To explore the association between the number of living children and dementia among older adults, as well as the influence of social support and lifestyle on this association.

This study included 6 232 participants aged ≥65 years from the Hubei Memory and Aging Cohort, categorized by number of living children (0, 1-2, ≥3). Multivariable logistic regression was used to analyze the associations with dementia, stratified by residence, sex, education level, and personal monthly income, while also examining the modifying effects of social support and lifestyle habits.

Compared to older adults with 1-2 living children, those with no living children (OR=1.705, 95% CI: 1.205-2.412) and ≥3 living children (OR=1.344, 95% CI:1.030-1.753) had an increased risk of dementia. Stratified analysis revealed that compared with elderly people with 1-2 living children, those without living children in rural areas (OR=2.392, 95% CI: 1.544-3.707), males (OR=2.013, 95% CI: 1.190-3.404), females (OR=1.854, 95% CI: 1.094-3.144), those with low education levels (OR=1.859, 95% CI: 1.278-2.702), and those with low personal monthly income (OR=1.802, 95% CI: 1.211-2.682) had significantly higher risks of dementia. Among older adults with ≥3 living children, urban residents (OR=2.677, 95% CI: 1.557-4.603), males (OR=2.058, 95% CI: 1.259-3.363), those with higher education levels (OR=2.550, 95% CI: 1.298-5.009), and those with higher personal monthly income(OR=2.424, 95% CI: 1.096-5.361) all showed significantly elevated risks of dementia. Compared to older adults with poor social support and unhealthy lifestyles, the overall population with good social support (OR=0.569, 95% CI: 0.453-0.716) and healthy lifestyles (OR=0.485, 95% CI: 0.381-0.618) showed significantly lower dementia risk. Among childless older adults, those maintaining healthy lifestyles demonstrated even greater risk reduction (OR=0.515, 95% CI: 0.276-0.960). Among those with ≥3 living children, both good social support (OR=0.410, 95% CI: 0.306-0.549) and healthy lifestyles (OR=0.419, 95% CI: 0.307-0.573) were associated with the most substantial protective effects against dementia.

Older adults with no living children or ≥3 living children had significantly higher dementia risk compared to those with 1-2 living children. Compared with the elderly with 1-2 living children, the elderly in rural areas, males, females, with low education levels and low monthly personal income without living children, and urban elderly with ≥3 living children, males, and those with higher education levels and high monthly personal income had a higher risk of developing dementia. Good social support and healthy living habits were associated with a lower risk of dementia in the ungrouped population and elderly people with multiple children. Moreover,healthy living habits were also associated with a lower risk of dementia in the elderly without living children. No significant association was observed among those with 1-2 living children.