BACKGROUND: Findings on the link between the number of children and dementia risk are inconsistent, mostly studied in females, suggesting pregnancy-related changes may be a key factor in this association. METHODS: The Adult Changes in Thought Study is a cohort of adults aged ≥65 years from Kaiser Permanente Washington. The primary exposure was the number of children (0, 1, 2, 3 or ≥4), and the outcome was an incident dementia diagnosis. Cox proportional-hazards models were adjusted for demographic and early-life socioeconomic confounders. Models were then stratified by sex and by birth year <1928 versus ≥1928. RESULTS: Among 4668 participants (average age at enrolment 74.1±SD 6.3 years; 59% female), 967 (21%) had 0 children, 484 (10%) had one child, 1240 (27%) had two children, 968 (21%) had three children and 1009 (22%) had four or more children. We found no association between the number of children and dementia overall or after stratification by birth cohort. When stratified by sex and adjusting for confounders, having ≥4 children compared with two children was associated with a higher rate of dementia in males (HR=1.31, 95% CI 1.01 to 1.71). CONCLUSIONS: The number of children was not consistently associated with the risk of dementia. We observed a greater risk of dementia only among males who had ≥4 children, with the lower bound of the 95% CI marginally exceeding 1. These findings suggest that the number of children may influence the risk of dementia through other than pregnancy-related pathways.

Department of Biostatistics Brown University School of Public Health Providence Rhode Island USA

Department of Epidemiology 2nd Faculty of Medicine Charles University Prague Czech Republic

Department of Epidemiology Columbia University New York New York USA

Department of Medicine University of Washington Seattle Washington USA

Department of Neurology Columbia University New York New York USA

Department of Psychiatry and Medical Psychology 3rd Faculty of Medicine Charles University Prague Czech Republic

Department of Social and Behavioral Sciences New York University School of Global Public Health New York New York USA

Herbert Wertheim School of Public Health and Human Longevity Science UC San Diego La Jolla California USA

Zobrazit více v PubMed

2020 Alzheimer’s disease facts and figures. Alzheimer’s & Dementia 16, 391–460, doi:10.1002/alz.12068 (2020). PubMed DOI

Mielke MM, Vemuri P & Rocca WA Clinical epidemiology of Alzheimer’s disease: assessing sex and gender differences. Clin Epidemiol 6, 37–48, doi:10.2147/clep.S37929 (2014). PubMed DOI PMC

Nebel RA et al. Understanding the impact of sex and gender in Alzheimer’s disease: A call to action. Alzheimers Dement 14, 1171–1183, doi:10.1016/j.jalz.2018.04.008 (2018). PubMed DOI PMC

Mielke MM Sex and Gender Differences in Alzheimer’s Disease Dementia. Psychiatr Times 35, 14–17 (2018). PubMed PMC

von Saenger I, Dahlberg L, Augustsson E, Fritzell J & Lennartsson C Will your child take care of you in your old age? Unequal caregiving received by older parents from adult children in Sweden. Eur J Ageing 20, 8, doi:10.1007/s10433-023-00755-0 (2023). PubMed DOI PMC

Bae JB et al. Does parity matter in women’s risk of dementia? A COSMIC collaboration cohort study. BMC Med 18, 210, doi:10.1186/s12916-020-01671-1 (2020). PubMed DOI PMC

Jung JH et al. Multiparity, Brain Atrophy, and Cognitive Decline. Front Aging Neurosci 12, 159, doi:10.3389/fnagi.2020.00159 (2020). PubMed DOI PMC

Peterson A & Tom SE A Lifecourse Perspective on Female Sex-Specific Risk Factors for Later Life Cognition. Curr Neurol Neurosci Rep 21, 46, doi:10.1007/s11910-021-01133-y (2021). PubMed DOI PMC

Adkins-Jackson PB et al. The structural and social determinants of Alzheimer’s disease related dementias. Alzheimer’s & Dementia 19, 3171–3185, doi:10.1002/alz.13027 (2023). PubMed DOI PMC

Gemmill A & Weiss J The Relationship Between Fertility History and Incident Dementia in the U.S. Health and Retirement Study. J Gerontol B Psychol Sci Soc Sci 77, 1118–1131, doi:10.1093/geronb/gbab183 (2022). PubMed DOI

Gong J, Harris K, Peters SAE & Woodward M Reproductive factors and the risk of incident dementia: A cohort study of UK Biobank participants. PLoS Med 19, e1003955, doi:10.1371/journal.pmed.1003955 (2022). PubMed DOI PMC

Mayeda ER & Shaw C Algorithmic dementia classification: promises and challenges. Am J Epidemiol, doi:10.1093/aje/kwad003 (2023). PubMed DOI

Tom SE et al. Association of Demographic and Early-Life Socioeconomic Factors by Birth Cohort With Dementia Incidence Among US Adults Born Between 1893 and 1949. JAMA Netw Open 3, e2011094, doi:10.1001/jamanetworkopen.2020.11094 (2020). PubMed DOI PMC

Nargund G Declining birth rate in Developed Countries: A radical policy re-think is required. Facts Views Vis Obgyn 1, 191–193 (2009). PubMed PMC

Kukull WA et al. Dementia and Alzheimer Disease Incidence: A Prospective Cohort Study. Archives of Neurology 59, 1737–1746, doi:10.1001/archneur.59.11.1737 (2002). PubMed DOI

Larson EB et al. Exercise Is Associated with Reduced Risk for Incident Dementia among Persons 65 Years of Age and Older. Annals of Internal Medicine 144, 73–81, doi:10.7326/0003-4819-144-2-200601170-00004 (2006). PubMed DOI

Teng EL et al. The Cognitive Abilities Screening Instrument (CASI): a practical test for cross-cultural epidemiological studies of dementia. Int Psychogeriatr 6, 45–58; discussion 62, doi:10.1017/s1041610294001602 (1994). PubMed DOI

GUZE SAMUELB. Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV). American Journal of Psychiatry 152, 1228–1228, doi:10.1176/ajp.152.8.1228 (1995). DOI

Cermakova P, Formanek T, Kagstrom A & Winkler P Socioeconomic position in childhood and cognitive aging in Europe. Neurology 91, e1602–e1610, doi:10.1212/wnl.0000000000006390 (2018). PubMed DOI PMC

Sommerlad A, Ruegger J, Singh-Manoux A, Lewis G & Livingston G Marriage and risk of dementia: systematic review and meta-analysis of observational studies. J Neurol Neurosurg Psychiatry 89, 231–238, doi:10.1136/jnnp-2017-316274 (2018). PubMed DOI PMC

Maccora J, Peters R & Anstey KJ What does (low) education mean in terms of dementia risk? A systematic review and meta-analysis highlighting inconsistency in measuring and operationalising education. SSM Popul Health 12, 100654, doi:10.1016/j.ssmph.2020.100654 (2020). PubMed DOI PMC

Read SL & Grundy EMD Fertility History and Cognition in Later Life. J Gerontol B Psychol Sci Soc Sci 72, 1021–1031, doi:10.1093/geronb/gbw013 (2017). PubMed DOI PMC

Kim M et al. Cox proportional hazards models with left truncation and time-varying coefficient: Application of age at event as outcome in cohort studies. Biom J 59, 405–419, doi:10.1002/bimj.201600003 (2017). PubMed DOI PMC

VanderWeele TJ Principles of confounder selection. Eur J Epidemiol 34, 211–219, doi:10.1007/s10654-019-00494-6 (2019). PubMed DOI PMC

Schuster NA, Hoogendijk EO, Kok AAL, Twisk JWR & Heymans MW Ignoring competing events in the analysis of survival data may lead to biased results: a nonmathematical illustration of competing risk analysis. Journal of Clinical Epidemiology 122, 42–48, doi:10.1016/j.jclinepi.2020.03.004 (2020). PubMed DOI

Fu C et al. Association of reproductive factors with dementia: A systematic review and dose-response meta-analyses of observational studies. EClinicalMedicine 43, 101236, doi:10.1016/j.eclinm.2021.101236 (2022). PubMed DOI PMC

Gilsanz P et al. Reproductive period and risk of dementia in a diverse cohort of health care members. Neurology 92, e2005–e2014, doi:10.1212/wnl.0000000000007326 (2019). PubMed DOI PMC

Prince MJ et al. Reproductive period, endogenous estrogen exposure and dementia incidence among women in Latin America and China; A 10/66 population-based cohort study. PLoS One 13, e0192889, doi:10.1371/journal.pone.0192889 (2018). PubMed DOI PMC

Geerlings MI et al. Reproductive Period and Risk of Dementia in Postmenopausal Women. JAMA 285, 1475–1481, doi:10.1001/jama.285.11.1475 (2001). PubMed DOI

McLaughlin KA, Weissman D & Bitrán D Childhood Adversity and Neural Development: A Systematic Review. Annu Rev Dev Psychol 1, 277–312, doi:10.1146/annurev-devpsych-121318-084950 (2019). PubMed DOI PMC

Mishra GD, Cooper R, Tom SE & Kuh D Early life circumstances and their impact on menarche and menopause. Womens Health (Lond) 5, 175–190, doi:10.2217/17455057.5.2.175 (2009). PubMed DOI PMC

Tomkinson J Age at first birth and subsequent fertility: The case of adolescent mothers in France and England and Wales. Demographic Research 40, 761–798 (2019).

Ning K et al. Parity is associated with cognitive function and brain age in both females and males. Sci Rep 10, 6100, doi:10.1038/s41598-020-63014-7 (2020). PubMed DOI PMC

Bordone V & Weber D Number of children and cognitive abilities in later life. Vienna Yearbook of Population Research 10, 95–126 (2012).

Bricard D, Legleye S & Khlat M Changes in Smoking Behavior over Family Transitions: Evidence for Anticipation and Adaptation Effects. Int J Environ Res Public Health 14, doi:10.3390/ijerph14060610 (2017). PubMed DOI PMC

Skirbekk V Fertility trends by social status. Demographic Research 18, 145–180, doi:https://www.demographic-research.org//volumes/vol18/5/files/StatusFertilityDataset.xls (2008).

Marden JR, Tchetgen Tchetgen EJ, Kawachi I & Glymour MM Contribution of Socioeconomic Status at 3 Life-Course Periods to Late-Life Memory Function and Decline: Early and Late Predictors of Dementia Risk. Am J Epidemiol 186, 805–814, doi:10.1093/aje/kwx155 (2017). PubMed DOI PMC

McGrath ER et al. Blood pressure from mid- to late life and risk of incident dementia. Neurology 89, 2447–2454, doi:10.1212/wnl.0000000000004741 (2017). PubMed DOI PMC

Korhonen K, Einiö E, Leinonen T, Tarkiainen L & Martikainen P Midlife socioeconomic position and old-age dementia mortality: a large prospective register-based study from Finland. BMJ Open 10, e033234, doi:10.1136/bmjopen-2019-033234 (2020). PubMed DOI PMC

Barclay K & Kolk M Parity and Mortality: An Examination of Different Explanatory Mechanisms Using Data on Biological and Adoptive Parents. Eur J Popul 35, 63–85, doi:10.1007/s10680-018-9469-1 (2019). PubMed DOI PMC