When Dr. J. was on the road last week, the latest AHA guidelines were published to great media fanfare. Indeed you, Gentle Reader, probably saw something in the news. Dr. J. decided to review the guidelines and share his reflections on the issue.
|Lady J., a source of peace and tranquility, unless she craps on the rug.|
|ABC, easy as 123…|
The recommendations come in four flavors, Class I which are absolutely recommended, IIa which are probably a good idea, IIb which are possibly a good idea and Class III which are either of no benefit or of harm to the patient. For any recommendation a level of evidence is provided. These are Level A though C. A is typically prospective randomized control trial data while B and C are less rigorous. If you have a Class I recommendation to do something but it comes with Level C type of evidence is still Class I.
|Barry’s the reason libs get a Boot-to-the-Gut™, and not ‘droned’ from orbit.|
Please note as well that below the recommendation classes there is language suggestions as to how to couch your recommendation linguistically. For example a class I recommendation ‘is recommended’ but a class IIb recommendation ‘might be reasonable’ or one might say that its ‘effectiveness is unclear’ or ‘not well established.’ They also have recommended verbage for comparing treatment A to treatment B for both Class I and IIa recommendations.
So without further ado, the evidence behind pet ownership and cardiovascular benefit.
|Sally, The Czar’s Royal Hound|
Pet ownership is associated with blood pressure, but these data are a mixed bag. There are a number studies that demonstrate this. In Australia, 5700 participants in a free blood pressure screening found a body mass index and socioeconomic status independent relationship between lower BP and pet ownership. A second study of married couples showed the same effect, but the sample size was limited. A third study when adjusted for possible age and other variables didn’t shake out. A community survey demonstrated similar systolic blood pressures but higher diastolic blood pressure. Dr. J. has not reviewed that particular survey, but depending on the numbers that could be good or bad. If the control arm was 120/60 while the treatment arm was 120/75, that might suggest better vascular health in the higher diastolic blood pressure arm, as low isolated diastolic blood pressure may represent premature vascular aging due to loss of elasticity of the aorta and other large vessels.
|Meet K-9, GorT’s cybernetic companion. Despite the faux-fur coat, he has the same tinny voice and snarky sense of humor that you remember!|
While all this evidence is well and good, the best evidence comes from a randomized control trial. Individuals with borderline hypertension who were planning on adopting a dog. One group was randomized to adopting their dog right away while the other arm was to randomized to waiting to adopt the dog until after the study period (2-5 months). The dog adoption arm enjoyed lower blood pressure during the study period. The most interesting part is that the control arm ALSO enjoyed blood pressure reduction after they adopted their dogs. This is a pretty robust finding.
With regard to cholesterol, your dog doesn’t do much for your bad cholesterol, or LDL cholesterol. LDL cholesterol is the most important modifiable lipid with regard to reducing cardiovascular risk. Triglycerides (the forgotten fat) is a less important risk factor which we target after LDL is controlled, and if it is elevated. Triglycerides is readily affected by both diet and exercise and indeed, Dr. J. can tell sometimes if his patients ‘fall off the exercise wagon’ if he sees their trigs bump. In a review of data from that same Australian health screening, male dog owners had lower triglycerides. Their drop in triglycerides accounted for the drop in total cholesterol (which is calculated by LDL + HDL + Triglycerides/5). A separate study of older adults found a big difference in triglyceride levels (109 mg/dl vs. 192 mg/dl). One could speculate that the lipid benefits are driven by a drive to exercise.
|Meet Ghettopuppy, Ghettoputer’s companion!|
Dog owners are more active than non-dog owners in several surveys and studies. Furthermore, the NHANES III database showed that dog walkers are less likely to be obese (17%) vs. the slug who sits on the couch while his kids walk the dog (28%) and non-dog owners (22%).
|There’s a highly variable response but a dog gets you off your ass.|
There are also some surrogate markers of cardiovascular benefit. A study of 48 hypertensive individuals who were randomized to adopting a pet vs. not were found to have lower blood pressure and heart rate responses to stress after adopting pets. Studies of heart rate variability in pet and non-pet owners showed less heart rate variability (a good thing) in the pet owners. These effects apply not only to dogs and cats, but also fish and even Tamagotchi.
There are no clear data as to a mortality reduction in the general population, however there appears to be a protective effect conferred by pet ownership a substudy of Dr. J.’s favorite study, the Cardiac Arrhythmia Suppression Trial (CAST), A second study of patients admitted for cardiac chest pain or a heart attack, there was a 6% mortality rate for pet owners compared to 28% in the non-pet owner arm. A home defibrillator study also showed pet ownership as a predictor for survival.
So with all of this, the AHA concludes that dog ownership is probably associated with decreased risk and that there may be a causal role in reducing that risk.
|Just like as you don’t see dogs and cats hanging around outside Chinese restaurants, you don’t see them outside of Volgi’s Sanctum Sanctorum. He does have a pet Yeti, however!|
Pet ownership is given a Class IIb (level of evidence B) recommendation for cardiovascular risk reduction, however they do not recommend pet adoption for the purpose of reducing risk (Class III, level of evidence C).
Dr. J. agrees with this. Pet ownership, clearly is a net stress reliever, because despite all the times that Dr. J.’s cats puke up a hairball, whenever they curl up on his lap or at his feet at night makes it worth it. Like Blofeld and Don Corleone, he finds his cats a source of relaxation as weaves his insidious plots. His puppy, Lady J. is an unending source of affection and she gets him of his Imperial Throne™ and makes him go on long walks and play fetch with her (she loves playing fetch).
So Dr. J. believes that there is a clear benefit, but the responsibility is so great that you have to want to be a pet owner to be a pet owner. If you do it for the CV benefits alone, it won’t be good for you, or your pet.
Kids, despite this warning, feel free to post this on mom and dad’s pillow as you lobby them for a puppy for your birthday or Christmas!