New Research Fails to Clarify Risk Factors for GDV
I’m a little paranoid about GDV (gastric dilatation and volvulus). I’ve never had to worry too much about it as a pet owner before, what with my penchant for small, mixed breed dogs. But now, as an inadvertent owner of a boxer with inflammatory bowel disease, I’m afraid I might experience the disease from the other side of the table, so to speak.
Therefore, I was really excited when I first saw a paper entitled "An Internet-based survey of risk factors for surgical gastric dilatation-volvulus in dogs" published in the June 15, 2012 issue of the Journal of the American Veterinary Medical Association. Unfortunately, the results didn’t do much to clarify how we might prevent GDV, but I thought I’d provide some excerpts here to outline what we do and do not know about the condition.
The introduction does a great job of reviewing past research into the risk factors for GDV:
To date, few risk factors for GDV have been clearly identified. The condition is assumed to be multifactorial8 and is influenced by dog-specific factors, management factors, environmental factors, personality factors, and combinations thereof. The breed, chest conformation, body condition, genetics, age, sex, and concurrent disease state have all been identified as dog-specific risk factors. Large- or giant deep-chested purebred dogs, including German Shepherd Dogs, Great Danes, Collies, Weimaraners, Irish and Gordon Setters, Bloodhounds, Akitas, Saint Bernards, Mastiffs, Standard Poodles, Labrador and Golden Retrievers, Doberman Pinschers, and Chow Chows, are at risk for GDV.2,4–7 Dogs with increased thoracic depth-to-width ratio9 or thin or lean body condition8,10,11 were associated with increased GDV risk. In a major prospective cohort study10 in 1,637 show dogs, a history of GDV in any first-degree relative significantly increased the risk of GDV. Age was the most important risk factor for GDV in Great Danes in 1 study12 and was significant in several others.10,11 Male gender was found to be a risk factor in 1 study.8 Chronic medical conditions (eg, inflammatory bowel disease) have also been implicated as risk factors for GDV.10,13,14
Dietary management is considered a contributing factor to the development of GDV. The type of food, frequency of meals, and volume fed have all been evaluated.13,15,16 Commercial dry dog food was implicated as causing GDV in 1 study.15 However, in a recent case-control study, feeding a commercial dry food did not increase the incidence of GDV.13 Feeding a single type of food was found to increase the likelihood of gastric dilatation,11 whereas the addition of table foods to a usual diet consisting primarily of dry dog food reduced the risk of acute GDV development.8 Dogs fed a larger volume of food per meal (regardless of the number of daily meals) were at a significantly increased risk of GDV, with the highest risk in dogs fed a larger volume once daily.13 In addition to single meals, small kibble (< 30 mm), rapid ingestion of meals, and aerophagia have all been suggested as risk factors.5,8,10–12 Contradicting previous management recommendations for the prevention of GDV, feeding from an elevated feed bowl, moistening of dry food prior to feeding, and restricting water and exercise before and after meals were found to increase the risk of GDV in a subsequent study.10
Environmental factors may influence the risk for GDV. Interestingly, for large-breed dogs, a rural residence represented a higher risk, but for giant-breed dogs, an urban residence was associated with increased risk of GDV.10 In military working dogs in Texas, GDV was most common from November through January and least common in the hot months of June and August.17,18 This seasonal GDV variation was not detected in client-owned dogs in Switzerland, where warmer environmental temperatures were significantly associated with the occurrence of GDV.19
The interaction between a dog and its environment represents an important component of risk. Personality factors such as aggression to people and fearfulness or agitation in response to strangers or environmental changes were associated with an increased risk of GDV,2,10 whereas a "happy" and easygoing temperament, submission to other dogs or to people, high activity level, and attending dog shows decreased the risk of GDV.8,10 In several studies,8,11 a variety of stressful events, including kenneling and riding in the car, appeared to precipitate an acute GDV episode.
Many of the current studies evaluating risk factors for GDV in dogs have focused on unique populations of dogs (i.e., show dogs and military working dogs), and most of them included relatively small numbers of dogs affected with GDV. The purpose of the study reported here was to evaluate the influence of risk factors for GDV in a large number of privately-owned dogs with GDV across a wide geographic area.
This new study supported some of these past findings, contradicted others, and came up with new ones that may or may not be relevant to the general dog-owning population. The authors concluded:
The most profound change in management [as a result of this new research] would be relaxing the recommendations for activity restriction after meals. In addition, regular moderate outside activity should be encouraged because dogs that spent an equal amount of time indoors and outdoors had a decreased risk of GDV in this study. Dietary management appears to play an important role, and dry kibble may not be the best choice for dogs at risk for GDV; however, supplements with fish or eggs may reduce this risk. Our study was unable to show an association between GDV and feeding frequency, speed of eating, or eating from a height; therefore, no specific recommendations concerning these factors can be made at this time.
My take home message is that we regrettably still don’t have the foggiest idea of how to manage dogs at risk of GDV. Or, as this paper’s authors more eloquently put it:
For owners and veterinarians, it is important to realize that despite multiple studies over the past 4 decades on the etiology of GDV, few consistent risk factors have been clearly identified, thereby making effective prevention very difficult.
Dr. Jennifer Coates