The Economic Effects of Facebook.
In countries such as Norway and Sweden, single-person households were rare a century ago, but today they account for nearly half of all households.
The bulk of evidence from observational studies and biological mechanisms, described above, implies that loneliness most likely matters for our health and well being.
The idea was to track the development of a group of teenage boys through periodic interviews and medical checkups, with the aim of understanding how their health and well-being evolved as they grew up.
Three-quarters of people in the 10 most developed countries own a smartphone.
So, yes, in rich countries we find that younger people are more likely to report feeling lonely.
Their study does not provide the raw data, but in general, a scatter plot with correlation 0.
The top 20% of smartphone users worldwide use their phones for more than 4.