Low body mass not vitamin D receptor polymorphisms predict osteoporosis in patients with inflammatory bowel disease.
BACKGROUND
Osteoporosis is a recognized complication of inflammatory bowel disease (IBD). Aim To investigate the role of environmental factors and vitamin D receptor (VDR) variants on the prevalence of osteoporosis.


METHODS
DEXA scans and case note review were performed on 440 IBD patients from 1997 to 2006. All the IBD patients and 240 healthy controls were genotyped for VDR variants Taq-1 and Apa-1 using PCR-RFLP.


RESULTS
Osteoporosis and osteopenia rates were 15% and 18% for IBD, 16% and 18% for Crohn's disease (CD) and 13% and 19% for ulcerative colitis, respectively. On univariate analysis of the CD patients, low body mass index (BMI, <18.5) and smoking status (P = 0.008 and 0.005 respectively) were associated with osteoporosis and osteopenia. Low BMI was also associated with osteoporosis on multivariate analysis in CD (P = 0.021, OR 5.83, CI 1.31-25.94). No difference was observed between Taq-1 and Apa-1 VDR polymorphisms in IBD, CD, ulcerative colitis and healthy controls. However, CD males were more likely to carry the variant Taq-1 polymorphism than healthy controls males (P = 0.0018, OR 1.94, CI 1.28-2.92) and female CD patients (P = 0.0061, OR 1.60, CI 1.17-2.44).


CONCLUSIONS
In this well-phenotyped cohort of IBD patients, a relatively low prevalence of osteoporosis was observed. Low BMI was the only independent risk factor identified to be associated with osteoporosis.
Noble
C L
CL
Gastrointestinal Unit, Molecular Medicine Centre, University of Edinburgh, Western General Hospital, Edinburgh, UK. noblecolin@hotmail.com
McCullough
J
J
Ho
W
W
Lees
C W
CW
Nimmo
E
E
Drummond
H
H
Bear
S
S
Hannan
J
J
Millar
C
C
Ralston
S H
SH
Satsangi
J
J
D015502:Absorptiometry, Photon; D000328:Adult; D015992:Body Mass Index; D005260:Female; D005838:Genotype; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000145:classification / Q000150:complications*; D008297:Male; D010024:Osteoporosis / Q000453:epidemiology / Q000209:etiology*; D011110:Polymorphism, Genetic; D011237:Predictive Value of Tests; D015995:Prevalence; D018167:Receptors, Calcitriol / Q000235:genetics*; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology
D018167:Receptors, Calcitriol