These disparities often result in increased morbidity and mortality in the homeless population. People experiencing homelessness have limited access to resources and are often disengaged from health services, making them that much more susceptible to extreme weather events (e.g., extreme cold or heat) and ozone levels.

Homelessness is also associated with a high risk of suicide attempts. Chronic disease severity, respiratory conditions, rates of mental health illnesses and substance use are all often greater in homeless populations than the general population.

When compared to the general population, people who are homeless experience higher rates of adverse physical and mental health outcomes. Homeless child and adult living on the streets There is no methodological consensus on counting homeless people and identifying their needs therefore in most cities only estimated homeless populations are known. Homelessness and poverty are interrelated. People who are homeless are most often unable to acquire and maintain regular, safe, secure and adequate housing due to income that is inconsistent or lacking altogether. United States government homeless enumeration studies also include people who sleep in a public or private place not designed for use as a regular sleeping accommodation for human beings.

The legal definition of homeless varies from country to country, or among different jurisdictions in the same country or region. People can be categorized as homeless if they are: living on the streets (primary homelessness) moving between temporary shelters, including houses of friends, family and emergency accommodation (secondary homelessness) living in private boarding houses without a private bathroom or security of tenure (tertiary homelessness). Homelessness is lacking stable and appropriate housing. For other uses, see Homeless (disambiguation).

Rise of nations population limit