The relationship between the number of children and dementia risk is gaining attention, based on a recent publication posted on the site of the Norwegian Institute of Public Health (provided below). The study suggests that having two or three children may reduce dementia risk compared to having none, one, or four or more children. This Directors Digest examines the implications of these findings for healthcare policy and system dynamics.

Decoding the Children-Dementia Connection

Dementia affects millions globally, with numbers expected to rise as populations age. The 2020 Lancet Commission highlights that 40% of late-onset dementia cases could be prevented by addressing modifiable factors. Among these, the number of children has emerged as a potential factor influencing dementia risk. Studies show a U-shaped risk curve, with increased risk for those with no children, one child, or four or more children, compared to those with two or three children.

Unveiling the Complexities

The study’s methodology has limitations. It does not account for time-varying exposures, which may lead to biased estimates. Also, the assumption of no unmeasured confounding is challenging, given the complex interplay of factors influencing dementia risk.

The mechanisms by which the number of children impacts dementia risk remain unknown. While having children may be neuroprotective, this effect is not observed for those with one child or no children, and is even less so for those with four or more children. The optimal number appears to be two or three children, but the specific combination of mediating factors and additional variables that contribute to this reduced risk remains unidentified.

Socioeconomic, psychosocial, lifestyle, and chronic disease factors were considered but did not mediate the relationship between the number of children and dementia risk. This suggests the presence of unmeasured factors, such as quality of life, diet, sleep, and social support, which may vary by the number of children and influence dementia risk.

Strategic Implications for Policymakers

Given the methodological weaknesses and unknown mechanisms, policymakers should exercise caution in basing policies on these findings. While the study provides valuable insights, it is not sufficient to inform policy decisions without further research.

There is a critical need for in-depth research to explore the underlying mechanisms linking the number of children to dementia risk. Longitudinal studies with comprehensive data collection on potential mediating factors are essential to provide a clearer understanding of this relationship.

Healthcare systems should focus on modifiable risk factors for dementia prevention, while remaining open to new insights from ongoing research. Healthcare systems should tailored interventions to the unique needs of individuals based on their family size and associated risks.

Charting the Path Forward

The relationship between the number of children and dementia risk presents a complex challenge for healthcare systems and policymakers. While the findings offer intriguing insights, the methodological weaknesses and unknown mechanisms highlight the need for cautious interpretation and further research. As the global population ages, understanding and addressing the factors influencing dementia risk will be crucial in shaping effective healthcare policies and strategies. Future research should continue to explore this relationship, providing a foundation for informed decision-making and policy development.

Healthcare professionals and policymakers are encouraged to consider these findings in their strategic planning and to support further research in this area. By doing so, we can enhance our understanding of dementia risk factors and develop more effective prevention strategies.

Resources

1. Norwegian Institute of Public Health. New study links number of children to dementia risk. Norwegian Institute of Public Health (2025) https://www.fhi.no/en/news/2025/new-study-links-number-of-children-to-dementia-risk/ [Accessed March 2, 2025]
2. Mekonnen T, Skirbekk V, Zotcheva E, Engdahl B, Bratsberg B, Jugessur A, Bowen C, Selbæk G, Kohler H-P, Harris JR, et al. Number of children and dementia risk: a causal mediation analysis using data from the HUNT study linked with national registries in Norway. BMC Neurology (2025) 25:39. doi: 10.1186/s12883-025-04044-4