Social isolation and feelings of loneliness can significantly increase a person’s risk of death. This is confirmed by an extensive analysis by a Chinese research team. A lack of social contacts goes hand in hand with an approximately 32 percent higher risk of death, and the feeling of loneliness with an approximately 14 percent higher risk, the scientists report in the journal “Nature Human Behaviour”.
The researchers see an increased release of the stress hormone cortisol as a physical reason for the increased risk, which has a negative effect on bodily functions in the long term. According to the analysis, there were no statistically significant differences between the sexes. However, women felt more lonely – although they usually had larger social networks. Men are more likely to live alone and have a lack of social contact, but their reported subjective feelings of loneliness often do not reflect this.
Social isolation and loneliness
The group led by Yashuang Zhao and Maoqing Wang from Harbin Medical University evaluated 90 studies from different countries with a total of more than 2.2 million participants. An objective lack of social contacts among people with a limited social network was regarded as social isolation. “In contrast, loneliness is a subjective sense of distress that arises when there is a mismatch between desired and actual social relationships,” the study authors write.
Studies in the past have shown that loneliness and isolation can lead to higher mortality – but there were also analytical results that did not confirm this. Zhao, Wang and colleagues selected 90 of more than 14,000 studies on social isolation and loneliness published between 1986 and 2022 that met certain criteria. Only studies were selected in which other factors such as age, gender, body mass index, smoking and alcohol consumption were taken into account in the study design and statistical analysis.
Increased risk of disease as a cause of death
The team calculated average values from the values determined for the influence of loneliness or social isolation on the risk of death. For example, social isolation increases the risk of dying from cancer by 22 percent and loneliness by 9 percent. With regard to cardiovascular disease as a cause of death, social isolation increases the risk of death by 34 percent. There was also an increased value for loneliness, but this was not statistically clear.
Loneliness and social isolation were measured differently in the studies considered, and 90 percent of the studies were carried out in countries with a high average income. Nevertheless, the authors of the study assume that there is a general connection between loneliness, social isolation and an increased risk of death. They demand that medicine should take these factors into account more in therapies and that strategies should be developed to tackle the social problem of loneliness in a targeted manner.
