People who develop a chronic illness are often beset by feelings of loneliness, even if they have a long-term partner, a new study has found.

According to Canadian researchers, while many studies have looked at the effect of loneliness on illness, few have considered whether illness contributes to loneliness.

"We were surprised by the amount of literature that examined whether people who are lonely are more likely to get sick. Yet none of them asked the opposite question: 'Do sick people get lonely?'" said the study's lead author, Meaghan Barlow, of Concordia University.

The study assessed changes in loneliness in 121 adults between 2004 and 2012. The participants were mostly in their 70s.

It found that in many cases, the onset of chronic illness led to feelings of loneliness, even among those who had been with the same partner for at least 50 years.

"The quality of our social ties plays a role when it comes to coping with the effects of serious disease in later life. And just having a partner around may not be enough," Ms Barlow noted.

She emphasised the importance of trying to stay involved socially with family and friends and warned that ‘putting a halt to socialising only contributes to a downward spiral'.

"Dealing with a chronic illness shouldn't prevent you from still trying to get out there if you can," she said.

The study also noted the importance of not blaming oneself for an illness, as this appeared to help prevent feelings of loneliness.

"Finding different ways to connect with other people means you are less likely to blame yourself for being sick, and you can't count on a partner to fill that gap," Ms Barlow added.

Details of these findings are published in the journal, Health Psychology.