The research team drew on data from the Australian Longitudinal Study of Aging (ALSA), which began in 1992 in Adelaide, South Australia. The study aimed to assess how economic, social, behavioural and environmental factors affected the health and wellbeing of people aged 70 and upwards.
In total, almost 1500 people were asked how much personal and phone contact they had with their various social networks, including children, relatives, friends, and confidants.
Survival was monitored over 10 years. The group was monitored annually for the first four years of the study and then at approximately three yearly intervals.
The research team also considered the impact of factors likely to influence survival rates, such as socioeconomic status, health, and lifestyle.
Close contact with children and relatives had little impact on survival rates over the 10 years. But a strong network of friends and confidants significantly improved the chances of survival over that period.
Those with the strongest network of friends and confidants lived longer than those with the fewest friends/confidants.
The beneficial effects on survival persisted across the decade, irrespective of other profound changes in individuals' lives, including the death of a spouse or close family members, and the relocation of friends to other parts of the country.
The authors speculate that friends may influence health behaviours, such as smoking and drinking, or seeking medical help for troubling symptoms. Friends may also have important effects on mood, self esteem, and coping mechanisms in times of difficulty.
An accompanying editorial suggests that feeling connected to others may provide meaning and purpose that is not only essential to the human condition, but also to longevity, conferring a positive physiological effect on the body in the same way that stress confers a negative effect.