A study on risk factors for bloat (gastric dilatation and volvulus - GDV) was recently published.¹ The study examined a host of potential risk factors for the development of this often fatal condition which is more frequent in large and giant breeds of dogs. The researchers made some observations, some of which contradict findings from previous studies by the same researchers. For instance, based upon this study, the researchers recommend slowing the rate of feeding in large dogs, but that doing the same for giant breeds is inadvisable. In an earlier study, however, it was found that faster eating was associated with an increased risk or GDV. The earlier study also found an association between eating dry food and an increased risk of GDV. Results of the current suggest this may not be true.

Comments from our Veterinary Staff:

Interpreting Study Results

Conflicting results from research studies is not that uncommon. Results may differ because different techniques are used, different populations are studied, or different statistical methods are applied. In most cases, we feel much more comfortable with the results of a study if the same results are obtained by a different study by different researchers. Beware of accepting a one-paragraph summary of the results of a study without carefully reading and understanding the entire study. Unexplainable or illogical results should raise a red flag and indicate more research is needed.

One common mistake is to conclude that one event causes another. Care must be taken when interpreting study results relative to cause and effect. Two events may be associated with each other, but one does not necessarily cause the other. Simply because Event A increases at the same time as Event B, does not mean Event A caused B or vice versa. There may be a third event, Event C, which is actually the cause of the other two. We can say Events A and B appear to be associated with each other, but to say one event is caused by another may lead us down the wrong path.

As an example, in Green Bay, Wisconsin, home of the Packers, on certain Sundays a large proportion of the people wear green and gold, and at the same time, there is a great increase in traffic in the city. Does one of these events cause the other? No. In fact, they are related to a third event: a home game.

The Question of Raised Food Bowls

In this study, when analyzing the association between the rate of GDV and the height of the food bowl some questions arise. First, the study found that large breed dogs whose food bowls are not elevated have the lowest risk of GDV. A confusing finding is that large breed dogs who have their bowl raised over 1 foot have the next lowest risk, and those who have their food bowl raised somewhere between the floor and one foot have the highest risk. So, the risk of GDV is not proportional to the height of the food bowl. If height of the food bowl is important, why doesn't the risk steadily increase the higher the food bowl is raised?

Secondly, it appears that the researchers did not consider the height of the animal in relationship to the height of the bowl when looking for an association between food bowl height and prevalence of GDV. It would be of interest to compare the height of the bowl to the height of the dog, since dogs in this study varied widely in height due to breed differences and age (some were only 6 months old).

The third question is, 'why weren't similar findings obtained in giant breed dogs?' In giant breeds, dogs with food bowls raised less than one foot had the same incidence of GDV as those dogs who did not have their dishes raised at all.

Finally, it is unclear if the researchers also analyzed whether the elevated feeders were being used because other medical problems were present, or if the elevated feeders could influence other factors such as the speed of eating. Could these medical problems or other factors, rather than the elevated feeders, have contributed to the increase in GDV in this group?

Comparison to Other Studies

The results of this study agree with most previous studies which also found that GDV increases with age. On the other hand, in several studies, dogs who ate faster had higher rates of GDV. In this study, we had a peculiar finding: eating at a fast rate was associated with an increased rate of GDV in large breed dogs, but a decreased rate in giant breed dogs. There have been other contradictory findings in research on GDV. In some studies, it was found that overweight dogs had higher rates of GDV, and in other studies, lean dogs had higher rates. In this study, weight did not seem to make a difference. In most studies, including this one, the rate of GDV between males and females were similar; in one study, however, males had an appreciably higher rate.

Summary

Bottom line: More research needs to be done on identifying risk factors for GDV. At this point, it is uncertain whether anything we do (e.g., changing the amount of exercise and water intake, height of food bowls, or speed of eating) will decrease or increase the rate of GDV. We should be aware that the risk of GDV appears to increase with age and it may be more common in certain families.