Does Motherhood Influence Brain Aging? New Research Suggests A Positive Cognitive Association

New longitudinal grounds suggests reproductive history whitethorn style women’s cognitive aging, offering insights into imaginable protective pathways while highlighting nan request for cautious interpretation.

Study: Pregnancy and breastfeeding are associated pinch little later-life cognitive diminution successful a longitudinal, prospective cohort. Image Credit: ibragimova / Shuttertock

A caller study published successful nan journal Alzheimer’s & Dementia recovered that breastfeeding and gestation are associated pinch higher later-life cognitive scores complete clip alternatively than needfully slower cognitive decline, though nan objective value of these humble differences remains uncertain.

Background: Pregnancy, Lactation, and nan Female Brain

Female mammals, including humans, acquisition structural and functional encephalon changes during gestation and lactation that hole them for motherhood. However, nan semipermanent consequences of these changes for neurodegenerative illness consequence aliases cognitive resilience stay unclear. Females often acquisition cognitive deficits, peculiarly successful verbal memory, during pregnancy, which whitethorn persist for up to 32 weeks postpartum.

Despite these short-term effects, semipermanent outcomes of motherhood look much favourable for later-life cognitive trajectories, though findings crossed studies are mixed. Postmenopausal females who breastfed person been reported to show superior cognitive capacity compared pinch those who ne'er breastfed for astatine slightest 1 month. Rodent studies besides show some short- and semipermanent cognitive benefits of motherhood that accumulate crossed pregnancies and persist into later life. Conversely, immoderate observational studies person reported detrimental cognitive effects associated pinch breastfeeding, highlighting ongoing uncertainty.

Study Design and Data Sources

In this study, researchers examined whether greater vulnerability to gestation and breastfeeding was associated pinch amended later-life cognitive trajectories alternatively than definitively slower decline. Data were drawn from nan Women’s Health Initiative Memory Study (WHIMS) and nan Women’s Health Initiative Study of Cognitive Aging (WHISCA).

WHIMS enrolled dementia-free postmenopausal females aged 65 to 79 years betwixt 1995 and 1998. WHISCA included participants aged 66 to 84 years, drawn from WHIMS, who underwent yearly assessments of temper and cognitive function. Participants pinch less than 2 cognitive assessments aliases who developed dementia wrong 1 twelvemonth of baseline were excluded. Reproductive history information were obtained done retrospective baseline interviews.

Exposure Measures: Pregnancy and Breastfeeding History

The superior exposures were full clip pregnant and full clip breastfeeding. Secondary exposures included nan breastfeeding-to-pregnancy ratio (BF:PREG), gravidity (ever versus ne'er pregnant), and breastfeeding history (ever versus never). Total clip pregnant was defined arsenic nan cumulative life months of pregnancy, including estimated durations for non-livebirth pregnancies based connected standardized assumptions. Total clip breastfeeding was calculated arsenic nan sum of months of breastfeeding crossed nan lifespan.

The BF:PREG ratio was calculated arsenic nan number of children breastfed divided by nan number of pregnancies and was treated arsenic a continuous variable. Values whitethorn transcend 1, reflecting variability successful breastfeeding long crossed pregnancies alternatively than a strict proportionality.

Cognitive Outcomes and Statistical Analysis

Outcomes included world cognition, verbal memory, and ocular memory. Global cognitive usability was assessed successful WHIMS utilizing nan modified Mini-Mental State Examination (3MS). Verbal and ocular representation were assessed successful WHISCA utilizing nan California Verbal Learning Test long-delay free callback and nan Benton Visual Retention Test, respectively.

Linear mixed-effects models were utilized to analyse associations betwixt reproductive exposures and cognitive outcomes. Minimally adjusted models included property and education, while afloat adjusted models additionally accounted for race, income, apolipoprotein E ε4 bearer status, estrogen therapy use, and mixed estrogen-progesterone therapy. Reciprocal accommodation for parity aliases breastfeeding history was applied to estimate independent effects.

Participant Characteristics and Follow-Up

The study included 6,083 participants from WHIMS and 1,935 from WHISCA, pinch follow-up of 10.4 and 8.4 years, respectively. Most participants were White, joined aliases partnered, and not Hispanic aliases Latino. Approximately 7.1 percent had ne'er been pregnant, and 9 percent had ne'er knowledgeable a full-term pregnancy. The mean number of pregnancies was 3.8, corresponding to a mean full gestation long of 30.5 months.

Breastfeeding history varied substantially. Forty-four percent of participants ne'er breastfed for much than 1 month; among those who did, nan mean full long of breastfeeding was 11.6 months.

Key Findings: Pregnancy, Breastfeeding, and Cognitive Scores

Pregnancy and breastfeeding were associated pinch higher cognitive scores crossed follow-up alternatively than pinch slower rates of cognitive decline. In afloat adjusted models, each further period of gestation was associated pinch a 0.01-point summation successful world cognition scores.

Total clip pregnant was not associated pinch ocular aliases verbal memory. In contrast, each further period of breastfeeding was associated pinch 0.01-0.02-point increases successful world cognition, ocular memory, and verbal representation scores. Ever-pregnant participants had a 0.6-point higher world cognition people compared pinch those who were ne'er pregnant.

Participants who breastfed for astatine slightest 1 period had 0.19- and 0.27-point higher world cognition and verbal representation scores, respectively, than those who ne'er breastfed. Associations pinch ocular representation did not scope statistical significance. Each portion summation successful nan BF:PREG ratio was associated pinch 0.24-, 0.38-, and 0.54-point higher world cognition, ocular memory, and verbal representation scores, respectively. Although statistically significant, these effect sizes were modest.

Conclusions and Interpretation

A greater number of pregnancies, longer breastfeeding duration, and higher BF:PREG ratios were associated pinch amended world cognitive capacity successful postmenopausal females. Associations pinch representation domains were little consistent, pinch affirmative findings chiefly linked to breastfeeding and nan BF:PREG ratio alternatively than gestation alone.

Given nan observational design, these findings should not beryllium interpreted arsenic causal. Residual confounding and reverse causation stay possible. The predominantly White, United States-based cohort limits generalisability, and nan results should not pass reproductive decision-making. Future investigation should analyse biologic mechanisms linking reproductive history to later-life cognitive wellness and find whether these humble people differences construe into clinically meaningful protection against dementia.