High prevalence of fractures and osteoporosis in patients with indolent systemic mastocytosis.
BACKGROUND
Indolent systemic mastocytosis (ISM) is a rare disease characterized by accumulation of abnormal mast cells in various tissues, including bone marrow. Symptoms are usually related to release of mast cell mediators. The aims are to establish the prevalence of osteoporotic fractures in ISM and to investigate the association with serum tryptase and the urinary histamine metabolites, methylhistamine (MH), and methylimidazole acetic acid.


METHODS
The fracture prevalence in 157 patients (65 men; 92 women), mean age 54 ± 12 years, was assessed by vertebral morphometry and data from patient records, supplemented by a questionnaire. Bone mineral density (BMD) of lumbar spine and femoral neck was measured, and tryptase and histamine metabolites were analysed.


RESULTS
We registered 235 lifetime fractures in 154 patients, including 140 osteoporotic (low-energy trauma) fractures, of which 62% were vertebral, 1% hip and 36% other nonvertebral fractures. Osteoporotic fractures and osteoporosis were found in 37% and 28% of the patients, respectively. In men, the prevalence of these osteoporotic manifestations (46% <50 years; 73% ≥50 years) was much higher compared with women (18% <50 years; 58% ≥50 years). Older age, male gender, and higher urinary MH were independently related to the osteoporotic manifestations.


CONCLUSIONS
This first publication about prevalence of fractures and osteoporosis in patients with ISM shows that the risk of osteoporotic fractures is high, especially in men. Higher urinary MH levels are associated with a higher risk of osteoporotic manifestations. Routine measurements of BMD and vertebral morphometry are warranted in these patients for early detection of osteoporosis.
Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, The Netherlands. e.van.der.veer@umcg.nl
E
E
van der Veer
W
W
van der Goot
J G R
JG
de Monchy
H C
HC
Kluin-Nelemans
J J
JJ
van Doormaal
D000328:Adult; D000368:Aged; D015519:Bone Density; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006632:Histamine / Q000378:metabolism; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D034721:Mastocytosis, Systemic / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D058866:Osteoporotic Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology; D015995:Prevalence; D011859:Radiography; D013131:Spine; D053802:Tryptases / Q000097:blood*
D006632:Histamine; D053802:Tryptases