Risk factors for feline hyperthyroidism in the UK.
ABSTRACT 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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ABSTRACT: Since first discovered just 35 years ago, the incidence of spontaneous feline hyperthyroidism has increased dramatically to the extent that it is now one of the most common disorders seen in middle-aged to senior domestic cats. Hyperthyroid cat goiters contain single or multiple autonomously (i.e. TSH-independent) functioning and growing thyroid nodules. Thus, hyperthyroidism in cats is clinically and histologically similar to toxic nodular goiter in humans. The disease in cats is mechanistically different from Graves' disease, because neither the hyperfunction nor growth of these nodules depends on extrathyroidal circulating stimulators. The basic lesion appears to be an excessive intrinsic growth capacity of some thyroid cells, but iodine deficiency, other nutritional goitrogens, or environmental disruptors may play a role in the disease pathogenesis. Clinical features of feline toxic nodular goiter include one or more palpable thyroid nodules, together with signs of hyperthyroidism (e.g. weight loss despite an increased appetite). Diagnosis of feline hyperthyroidism is confirmed by finding the increased serum concentrations of thyroxine and triiodothyronine, undetectable serum TSH concentrations, or increased thyroid uptake of radioiodine. Thyroid scintigraphy demonstrates a heterogeneous pattern of increased radionuclide uptake, most commonly into both thyroid lobes. Treatment options for toxic nodular goiter in cats are similar to that used in humans and include surgical thyroidectomy, radioiodine, and antithyroid drugs. Most authorities agree that ablative therapy with radioiodine is the treatment of choice for most cats with toxic nodular goiter, because the animals are older, and the disease will never go into remission. Download here: http://joe.endocrinology-journals.org/content/223/2/T97.full.pdf+htmlJournal of Endocrinology 11/2014; 223(2):T97-T114. DOI:10.1530/JOE-14-0461 · 3.59 Impact Factor
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ABSTRACT: PBDE concentrations were measured in hyperthyroid and euthyroid cat serum.•No difference was observed in PBDE levels or profile between cat groups.•The median PBDE level in Australian cats was 118 ng g−1 lw.•Congener composition was dominated by congener BDE-99.•The high PBDE levels in cats were attributed to indoor dust ingestion.Environmental Research 01/2015; 136. DOI:10.1016/j.envres.2014.09.027 · 3.95 Impact Factor
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ABSTRACT: The purpose of this study was to assess the prevalence of feline hyperthyroidism in a cat population in Warsaw, considering risk factors. The study was conducted between June 2007 and July 2011. Seven-year-old and older cats were examined. Diagnosis of feline hyperthyroidism was based on the results of clinical examination, data from clinical history, and serum concentrations of thyroid hormones. Hyperthyroidism was diagnosed in 20.14% of 417 cats (95% confidence interval (CI): 16.28%-24.01%). Statistically significant risk factors were age (odds ratio (OR) = 1.17; 95% CI: 1.08-1.27), feeding with a commercial wet feed (OR = 6.74, 95% CI: 2.03-22.37), and an indoor lifestyle (OR = 2.25, 95% CI: 1.04-4.84). There were no effects of breed, gender, castration, or the frequency of deworming on the occurrence of hyperthyroidism. Feline hyperthyroidism in Warsaw is a prevalent disease. This probably results from chronic exposure to dietary and environmental factors.01/2014; 58(2). DOI:10.2478/bvip-2014-0040