Objective: Explore how dynamic patterns of psychological stress predict first-onset TMD. We hypothesized that elevated stress would precede onset of clinical TMD by a window of up to 12 months.
Methods: This was a nested case-control study of TMD incidence. Data were from OPPERA; a prospective cohort study of 2,737 adults with no lifetime experience of TMD when enrolled at four U.S. study sites. During the median 3-year observation period, participants completed baseline and quarterly (3-monthly) follow-up questionnaires that measured stress with the Perceived Stress Scale (PSS). Symptomatic participants were re-examined, yielding 260 incident cases of first-onset TMD. Each incident case was frequency matched with a participant who did not develop TMD. Matching criteria were baseline PSS score, duration of follow-up and study site. Lag-times and cumulative exposures were assessed in separate generalized estimating equation models to identify windows of time in which post-enrollment change in stress was associated with odds of incident TMD.
Results: TMD incidence was most strongly associated with a concurrent increase in stress (i.e., during the same quarterly window as TMD onset): TMD incidence odds ratio (IOR) = 1.44, 95% confidence limits (CL): 1.21, 1.70 for each standard deviation increase in PSS score. TMD incidence was only modestly associated with increases in stress that occurred 3-12 months before onset (IOR= 1.22, 95%CL: 1.03, 1.44), and there was no significant effect of increases in stress >12 months before onset (IOR= 1.10, 95% CL: 0.83, 1.47). Cumulative increases in stress prior to the quarterly window of TMD onset did not contribute to TMD risk (IOR=1.00, 0.95, 1.06).
Conclusions: Psychological stress was strongly associated with TMD incidence, although only within a short window of exposure.
Supported by: NIH/NIDCR