Endocrine Abstracts

The purpose of this study was to compare bone mineral density (BMD) and bone metabolism in patients suffering from adrogenital syndrome due to deficit of 21-hydroxylase with those of a group of healthy subjects. A longitudinal follow-up was also carried out in a subgroup of patients.

Thirty-eight patients 19-47 years old were compared with a group of healthy, age- and sex-matched controls. Sodium, potassium, calcium, phosphorus, parathyroid hormone (PTH), bone alkaline phosphatase (bALP), serum CrossLaps (CTx), 25-hydroxy vitamin D, creatinine, daily urinary calcium excretion (uCa), 17-hydroxy progesterone, testosterone and androstenedione were dosed. Bone mineral density (BMD) was evaluated at lumbar spine L1-L4, femur (neck and total) and total body by a Dual X-Ray densitometry (Hologic-Discovery). A densitometric follow up was performed in 15 patients, 10 years after the first observation, with the same device.

A significant increase of CTx was observed only in female patients compared to normal women (369±171 vs 237.7±152 pg/ml; P=0.04); no difference was found in bALP serum levels. BMD was lower in patients at any site, however, adjusting BMD values for height, the difference remained significant only at the femoral neck (0.422±0.16 vs 0.498±0.05 g/cm²; P=0.0085). In the 10-years follow-up lumbar spine BMD showed a slight increase, while the femoral parameters showed a slight decrease (L1L4 BMD basal=0.982±0.10 vs 10-years BMD=1.007±0.10 g/cm², P=0.04; femoral neck BMD basal=0.813±0.12 vs 10-years BMD=0.752±0.11 g/cm², P=0.0004; total femur BMD basal=0.911±0.11 vs 10-years BMD=0.870±0.10 g/cm², P=0.004). The same trend is observed in the healthy population. No correlation was found between the densitometric and biochemical variables and the cumulative GCs dose assumed in the last 1-3 years or the time from diagnosis. The lower BMD in AS patients does not seem to be related to the GCs replacement therapy. It could be a consequence of the pathology itself, which causes a precocious bone development, thus leading to an earlier achievement of the peak of bone mass, that is consequently reduced.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.