Just published this year (2025) was an 18-year study of dementia among more than 24,000 older adults. All of the unmarried adults – whether divorced or widowed or never married – were at lower risk of developing dementia than the married adults. Their risk was at least 50 percent lower. The people who had always been single (never married) had the lowest risk of all, though the difference between them and the other unmarried groups was not statistically significant.