Table 1.
RRs and 95% CIs for selected risk factors associated with background incidence of thyroid cancer.
| Characteristic | PY (n = 73,004) | Cases (n = 65) | RR (95% CI) | |||
| Sex | ||||||
| Male | 35,240 | 28 | 1.00 (Referent)a | |||
| Female | 37,764 | 37 | 1.34 (0.82–2.20) | |||
| p-Value for homogeneity | 0.24 | |||||
| Attained age (years)b | ||||||
| < 22 | 26,440 | 16 | 1.00 (Referent)c | |||
| 22 to < 30 | 34,374 | 25 | 1.73 (0.90–3.33) | |||
| 30 to < 40 | 12,190 | 24 | 5.10 (2.60–9.99) | |||
| p-Value for homogeneity | < 0.001 | |||||
| Oblast of residenceb | ||||||
| Zhytomyr | 20,254d | 11 | 1.00 (Referent)e | |||
| Kyiv | 14,710 | 15 | 2.78 (1.24–6.22) | |||
| Chernihiv | 37,988 | 39 | 4.12 (1.96–8.67) | |||
| p-Value for homogeneity | < 0.001 | |||||
| Type of residencyb | ||||||
| Rural | 52,690d | 43 | 1.00 (Referent)f | |||
| Urban | 20,309 | 22 | 1.32 (0.76–2.28) | |||
| p-Value for homogeneity | 0.33 | |||||
| Smoking statusb,g | ||||||
| Nonsmoker | 50,718d | 44 | 1.00 (Referent)f | |||
| Current smoker | 22,279 | 21 | 1.12 (0.61–2.06) | |||
| p-Value for homogeneity | 0.71 | |||||
| Family history of any thyroid diseaseb | ||||||
| No | 48,030 | 46 | 1.00 (Referent)f | |||
| Yes | 7,426 | 7 | 0.97 (0.43–2.16) | |||
| p-Value for homogeneity | 0.90 | |||||
| Unknown | 17,547 | 12 | 0.80 (0.42–1.52) | |||
| Thyroid volume (mL)b | ||||||
| < 8.0 | 16,868 | 15 | 1.00 (Referent)f | |||
| 8.0 to < 12.0 | 29,795 | 18 | 0.61 (0.30–1.22) | |||
| 12.0 to < 16.0 | 14,519 | 13 | 0.86 (0.40–1.85) | |||
| 16.0–90.5 | 11,823 | 19 | 1.49 (0.72–3.04) | |||
| p-Value for homogeneity | 0.06 | |||||
| Diffuse goiterb,h | ||||||
| No | 57,122 | 45 | 1.00 (Referent)f | |||
| Yes | 15,882 | 20 | 1.55 (0.92–2.63) | |||
| p-Value for homogeneity | 0.11 | |||||
| Characteristic | PY (n = 73,004) | Cases (n = 65) | RR (95% CI) | |||
| Ultrasound-detected noduleb | ||||||
| No | 71,335 | 60 | 1.00 (Referent)f | |||
| Yes | 1,669 | 5 | 2.44 (0.96–6.19) | |||
| p-Value for homogeneity | 0.09 | |||||
| Serum TG (ng/mL)b | ||||||
| < 15 | 30,845 | 20 | 1.00 (Referent)f | |||
| 15.0 to < 24.0 | 13,642 | 13 | 1.41 (0.70–2.84) | |||
| 24.0 to < 60.0 | 18,503 | 17 | 1.35 (0.70–2.58) | |||
| 60.0–643.0 | 4,649 | 12 | 3.78 (1.83–7.81) | |||
| p-Value for homogeneity | 0.01 | |||||
| Unknown | 5,363 | 3 | 1.42 (0.40–4.97) | |||
| Serum TSH (mIU/L)b | ||||||
| < 1.26 | 18,443 | 14 | 1.00(Referent)f | |||
| 1.26 to < 1.80 | 16,684 | 14 | 1.13 (0.54–2.37) | |||
| 1.80 to < 2.70 | 21,140 | 17 | 1.08 (0.53–2.19) | |||
| 2.70–25.40 | 16,011 | 19 | 1.52 (0.76–3.04) | |||
| p-Value for homogeneity | 0.60 | |||||
| Unknown | 725 | 1 | 1.93 (0.25–14.79) | |||
| Urinary iodine (μg/L)b | ||||||
| < 25.0 | 14,317 | 15 | 1.00 (Referent)f | |||
| 25.0 to < 50.0 | 23,931 | 23 | 0.93 (0.48–1.78) | |||
| 50.0 to < 70.0 | 12,519 | 11 | 0.82 (0.38–1.80) | |||
| 70.0–750.3 | 15,634 | 11 | 0.63 (0.29–1.38) | |||
| p-Value for homogeneity | 0.67 | |||||
| Unknown | 6,604 | 5 | 0.64 (0.23–1.79) | |||
| Serum ATPO (U/mL)b | ||||||
| < 10.0 | 25,165 | 20 | 1.00 (Referent)f | |||
| 10.0 to < 25.0 | 19,668 | 17 | 1.08 (0.57–2.07) | |||
| 25.0 to < 60.0 | 18,092 | 19 | 1.40 (0.75–2.63) | |||
| 60.0–18066.0 | 9,347 | 8 | 1.00 (0.44–2.28) | |||
| p-Value for homogeneity | 0.53 | |||||
| Unknown | 732 | 1 | 1.82 (0.24–13.63) | |||