Doctors, health professionals, social services and the Government have been warned of the need to find new ways of helping the vast numbers of elderly who live by themselves.
By 2037, about 488,200 people aged 65 and over, a figure equivalent to the current population of Edinburgh, are expected to be living by themselves. The statistics released yesterday by the National Records of Scotland represent an increase of 51 per cent compared to 2012.
The rise is even more dramatic for the over-85s, with the number in this age group living alone due to be 161 per cent higher within 25 years.
The trend comes as The Herald keeps up its long-running NHS Time for Action campaign calling for a review of capacity within both the service and social care, as part of a plan to ensure services can cope with the growing elderly population.
Last year, another study found 83 per cent of doctors estimated that between one and five patients visiting their surgeries every day were really there because of loneliness. The latest statistics have led to renewed calls from experts for more to be done to support pensioners left feeling isolated from the rest of society.
Professor Paul Knight, president of the British Geriatrics Society and a specialist in elderly medicine at Glasgow Royal Infirmary, warned loneliness could affect physical and psychological health and the new figures underlined the need to help people keep up social networks as they aged.
He said: "If you do not have that engagement what it means is people sit and they do not exercise, they do not cook for themselves, because they have only got themselves to manage, and therefore that has a knock-on effect on health."
Enabling people to keep going out, to use public transport easily and continue being consumers were all important, he said.
The rise in the number of elderly people likely to be living alone is a reflection of improvements in health and care services, which mean people are living longer and maintaining more independence into older age.
However, Peter Johnston, health and social care spokesman for council umbrella body the Convention of Scottish Local Authorities, said this also meant "councils are facing rising demand during the worst squeeze on public finance in decades".
He continued: "Having to meet the needs of more people with less resource in a fair and transparent way inevitably means prioritising those with the most critical need, and so there's an increased need for families and others to provide care in partnership with the state. This is particularly important for older people living alone who may not be in critical need of support to live independently, but nonetheless may be isolated and at risk of depression."
He called for more creative thinking about how scarce resources could be used to help communities look after their more isolated elderly residents.
Tim Ellis, chief executive of National Records of Scotland, said: "The number of households in Scotland is projected to grow by nearly 400,000 over the next 25 years. Most of this increase is in the older age groups. Scotland's population is growing, but the number of households is increasing faster, due to changes in the types of households people are living in, and the ageing population."
The report says the greatest increases are for households headed by someone aged over 65. They are projected to increase by 54 per cent between 2012 and 2037 to 966,600 homes. The number of households headed by someone aged over 85 are projected to more than double, from 77,400 to 201,200.
Laura Ferguson, director of the Campaign to End Loneliness, which carried out the earlier study, said GPs, health professionals and social services "have a role to play in identifying and supporting people at risk of loneliness: a role that becomes ever more important as the number of single-occupancy homes increases."
The previous 2010 projections for the number of single households were produced before the results of the 2011 Census were known. Since then, household growth has slowed.