Table 4

Lifetime gonadal hormone exposure and bone sarcoma risk in a cohort of 683 Rottweiler dogs

Dogs with bone sarcoma (no.)Dogs without bone sarcoma (no.)Total dog-monthsBone sarcoma incidence rate (95% CI)aRR (95% CI)P
Total population8659771,00412.1 (9.6–14.7)
Gender
 Male3525930,22811.6 (7.8–15.4)1.0
 Female5133840,77612.5 (9.1–15.9)1.1 (0.7–1.7)0.74
Male gonadal exposure subgroup
 Castrated before 1 yr of age9253,16828.4 (9.8–47.0)3.8 (1.5–9.2)0.002
 Castrated 1–3.5 yr of age8576,22812.8 (3.9–21.8)1.7 (0.7–4.3)0.31
 Castrated after 3.5 yr of age8577,63210.5 (3.3–17.8)1.4 (0.6–3.5)0.48
 Sexually intact1012013,2127.6 (2.9–12.3)1.0
P trend = 0.008
Female gonadal exposure subgroup
 Spayed before 1 yr of age18577,17625.1 (13.5–36.7)3.1 (1.1–8.3)0.02
 Spayed 1–5 yr of age1410812,61211.1 (5.3–16.9)1.4 (0.5–3.8)0.63
 Spayed after 5 yr of age1410814,8569.4 (4.5–14.3)1.2 (0.4–3.2)1.00
 Sexually intact5646,1448.1 (1.0–15.3)1.0
P trend = 0.006
  • a Incidence rate expressed as number of bone sarcomas per 10,000 dog-months.