Longitudinal analysis of BMD in KO mice and WT littermates.

In this model, b0+b1 corresponds to BMD at age = 1 month, b1 represents the curvature of the relationship from 1 month up to b2, b2 is the age at peak bone mass, and b3 is the slope of the relationship for age greater than b2. Two-way significance tests (main effects of gender and genotype and the gender by genotype interaction) for each parameter were performed. Estimates and standard errors of BMD at age 1 month (b0+b1), curvature (b1), age at peak bone mass (b2), slope after peak (b3), BMD at peak ((b0+(b1/b2)), and BMD at age 15 months ((b0+(b1/b2)+b3*(15-b2)) were calculated.