Demographic and clinical characteristics at baseline of the incidence subcohort of the OAI and CHECK cohorts grouped by mtDNA haplogroups
| OAI | CHECK | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| mtDNA haplogroups | H (N=1042, 40.4%) | UK (N=612, 23.7%) | T (N=275, 10.7%) | J (N=236, 9.2%) | Others* (N=414, 16.1%) | p Value | Total (N=2579) | H (N=269, 42.4%) | UK (N=144, 22.7%) | T (N=68, 10.7%) | J (N=56, 8.8%) | Others* (N=98, 15.4%) | p Value | Total (N=635) |
| Age at baseline (years) | 60.8±9.4 | 61.1±9.1 | 60.4±9.0 | 60.1±9.4 | 60.6±9.2 | 0.597† | 60.7±9.3 | 55.2±5.3 | 56.1±5.2 | 55.6±5.5 | 57.0±5.1 | 55.2±5.2 | 0.110† | 55.6±5.3 |
| Gender | 0.024‡ | 0.247‡ | ||||||||||||
| Male | 437 (41.9) | 297 (48.5) | 134 (48.7) | 100 (42.4) | 201 (48.6) | 1169 (45.3) | 57 (21.2) | 25 (17.4) | 21 (30.9) | 12 (21.4) | 24 (24.5) | 139 (21.9) | ||
| Female | 605 (58.1) | 315 (51.5) | 141 (51.3) | 136 (57.6) | 213 (51.4) | 1410 (54.7) | 212 (78.8) | 119 (82.6) | 47 (69.1) | 44 (78.6) | 74 (75.5) | 496 (78.1) | ||
| BMI (kg/m2) | 27.4±4.4 | 27.5±4.6 | 27.9±4.6 | 27.5±4.4 | 27.7±4.4 | 0.500† | 27.5±4.5 | 25.8±3.9 | 25.8±3.6 | 26.1±3.4 | 26.0±3.4 | 25.9±4.1 | 0.892† | 25.9±3.8 |
| WOMAC | ||||||||||||||
| Pain | 3.2±4.3 | 3.2±4.2 | 2.9±3.4 | 2.8±3.3 | 3.6±4.5 | 0.675† | 3.2±4.2 | 4.4±3.2 | 5.1±3.5 | 4.8±3.0 | 4.8±3.4 | 4.8±3.6 | 0.489† | 4.7±3.3 |
| Stiffness | 2.2±2.4 | 2.2±2.4 | 2.2±2.4 | 2.2±2.1 | 2.4±2.5 | 0.805† | 2.2±2.4 | 2.5±1.6 | 2.5±1.7 | 2.7±1.7 | 2.8±1.9 | 2.7±1.7 | 0.754† | 2.6±1.7 |
| Disability | 10.2±14.4 | 11.0±15.5 | 9.3±12.6 | 9.5±11.9 | 11.3±14.7 | 0.573† | 10.4±14.3 | 14.1±10.8 | 15.5±11.3 | 15.0±10.9 | 16.8±12.3 | 15.3±11.8 | 0.627† | 14.9±11.2 |
| Total | 15.6±20.1 | 16.5±21.1 | 14.4±17.3 | 14.6±16.1 | 17.3±20.5 | 0.540† | 15.8±19.8 | 20.9±14.6 | 23.2±15.5 | 22.6±14.7 | 23.6±16.4 | 22.9±16.3 | 0.673† | 22.2±15.2 |
| Contralateral OA at baseline | 402 (38.6) | 234 (38.2) | 110 (40.0) | 89 (37.7) | 139 (33.6) | 0.402‡ | 974 (37.8) | 88 (32.7) | 40 (27.8) | 26 (38.2) | 24 (42.9) | 29 (29.6) | 0.232‡ | 207 (32.6) |
Values are mean±SD or number of patients with percentage in parentheses.
*The group ‘others’ include mtDNA variants with a frequency below 5%.
†Kruskal-Wallis non-parametric test for comparison between mtDNA haplogroups.
‡χ2 test; statistical significance declared at p≤0.05 (in bold).
BMI, body mass index; CHECK, cohort hip and cohort knee; mtDNA, mitochondrial DNA; OA, osteoarthritis; OAI, osteoarthritis initiative, WOMAC, Western Ontario and McMaster Universities Arthritis Index.