Normal parathyroid function with decreased bone mineral density in treatedceliac disease

Decreased bone mineral density (BMD) has been reported in patients with cel iac disease in association with secondary hyperparathyroidism. The present study investigated whether basal parathyroid hormone (PTH) remained elevate d and whether abnormalities of parathyroid function were still present in c eliac disease patients treated with a gluten-free diet. Basal seric measure ments of calcium and phosphate homeostasis and BMD were obtained in 17 biop sy proven patients under treatment for a mean period of 5.7+/-3.7 years (ra nge 1.1 to 15.9). In addition, parathyroid function was scud led with calci um chloride and sodium citrate infusions in seven patients. Basal measureme nts of patients were compared with those of 26 normal individuals, while pa rathyroid function results were compared with those of seven sex- and age-m atched controls. Basal results were similar in patients and controls except for intact PTH (I-PTH) (3.77+/-0.88 pmol/L versus 2.28+/-0.63 pmol/L, P<0. 001), which was higher in the former group but still within normal limits. Mean 25-hydroxy vitamin D and 1,25 dihydroxy vitamin D values were normal i n patients. Parathyroid function results were also found to be similar in b oth groups. Compared with a reference population of the same age (Z score), patients had significantly lower BMDs of the hip (-0.60+/-0.96 SDs, P<0.05 ) and lumbar spine (-0.76+/-1.15 SDs, P<0.05). T scores were also decreased for the hip (-1.3+/-0.9 SDs, P<0.0001) and lumbar spine (-1.4+/-1.35 SDs, P<0.0001), with two to three patients being osteoporotic (T score less than -2.5 SDs) and seven to eight osteopenic (T score less than -1 SDs but grea ter than or equal to -2.5 SDs) in at least one site. Height and weight were the only important determinants of BMD values by multivariate or logistica l regression analysis in these patients. The results show higher basal I-PT H values with normal parathyroid function in treated celiac disease. Height and weight values are, but I-PTH values are not, an important determinant of the actual hone mass of patients. Normal parathyroid function in treated patients suggests a lack of previous severe secondary hyperparathyroidism and/or complete adaptation to prior changes in parathyroid function.