Alzheimer's disease and related dementias (ADRD) is a growing public health crisis, with an annual global cost of more than $1 trillion US. There has been increasing evidence that social isolation is associated with an increased risk of ADRD, but the links between social lifestyle and other known ADRD risk factors are less well understood.

In the new work, the researchers studied data on 502,506 UK Biobank participants and 30,097 people enrolled in the Canadian Longitudinal Study of Aging. Both studies had questionnaires that included questions about loneliness, frequency of social interaction and social support.