Table 4. Random-coefficients linear mixed model to analyze the influence of mtDNA haplogroups on change in cartilage volume (upper) and thickness (lower) over time in 381 knee OA patients in the progression subcohort of the OAI.
| Normalized cartilage volume in medial tibia femoral compartment | Normalized cartilage volume in central medial femoral | Cartilage volume in medial tibia femoral compartment | Cartilage volume in central medial femoral | |||||||||
| B | SE | p-value# | B | SE | p-value# | B | SE | p-value# | B | SE | p-value# | |
| Age | −0.011 | 0.003 | 0.001* | −0.008 | 0.002 | <0.001* | −10.432 | 4.044 | 0.010* | −6.470 | 2.196 | 0.003* |
| Gender (Female) | −0.498 | 0.062 | <0.001* | −0.294 | 0.042 | <0.001* | −1211.529 | 71.933 | <0.001* | −510.377 | 39.069 | <0.001* |
| BMI | −0.008 | 0.006 | 0.193 | −0.008 | 0.004 | 0.064 | −0.34 | 7.543 | 0.964 | −0.994 | 4.097 | 0.808 |
| Haplogroup† | ||||||||||||
| H (n = 152) | 0 | 0 | 0 | 0 | ||||||||
| J (n = 32) | −0.239 | 0.120 | 0.047* | −0.173 | 0.080 | 0.032* | −353.483 | 135.435 | 0.009* | −191.118 | 74.039 | 0.010* |
| T (n = 38) | 0.008 | 0.112 | 0.936 | 0.023 | 0.075 | 0.756 | −66.358 | 126.596 | 0.600 | −14.524 | 69.205 | 0.840 |
| Uk (n = 95) | 0.037 | 0.080 | 0.641 | 0.023 | 0.054 | 0.671 | 8.972 | 91.019 | 0.921 | −6.14 | 49.759 | 0.902 |
| Others (n = 64) | −0.112 | 0.092 | 0.222 | −0.067 | 0.062 | 0.276 | −239.768 | 103.953 | 0.022* | −120.847 | 56.828 | 0.034* |
| Time (years) | −0.061 | 0.008 | <0.001* | −0.042 | 0.006 | <0.001* | −57.915 | 8.369 | <0.001* | −33.201 | 4.979 | <0.001* |
| Time x Haplogroup¥ | ||||||||||||
| Time x H | 0 | 0 | 0 | 0 | ||||||||
| Time x J | 0.002 | 0.020 | 0.927 | 0.008 | 0.014 | 0.552 | 1.708 | 20.069 | 0.932 | 5.474 | 11.940 | 0.647 |
| Time x T | 0.043 | 0.019 | 0.023* | 0.029 | 0.013 | 0.030* | 45.808 | 18.715 | 0.015* | 27.020 | 11.134 | 0.015* |
| Time x Uk | 0.021 | 0.013 | 0.121 | 0.013 | 0.010 | 0.155 | 17.160 | 13.495 | 0.204 | 11.489 | 8.029 | 0.153 |
| Time x Others | 0.016 | 0.015 | 0.292 | 0.015 | 0.011 | 0.183 | 18.899 | 15.375 | 0.219 | 13.807 | 9.148 | 0.132 |
BMI: body mass index; B: regression coefficient; SE: standard error; (†) the coefficient of each haplogroup represents the mean difference between a particular haplogroup and the reference haplogroup H at baseline; (¥) shows the interaction between the mtDNA haplogroups and the loss rate of cartilage volume and thickness over time; (#) linear mixed-effects random-intercept and random-slope repeated measures analysis adjusting for gender, age and BMI at baseline and considering the most common mtDNA haplogroup, H, as the reference group; (*): indicates statistical significance at p≤0.05.