Table 2.
Incidence rate of temporomandibular disorder (TMD) after the index date in each group.
| Variables | Study Arm A | Study Arm B | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Suspected SA | Control A | Crude IRR [95% CI] |
Adjusted IRR [95% CI] |
Probable SA | Control B | Crude IRR [95% CI] |
Adjusted IRR [95% CI] |
|||||||||||||
| N | TMD | PY | IR | N | TMD | PY | IR | N | TMD | PY | IR | N | TMD | PY | IR | |||||
| Whole study population | 10,408 | 184 | 62,825.7 | 2.9 | 104,080 | 715 | 634,918.6 | 1.1 | 2.3 [2.2–2.5] *** | 2.0 [1.9–2.1] *** | 4105 | 66 | 23,204.8 | 2.8 | 41,050 | 239 | 232,345.4 | 1.0 | 3.1 [2.9–3.4] *** | 2.5 [2.3–2.7] *** |
| Stratified analyses | ||||||||||||||||||||
| Sex | ||||||||||||||||||||
| Female | 3823 | 88 | 23,241.7 | 3.8 | 38,230 | 363 | 236,432.3 | 1.5 | 1.7 [1.5–1.9] *** | 1.4 [1.3–1.6] *** | 894 | 16 | 4716.4 | 3.4 | 8940 | 76 | 47,813.4 | 1.6 | 1.5 [1.3–1.9] *** | 1.2 [1.0–1.5] * |
| Male | 6585 | 96 | 39,584.0 | 2.4 | 65,850 | 352 | 398,486.3 | 0.9 | 3.1 [2.9–3.3] *** | 2.7 [2.6–2.9] *** | 3211 | 50 | 18,488.5 | 2.7 | 32,110 | 163 | 184,532.0 | 0.9 | 4.1 [3.8–4.5] *** | 3.4 [3.1–3.7] *** |
| Age | ||||||||||||||||||||
| ≤50 | 6105 | 100 | 38,558.2 | 2.6 | 61,050 | 415 | 389,170.4 | 1.1 | 2.3 [2.1–2.4] *** | 1.9 [1.8–2.1] *** | 2437 | 37 | 14,314.6 | 2.6 | 24,370 | 130 | 143,405.1 | 0.9 | 2.5 [2.3–2.8] *** | 2.5 [2.2–2.8] *** |
| >50 | 4303 | 84 | 24,267.6 | 3.5 | 43,030 | 300 | 245,748.2 | 1.2 | 2.4 [2.3–2.7] *** | 2.1 [2.0–2.3] *** | 1668 | 29 | 8890.3 | 3.3 | 16,680 | 109 | 88,940.4 | 1.2 | 3.7 [3.3–4.1] *** | 2.6 [2.3–3.0] *** |
| Residents in | ||||||||||||||||||||
| Northern Taiwan | 5605 | 103 | 33,394.5 | 3.1 | 52,331 | 377 | 317,999.4 | 1.2 | 2.3 [2.1–2.5] *** | 2.0 [1.8–2.1] *** | 2330 | 40 | 13,652.2 | 2.9 | 20,771 | 135 | 116,551.1 | 1.2 | 3.1 [2.8–3.5] *** | 2.7 [2.4–3.0] *** |
| Other areas | 4803 | 81 | 29,431.2 | 2.8 | 51,749 | 338 | 316,919.2 | 1.1 | 2.4 [2.2–2.6] *** | 2.1 [1.9–2.2] *** | 1775 | 26 | 9552.7 | 2.7 | 20,279 | 104 | 115,794.3 | 0.9 | 3.0 [2.6–3.4] *** | 2.3 [2.0–2.6] *** |
| Monthly income | ||||||||||||||||||||
| ≤NT$24,000 | 6031 | 101 | 36,318.0 | 2.8 | 65,840 | 424 | 398,259.6 | 1.1 | 2.5 [2.3–2.6] *** | 2.1 [2.0–2.3] *** | 2022 | 32 | 111,75.7 | 2.9 | 24,501 | 127 | 135,874.1 | 0.9 | 3.8 [3.4–4.2] *** | 2.7 [2.4–3.0] *** |
| NT$24,000 | 4377 | 83 | 26,507.8 | 3.1 | 38,240 | 291 | 236,659.0 | 1.2 | 2.2 [2.0–2.4] *** | 1.9 [1.8–2.1] *** | 2083 | 34 | 12,029.2 | 2.8 | 16,549 | 112 | 96,471.3 | 1.2 | 2.5 [2.2–2.8] *** | 2.3 [2.1–2.6] *** |
| Comorbidity | ||||||||||||||||||||
| No (CCI score = 0) | 3419 | 53 | 23,465.9 | 2.3 | 54,800 | 307 | 364,963.6 | 0.8 | 2.5 [2.3–2.7] *** | 2.4 [2.2–2.7] *** | 1287 | 20 | 8271.1 | 2.4 | 21,585 | 103 | 132,653.4 | 0.8 | 3.1 [2.7–3.5] *** | 2.7 [2.4–3.1] *** |
| Yes (CCI score ≥1) | 6989 | 131 | 39,359.8 | 3.3 | 49,280 | 408 | 269,955.0 | 1.5 | 2.0 [1.8–2.1] *** | 1.9 [1.7–2.0] *** | 2818 | 46 | 14,933.7 | 3.1 | 19,465 | 136 | 99,692.1 | 1.4 | 2.6 [2.4–2.9] *** | 2.4 [2.2–2.7] *** |
The adjusted IRRs were calculated by multivariable analyses adjusting for sex, age, residency, income level, and the presence of various comorbidities (except for the stratifying variable). * p < 0.05; *** p < 0.0001. Abbreviations: SA = sleep apnea; N = number of patients; TMD = number of patients with temporomandibular disorder; PY = total patient-years; IR = incident rate (incidence of temporomandibular disorder per thousand-patient-years); IRR = incidence rate ratio; CI = confidence interval; CCI = Charlson Comorbidity Index.