Figure 4.

Sleep quality worsens prior to onset of temporomandibular disorder (TMD) in incident cases while remaining unchanged for matched controls. Reproduced from Sanders et al. (2016). Sleep quality was rated on a scale of 0 to 10 (0 = worst sleep, 10 = best sleep) in questionnaires completed once every quarter during follow-up of first-onset TMD cases (n = 220) and controls (n = 193) in the OPPERA nested case-control study. The 4 periods on the horizontal axis refer to the following: the first quarter (i.e., 3 mo) after enrollment; the intermediate quarters, between the first and penultimate quarters; the penultimate quarter, 3 mo before the final quarter; and the final quarter, the 3-mo interval prior to the follow-up visit at which presence or absence of TMD was determined. Error bars represent ±1 standard error (se) of the adjusted mean. Estimates are adjusted for study site, sex, age in years, and race/ethnicity. Asterisk (*) signifies a statistically significant difference (P < 0.05) as compared with the first quarter in the same study group. OPPERA, Orofacial Pain: Prospective Evaluation and Risk Assessment.