Risk factors for development of chronic superficial keratitis in dogs.

Proportional hospital accession ratios for chronic superficial keratitis (CSK) of dogs were determined for 16 US veterinary teaching hospitals participating in the Veterinary Medical Data Base between Jan 1, 1976 and Dec 31, 1991. The prevalence of CSK was significantly correlated (r = 0.90) with altitude of residence, but not with latitude, longitude, mean annual solar radiation, or mean annual relative humidity. Medical records of dogs with (n = 595) and without (n = 72,877) CSK examined at the Colorado State University Veterinary Teaching Hospital between Jan 1, 1976 and Oct 28, 1991 were also reviewed. Belgian Tervuren, German Shepherd Dogs, Border Collies, Greyhounds, Siberian Huskies, and Australian Shepherds were disproportionately affected. Dogs between 4 and 7 years old were 2.36 times more likely to develop lesions than were dogs < 4 years old (P < 0.05). Among dogs < 4 years old, spayed females, sexually intact males, and castrated males were more likely to develop the condition (P < 0.05) than were sexually intact females. Altitude of residence was a significant risk factor in the development of CSK among dogs in Colorado. Dogs living at altitudes > 7,000 ft above sea level were 7.75 times more likely to develop lesions than were dogs living at elevations between 3,000 and 5,000 ft.