The study is very thorough. Two aspects of the study are relevant:

• The size of the sample (458,146 subjects) and
• the fact that the authors analysed, both separately and jointly, the functional effects (feeling of loneliness) and structural effects (living alone and frequency of activities and visits) on general mortality and cardiovascular disease.

The study provides a thorough analysis of all functional and structural factors. The conclusions are not new, although they are more detailed. Those who live alone and have fewer family visits have a higher risk of general mortality and cardiovascular disease.

In Spain, the effect of structural loneliness (living alone) could be greater, since in southern Europe societies are more familial (support from family) and living alone is less frequent but the negative effects are greater.

In every study there are limitations, but in this one it does not seem that the limitations are relevant. The negative effects of feelings of loneliness and isolation have already been documented. Support for people who live alone and are socially isolated would require greater monitoring of their health by health and social institutions.

This study, published in the prestigious journal BMC Medicine, explores the individual and combined effect of various social factors on mortality. Specifically, the authors showed that two functional aspects (unwanted loneliness and the ability to confide in someone close) and three structural measures of social connectedness (frequency of visits from friends and/or family, participation in weekly group activities, and living alone) were associated with mortality. 

While the results are in line with previous work highlighting the importance of social factors as predictors of mortality, this study showed the relevant role of the absence of visits from friends and family in people living alone, compared to other structural aspects of social connectedness. The authors conclude that the combined assessment of social connectedness factors may be useful to identify populations at higher risk. 

Unlike previous studies, this one has a sample of over 450,000 UK adults followed for over 10 years. This has allowed the authors to analyse not only various components of social connectedness in mortality, but also to consider other possible factors that might influence this association. Despite the above, the sample analysed is not representative of the UK population, so generalising the results to other populations would require testing. In addition, the measures used to assess the different social components may not have captured their complexity, severity or intensity.