## Table 1 |
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Baseline characteristics of both treatment groups |
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Baseline data |
Fish oil |
Placebo (corn oil) |
P-value |

Total no of subjects (finished the study) | 39 (35) | 38 (36) | P = 1.000 |

Male / female | 17/22 | 17/21 | P = 1.000 |

Castrated / sterilized / intact | 7/15/17 | 10/10/18 | P = 0.427 |

Body condition score (median, total range 1–5) | 3 (2–5) | 3 (2–4) | P = 0.852 |

Mean bodyweight ± SD, kg | 33.5 ± 12.0 | 34.2 ± 8.6 | P = 0.755 |

Mean age ± SD, years | 5.6 ± 2.9 | 6.5 ± 3.0 | P = 0.227 |

Food eaten at study end (beef / chicken / other) | 33/5/1 | 31/7 | P = 0.961 |

Hip OA (only hip OA) | 34 (17) | 36 (14) | P = 0.431 |

Stifle OA (only stifle OA) | 5 (1) | 5 (0) | P = 1.000 |

Elbow OA (only elbow OA) | 13 (1) | 13 (1) | P = 1.000 |

Any OA + spondylosis or vertebra-OA | 8 | 13 | P = 0.208 |

Duration of symptoms (median) | over 2 years | 1-2 years | P = 0.312 |

Mean HCPI score at inclusion (W_{−2}) ± SD |
16.6 ± 5.8 | 17.4 ± 5.8 | P = 0.464 |

Number of High (>17) / Low (0–17) HCPI in group | 18/21 | 18/20 | P = 1.000 |

Peak vertical force at baseline ± SD | 76.7 ± 19.6 | 77.2 ± 20.5 | P = 0.918 |

Impulse at baseline ± SD | 9.9 ± 3.5 | 10.0 ± 2.9 | P = 0.909 |

Mean Lameness VAS at baseline ± SD | 3.8 ±1.9 | 4.5 ± 1.9 | P = 0.138 |

Mean Quality of life VAS at baseline ± SD | 3.6 ± 1.8 | 3.8 ± 1.8 | P = 0.712 |

Mean Veterinary index at baseline ± SD | 2.4 ± 2.4 | 2.5 ± 2.2 | P = 0.881 |

Median NSAID use, first questionnaire (W_{−8}) |
0-2 x/month | 0-2 x/month | P = 0.317 |

P values are for comparison between groups: In 2 x 2 tables the exact Fisher’s tests were used, in nominal to ordinal/scale Linear-by-linear association Chi-Square test were used.

Hielm-Björkman * et al.*

Hielm-Björkman * et al.* *BMC Veterinary Research* 2012 **8**:157 doi:10.1186/1746-6148-8-157