A charity that supports older people says the numbers using its befriending service have grown by 42%.
The figure is part of the annual report from Alone.
It says 4,500 people were supported by its befriending services nationwide in 2016 - an increase of 42%.
The befriending service provides companionship to older people who are socially isolated.
This is through a weekly volunteer visit, as well as a range of social events.
Sean Moynihan, CEO of Alone, said: "As an organisation that works with older people, we see firsthand the effects of loneliness.
"I don't think that people are aware just how devastating loneliness can be for your general health.
"Not only can loneliness lead to depression, but it is also a predictor for dementia, cardiovascular disease and decreased immune system responsivity.
"As we enter the winter, calls for support dramatically increase and loneliness is one of the main issues that older people in Ireland are facing today."
- Other key findings in the annual report include:
937 older people were supported by Alone support coordination service
108 older people were housed in its housing with supports
Volunteers provided 46,800 hours
One-in-10 older people require support beyond homecare to live at home
The report also echoes last week's ESRI report, which stated that the demand for healthcare is projected to increase substantially with rapid growth and ageing of Ireland's population.
Mr Moynihan added: "As last week's ESRI report stated, the demand for home help care and for residential and intermediate care places in nursing homes and other settings is projected to increase by up to 54% by 2030.
"Alone believe that right to home care is a major part of solving the impending demand on healthcare, as older people are being forced to remain in acute hospital beds due to lack of supports to go home."
In 2016, 20% of older people had issues with home adaptations and 10% were unable to keep their home warm.
Alone says these numbers highlight "the lack of housing choices and supports" for older people in the community.
Read the report in full here
