Age-related changes in bone density among healthy Greek males

Osteoporosis in men is increasingly recognized as a problem in clinical med icine, but it has received much less attention than its counterpart in wome n. It is termed idiopathic if no known cause of bone disease can be identif ied clinically or in the laboratory. The true incidence of idiopathic osteo porosis (IO) in males is difficult to estimate because population character istics and referral patterns differ so widely. The aim of this study was to investigate the incidence of IO in healthy Creek male volunteers by measur ing bone mineral density (BMD) at four skeletal sites and examining the rel ations among age, BMI, and bone status. This type of information has not ye t been published. We considered osteoporosis to be present when the BMD was less than or equal to -2.5 SD from the average value for healthy young men . Three hundred and sixty-three normal male volunteers were investigated. T he mean age was 51.3 +/-8.7 yr, and BMI was 27.5 +/-3.7 kg/m(2). In all sub jects BMD at four skeletal sites - lumbar spine (LS), femoral neck (FN), Wa rd's triangle (WT), and finally trochanter (T)- was measured using dual-ene rgy X-ray absorptiometry (DEXA). T-score, Z-score and g/cm(2) values were e stimated. Forty-four subjects (11%) had BMD less than or equal to -2.5 SD ( T-score). The mean age and BMI for the men with decreased BMD was 54.8 +/-6 .4 yr and 26.3 +/-3.3 kg/m(2), whereas mean age and BMI for those with norm al BMD was 51.0 +/-8.9 yr and 27.6 +/-3.6 kg/m(2), respectively. These diff erences were statistically significant(p <0.001 and p <0.05, respectively). A positive correlation was found between BMI and bone density (g/cm(2)) at three skeletal sites: LS (r=0.235, p <0.001), WT (r=0.126, p <0.001) and F N (r=0.260, p <0.001). A positive correlation was also found between BMI an d T-score at all skeletal sites studied: LS (r=0.276, p <0.001), WT (r=0.13 3, p <0.05), FN (r=0.233, p <0.001), and T (r=0.305, p <0.001). Finally, a positive correlation was also found between BMI and Z-score: LS (r=0.256, p <0.001), WT (r=0.117, p <0.005), FN (r=0.240, p <0.001), and T (r=0.187, p <0.001). A negative correlation was found between age and bone density (g/ cm(2)) at FN (r=-0.157, p <0.01) and WT (r=-0.183, p <0.001). The same was true between age and T-score at FN only (r=0.137, p <0.05). Furthermore, a similar correlation was found between age and Z-score at LS (r=0.174, p <0. 001). When ANOVA one-way analysis was used, a significant difference was fo und between the different age groups and BMD (g/cm(2)) at FN, T, and WT (p <0.001 for all sites). For T-score, a significant difference between age gr oups was found only at FN (p <0.005). Finally, a significant difference in Z-score was found at FN (p <0.001) and LS (p <0.005). When multiple regress ion analysis was applied, it was found that BMD (g/cm(2)) at two sites, FN and WT, independently correlated with age and BMI (FN: p <0.001 for both, W T: p <0.01 and p <0.05, respectively). Finally, we found an accelerated tre nd toward decreased BMD (g/cm(2)), when the odds ratio was applied. In conc lusion, this study demonstrated that 11% of otherwise healthy Greek men had BMD less than or equal to -2.5 SD. A strong association was found between BMD (g/cm(2)) and age at three skeletal sites when ANOVA one-way analysis w as applied. Moreover, BMD was positively correlated with BMI and negatively correlated with age. Currently available data are sparse and much more res earch is needed to increase our understanding concerning the etiology of th is condition as well as illuminating the relationship between bone density and fracture.