Skip to main content

Advertisement

Table 2 Association between body mass index (BMI) z score at 11 years old and bone mass at 18 years mediated by BMI z score, fat mass and fat free mass at 18 years among men

From: Body mass index at 11 years and bone mass at age 18: path analysis within the 1993 Pelotas (Brazil) birth cohort study

Association entre BMI z score at 11 y and BMC/BMD BMC (g) BMD (g/cm2)
β (95% CI)p-value β (95% CI)p-value
Association % mediation Association % mediation
Overall association(A) 179.714(161.401; 198.027)p < 0.001 n/a 0.030(0.024; 0.035)p < 0.001 n/a
Association after accounting for mediation by BMI z score at 18 years old(B) 25.764(8.536; 42.993)p = 0.003 85.7 0.005(−0.0004; 0.010)p = 0.068 83.3
Association after accounting for mediation by fat mass at 18 years old(B) 167.344(151.041; 183.648)p < 0.001 6.9 0.037(0.032; 0.041)p < 0.001 -a
Association after accounting for mediation by fat free mass at 18 years old(B) 38.820(27.874; 49.766)p < 0.001 78.4 −0.003(−0.007; −0.0001)p = 0.044 90.0
Association after accounting for mediation by BMI z score, fat mass and fat free mass at 18 years old(B) 20. 375(6.717; 34.033)p = 0.003 88.7 0.003(−0.001; 0.007)p = 0.160 90.0
  1. The 1993 Pelotas Birth Cohort. Brazil. N = 1601 males.
  2. β - Linear regression coefficient; 95% CI - 95% confidence interval; p-value from Wald’s test; BMC - bone mineral content; BMD - bone mineral density; BMI - body mass index; BMI z score: according to the World Health Organization for children and teenagers from 5 to 19 years.
  3. % mediation = 100 - (Direct effect/Total effect)*100, ie, 100 - (B/A)*100
  4. aPercentage of mediation cannot be calculated because of the negative association of FM with BMD in males.