Background: Metabolic syndrome (MetS) and its components (waist circumference, triglycerides, HDL, blood pressure, fasting glucose) have been associated with bone health, but studies in men are moderate-sized and unequivocal.
Methods: Men 40-80 years were recruited to eight centres across Europe. Medications, smoking, drinking, physical activity, weight, height, blood pressure and walking speed were recorded. We measured glucose, insulin, HDL/LDL cholesterol, triglycerides; SHBG, IGF1, 25(OH)D, PTH, leptin by immunoassay; and sex steroids and 1,25(OH)2-D by mass spectrometry. MetS was defined by 2009 NCEP-ATPIII criteria. Outcomes included bone turnover markers (BTMs) and heel quantitative ultrasound [broadband ultrasound attenuation (BUA), speed of sound (SOS) and quantitative ultrasound index (QUI)].
Results: After excluding men on glucocorticoids, hormonal/bone drugs or those with missing data, 3068 were analysed. Men with MetS men (31.7%) were older, more ex-smokers, and had lower alcohol intake and physical performance. They also had lower total and free testosterone, SHBG, 25(OH)D and 1,25(OH)2-D, IGF1, and higher FSH, bioavailable and free E2, leptin, CRP and HOMA-IR. In linear regression analyses (unadjusted; adjusted for age, centre, smoking, alcohol; and additionally adjusted for BMI), MetS status was inversely associated with β-cTX, P1NP and osteocalcin (P<0.0001). However, only triglycerides and glucose were associated independently of other MetS components and BMI. BMI was not associated with BTMs independent of MetS components. Measures of insulin resistance (HOMA-IR/QUICKI, fasting insulin, HOMA-S and SHBG) consistently attenuated the association between MetS and BTMs, but hormones or physical activity did not. MetS was positively associated with BUA and QUI, but not following BMI adjustment. BMI was positively associated with BUA, SOS and QUI, independent of MetS components. Fasting glucose, insulin and HOMA-IR were negatively associated with BUA following BMI adjustment.
Conclusion: Men with MetS have lower bone turnover and higher bone density, which are differentially linked to insulin resistance and obesity, respectively.
Disclosure: The authors declared no competing interests. Funded by the Commission of the European Communities Fifth Framework Program, Arthritis Research UK, the Research Foundation Flanders (FWO) and the Clinical Research Fund of the University Hospitals Leuven.