved Bone Mineral Density In Adults With Classical Forms Of Congenital Adrenal Hyperplasia Submitted To Long-term Low Glucocorticoid Doses

The impact of long-term and supposedly physiological doses of corticosteroids on bone mineral density (BMD) in congenital adrenal hyperplasia (CAH) remains unknown. There are few studies with discordant results performed with mixed clinical forms and glucocorticoid (GC) regimens. Additionally, the effect of mineralocorticoid (MC) therapy has rarely been evaluated. Objective: To evaluate the BMD in adults with classical forms of CAH receiving the same GC regimen and to correlate with cumulative GC and MC doses since diagnosis. Methods: 34 adults (20 simple virilizing-SV/ 21 females) with good compliance (normal serum androgens levels for sex/age), who used cortisone acetate during childhood (16±3.3mg/m(2)/d) and dexamethasone after final height achievement (0.19±0.07mg/m(2)/d). The cumulative cortisone acetate, dexamethasone, total GC and MC doses (mg/m(2)) were calculated from diagnosis until the last evaluation. BMD was evaluated by z-scores (z) in the first and last densitometry. Physical activity and calcium intake were assessed by questionnaires; PTH and 25OH-Vitamin D levels were measured in the latter evaluation. GC/MC doses, clinical/laboratory data were correlated with z scores by linear regression, chi-square and t-tests. Results: The mean age in the last evaluation was 26±6yrs, duration of cortisone acetate therapy in the salt-wasting (SW) and SV forms was 14.8±4.2 and 10.5±4.3 yrs, respectively (p<0.01). The mean total femur z score was lower in the SW than SV form (p=0.04). The cumulative cortisone acetate dose had an inverse correlation with femoral neck z score (p<0.01). The total cumulative GC/MC doses had an inverse correlation with total femur z score (p<0.01). Low BMD (z<-2) was observed in 4 patients, 2/4 were recently pregnant. Serum vitamin D and PTH levels, frequency of physical activity, and calcium intake did not influence BMD. In the analysis of sequential BMD, during dexamethasone therapy, the mean interval between exams was 10.5±6yrs, and no association was found between dexamethasone cumulative dose and delta of lumbar z score. Conclusions: In this low GC dose regimen, CAH young adults do not present higher frequency of low BMD. In spite of a preserved BMD, cortisone acetate therapy during growth period in addition to MC replacement appear to have a synergistic negative effect on BMD at femoral sites. Low dexamethasone dose was not deleterious for bone health in adulthood.