While Ms. Peveler is trying to control the risks of aging alone, many so-called elder orphans may not fare as well. Older single and childless people are at higher risk than those with children for facing medical problems, cognitive decline and premature death, according to a 2016 study led by Dr. Maria Torroella Carney, chief of geriatric and palliative medicine at the Northwell Health system on Long Island. The study noted that about 22 percent of people 65 and older either are childless or have children who are not in contact.

Adult children typically help elderly parents negotiate housing, social-service and health care options. Without such a fallback, elder orphans can reduce their risks by building their own support structures, Dr. Carney said.

“People who are aging alone need to make plans when they are independent and functional,” she said. “They need to learn about the resources in the community and the appropriate time to start using them.” Those services could include senior-friendly housing and the growing number of home-delivered products and services aimed at the aging-solo market, such as healthy meals and doctors who make house calls, she said.

One of the first steps childless people should take is to hire an elder law lawyer, who can draw up documents that will protect them if they become incapacitated. Childless people typically turn to a friend, a lawyer, clergy, or a niece or nephew to make medical decisions, according to experts. A bank’s trust unit can take on financial tasks, with a friend, a relative or a lawyer monitoring the bank’s decisions.

Christina Lesher, an elder law lawyer in Houston, suggests appointing a “micro board,” which includes the lawyer, the health care and financial agents, an accountant and a geriatric care manager. “The board can step in if a client cannot make decisions,” Ms. Lesher said. The client could assign a network of friends and neighbors to call the lawyer in an emergency or if they notice any cognitive decline.

As for housing, Dr. Carney recommends that people aging alone consider a senior-friendly “congregate living” arrangement. Besides offering a variety of services, such housing can lessen isolation, which her research shows can lead to physical and cognitive decline. If that is not possible, she said, elder orphans should move closer to shopping, medical care, recreation and senior support services.