A recent study discovered an intriguing relationship between social isolation and the development of type 2 diabetes, suggesting that having a smaller network of friends could possibly make us prone to the illness.

As with any such research, the precise nature of this link isn't clear. But it's as good a reason as any to reach out and make sure those isolated and alone this Christmas know they have friends to share the holiday with.

While type 1 diabetes is a lifelong auto-immune disease that typically develops in childhood, type 2 diabetes refers to the body's increasing resistance to insulin, which can develop at any age and slowly progress.

While we know of various genetic and lifestyle factors that can raise the risk of its onset, the exact mechanisms are still unknown.

Past investigations have explored the links between social structures and type 2 diabetes, looking for clues in factors such as stress and emotional support that could help us improve lifestyle decisions.

While it seems fairly clear that there's some kind of link, and intervention can be of benefit, there are still questions over which social elements play a crucial role in the relationship.

Researchers at Maastricht University Medical Centre in the Netherlands made use of an existing study's database of individuals with type 2 diabetes to determine exactly what features of isolation might be linked with the condition.

They analysed 2,861 subjects aged between 40 and 75, about a third of which were diagnosed with type 2 diabetes either previously or as part of the study.

Characteristics of their social groups were collected through a questionnaire, giving researchers a range of details on their friend network's size, frequency of contact, and how far away they lived.

They discovered that having a smaller network was highly associated with a new or previous diagnosis of type 2 diabetes among both men and women.

It was also found that the proximity of friends, family, and acquaintances made a difference for women – having nearby people to hang out with meant they were less likely to have a diagnosis.

For men, living alone seemed to make a big difference - those who had housemates were also less likely to have type 2 diabetes.

"Our findings support the idea that resolving social isolation may help prevent the development of type 2 diabetes," says Stephanie Brinkhues from Maastricht University, the study's lead author.

What does it all mean? Diabetes isn't the only long-term disorder connected to social isolation, and it's unlikely that such health conditions are themselves responsible for the isolation.

The underlying reasons behind the link aren't known. But the authors believe the implications are still clear.

"High risk groups for type 2 diabetes should broaden their network and should be encouraged to make new friends, as well as become members of a club, such as a volunteer organisation, sports club, or discussion group," advises Maastricht University diabetes researcher, Miranda Schram.

"In addition, social network size and participation in social activities may eventually be used as indicators of diabetes risk."

Healthcare is a two-way street - we can do more to help those in need as well. So this Christmas, maybe reach out to a lonely neighbour.

It's not only a nice gesture, it could help save their health.

This research was published in BMC Public Health.