Risk factors for feline hyperthyroidism in the UK

Royal Veterinary College, Hawkshead, North Mymms, Hatfield, Hertfordshire, UK.
Journal of Small Animal Practice (Impact Factor: 1.09). 09/2009; 50(8):406-14. DOI: 10.1111/j.1748-5827.2009.00756.x
Source: PubMed


Previous studies of cats in the USA and New Zealand have identified a number of risk factors for the development of hyperthyroidism including feeding of canned cat food and being non-purebred. The objective of this study was to examine these and other risk factors in cats from London, UK.
A questionnaire-based case-control study of hyperthyroidism in cats greater than eight years of age was undertaken. Cases and controls were recruited from two groups of first opinion clinics in London, UK (five locations in total). The two-page questionnaire investigated details of lifestyle, diet and exposure to environmental chemicals. Data analysis included multivariable analysis of risk factors using binary logistic regression.
One hundred and nine hyperthyroid cats and 196 control cats were surveyed. Increasing age, non-pure breed, use of a litter box, more than 50 per cent wet food in the diet, a diet that included fish and exposure to food in a can were identified as risk factors for the development of hyperthyroidism using multivariable analysis.
Risk factors for hyperthyroidism in cats from the UK appear similar to those of other countries. Exposure to food packaged in a can was identified as the major risk factor for the development of hyperthyroidism.

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    • "Several substantial epidemiological studies from the United States of America, UK, Hong Kong and New Zealand have revealed some contradictory results (De Wet et al. 2009; Edinboro, Scott-Moncrieff, Janovitz, Thacker & Glickman 2004; Kass et al. 1999; Martin et al. 2000; Olczak et al.2005; Scarlett et al. 1998; Wakeling et al. 2009). These include an increased risk in indoor cats, female cats, cats in multi-cat households, cats with dental disease (independent of age), use of topical flea preparations and pesticides, use of cat litter (not linked to increased risk in indoor cats), consumption of certain flavours of canned foods (fish or liver and giblet flavour) and in non-purebred cats. "
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