Serum 25-hydroxyvitamin D and cognitive decline: a longitudinal study among non-demented older adults

Vitamin D status and cognitive performance in community-dwelling adults: A dose-response meta-analysis of observational studies

Low vitamin D status is linked with poorer cognition in adults while findings in relation to high levels are mixed.We performed a systematic review and meta-analyses to examine dose-response associations between 25-hydroxyvitamin D (25OHD) levelsand cognitive performance in community-dwelling adults. Thirty-eight observational studies were included in dose-response meta-analyses. Positive, nonlinear associations were identified between baseline25OHD levels and global cognition incross-sectional and longitudinal analyses, and for performance in memory and executive function in longitudinal analyses. When restricted to studies involving older adults, thepattern emerged forspecific domains in cross-sectional analyses. Poorer performance was associated with low 25OHD levels, while a sharp improvement was associated withlevels up to 60-70 nM/L. Further improvement was observed only for longitudinal global cognition. Our findings support the association between low vitamin D and poorer cognition and suggest levels of at least 60 nM/L are associated with better cognition during ageing.

Musical and psychomotor interventions for cognitive, sensorimotor, and cerebral decline in patients with Mild Cognitive Impairment (COPE): a study protocol for a multicentric randomized controlled study

BACKGROUND

Regular cognitive training can boost or maintain cognitive and brain functions known to decline with age. Most studies administered such cognitive training on a computer and in a lab setting. However, everyday life activities, like musical practice or physical exercise that are complex and variable, might be more successful at inducing transfer effects to different cognitive domains and maintaining motivation. "Body-mind exercises", like Tai Chi or psychomotor exercise, may also positively affect cognitive functioning in the elderly. We will compare the influence of active music practice and psychomotor training over 6 months in Mild Cognitive Impairment patients from university hospital memory clinics on cognitive and sensorimotor performance and brain plasticity. The acronym of the study is COPE (Countervail cOgnitive imPairmEnt), illustrating the aim of the study: learning to better "cope" with cognitive decline.

METHODS

We aim to conduct a randomized controlled multicenter intervention study on 32 Mild Cognitive Impairment (MCI) patients (60-80 years), divided over 2 experimental groups: 1) Music practice; 2) Psychomotor treatment. Controls will consist of a passive test-retest group of 16 age, gender and education level matched healthy volunteers. The training regimens take place twice a week for 45 min over 6 months in small groups, provided by professionals, and patients should exercise daily at home. Data collection takes place at baseline (before the interventions), 3, and 6 months after training onset, on cognitive and sensorimotor capacities, subjective well-being, daily living activities, and via functional and structural neuroimaging. Considering the current constraints of the COVID-19 pandemic, recruitment and data collection takes place in 3 waves.

DISCUSSION

We will investigate whether musical practice contrasted to psychomotor exercise in small groups can improve cognitive, sensorimotor and brain functioning in MCI patients, and therefore provoke specific benefits for their daily life functioning and well-being.

TRIAL REGISTRATION

The full protocol was approved by the Commission cantonale d'éthique de la recherche sur l'être humain de Genève (CCER, no. 2020-00510) on 04.05.2020, and an amendment by the CCER and the Commission cantonale d'éthique de la recherche sur l'être humain de Vaud (CER-VD) on 03.08.2021. The protocol was registered at clinicaltrials.gov (20.09.2020, no. NCT04546451).

Association between Vitamin D and Cognitive Deficiency in Alcohol Dependence

There are still not enough findings to elucidate how exactly alcohol use impairs cognitive abilities. Some studies have shown that there is a link between alcohol intake and vitamin D levels, but these findings are inconsistent so further research is needed. The aim of this study was to investigate the association between serum vitamin D levels and cognitive impairment in alcohol-dependent individuals. A case-control study was carried out including a total of N = 132 respondents with a medical history of alcoholism, and healthy volunteers. The Montreal Cognitive Assessment (MoCa) and Addenbrooke’s Cognitive Examination-Revised (ACE-R) screening tools were used for cognitive status assessment and serum vitamin D levels analysis (blood samples of respondents). Significant difference (p = 0.022), was found in vitamin D levels in the alcohol-dependent group with cognitive deficiency 13.7 ± 9.4 (ng/mL), alcohol-dependent group without cognitive deficiency 19.5 ± 11.2 (ng/mL) and healthy controls 19.9 ± 11.1 (ng/mL), respectively. Furthermore, vitamin D levels were significantly different across all groups based on MoCa (p = 0.016) and ACE-R (p = 0.004) scores. All three groups exhibited vitamin D deficiency. A significant correlation was found between vitamin D deficiency and cognitive impairment, but it yielded no significant difference in alcohol-dependent individuals.

Characterization of Vitamin D Status in Older Persons with Cognitive Impairment

Vitamin D exerts a role in the maintenance of cognitive abilities and in frailty. Although several studies evaluated the interactions between vitamin D and cognitive impairment, results were conflicting. In a cohort of community-dwelling older persons, we described the association between vitamin D levels and cognitive decline and all-cause dementia evaluating frailty’s contribution. Our cohort included 509 adults, aged 64–92 years: 176 patients with mild cognitive impairment (MCI), 59 with Alzheimer’s Disease (AD), 26 with idiopathic Normal Pressure Hydrocephalus (iNPH), 133 with mixed dementia (MD) and 115 without cognitive decline. Frailty was measured by frailty index, and serum 25-hydroxyvitamin D concentrations through electrochemiluminescence immunoassays. We found a significant association between vitamin D levels and Mini Mental State Examination independently of cognitive impairment, age, sex and frailty. The patients with dementia (AD and MD) showed the lowest vitamin D levels, while MCI patients showed higher levels than the other groups. The most severe deficiency was observed in MD patients, the most aged as well as cognitively and functionally impaired. In conclusion, in our community-dwelling older persons investigated for a suspected cognitive impairment, we observed an association between vitamin D levels and cognitive decline, regardless of the frailty status.

Association of vitamin D metabolites with cognitive function and brain atrophy in elderly individuals - the Austrian stroke prevention study

BACKGROUND

Vitamin D is a well-established regulator of calcium and phosphate metabolism that has neurotrophic and neuroprotective properties. Deficiency of vitamin D has been proposed to promote cognitive dysfunction and brain atrophy. However, existing studies provide inconsistent results. Here we aimed to investigate the association between vitamin D metabolites, cognitive function and brain atrophy in a cohort of well-characterized community-dwelling elderly individuals with normal neurological status and without history of stroke and dementia.

METHODS

25(OH)D3, 25(OH)D2 and 24,25(OH)2D3 were measured by liquid-chromatography tandem mass-spectrometry in serum samples from 390 community-dwelling elderly individuals. All participants underwent thorough neuropsychiatric tests capturing memory, executive function and visuopractical skills. In 139 of these individuals, MRI of the brain was performed in order to capture neurodegenerative and vascular changes.

RESULTS

Total 25(OH)D (ß=0.003, 0.037), 24,25(OH)2D3 (ß=0.0456, p=0.010) and vitamin D metabolite ratio (VMR) (ß=0.0467, p=0.012) were significantly related to memory function. Adjustment for multiple testing weakened these relationships, but trends (p≤0.10) remained. 24,25(OH)2D3 and VMR showed similar trends also for visuopractical skills and global cognitive function. No significant relationships existed between vitamin D metabolites and MRI derived indices of neurodegeneration and vascular changes. Sub-group analyses of individuals with low concentrations of 25(OH)D and 24,25(OH)2D3 showed significantly worse memory function compared to individuals with normal or high concentrations.

CONCLUSIONS

Vitamin D deficient individuals appear to have a modest reduction of memory function without structural brain atrophy. Future studies should explore if vitamin D supplementation can improve cognitive function.

Vitamin D status, cognitive decline and incident dementia: the Canadian Study of Health and Aging

OBJECTIVE

Vitamin D could prevent cognitive decline because of its neuroprotective, anti-inflammatory and antioxidant properties. This study aimed to evaluate the associations of plasma 25-hydroxyvitamin D (25(OH)D) concentrations with global cognitive function and incident dementia, including Alzheimer's disease (AD).

METHODS

The Canadian Study of Health and Aging is a 10-year cohort study of a representative sample of individuals aged 65 years or older. A total of 661 subjects initially without dementia with frozen blood samples and follow-up data were included. Global cognitive function was measured using the validated Modified Mini-Mental State (3MS) examination. A consensus diagnosis of all-cause dementia and AD was made between the physician and the neuropsychologist according to published criteria. Cognitive decline for a 5-year increase in age at specific 25(OH)D concentrations was obtained using linear mixed models with repeated measures. Hazard ratios of incident dementia and AD were obtained using semi-parametric proportional hazards models with age as time scale.

RESULTS

Over a mean follow-up of 5.4 years, 141 subjects developed dementia of which 100 were AD. Overall, no significant association was found between 25(OH)D and cognitive decline, dementia or AD. Higher 25(OH)D concentrations were associated with an increased risk of dementia and AD in women, but not in men.

CONCLUSION

This study does not support a protective effect of vitamin D status on cognitive function. Further research is needed to clarify the relation by sex.

25-OH Vitamin D Levels and Cognitive Performance: Longitudinal Assessment in a Healthy Aging Cohort

Background: Declining serum levels of 25-hydroxyvitamin D [25(OH)D, a biomarker of vitamin D status] with aging is a well-recognized phenomenon. However, scarce information is available on the relation between 25(OH)D levels and cognitive performance over time in older individuals. Our purpose was to evaluate, longitudinally, the association of 25(OH)D with cognitive function in a healthy older adults’ cohort.

Methods: Sixty-four individuals over 55 years-old with no cognitive impairment, clustered as healthy “Poor” and “Good” cognitive performers, were followed for an average of 18 months. Seasonal-adjusted 25(OH)D serum levels (measured by high-performance liquid chromatography-tandem mass spectrometry) were related, longitudinally, with cognitive (memory and general/executive) composite scores.

Results: Overall seasonal-adjusted median serum 25(OH)D level was of 47 nmol/l [interquartile range (IQR), 38–60 nmol/l]. A negative correlation between baseline 25(OH)D and the general/executive composite score was found in the “Poor” cognitive performers (r^s = −0.52, p = 0.006), an association lost after adjusting 25(OH)D levels for the season. No effect was found in both groups between seasonal-adjusted 25(OH)D levels and the variation of both memory and general/executive composites during follow-up when adjusted for age, gender and education level.

Conclusion: In this healthy older population with no cognitive impairment, lower serum levels of 25(OH)D were not longitudinally associated with poorer cognitive scores.

Relation between vitamin D and geriatric syndrome

BACKGROUND

Vitamin D level is a common health problem for elderly persons and it is associated with a decrease in physical performance, furthermore, it has been demonstrated that those with low serum vitamin D level has more risk of cognitive impairment, depression and anxiety.

AIM

The aim of the study was to estimate relation of vitamin D and geriatric syndrome.

METHODS

A prospective study was done on 50 subjects who were normal elderly persons above 65 years. All the participants were subjected to full history taking, complete physical examination, laboratory assessment including serum 25-hydroxyvitamin D (OH)D by enzyme linked immunosorbent assay (ELISA) and geriatric syndrome assessment using 5 methods namely fall risk assessment using timed up &go test, mini-mental state examination (MMSE), geriatric depressive scale, mini nutritional assessment and Tinetti performance - oriented mobility assessment (POMA).

RESULTS

The number of patients who were vitamin D deficient (<12 ng/ml), insufficient (12-20 ng/ml) and sufficient (>20 ng/ml) were 11, 24 and 15 respectively. There was significant p association between low vitamin D level and female gender (p = 0.024), advanced age (p = 0.026), no-sun exposure jobs (p = 0.001) and nursing home residency. Mini mental state examination (p = 0.006) and geriatric depressive scale (p = 0.002) had a significant positive correlation with low vitamin D level while mini nutritional assessment (p = 1.000), timed up and go test (p = 0.225) and POMA score (p = 0.133) had no significant correlation with low vitamin D level.

CONCLUSION

There is correlation finding between vitamin D deficiency and advanced age, cognitive dysfunction, and depression.

A systematic review of existing peripheral biomarkers of cognitive aging: Is there enough evidence for biomarker proxies in behavioral modification interventions?: An initiative in association with the nutrition, exercise and lifestyle team of the Canadian Consortium on Neurodegeneration in Aging

Peripheral biomarkers have shown significant value in predicting brain health and may serve as a useful proxy measurement in the assessment of evidence-based lifestyle behavior modification programs, including physical activity and nutrition programs, that aim to maintain cognitive function in late life. The aim of this systematic review was to elucidate which peripheral biomarkers are robustly associated with cognitive function among relatively healthy non-demented older adults. Following the standards for systematic reviews (PICO, PRIMSA), and employing MEDLINE and Scopus search engines, 222 articles were included in the review. Based on the review of biomarker proxies of cognitive health, it is recommended that a comprehensive biomarker panel, or biomarker signature, be developed as a clinical end point for behavior modification trials aimed at enhancing cognitive function in late life. The biomarker signature should take a multisystemic approach, including lipid, immune/inflammatory, and metabolic biomarkers in the biological signature index of cognitive health.

Examining the relationship between nutrition and cerebral structural integrity in older adults without dementia

The proportion of adults aged 60 years and over is expected to increase over the coming decades. This ageing of the population represents an important health issue, given that marked reductions to cerebral macro- and microstructural integrity are apparent with increasing age. Reduced cerebral structural integrity in older adults appears to predict poorer cognitive performance, even in the absence of clinical disorders such as dementia. As such, it is becoming increasingly important to identify those factors predicting cerebral structural integrity, especially factors that are modifiable. One such factor is nutritional intake. While the literature is limited, data from available cross-sectional studies indicate that increased intake of nutrients such as B vitamins (for example, B6, B12 and folate), choline, n-3 fatty acids and vitamin D, or increased adherence to prudent whole diets (for example, the Mediterranean diet) predicts greater cerebral structural integrity in older adults. There is even greater scarcity of randomised clinical trials investigating the effects of nutritional supplementation on cerebral structure, though it appears that supplementation with B vitamins (B6, B12 and folic acid) or n-3 fatty acids (DHA or EPA) may be beneficial. The current review presents an overview of available research examining the relationship between key nutrients or adherence to select diets and cerebral structural integrity in dementia-free older adults.

Serum Vitamin D Concentrations and Cognitive Change Over 20 Years: The Atherosclerosis Risk in Communities Neurocognitive Study

BACKGROUND/AIMS

25-hydroxyvitamin D (25[OH]D) concentrations have been associated with cognitive decline and incident dementia in elderly populations; however, these relationships are susceptible to reverse causation. Less is known about the association of midlife 25(OH)D with long-term cognitive decline.

METHODS

This was a prospective cohort study of 13,044 participants (mean age 57 years at baseline) in the Atherosclerosis Risk in Communities Study. 25(OH)D was measured from serum collected at baseline (1990-1992) using liquid chromatography tandem high-sensitivity mass spectrometry. Cognition was assessed using 3 neuropsychological tests at 3 time points, which were combined into a composite cognitive Z-score. Multivariable-adjusted linear mixed-effects models with random intercepts and slopes were used to estimate associations between 25(OH)D and cognitive change over 20 years.

RESULTS

Compared to persons with sufficient 25(OH)D (≥30 ng/mL), those with deficient (< 20 ng/mL) and intermediate (20-< 30 ng/mL) 25(OH)D concentrations had similar cognitive decline in composite cognitive Z-scores (deficient versus sufficient: -0.035 [95% CI -0.104 to 0.033] and intermediate versus sufficient: -0.029 [95% CI -0.080 to 0.023]).

CONCLUSIONS

Lower concentrations of 25(OH)D measured in midlife were not significantly associated with more rapid cognitive decline over a 20-year follow-up period. The results of this prospective study are less susceptible to reverse causation than prior studies.

Vitamin D Status and Intakes and Their Association With Cognitive Trajectory in a Longitudinal Study of Urban Adults

CONTEXT

Serum 25-hydroxyvitamin D [25(OH)D], and dietary and supplemental vitamin D may influence cognitive outcomes.

OBJECTIVES

Sex-, age-, and race-specific associations of vitamin D status and intake with longitudinal change in various cognitive domains were examined in a large sample of ethnically and socioeconomically diverse US urban adults.

DESIGN

Two prospective waves of data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study were used.

PARTICIPANTS

Adults in Baltimore, Maryland, aged 30 to 64 years at baseline (n = 1231 to 1803), were followed for a mean (± standard deviation) of 4.64 ± 0.93 years. Visit 1 occurred between 2004 and 2009; visit 2, between 2009 and 2013; there were 1.5 to 2.0 visits per participant.

MAIN OUTCOME AND EXPOSURE MEASURES

Cognitive performance was assessed using 11 test scores covering domains of global cognition, attention, learning/memory, executive function, visuospatial/visuoconstruction ability, psychomotor speed, and language/verbal. Serum 25(OH)D, vitamin D intake, and use of supplements containing vitamin D were the key exposures.

RESULTS

A consistent relationship was found between vitamin D status (overall) and supplemental intake (older women and black adults), with a slower rate of decline in the domain of verbal fluency. Higher dietary intake of vitamin D was linked to slower rate of decline in verbal memory among younger women, and a slower rate of decline in visual memory/visuoconstructive abilities among white adults. All other associations were inconsistent.

CONCLUSIONS

Vitamin D status and intakes were inversely related to domain-specific cognitive decline in US urban adults.

Vitamin D deficiency accelerates ageing and age-related diseases: a novel hypothesis

Ageing can occur at different rates, but what controls this variable rate is unknown. Here I have developed a hypothesis that vitamin D may act to control the rate of ageing. The basis of this hypothesis emerged from studyng the various cellular processes that control ageing. These processes such as autophagy, mitochondrial dysfunction, inflammation, oxidative stress, epigenetic changes, DNA disorders and alterations in Ca²⁺ and reactive oxygen species (ROS) signalling are all known to be regulated by vitamin D. The activity of these processes will be enhanced in individuals that are deficient in vitamin D. Not only will this increase the rate of ageing, but it will also increase the probability of developing age-related diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis and cardiovascular disease. In individual with normal vitamin D levels, these ageing-related processes will occur at lower rates resulting in a reduced rate of ageing and enhanced protection against these age-related diseases.

The Cognitive Telephone Screening Instrument (COGTEL): A Brief, Reliable, and Valid Tool for Capturing Interindividual Differences in Cognitive Functioning in Epidemiological and Aging Studies

Aims

The present study set out to evaluate the psychometric properties of the Cognitive Telephone Screening Instrument (COGTEL) in 2 different samples of older adults.

Methods

We assessed COGTEL in 116 older adults, with retest after 7 days to evaluate the test-retest reliability. Moreover, we assessed COGTEL in 868 older adults to evaluate convergent validity to the Mini-Mental State Examination (MMSE).

Results

Test-retest reliability of the COGTEL total score was good at 0.85 (p < 0.001). Latent variable analyses revealed that COGTEL and MMSE correlated by 0.93 (p < 0.001), indicating convergent validity of the COGTEL.

Conclusion

The present analyses suggest COGTEL as a brief, reliable, and valid instrument for capturing interindividual differences in cognitive functioning in epidemiological and aging studies, with the advantage of covering more cognitive domains than traditional screening tools such as the MMSE, as well as differentiating between individual performance levels, in healthy older adults.

A Systematic Review and Meta-Analysis of The Effect of Low Vitamin D on Cognition

BACKGROUND/OBJECTIVE

With an aging population and no cure for dementia on the horizon, risk factor modification prior to disease onset is an urgent health priority. Therefore, this review examined the effect of low vitamin D status or vitamin D supplementation on cognition in midlife and older adults without a diagnosis of dementia.

DESIGN

Systematic review and random effect meta-analysis.

SETTING

Observational (cross-sectional and longitudinal cohort) studies comparing low and high vitamin D status and interventions comparing vitamin D supplementation with a control group were included in the review and meta-analysis.

PARTICIPANTS

Studies including adults and older adults without a dementia diagnosis were included.

MEASUREMENTS

Medline (PubMed), AMED, Psych INFO, and Cochrane Central databases were searched for articles until August 2016. The Newcastle-Ottawa Scale and Physiotherapy Evidence Database assessed methodological quality of all studies.

RESULTS

Twenty-six observational and three intervention studies (n = 19-9,556) were included in the meta-analysis. Low vitamin D was associated with worse cognitive performance (OR = 1.24, CI = 1.14-1.35) and cognitive decline (OR = 1.26, CI = 1.09-1.23); with cross-sectional yielding a stronger effect compared to longitudinal studies. Vitamin D supplementation showed no significant benefit on cognition compared with control (SMD = 0.21, CI = -0.05 to 0.46).

CONCLUSION

Observational evidence demonstrates low vitamin D is related to poorer cognition; however, interventional studies are yet to show a clear benefit from vitamin D supplementation. From the evidence to date, there is likely a therapeutic age window relevant to the development of disease and therefore vitamin D therapy. Longitudinal lifespan studies are necessary to depict the optimal timing and duration in which repletion of vitamin D may protect against cognitive decline and dementia in aging, to better inform trials and practice towards a successful therapy.

Relationship of serum vitamin D level on geriatric syndromes and physical performance impairment in elderly hypertensive patients

Objective

To investigate the relationship among serum vitamin D levels, physical performance impairment, and geriatric syndromes in elders with hypertension.

Methods

According to the concentration of vitamin D levels, a total of 143 elderly patients with hypertension were classified into vitamin D deficient group (vitamin D ≤ 20 ng/mL, n = 94) and vitamin D appropriate group (vitamin D > 20 ng/mL, n = 49). Geriatric syndromes and physical performance were assessed by using comprehensive geriatric assessment (CGA). Correlation among vitamin D levels, geriatric syndromes and physical performance was analyzed.

Results

No statistical differences were found in various aspects of geriatric syndromes between the two groups (P > 0.05). While correlation analysis indicated that vitamin D levels had a positive association with ADL score (r = 0.235, P < 0.01) and a negative association with Morse fall scale score (r = –0.238, P < 0.01). Patients with deficient vitamin D level had longer time both in the Five Time Sit to Stand Test (5tSTS), (15.765 ± 5.593) and the four-meter walk test [7.440 (5.620, 9.200)], a weaker hand-grip in the grip strength test (28.049 ± 9.522), and a lower Tinetti performance-oriented mobility assessment (Tinetti POMA) [26 (22, 27)] and Balance subscale of the Tinetti performance-oriented mobility assessment (B-POMA) score [14 (12, 16)], compared with appropriate vitamin D level [(13.275 ± 3.692); 5.810 (4.728, 7.325)]; (31.989 ± 10.217); [26.5 (25, 28)]; [15 (14, 16), respectively, all P < 0.05]. Furthermore, results of logistic regression indicated that vitamin D was significantly associated with 5tSTS (OR = 1.2, 95% CI = 1.050–1.331, P < 0.01), Tinetti POMA (OR = 3.7, 95% CI:1.284–10.830, P < 0.05) and B-POMA (OR = 0.8, 95% CI:0.643–0.973, P < 0.05).

Conclusions

In elderly hypertensive patients, serum vitamin D deficient level is associated with physical performance impairment. However, no statistical significance was found between vitamin D and geriatric syndromes. Further study is required to investigate possible mechanisms for the association between vitamin D and physical performance.

Vitamin D Levels and the Risk of Cognitive Decline in Chinese Elderly People: the Chinese Longitudinal Healthy Longevity Survey

BACKGROUND

Vitamin D has a neuroprotective function, potentially important for the prevention of cognitive decline. Prospective studies from Western countries support an association between lower vitamin D level and future cognitive decline in elderly people. No prospective study has examined this association in Asia.

METHODS

This community-based cohort study of elderly people in China follows 1,202 cognitively intact adults aged ≥60 years for a mean duration of 2 years. Plasma vitamin D level was measured at the baseline. Cognitive state of participants was assessed using the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score <18. Cognitive decline was defined as ≥3 points decline from baseline. Multivariable logistic regression models were used to examine the association between quartiles of vitamin D levels with cognitive decline and incidence of cognitive impairment.

RESULTS

Participants with low vitamin D level had an increased risk of cognitive decline. Compared with the highest quartile of vitamin D levels, the multivariable odds ratios (ORs; 95% confidence interval) for cognitive decline were 2.1 (1.3-3.4) for the second highest quartile, 2.2 (1.4-3.6) for the third highest quartile, and 2.0 (1.2-3.3) for the lowest quartile. The multivariable ORs of incident cognitive impairment for the second highest, third highest, and lowest versus highest quartiles of vitamin D levels were 1.9 (0.9-4.1), 2.6 (1.2-5.6), and 3.2 (1.5-6.6), respectively.

CONCLUSIONS

This first follow-up study of elderly people, including the oldest-old, in Asia shows that low vitamin D levels were associated with increased risk of subsequent cognitive decline and impairment.

Cross-sectional and longitudinal associations between serum 25-hydroxyvitamin D and cognitive functioning

BACKGROUND

Vitamin D deficiency is common in older persons. The objectives of this study were: To examine the cross-sectional and longitudinal association between serum 25-hydroxyvitamin D (25(OH)D) and cognitive functioning in older persons; and to explore the optimal cut-off for serum 25(OH)D.

METHODS

Data of the Longitudinal Aging Study Amsterdam (LASA) were used. Serum 25(OH)D was determined using a competitive protein binding assay in 1995/6 (n = 1,320). Cognitive functioning was assessed in 1995/6 and 1998/9 using the Mini-Mental State Examination (MMSE, general cognitive functioning), Raven's Colored Progressive Matrices (RCPM, ability of nonverbal and abstract reasoning), the Coding Task (CT, information processing speed), and the 15 Words Test (15WT, immediate memory and delayed recall). The data were analyzed using linear regression analyses and restricted cubic spline functions. The MMSE was normalized using ln(31-MMSE).

RESULTS

Mean serum 25(OH)D was 53.7 nmol/L. After adjustment for confounding, patients with serum 25(OH)D levels below 30 nmol/L had significantly lower general cognitive functioning (beta of ln(31-MMSE) = 0.122; p = 0.046) and slower information processing speed (beta = -2.177, p = 0.001) as compared with patients having serum 25(OH)D levels ≥ 75 nmol/L in the cross-sectional analyses. For both outcomes, the optimal cut-off was about 60 nmol/L. No other significant associations were observed.

CONCLUSIONS

A lower serum 25(OH)D was significantly associated with lower general cognitive functioning and slower information processing speed, but not with a faster rate of cognitive decline.

Serum 25-hydroxyvitamin D predicts cognitive performance in adults

BACKGROUND

Vitamin D is an endogenous hormone known to regulate calcium levels in the body and plays a role in cognitive performance. Studies have shown an association between vitamin D deficiency and cognitive impairment in older adults. Lebanon has a high 25-hydroxyvitamin D (25(OH)D) deficiency prevalence across all age groups.

METHODS

In this cross-sectional study, we explored the cognitive performance and serum 25(OH)D levels using an electrochemoluminescent immunoassay in 254 older (>60 years) as well as younger (30-60 years) adults. Subjects' characteristics, including age, years of education, wearing of veil, alcohol consumption, smoking, and physical exercise, were collected. Participants were screened for depression prior to cognitive screening using the Montreal Cognitive Assessment Arabic version. Visuospatial memory was tested using the Rey Complex Figure Test and Recognition Trial, and speed of processing was assessed using the Symbol Digit Modalities test.

RESULTS

Pearson's correlation and stepwise linear regression analyses showed that a low vitamin D level was associated with greater risk of cognitive impairment in older as well as younger adults.

CONCLUSION

These findings suggest that correction of vitamin D needs to be explored as an intervention to prevent cognitive impairment. Prospective longitudinal studies are needed to ascertain the effect of such interventions.

Association of serum 25-hydroxyvitamin D with symptoms of depression after 6 months in stroke patients

Our aim was to determine whether there was a relationship between 25-hydroxyvitamin D (25[OH] D) and post-stroke depression (PSD). Two hundred and forty-four ischemic stroke patients admitted to the hospital within the first 24 h after stroke onset were consecutively recruited and followed up for 6 months. Clinical information was collected. Serum 25[OH] D levels were measured at baseline. Based on the symptoms, diagnoses of depression were made in accordance with DSM-IV criteria for depression at 6-month after stroke. At 6-month, 91 patients (37.3 %) showed depression and in 60 patients (24.6 %) this depression was classified as major. There was a significant difference in median serum 25[OH] D levels between PSD patients and no depression cases [8.3 (IQR, 6.8-9.5) vs. 15.6 (IQR, 13.2-20.3) ng/ml, respectively; P < 0.001]. Serum 25[OH] D levels ≤ 11.2 ng/ml were independently associated with PSD [odds ratio 10.32, 95 % confidence interval 4.97-28.63; P < 0.001], after adjusting for possible confounders. Serum 25[OH] D levels reduced at admission was found to be associated with PSD. Additional research is needed on vitamin D supplementation to improve the outcome of patients with PSD.