It is generally accepted that often being sick or being predisposed to sickness will lead to a shorter life span and that those who have a bolstered immune system will fair better in the long run. You will live longer if you stay healthy. Environment, culture and ethnicity are likely much larger factors in longevity than pets. For whatever correlative reason however, statistics do show a slight increase in the level of health for individuals who have owned pets.
“We think the exposure to pets somehow matures the immune system so when the child meets the microbes, he might be better prepared for them,” says Dr. Eija Bergroth, a pediatrician at Kuopio University Hospital in Finland who led current study.
Kids with dogs fared better than those with cats: Overall, babies who lived with a dog were 31% more likely to be healthy in their first year than babies without a dog; kids from homes with cats were 6% more likely to be healthy than those in cat-free families. -Study: Why Dogs and Cats Make Babies Healthier, healthland.time.com
NCBI, Cat ownership and the Risk of Fatal Cardiovascular Diseases.
-Adnan I Qureshi, MD, Muhammad Zeeshan Memon, MD, Gabriela Vazquez, PhD, MS, and M Fareed K Suri, MD
The data regarding pet ownership and physical health has not been consistent. Friedmann et al.3 demonstrated that pet owners with medical heart conditions had a higher survival after 1 year of follow-up. A post-hoc analysis of Cardiac Arrhythmia Suppression Trial,4 again demonstrated lower mortality at 1 year after recruitment with pet ownership. However, there is paucity of data regarding this relationship derived from general population with almost no study addressing the risk of stroke. We performed this study to determine the effect of pet ownership on fatal cardiovascular events in a nationally representative cohort of persons followed for mean period of 13.4±3.6 years.
... Age, cholesterol, race/ethnicity and cigarette smoking were associated with cat ownership. Same characteristics in addition to gender and systolic blood pressure were associated with dog ownership. After adjustment for potential confounders, a significantly lower RR for death due to MI was observed in participants with past cat ownership (RR, 0.63; 95% confidence interval [CI], 0.44 to 0.88) compared with those without cats as pet at any time (see Table 3).
We found an independent association between cat ownership and risk of fatal MI [heart attacks] in the present cohort study. The protective effect may be related to a spontaneous relaxing effect with buffering effect on autonomic reactivity to acute stressors, and/or classical conditioning of relaxing response.1, 6, 7 We cannot exclude that this effect may be an indirect effect i.e. personalities of cat owners may have traits that are protective towards cardiovascular diseases independent of cat ownership. The study did not allow us to quantitate cat exposure in terms of years, intensity of physical interaction, and nature of interaction (tactile or visual). We only found the relationship between past cat ownership and fatal cardiovascular events. It is possible that cat ownership at an early age in life may be more protective than at a later age when sub clinical cardiovascular disease has already occurred.
J Vasc Interv Neurol. Jan 2009; 2(1): 132–135.