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Table 3 Results of simulation studies: distribution of correlations between variables, regression coefficients, and frequency of "significance" results

From: Contributions of lean mass and fat mass to bone mineral density: a study in postmenopausal women

Parameters Sample size
  50 100 200 300 400 500 1000
Correlation between        
   Fat mass and weight* 0.83 0.83 0.83 0.83 0.83 0.83 0.83
  0.74 0.77 0.79 0.80 0.80 0.80 0.81
  0.89 0.88 0.86 0.86 0.85 0.85 0.84
   Lean mass and weight* 0.80 0.80 0.80 0.80 0.80 0.80 0.80
  0.70 0.73 0.76 0.76 0.77 0.77 0.78
  0.87 0.85 0.84 0.83 0.83 0.82 0.82
   Fat mass and lean mass* 0.37 0.37 0.37 0.37 0.37 0.37 0.37
  0.15 0.22 0.27 0.28 0.29 0.30 0.32
  0.56 0.50 0.46 0.45 0.43 0.43 0.41
   Fat mass and LSBMD* 0.21 0.20 0.20 0.20 0.20 0.20 0.20
  -0.04 0.04 0.09 0.11 0.12 0.13 0.15
  0.42 0.35 0.31 0.29 0.28 0.27 0.25
   Lean mass and LSBMD* 0.34 0.34 0.34 0.34 0.34 0.34 0.34
  0.12 0.19 0.24 0.26 0.27 0.27 0.29
  0.53 0.48 0.44 0.42 0.41 0.40 0.38
Regression coefficient**        
   Lean mass 0.011 0.011 0.011 0.011 0.011 0.011 0.011
  0.002 0.005 0.007 0.007 0.008 0.008 0.009
  0.019 0.015 0.015 0.014 0.014 0.013 0.013
   Fat mass 0.003 0.002 0.003 0.003 0.003 0.003 0.003
  -0.005 -0.002 -0.001 -0.000 0.000 0.000 0.001
  0.010 0.007 0.006 0.005 0.005 0.005 0.004
Frequency (%) of "significance"        
   Not lean mass, not fat mass 37.4 10.9 0.3 0.02 0.0 0.0 0.0
   Lean mass, not fat mass 52.9 75.6 75.6 67.7 58.8 50.6 22.1
   Fat mass, not lean mass 6.3 3.8 0.5 0.05 0.0 0.0 0.0
   Lean mass and fat mass 3.4 9.7 23.6 32.2 41.2 49.4 77.8
  1. *For each pair of variables, the values are average coefficient (first row), lower 95% confidence interval (second row) and upper 95% confidence interval (third row).
  2. Ten thousand pseudo-studies were simulated; each study had 50, 100, 200, 300, 400, 500, and 1000 individuals. The results presented here represent summaries of 10,000 iterations.
  3. **The model considered was: LSBMD = a + b(lean mass) + c(fat mass). The figures shown here are estimates of b (for lean mass) and c (for fat mass). For each parameter, the numbers are median, 5th and 95th percentiles (in brackets).
  4. The "significance" was defined as P < 0.05 for each or both regression coefficients.