Association Between Sleep Efficiency Variability and Cognition Among Older Adults: Cross-Sectional Accelerometer Study

To investigate whether exposure to secondhand smoke (SHS) aggravates the detrimental effect of vitamin D deficiency (VDD) on cognitive performance in the elderly. Based on National Health and Nutrition Examination Surveys (NHANES) 2011-2014, 1,446 non-smoking participants (≥ 60 years old) with detailed serum 25-hydroxyvitamin D [25(OH)D], concentration of cotinine and tests score of cognitive function were included. Cognitive impairment was defined as having a cognitive score in the lowest quartile. The possible synergistic effect of SHS with VDD on cognitive impairment was evaluated by using a multivariable logistic regression model. VDD was independently associated with risk of low the Digit Symbol Substitution Test (DSST) scores, increased by nearly 60% [< 34, adjusted odds ratio (aOR) = 1.62, 95% CI: 1.03 ~ 2.53]. Although it only had an association with cognitive impairment indicated by DSST and the Animal Fluency test (AFT) in the crude model, SHS exposure showed significant synergistic effects with VDD on DSST (aOR: 3.03, 95% CI: 1.57 ~ 5.83, Pinteraction = 0.001) and AFT (aOR: 2.40, 95% CI: 1.34 ~ 4.29, Pinteraction = 0.003), respectively, after adjusting for the possible confounders. In further stratified analysis, a more obvious synergistic effect of SHS with VDD on DSST (aOR: 4.73, 95%CI:1.77 ~ 12.68, Pinteraction = 0.002) and AFT (aOR: 5.30, 95%CI: 1.63 ~ 17.24, Pinteraction = 0.006) was found in obese and overweight subjects, respectively. SHS exposure had synergistic effect with VDD on cognitive impairment among elderly and the interaction effect was more obvious in overweight and obese individuals.

PurposeThis study evaluated the association between ultra-processed food (UPF) consumption and cognitive performance among older US adults.MethodsThis cross-sectional study assessed 3632 participants aged 60+ years from the National Health and Nutrition Examination Survey (NHANES) 2011–14. Cognitive performance was assessed using the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), Word Learning test, Animal Fluency test, and the Digit Symbol Substitution test (DSST). Dietary intake was assessed using two 24-h diet recalls. Food items were classified according to the NOVA system, a classification based on the nature, extent, and purpose of industrial food processing. Linear regression models were used to evaluate the association of dietary share of UPF (% of daily energy intake) (categorized as tertiles) and cognitive test scores, adjusting for socio-demographic variables, physical activity, smoking status, and chronic diseases (cardiovascular diseases, diabetes, and depression). Models excluding participants with pre-existing diseases were carried out to address potential reverse causality.ResultsOn average, UPF accounted for 53% of total energy intake, ranging from 33 to 70% across extreme tertiles. Inverted U-shape association between UPF consumption and Animal fluency and DSST was observed. No significant associations were observed between the UPF intake tertiles and the cognitive test results. Nonetheless, UPF consumption was significantly associated with worse performance in Animal Fluency in older adults without pre-existing diseases (P < 0.05).ConclusionUPF consumption was associated with worse performance in Animal Fluency among older people without pre-existing diseases. Decreasing UPF consumption may be a way to improve impaired cognition among older adults.

BackgroundPrevious studies had showed that physical activity (PA) can effectively reduce cognitive decline. Nonetheless, it is still unclear whether depression can mediate the relationship between PA and cognitive decline.MethodsThis study encompassed 2,681 older adults (≥ 60 years) from the National Health and Nutrition Examination Survey (NHANES) study during 2011–2012 and 2013–2014 cycles. PA was assessed, including recreation activity, work activity, and walking/bicycling. Depression was evaluated using the Patient Health Questionnaire-9, and cognitive function was assessed through a series of cognitive tests at the Mobile Examination Center. Utilizing weighted multivariable linear regression, we assessed the associations among PA, depression, and cognitive function. Additionally, a mediation model was employed to investigate how depression mediates the relationship between PA and cognitive decline.ResultsWe found that only moderate to high-intensity recreation activity and depression were associated with better cognitive function, including performance on the Animal Fluency Test (AFT), the Digit Symbol Substitution Test (DSST), and the overall cognitive function (composite z-score), following adjustments for potential confounding factors. Depression emerged as a mediator in the relationship of moderate to high-intensity recreation activity with AFT, DSST, and the composite z-score, mediating 6.5%, 12.3%, and 10.5% of the overall association, respectively. Furthermore, in the sensitivity analysis that excluded participants with a history of stroke, the sensitivity analysis results remained consistent and stable.ConclusionThis study found that in older adults, increasing engagement in moderate to high-intensity recreation activity, rather than work activity or walking/bicycling, is related with a reduction in cognitive decline. Notably, depression emerged as a pivotal mediating factor in this relationship.

Patients suffering from periodontitis are at a higher risk of developing cognitive dysfunction. However, the mediation effect of an inflammatory diet and serum vitamin D levels in this link is unclear. In total, 2062 participants aged 60 years or older with complete periodontal diagnosis and cognitive tests from the National Health and Nutrition Examination Survey (NHANES) 2011–2012 and 2013–2014 were enrolled. The Consortium to Establish a Registry for Alzheimer’s disease (CERAD) word learning subtest (WLT) and CERAD delayed recall test (DRT), the animal fluency test (AFT) and the digit symbol substitution test (DSST) was used. Dietary inflammatory index (DII) was computed via nutrition datasets. Mediation analysis tested the effects of DII and vitamin D levels in the association of mean probing depth (PD) and attachment loss (AL) in all four cognitive tests. Periodontitis patients obtained worse cognitive test scores than periodontally healthy individuals. DII was negatively associated with CERAD-WLT, CERAD-DRT, AFT and DSST, and was estimated to mediate between 9.2% and 36.4% of the total association between periodontitis with cognitive dysfunction (p < 0.05). Vitamin D showed a weak association between CERAD-DRT, AFT and DSST and was estimated to between 8.1% and 73.2% of the association between periodontitis and cognitive dysfunction (p < 0.05). The association between periodontitis and impaired cognitive function seems to be mediated both by a proinflammatory dietary load and vitamin D deficiency. Future studies should further explore these mediators in the periodontitis-cognitive decline link.

BackgroundThe Hemoglobin Glycation Index (HGI) quantifies the difference between the actual and expected values of glycosylated hemoglobin (HbA1c), a marker that has been closely linked to various adverse health outcomes. Nonetheless, a significant gap exists in the current literature concerning the association between HGI and cognitive function. This study aims at testing such association in older adults with hypertension, a topic that has not yet been extensively investigated.MethodsA linear regression model between glycated hemoglobin A1c (HbA1c) levels and fasting plasma glucose (FPG) was constructed for the calculation of the HGI. The cross-sectional study focused on evaluating the cognitive function of hypertensive individuals (≥ 60 years old), based on the data from the 2011–2014 National Health and Nutrition Examination Survey (NHANES), by using a series of standardized tests, including the Word List Learning (CERAD-WL) and Delayed Recall (CERAD-DR) tests from the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Weighted logistic and linear regression models served for evaluating the effect of HGI on hypertensive patients’ cognitive function. Restricted cubic spline (RCS) curves assisted in detecting the underlying nonlinear associations between HGI and cognitive outcomes. Furthermore, subgroup analyses and interaction tests were performed to gain deeper insights into these associations.ResultsThe study included 1023 participants ≥ 60 years old from 2011 to 2014 NHANES. Higher HGI was accompanied by lower DSST score (P = 0.009). In the fully adjusted model, participants in the highest quartile (Q4) of HGI possessed a lower DSST score (β = -4.50, 95% CI -8.10– -0.88) versus the lowest quartile (Q1), and were more likely to exhibit low cognitive function as evaluated by the DSST (OR = 2.21, 95% CI 0.98–5.03). According to the results from RCS analysis, HGI presented a linear relevance to cognitive function scores in older adults with hypertension. There is no interaction between HGI and the stratifying variables (sex, age, BMI, alcohol consumption, and smoking status).ConclusionHigh HGI was an important risk factor leading to reduced cognitive performance in hypertensive patients, ensuring HGI to be used for effectively predicting patients’ cognitive decline.

The association of zinc, iron, copper, and selenium intakes with cognitive function is poorly understood so far. To examine the associations of dietary and total zinc, iron, copper, and selenium intakes with low cognitive performance. Cross-sectional study data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 was used. Zinc, iron, copper, and selenium intakes from foods and supplements were estimated from two non-consecutive 24-hour diet recalls. Cognitive function was measured by the Consortium to Establish a Registry for Alzheimer's disease (CERAD) Word Learning sub-test, Animal Fluency test, and Digit Symbol Substitution test (DSST). For each cognitive measurement, people whose score were lower than the age group stratified lowest quartile were defined as low cognitive performance. Logistic regression and restricted cubic spline models were applied to examine the associations of dietary and total zinc, iron, copper, and selenium intakes with different measures of low cognitive performance. A total of 2,332 adults aged 60 years or older were included. The association between zinc, iron, copper, and selenium intake and low cognitive performance was significant in different test. Compared with the lowest quartile of total copper intake, the weighted multivariate adjusted ORs (95% CI) of the highest quartile were 0.34 (0.16-0.75) for low cognitive performance in DSST. L-shaped associations between total copper or selenium and low cognitive performance in DSST and animal fluency were found. Dietary and total zinc, copper, and selenium intakes might be inversely associated with the prevalence of low cognitive performance.

Neurodegenerative diseases pose increasing challenges to global aging populations. Cognitive decline in older adults is an initial indicator of neurodegenerative diseases, yet comprehensive research on environmental chemical exposures related to cognitive decline is limited. This study uses Exposome-Wide Association Study (ExWAS) framework to investigate associations of environmental chemicals with cognitive function in individuals aged ≥60 years. We used the Digit Symbol Substitution Test (DSST) scores and chemical biomarker data of the US National Health and Nutrition Examination Survey (NHANES) spanning four cycles (1999-2000, 2001-2002, 2011-2012, 2013-2014). We conducted multiple survey-weighted regression to identify biomarkers associated with DSST scores, Bayesian weighted quantile sum regression to estimate odds ratio (OR) of cognitive decline from multiple exposures to the identified biomarkers, and correlation network analyses to examine relationships among possible important biomarkers and cognitive decline. After correction for multiple comparisons, among 229 biomarkers having a ≥10% detection rate, 40 were associated with DSST scores (q-value &amp;lt;0.05). When assessing the effects of chemical mixtures on cognitive decline, no association between mixtures of chemicals and DSST scores was observed. Correlation network showed that cognitive decline is directly related with age and education level and identified that thiocyanate, m-/p-xylene, triclosan, benzophenone-3 and diphenyl phosphate were weakly related to cognitive function. In conclusion, leveraging the ExWAS framework enables us to identify chemical biomarkers that were not previously discovered from traditional approaches of examining a small number of chemicals at a time. While our findings provide foundation for further research, longitudinal studies are warranted to elucidate causal relationships.

BackgroundIncreasing evidence from community‐based population cohorts suggests that following healthy dietary patterns is protective against cognitive decline, Alzheimer’s disease, or other dementia in older adults. However, such findings have rarely been confirmed in nationally representative samples.MethodThe current study included 2,864 participants (≥60 years) of the NHANES 2011–2014 who completed both dietary and cognitive assessments. Self‐reported dietary intake was collected by trained interviewers using the USDA’s Automated Multiple‐Pass Method in two nonconsecutive 24‐hour dietary recalls. Intakes of nutrients and food groups were calculated using reference from the USDA 'Food and Nutrient Database for Dietary Studies' and 'Food Patterns Equivalents Database', 2011‐2014, respectively. Mediterranean‐type Diet (MeDi) and Healthy Eating Index 2015 (HEI15) scores were estimated from the mean intakes of the two diet recalls. Cognitive function was measured by the Consortium to Establish a Registry for Alzheimer’s disease Word Learning sub‐test (WL), Animal Fluency test (AF), and Digit Symbol Substitution test (DSST). Age, sex, race/ethnicity adjusted z‐score was calculated for each cognitive score, which were then averaged to get a composite cognitive score. Complex samples plan linear regression models were applied to examine the associations of diet and cognition, adjusted for age, sex, education, race (white/black/Hispanic/others), caloric intake, cycles (2011‐2012 /2013‐2014), and annual household income (&lt; or ≥ $45,000).ResultMeDi and HEI2015 were associated with 0.028 (95%CI=0.004‐0.05, p=0.023) and 0.004 (95%CI=0.0002‐0.007, p=0.038) higher mean cognitive z‐score, respectively. Compared to the lowest tertile of MeDi, the highest tertile of MeDi was associated with 0.141 (95%CI=0.029‐0.253, p=0.015; p‐trend=0.016) higher mean cognitive z‐score. Compared to the lowest tertile, the highest MeDi tertile was associated with 1.001 (95%CI=0.161‐1.840, p=0.021; p‐trend=0.021), 1.05 (95%CI=0.227‐1.875, p=0.014; p‐trend=0.015) and 3.02 (95%CI=1.004‐5.027, p=0.005; p‐trend=0.004) higher WL, AF, and DSST, respectively, and the highest HEI15 tertile was associated with 0.827 (95%CI=0.154‐1.499, p=0.018; p‐trend=0.018) higher AF. The effect size of the highest tertile of dietary score was approximately equivalent to 3‐4 less years of aging (b of 1‐year aging=‐0.316, ‐0.229, and ‐0.867 for WL, AF, and DSST, respectively).ConclusionFollowing a healthy diet is associated with better cognitive performance in a nationally representative sample of older adults.

Introduction: This study aimed to assess the association of Geriatric Nutritional Risk Index (GNRI) with cognitive function level and cognitive impairment risk among older adults with cardiometabolic disease using data from the National Health and Nutrition Examination Survey (NHANES). Methods: Using cross-sectional data from the NHANES, this research included 1,937 participants aged 60 years or older with at least one cardiometabolic disease (diabetes, hypertension, stroke, or congestive heart failure). Cognitive function was assessed using the CERAD tests, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). Multivariable linear and logistic regression analyses were used to estimate the β coefficients and odds ratios (ORs) with 95% confidence intervals (CIs) for the associations of GNRI with cognitive function level and risk of cognitive impairment. Results: A total of 1937 participants aged≥60 years with cardiometabolic disease were included. The results showed that per 1-SD increase in GNRI was associated with increased cognitive function levels, including CERAD: Trial 1 (β=0.11, 95% CI: 0.03-0.19), CERAD: Trial 3 (β=0.12, 95% CI: 0.04-0.21), CERAD: Delayed Recall (β=0.21, 95% CI: 0.11-0.32), CERAD test (β=0.53, 95% CI: 0.23-0.82), and AFT (β=0.34, 95% CI: 0.11-0.57) scores. Restricted cubic splines showed significantly positive linear dose-response associations between GNRI and cognitive function. Compared to participants with the lowest quartile (Q1) of GNRI, those with the highest quartile (Q4) had a lower cognitive impairment risk (OR=0.59, 95% CI: 0.41-0.85). Discussion: Potential mechanisms underlying GNRI’s protective effect against cognitive impairment may involve the pleiotropic neuroprotection of albumin and body mass index-mediated brain structural changes. Conclusion: Higher GNRI is independently associated with better cognitive function and reduced risk of cognitive impairment in older adults with cardiometabolic diseases. To mitigate cognitive risk, implementing GNRI screening may identify high-risk older adults with cognitive impairment, prompting timely nutritional support that improves cognitive health and disease management.

Sleep quality in patients studied with laboratory-based polysomnography may differ from sleep quality in patients studied at home but remains clinically relevant and important to describe. We assessed objective sleep quality and explored factors associated with poor sleep in patients undergoing laboratory-based polysomnography. We reviewed diagnostic polysomnography studies from a 10-year period at a single sleep center. Total sleep time (TST) and sleep efficiency (SE) were assessed as markers of sleep quality. Poor sleep was defined as TST ≤ 4 hours or SE ≤ 50%. Multivariable analysis was performed to determine associations between objective sleep quality as an outcome and multiple candidate predictors including age, sex, race, body mass index, comorbidities, severity of obstructive sleep apnea, and central nervous system medications. Among 4957 patients (age 53 ± 15 years), average TST and median SE were 5.8 hours and 79%, respectively. There were 556 (11%) and 406 (8%) patients who had poor sleep based on TST and SE, respectively. In multivariable analysis, those who were older (per 10 years: 1.48 [1.34, 1.63]), male (1.38 [1.14,1.68]), and had severe obstructive sleep apnea (1.76 [1.28, 2.43]) were more likely to have short sleep. Antidepressant use was associated with lower odds of short sleep (0.77 [0.59,1.00]). Older age (per 10 years: 1.48 [1.34, 1.62]), male sex (1.34 [1.07,1.68]), and severe obstructive sleep apnea (2.16 [1.47, 3.21]) were associated with higher odds of poor SE. We describe TST and SE from a single sleep center cohort. Multiple demographic characteristics were associated with poor objective sleep in patients during laboratory-based polysomnography. Harrison EI, Roth RH, Lobo JM, et al. Sleep time and efficiency in patients undergoing laboratory-based polysomnography. J Clin Sleep Med. 2021;17(8):1591-1598.

Objective: Current evidence on the association between serum testosterone and cognitive performance has been inconsistent, especially in older adults. To investigate the associations between serum testosterone and cognitive performance in a nationally representative sample of older men and women.Methods: We used data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014. 1,303 men and 1,349 women aged 60 years or older were included in the study. Serum total testosterone was preformed via isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) method. Free testosterone was calculated by Vermeulen’s formula. Cognitive performance was evaluated by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) test, Animal Fluency test, and Digit Symbol Substitution Test (DSST). Binary logistic regression and restricted cubic spline models were applied to evaluate the association of testosterone and cognitive performance.Results: In men, higher concentrations of total testosterone were associated with better performance on CERAD test (OR = 0.51; 95%CI = 0.27–0.95) and DSST (OR = 0.54; 95%CI = 0.30–0.99) in adjusted group. Similarly, higher concentrations of free testosterone were associated with better performance on CERAD test (OR = 0.32; 95%CI = 0.17–0.61) and DSST (OR = 0.41; 95%CI = 0.17–0.96) in men. These associations were not seen in women.Conclusion: Serum testosterone concentrations were inversely associated with cognitive performance in older men but not women in the United States.

PurposePrevious studies suggest an association between chronic kidney disease (CKD) and cognitive impairment. The purpose of this study was to explore the association between the diverse stages of CKD and the cognitive performance of elderly American adults.MethodsData from the National Health and Nutrition Examination Survey (NHANES) 2011–2014 were used. Multivariate adjusted logistic regression, subgroup analysis, and the restricted cubic spline model were used to assess the associations of CKD stage and estimated glomerular filtration rate (eGFR) with cognitive performance. The measures used to evaluate cognitive function included the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) test, the Animal Fluency test, and the Digit Symbol Substitution test (DSST).ResultsThis study included 2234 participants aged ≥ 60 years. According to the fully adjusted model, stages 3–5 CKD were significantly associated with the CERAD test score (OR = 0.70, 95% CI [0.51, 0.97], p = 0.033), the Animal Fluency test score (OR = 0.64, 95% CI [0.48, 0.85], p = 0.005), and the DSST score (OR = 0.60, 95% CI [0.41, 0.88], p = 0.013). In addition, the incidence of poor cognitive function increased with decreasing eGFR, especially for individuals with low and moderate eGFRs. Both the DSST score (p nonlinearity < 0.0001) and the Animal Fluency test score (p nonlinearity = 0.0001) had nonlinear dose–response relationships with the eGFR. However, a linear relationship was shown between the eGFR and CERAD test score (p nonlinearity = 0.073).ConclusionsCKD, especially stages3–5 CKD, was significantly associated with poor cognitive performance in terms of executive function, learning, processing speed, concentration, and working memory ability. All adults with CKD should be screened for cognitive impairment.

The impact of vitamin B2 (riboflavin) intake on cognitive performance among older adults in the United States (US) remains inadequately understood. This study aimed to explore the association between vitamin B2 intake and cognitive performance among non-institutionalized elderly people in the US. Weighted logistic regression was used to evaluate the association between vitamin B2 intake and cognitive performance. Vitamin B2 intake was determined from the mean of two 24-hour dietary recall interviews. Three cognitive ability assessment tests, namely the Immediate Recall Test (IRT), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST), were performed. Participants included all older adults over 60 who underwent cognitive scoring, with cut-offs defined based on the lowest quartile (25th percentile) for each test (the cut-offs for the three scores were 15.625, 12, and 33, respectively). Sensitivity analysis, including dose-response curves, subgroup analyses, interaction effects, per 1 standard deviation (SD), recommended dietary allowance (RDA), and residual energy model analysis, were performed to solidify the solid association between vitamin B2 and cognitive performance. A total of 2893 individuals aged over 60 were included, with a mean age of 69 (7) years, and 46% were men. There was a significant association between vitamin B2 intake and all three cognitive scores (IRT, Odds Ratio = 0.77, 95% confidence interval: [0.65,0.92]; AFT, 0.75, [0.64,0.88]; DSST, 0.72, [0.59,0.88]). Moreover, vitamin B2 intake above the RDA reduced the risk of low cognitive performance (IRT, 0.66, [0.46,0.93]; AFT, 0.83, [0.62,1.11]; DSST, 0.65, [0.45,0.92]) compared to intake below the RDA. Dose-response curves indicated that higher vitamin B2 intake was negatively associated with the risk of low cognitive performance. Physical activity may modify the association between vitamin B2 and cognitive performance. Vitamin B2 intake was positively associated with cognitive performance among older adults. Adequate vitamin B2 intake could help protect cognitive function.

Association between caffeine intake and cognitive function in adults; effect modification by sex: Data from National Health and Nutrition Examination Survey (NHANES) 2013-2014.

ABSTRACTBackgroundPopulation aging is intensifying worldwide, increasing the prevalence of dementia. More than 50 million people globally are affected by dementia. There is some evidence that physical activity (PA) benefits cognitive function (CF). However, it is unclear which types and amounts of PA are best for specific cognitive domains.MethodsThis study used a cross‐sectional design and genetic analysis to test its hypotheses. Participants were drawn from the National Health and Nutrition Examination Survey (NHANES) 2011–2014, including 2578 adults aged 60 years or older. Cognitive abilities were measured using standardized tests, and PA levels were assessed with the Global Physical Activity Questionnaire (GPAQ). The analysis included multivariable regression, threshold effect testing, and subgroup analysis to explore links between PA patterns, intensities, and specific CF domains. Furthermore, a Mendelian randomization (MR) approach was employed to assess whether PA intensity exerts an effect on CF.ResultsNHANES data analysis showed that the regular activity (RA) pattern was positively associated with the Consortium to Establish a Registry for Alzheimer's Disease Word Learning test (CERAD‐WL) scores (β = 0.07; 95% confidence interval [CI]: 0.02, 0.16; p = 0.018), Animal Fluency Test (AFT) scores (β = 0.31; 95% CI: 0.21, 0.41; p = 0.002), Digit Symbol Substitution Test (DSST) scores (β = 0.19; 95% CI: 0.09, 0.30; p = 0.017), and overall CF (β = 0.23; 95% CI: 0.14, 0.32; p < 0.004). Threshold‐effect analysis revealed an inverted U‐shaped relationship between PA levels and cognitive performance. The inflection points occurred at 650, 535, and 550 min per week for AFT, DSST, and overall CF, respectively. Above these values, further cognitive gains plateaued. The inverse‐variance weighted (IVW) method of the MR analyses showed that moderate‐intensity physical activity (MPA) increased correct counting (odds ratio [OR] = 0.710; 95% CI: 0.606, 0.832; p < 0.001), fluid intelligence (OR = 0.470; 95% CI: 0.346, 0.638; p < 0.001), and overall cognitive performance (OR = 0.707; 95% CI: 0.653, 0.764; p < 0.001). For vigorous‐intensity physical activity (VPA), we observed causal associations with memory outcomes, reaction time, correct matches, fluid intelligence, and cognitive performance.ConclusionThe findings suggest that PA is associated with multiple domains of CF, and the RA pattern is linked to better cognitive performance. Genetically, VPA appears to have a stronger promotive effect. Thus, different patterns and intensities of PA may help delay cognitive decline and maintain brain health in older adults.