Table 5.
Univariate associations jaw mobility and body palpation scores measured as continuous measures of etiologic risk factors reporting and incidence rate of first-onset TMD hazard ratios with 95% confidence limits (CL), OPPERA prospective cohort study, USA (2006–2011)
| Distribution of risk factor at enrolment | Site-adjusted(1) TMD incidence rate in each tercile of risk factor (% of people per annum) | Standardized hazard ratios (95%CL)(2) adjusted for: | Standardized hazard ratios (95%CL) adjusted for study site + demographics with imputation(3) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Putative risk factor | n | mean (sd) [1st, 2nd tercile] | Lower | Mid | Upper | Study site(4) | Demographic(5) | P-value | n | Loss to follow-up(6) | P-value(7) |
| Pain-free jaw opening | 2714 | 47.8 (7.4) [45.0; 51.0] | 3.86 | 4.33 | 3.58 | 0.97 (0.85, 1.09) | 0.96 (0.84, 1.09) | 0.560 | 2714 | 0.96 (0.84, 1.10) | 0.560 |
| Maximum unassisted jaw opening | 2714 | 53.3 (7.0) [50.0; 56.0] | 3.87 | 4.36 | 3.50 | 1.00 (0.88, 1.13) | 1.03 (0.90, 1.17) | 0.650 | 2714 | 1.03 (0.90, 1.18) | 0.700 |
| Maximum assisted jaw opening (un-terminated) | 2107 | 55.9 (7.3) [53.0; 59.0] | 3.67 | 4.3 | 3.61 | 1.00 (0.86, 1.15) | 0.99 (0.84, 1.15) | 0.870 | 2107 | 0.99 (0.84, 1.16) | 0.820 |
| Maximum assisted jaw opening (terminated) | 596 | 56.1 (7.3) [53.0; 59.0] | 4.69 | 3.44 | 3.86 | 0.93 (0.73, 1.18) | 1.03 (0.78, 1.35) | 0.810 | 596 | 1.10 (0.82, 1.46) | 0.540 |
| Number of neck sites tender to palpation | 2736 | 1.2 (2.5) [0.0; 0.0] | 1.14 (1.02, 1.25) | 1.14 (1.02, 1.26) | 0.016 | 2736 | 1.13 (1.01, 1.26) | 0.024 | |||
| Number of body sites tender to palpation | 2737 | 2.3 (3.0) [0.0; 2.0] | 1.17 (1.04, 1.31) | 1.16 (1.02, 1.30) | 0.015 | 2737 | 1.17 (1.03, 1.33) | 0.011 | |||
Adjusted rates computed using Poisson regression controlling for study site (categorical variable, 4 levels). Estimated rate is for reference study site (University of Buffalo)
Values are standardized hazard ratios (95% confidence limits), which express the risk per s.d. increase in the putative risk factor
Imputed for loss to follow-up and missing values at baseline
Rate ratio represents relative increase in incidence rate of TMD associated with an increase of 1 s.d. in risk factor. Computed using Cox proportional hazard regression model adjusting for study site (categorical variable, 4 levels)
As for footnote 2, with additional adjustment for age in years, gender (categorical, 2 levels) race/ethnicity (categorical, 5 levels) and lifetime U.S. residence (categorical, 2 levels)
As for footnote 3, with inclusion of imputed TMD rates for subjects lost to follow-up and imputed data for values missing at baseline
P-value is for hazard ratio adjusted for study site and demographic characteristics, evaluating null hypothesis that the hazard ratio equals one