FLUTD can occur in both male and female cats, and more commonly happens in cats between two and six years of age. However, cats of any age may be affected. FLUTD tends to be associated with a number of factors, including stress of any kind affecting the cat, obesity, cats housed indoors, urolithiasis (or stone formation), bacterial infections, seasonal weather, genetics or a difference among breeds, anatomic abnormalities, and stone formation in the lower urinary tract. Because male cats have a narrow urethra, they tend to be more prone to complete obstruction by the stones they form than are females, and without prompt veterinary treatment these obstructions can be serious.