Table 2.
Hazard ratios (HR) of thyroid carcinoma according to reproductive variables
| Characteristics | Person years | Cancers | HR (95% CI) | ||||
|---|---|---|---|---|---|---|---|
| Unadjusted | Adjusteda | ||||||
| Parity | Nulliparous | 669,552.30 | 119 | ref. | – | ref. | – |
| Parous | 6,252,016.15 | 1656 | 1.48 | 1.23, 1.79 b | 1.45 | 1.20, 1.75 | |
| Number of children | 1 | 1,442,607.45 | 357 | 1.39 | 1.13, 1.70 | 1.27 | 1.03, 1.57 |
| 2 | 2,996,507.76 | 918 | 1.71 | 1.41, 2.07 | 1.60 | 1.32, 1.93 | |
| 3 | 1,094,621.74 | 262 | 1.34 | 1.08, 1.67 | 1.44 | 1.16, 1.79 | |
| 4 | 379,098.81 | 67 | 0.99 | 0.74, 1.34 | 1.21 | 0.89, 1.64 | |
| 5 + | 339,180.39 | 52 | 0.87 | 0.63, 1.20 | 1.14 | 0.82, 1.59 | |
aAdjusted for age at the census, residence, and education
bStatistically significant differences are marked in bold