Bone mineral densities in individuals with Gilbert's syndrome: A cross-sectional, case-control pilot study
GY Minuk | R Greenberg | J Uhanova | K Hawkins | WD Leslie
BACKGROUND: Unconjugated bilirubin inhibits osteoblastic proliferative
activity in vitro, raising the possibility that Gilbert's syndrome
(GS) patients are at increased risk of osteoporosis.
OBJECTIVES: To compare bone mineral density (BMD), serum
parathyroid hormone (PTH), C-telopeptide (CTX) and osteocalcin
levels in GS subjects versus matched controls in a cross-sectional,
METHODS: BMD determinations were obtained with central dualenergy
x-ray absorptiometry. Serum PTH, CTX and osteocalcin levels
were measured by enzyme immunoassay.
RESULTS: A total of 17 GS and 30 control subjects were studied.
Overall, there were no significant differences in BMD, PTH, CTX or
osteocalcin levels between the two groups. However, when older
(older than 40 years of age) and younger (40 years of age and younger)
cohorts were considered separately, the older GS cohort had significantly
decreased total hip BMD, T scores and Z scores, and femoral
neck BMD, T scores and Z scores (P<0.005 for each parameter, respectively)
compared with older control subjects. Serum osteocalcin levels
were lower in the older versus younger GS cohort (P=0.006). An
inverse correlation existed between all subjects' serum unconjugated
bilirubin levels and total body BMD determinations (r=-0.42; P=0.04).
On univariate analysis, the association between serum unconjugated
bilirubin and total body BMD was not significant (P=0.066), nor was
serum unconjugated bilirubin identified as a risk factor for low BMD
when entered into multivariate analyses.
CONCLUSIONS: The results of the present pilot study warrant further
research involving larger numbers of subjects and longitudinal
measurements to determine whether GS is associated with decreased
BMD, particularly in older GS subjects.