Page 905 - Small Animal Clinical Nutrition 5th Edition

Feline Lower Urinary Tract Diseases 937

MISCELLANEOUS FACTORS (i.e., municipal, well or bottled) were similar to those for hospi-
Cats described as lazy, or that exercise little, appear at in-
VetBooks.ir creased risk for lower urinary tract disorders (Walker et al, tal control cats; more than 80% of cats in both groups received
water from municipal supplies (Kirk et al, 1995). Mineral con-
1977; Jones et al, 1997). It may be that these cats are over-
tent of water is expressed as parts per million whereas mineral
weight, which also is a risk factor for lower urinary tract dis- content of food is expressed as parts per hundred. Therefore,
eases. In a study of indoor-housed cats, significantly more own- even water with high mineral content (i.e.,“hard water”) would
ers of those with lower urinary tract signs observed gastroin- contribute little to the total daily mineral intake compared with
testinal signs, scratching and fearful, nervous or aggressive be- the amount supplied in food (Kirk et al, 1995).
haviors than owners of healthy cats (Buffington et al, 2006). A case-control study was performed to identify nutritional
factors associated with struvite and calcium oxalate uroliths in
Environment cats (Lekcharoensuk et al, 2001a). Data were collected from
Living in a multi-cat household has been identified as a risk cats whose uroliths were submitted to the Minnesota Urolith
factor for lower urinary tract disorders in some studies (Walker Center between 1990 and 1992. A content-validated question-
et al, 1977; Jones et al, 1997). Cats that live indoors (or have naire was mailed to owners to obtain information about their
restricted access to the outdoors) and/or are provided a litter cat’s food (e.g., types and quantities fed), feeding methods,
box are also at increased risk for lower urinary tract diseases mineral and vitamin supplements and source of drinking water.
(Walker et al, 1977; Jones et al, 1997; Kirk et al, 1995). Nutrient information and expected urinary pH ranges for each
Conditions that may cause increased stress (e.g., living in con- food were obtained from pet food manufacturers. Data from
flict with another cat or moving to another home) have been 290 cats with magnesium ammonium phosphate uroliths and
associated with FIC (Jones et al, 1997; Cameron et al, 2004). 216 cats with calcium oxalate uroliths were compared with data
from 827 control cats without urinary tract disease. Dis-
Nutritional Factors tributions for breed, age, gender, body condition and living
Decreased moisture content of foods (feeding dry food) and/or environment were significantly different between case and con-
decreased water intake have been associated with increased risk trol cats; therefore, multivariate analyses were performed to
of FIC and calcium oxalate uroliths but not struvite uroliths adjust for potential confounding variables. The authors identi-
(Walker et al, 1977; Kirk et al, 1995; Lekcharoensuk et al, fied several associations between food components and occur-
2001a). In one study, cats fed foods with a high moisture con- rence of uroliths. Cats fed foods with high amounts of magne-
tent (74.4 to 81.2%) were about a third as likely to develop cal- sium, phosphorus, fiber, calcium, sodium, chloride or potassi-
cium oxalate uroliths as were cats fed foods low in moisture (7 um, or moderate protein content had increased risk of struvite
to 7.9%) (Lekcharoensuk et al, 2001a). In another study, cats uroliths (Lekcharoensuk et al, 2001a). In addition, cats fed
with FIC were significantly more likely to eat dry pet food foods formulated to produce urinary pH values between 6.5
exclusively (59%) compared with cats in the general population and 6.9 were two times as likely to develop struvite uroliths as
(19%); however, this study did not include a control group cats fed foods formulated to produce a urinary pH between
(Buffington et al, 1997). Instead, results of a survey conducted 5.99 and 6.15. Cats fed foods with low amounts of sodium,
by another organization regarding feeding practices of pet own- potassium or protein, low or high amounts of magnesium,
ers were used. These survey results differ from other studies, phosphorus or calcium,or those formulated to produce an over-
which show 95 to 99% of cat owners feed either dry food exclu- ly acidified urinary pH had increased risk for calcium oxalate
sively or a mixture of dry and moist (Habits and Practices, uroliths (Lekcharoensuk et al, 2001a) (Table 46-10). Increased
2002; Gunn-Moore and Shenoy, 2004). Eating dry cat food dietary magnesium was previously associated with struvite
has been associated with increased occurrence of FIC, whereas urolith formation; however, presence of a concomitant alkaline
eating food with higher moisture content (e.g., canned food) urinary pH was likely a more important factor (Taton et al,
has been associated with decreased occurrence (Walker et al, 1984; Buffington et al, 1985, 1990).
1977; Jones et al, 1997; Willeberg, 1984). In addition, feeding To date, the strongest association with occurrence of calcium
moist food to cats with FIC has been associated with reduced oxalate urolithiasis has been use of acidifying foods (Kirk et al,
recurrence of clinical signs compared with feeding dry food 1995; Lekcharoensuk et al, 2001a). It has been hypothesized
(Markwell et al, 1999). Additional study, however, is needed to that uniform use of these foods for managing struvite disease
determine if dry food causes FIC. As noted previously, more may be the cause for increased occurrence of calcium oxalate
than 95% of owners feed their cats dry food exclusively or a uroliths in cats (Buffington et al, 1994; Kirk et al, 1995;
combination of dry and moist food, yet the reported incidence Thumchai et al, 1996; Lekcharoensuk et al, 2001a). In one epi-
of lower urinary tract diseases overall is less than 2% (Habits demiologic study, cats with calcium oxalate urolithiasis were
and Practices, 2002; Gunn-Moore and Shenoy, 2004; Lawler et more than three times as likely as hospital control cats to have
al, 1985; Willeberg, 1984). been fed foods that typically promote urinary pH equal to or
The source of water (e.g., tap vs. well) is not believed to be a lower than 6.29 (Kirk et al, 1995). In another study, cats fed
contributing factor in cats with lower urinary tract disorders; foods formulated to produce urinary pH values between 5.99
however, it has not been carefully evaluated. In an epidemiolog- and 6.15 were three times as likely to develop calcium oxalate
ic study, water sources for cats with calcium oxalate uroliths uroliths as cats fed foods formulated to produce urinary pH val-