• Senior –
    • In dogs, aging occurs at different rates in different sizes of dogs; larger dogs age more quickly while smaller dogs tend to have longer life spans
    • For dogs, AAHA Senior Care Guidelines task force suggests that practitioners apply this designation to dogs and cats that are in the last 25% of the predicted life span for their species and breed.
  • Geriatric – a term used to describe a dog at the end of its life stages, living after its expected lifespan, or one with significant disease. In cats, it has been defined in the past as those 15 years of age and older, though in the 2021 AAFP Life Stage Guidelines, the stage after senior is now defined as ‘end-of-life’, which can happen at any age.
  • Aging – Aging can be defined as the decline and deterioration of functional properties at the cellular, tissue and organ level. This loss of functional properties yields a loss of homeostasis and decreased adaptability to internal and external stress yielding an increased vulnerability to disease and mortality.
  • Relative Age – because of the variation in rates of aging of dogs, typically according to body size, the life stage designations of senior and geriatric cannot be determined just by their biological age. If the actual predicted life span for a breed is determined, then the senior designation of the last 25% of that life expectancy can be determined. As such, there are various charts and guidelines to help determine the relative age of a dog (age relative to human years) for better classification of life stages. This is important for individual care, as well as for demographics for clinic outreaches for senior pet programs.
  • Inflammaging – (also known as inflamm-ageing) is a chronic, sterile low-grade inflammation that develops with advanced age, in the absence of overt infection, and may contribute to clinical manifestations of other age-related pathologies. Inflammaging is thought to be caused by a loss of control over systemic inflammation resulting in chronic, overstimulation of the innate immune system. Inflammaging is a significant risk factor in mortality and morbidity in aged individuals.
  • Fragility – in people, fragility or frailty is a geriatric syndrome characterized by weakness, weight loss, and low activity that is associated with adverse health outcomes.
  • Immunosenescence – The age-associated decline of the immune system and host defense mechanisms. Elderly individuals frequently have a decline in cell-mediated immunity and secondary declines in humoral immunity. The clinician caring for an older patient can assume that the individual has defective host defenses, is at greater risk for developing an infectious disease, and has an increased risk of morbidity and mortality from infectious diseases.