The association between serum 25-hydroxyvitamin D concentrations and depressive symptoms in Korean adults: findings from the fifth Korea National Health and Nutrition Examination Survey 2010

Screening dementia and predicting high dementia risk groups using machine learning

New technologies such as artificial intelligence, the internet of things, big data, and cloud computing have changed the overall society and economy, and the medical field particularly has tried to combine traditional examination methods and new technologies. The most remarkable field in medical research is the technology of predicting high dementia risk group using big data and artificial intelligence. This review introduces: (1) the definition, main concepts, and classification of machine learning and overall distinction of it from traditional statistical analysis models; and (2) the latest studies in mental science to detect dementia and predict high-risk groups in order to help competent researchers who are challenging medical artificial intelligence in the field of psychiatry. As a result of reviewing 4 studies that used machine learning to discriminate high-risk groups of dementia, various machine learning algorithms such as boosting model, artificial neural network, and random forest were used for predicting dementia. The development of machine learning algorithms will change primary care by applying advanced machine learning algorithms to detect high dementia risk groups in the future.

Serum Vitamin D and Depressive Symptomatology among Boston-Area Puerto Ricans

BACKGROUND

Low vitamin D status, assessed using serum 25-hydroxyvitamin D [25(OH)D] concentration, has been associated with depression, but research among minority populations, such as Puerto Ricans is limited. We examined the association between serum 25(OH)D and self-reported depressive symptomatology across 3 waves of follow-up in a cohort of Puerto Rican adults residing in Massachusetts.

OBJECTIVES

We evaluated the cross-sectional and longitudinal associations between serum 25(OH)D and self-reported depressive symptoms in the Boston Puerto Rican Health Study (BPRHS) cohort.

METHODS

Participants of the BPRHS were evaluated for depressive symptoms using the Center for Epidemiologic Studies Depression Scale (CES-D). Serum 25(OH)D was measured at baseline (n = 1434), year 2 (n = 1218), and year 5 (n = 914). We categorized serum 25(OH)D concentration as sufficient (≥20 ng/mL), insufficient (12 to <20 ng/mL), and deficient (<12 ng/mL). Multivariable linear regression was used for cross-sectional analyses at baseline, and repeated measures mixed effects modeling was used over 3 waves of follow-up for longitudinal analyses. We conducted sensitivity analyses in vitamin D supplement nonusers and participants with complete data on baseline serum 25(OH)D and CES-D at all 3 visits.

RESULTS

Serum 25(OH)D concentration was not associated with CES-D score in cross-sectional analysis [β = -0.85; 95% CI: -2.80, 1.10 for deficient compared with sufficient 25(OH)D; P-trend = 0.59] or in longitudinal analyses over 5 y [β = -0.41; 95% CI: -1.95, 1.13 for deficient compared with sufficient 25(OH)D; P-trend = 0.93]. Results were similar in sensitivity analyses restricted to vitamin D supplement nonusers (n = 1371) and in analyses conducted in participants with complete measures of baseline serum 25(OH)D and CES-D score at all 3 visits (n = 887) [β = -0.12; 95% CI: -1.98, 1.74 for deficient compared with sufficient 25(OH)D; P-trend = 0.93].

CONCLUSIONS

We did not observe a significant association between serum 25(OH)D and depressive symptomatology in the BPRHS cohort.

Effects of vitamin D on mood and sleep in the healthy population: Interpretations from the serotonergic pathway

Vitamin D insufficiency is common in the healthy population. Recent insights addressed the role of vitamin D in serotonin and melatonin regulation, suggesting that increasing vitamin D status may be helpful for improving mood and sleep. This literature review covers the current state of evidence regarding potential effects of vitamin D on mood and sleep indicators in healthy people. In total, 11 observational studies were found for sleep, and 54 studies on mood (including ten RCTs). These studies revealed mixed results for both sleep and mood. The findings were interpreted based on the previously proposed serotonergic pathway of vitamin D. Implications and challenges for future research regarding the timing of blood sampling, timing and dosage of supplement intake and investigating the response dynamics are discussed.

Is there an association between serum 25(OH)D3 and mental well-being in patients with type 2 diabetes? Results from a cohort study in primary care

PURPOSE

There are limited and inconsistent results on the correlation between vitamin D and mental health in patients with type 2 diabetes (T2D). Thus, our aim was to explore the association between vitamin D and mental well-being in a community-based sample of participants with T2D.

METHODS

We analyzed serum 25-hydroxyvitamin D₃ (25(OH)D₃) in 698 patients with T2D at the baseline examination. The cohort was reinvestigated after 4 years. Data from SF-36 questionnaires measuring vitality and mental health at baseline and after 4 years were used for analyses.

RESULTS

Serum 25(OH)D₃ was inversely associated with poor mental health at baseline (odds ratio (OR) for 10 nmol/l increase in 25(OH)D₃, 0.90 (95% confidence interval (CI) 0.83-0.96, p = 0.003)) but not at follow-up (p > 0.05). Serum 25(OH)D₃ was not associated with vitality at baseline (p > 0.05). At follow-up, there was an inverse association between 25(OH)D₃ and low vitality (OR for 10 nmol/l increase in 25(OH)D₃, 0.89 (95% CI 0.82-0.97, p = 0.009)) but not after adjustment.

CONCLUSION

We found an inverse association between 25(OH)D₃ and mental health in patients with T2D at baseline. We found no association between 25(OH)D₃ and vitality after adjustment. Future studies are needed to determine the association between vitamin D and mental well-being in patients with T2D.

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.

Comparing the effectiveness of vitamin D plus iron vs vitamin D on depression scores in anemic females: Randomized triple-masked trial

Background: Low levels of 25-hydroxyvitamin D (25(OH)D) have been related to depression and anxiety. It seems that anemia is associated with vitamin D deficiency. We aimed to evaluate the effects of iron-vitamin D co-supplementation versus vitamin D alone on depression scores in anemic females with low levels of serum 25-hydroxyvitamin D. Methods: This randomized controlled trial was conducted on eighty premenopausal females who were recruited between May 2015 and October 2015 from primary health care centers. Women with anemia and low concentrations of 25(OH)D were randomized to either 1000 IU/d vitamin D plus 27 mg/d iron (D-Fe) or vitamin D plus placebo supplements (D-P) for 12 weeks. Depressive and anxious symptoms were evaluated with the Beck Depression Inventory (BDI) with subscales 1-13 and 14-21 and Beck Anxiety Inventory (BAI). To compare the groups, Mann-Whitney or chi-squared tests were used and within groups comparison was performed using Wilcoxon signed ranks test. The study was registered on www.clinicaltrial.org as NC 01876563. Results: The serum concentrations of 25(OH)D were increased significantly in both groups at the end of the study. In both groups, there was a significant improvement in total BDI, the BDI subscale, and the BAI scores (p<0.001). No differences were found between groups (p>0.05). Conclusion: Although the potential positive effect of vitamin D on mental health was evident, iron plus vitamin D co-supplementation did not demonstrate any significant benefits over vitamin D alone, neither in depression score reduction nor anxiety symptoms.

Irritable bowel syndrome: a review of the general aspects and the potential role of vitamin D

Irritable Bowel Syndrome (IBS) is a bowel disorder leading to symptoms such as abdominal pain, modifications in the motility and bowel habits, distention, bloating, and gas. Vitamin D (VD) may interfere in a plethora of cellular mechanisms, and act directly or indirectly in the regulation of the microbiome, the release of anti-microbial peptides, modulation of the immune system and inflammation processes; which in turn, may positively interfere with the altered gut function. The main purpose of this review was to survey studies involving the impacts of VD on IBS. Area covered: Eligible studies including the term VD and IBS were searched in the MEDLINE-PubMed and EMBASE (2009-2018). VD may act direct or indirectly in the regulation of the gut microbiome, immune response, and psychosocial factors that may be included in the list of IBS triggering factors. Expert opinion: Once VD plays an essential role in many processes associated with IBS, its deficiency may be associated with IBS, and the supplementation could help in the therapeutic approach for this condition. For these reasons, the understanding of the association of VD in IBS is indispensable for the development of new strategies that could improve the quality of life of the patient.

Serum Concentrations of 25-Hydroxyvitamin D and Depression in a General Middle-Aged to Elderly Population in Finland

OBJECTIVES

Low concentrations of serum 25-hydroxyvitamin D [25(OH)D] have been postulated to associate with an increased prevalence of depression. As there are a limited number of publications on this issue, we examined the association between serum 25(OH)D and depression in a general middle-aged or older population.

DESIGN

A population-based cross-sectional study.

SETTING AND PARTICIPANTS

A total of 1602 men and women from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) in Eastern Finland, aged 53-73 y in 1998-2001, were analysed.

MEASUREMENTS

Depressive symptoms were assessed with the DSM-III depression scale, and those individuals who had scores over 4 (range 0-12) or had reported undergoing current antidepressant therapy, were considered as suffering from depression. Associations were estimated in serum 25(OH)D tertiles using logistic regression.

RESULTS

Among the participants, 183 subjects (11.4%) were considered to have depression. The mean age of the subjects was 62.6 years (SD 6.4, range 53.4-73.8 years). The mean serum 25(OH)D concentration was 43.8 nmol/L (SD 17.7, range 8.5-112.8 nmol/L), concentrations <50 nmol/L were observed in 65.0% of the subjects, and only 5.0% displayed concentrations ≥75 nmol/L. After multivariable adjustments, the odds ratios for having depression in the tertiles (from highest to the lowest) of serum 25(OH)D were 1, 1.35 (95 % CI: 0.87, 2.09) and 1.64 (95 % CI: 1.03, 2.59), P for trend=0.036.

CONCLUSION

These findings indicate that a lower concentration of serum 25(OH)D is associated with a higher prevalence of depression in an elderly general population.

Association between Dietary Carotenoid Intake and Bone Mineral Density in Korean Adults Aged 30-75 Years Using Data from the Fourth and Fifth Korean National Health and Nutrition Examination Surveys (2008-2011)

Age-related bone loss is a major public health problem. This cross-sectional study examined the association between the dietary intake of carotenoids and bone mineral density (BMD). Data from 8022 subjects (3763 males and 4259 females) aged 30–75 years included in the Korean National Health and Nutrition Examination Survey (2008–2011) were analyzed. BMD was measured by dual-energy X-ray absorptiometry. Intake of carotenoids was estimated using 24-h dietary recall. In multiple linear analysis, after adjusting for covariates, lutein + zeaxanthin and β-cryptoxanthin intake was positively associated with total hip BMD in males and premenopausal women respectively, while β-carotene intake was positively correlated with femoral neck, total hip, and whole-body BMD in postmenopausal women. Postmenopausal women in the highest quintile of daily β-carotene intake, showed a lower risk of osteopenia at the lumbar spine (odds ratio (OR): 0.35, 95% CI: 0.16–0.79, P for trend = 0.009) than those in the lowest quintile, after adjusting for covariates. Daily β-cryptoxanthin intake was significantly associated with a lower risk of osteopenia at the total hip (OR per 1 mg/day increase: 0.76; 95% CI: 0.59–0.97), and lumbar spine (OR per 1 mg/day increase: 0.79; 95% CI: 0.70–0.89) in postmenopausal women. These results suggest that the dietary intake of β-carotene and β-cryptoxanthin may have a positive effect on bone health.

Vitamin D deficiency is significantly associated with depression in patients with chronic kidney disease

Background

Depression is reported to be the most common psychological problem in patients with chronic kidney disease (CKD). Several studies have reported that lower levels of serum vitamin D are significantly associated with depression. Both vitamin D deficiency and depression are prevalent in patients with CKD, yet the relationship between these two factors remains poorly understood. This study aimed to investigate the association between vitamin D levels and depression among CKD patients.

Methods

Totally, 21,257 individuals who participated in the Korean National Health and Nutrition Examination Survey (KNHANES V, VI) from 2010–2014 were screened for the study; 533 CKD patients were included. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D3 [25(OH)D3] ≤10 ng/mL. Patients were divided into vitamin D deficient or sufficient groups. Depression was screened for using the Korean version of the WHO Composite International Diagnostic Interview-Short Form. The association between vitamin D deficiency and depression was evaluated by multivariate logistic regression analysis.

Results

The mean participant age was 70.1±9.4 years; 262 patients (49.2%) were male. The median 25(OH)D₃ level was 19.1±6.9 ng/mL. The prevalence of depression was higher in CKD patients than in the general population (14.3 vs. 11.1%, P = 0.03). Additionally, the prevalence of depression was significantly higher in CKD patients with (vs. without) vitamin D deficiency (32.5% vs. 50.0%, P<0.001). Multivariate logistic regression analysis showed that vitamin D deficiency was a significant independent predictor of depression after adjusting for confounding factors (adjusted odds ratio, 6.15; 95% confidence interval, 2.02–8.75; P = 0.001).

Conclusion

Depression was highly prevalent in CKD patients, in whom vitamin D deficiency was a significant independent predictor of depression. Therefore, management of vitamin D deficiency might help prevent depression in CKD patients.

Is Hypovitaminosis D Associated with Stress Perception in the Elderly? A Nationwide Representative Study in Korea

Hypovitaminosis D and stress are common problems among the elderly. The aim of this cross-sectional nationally representative study was to evaluate the association between hypovitaminosis D and stress perception using large-scale nationally representative data from the Korea National Health and Nutrition Examination Survey (2012-2013). In our study, a total of 1393 elders (≥65 years old) were included to evaluate the association between hypovitaminosis D and stress perception. Serum 25-hydroxyvitamin D levels were determined using radioimmunoassay, and perceived stress status was assessed by a self-reporting questionnaire. The association between hypovitaminosis D and stress perception according to sex was examined using logistic regression analysis. After multivariate adjustment for sociodemographic and lifestyle factors and comorbidities, hypovitaminosis D was significantly associated with perceived stress (odds ratio, 2.73; 95% confidence interval, 1.10-6.77; p = 0.029) among women; however, this association was not significant among men. Hypovitaminosis D was a risk factor for higher stress perception in older Korean women. Even though the role of vitamin D in stress perception is still unclear, we suggest screening for hypovitaminosis D among the elderly.

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.

Association between serum 25-hydroxyvitamin D concentrations and depressive symptoms in an older Korean population: A cross-sectional study

BACKGROUND

This study aims to examine associations between serum 25-hydroxyvitamin D [25(OH)D] concentrations and depressive symptoms in an older Korean population.

METHODS

The study used data from the Korean Urban Rural Elderly study, which enrolled 2942 participants aged 65 years or older from urban and rural communities. After excluding those treated with antidepressants, we conducted cross-sectional analysis of 2853 participants (962 men and 1891 women). Serum 25(OH)D was analyzed as both a continuous and categorized variable. Depressive symptoms were assessed using the Korean version of the Geriatric Depression Scale - Short Form. Multivariate logistic regression analyses were conducted to examine relationships between serum 25(OH)D and depressive symptoms for men and women separately.

RESULTS

In men, ORs (95% CIs) for depressive symptoms were 1.74 (0.85, 3.58), 2.50 (1.20, 5.18), and 2.81 (1.15, 6.83) for those with a 25(OH)D concentration of 20.0-29.9, 10.0-19.9, and <10.0ng/mL, respectively (P-trend=0.013), compared with those with a 25(OH)D concentration of ≥30.0ng/mL, after adjustment for study year, month of assay, age, parathyroid hormone, body mass index, number of comorbidities, smoking status, alcohol intake, exercise, sleep duration, income, education, cohabitation status, and residential area. In women, the associations between 25(OH)D and depressive symptoms were significant neither before nor after adjustment.

LIMITATIONS

Due to the cross-sectional study design, causal association is uncertain. Intake of vitamin D supplements and outdoor activity were not examined.

CONCLUSIONS

Our findings suggest that lower concentrations of vitamin D are independently associated with depressive symptoms in older Korean adults.

Vitamin D supplementation for the prevention of type 2 diabetes in overweight adults: study protocol for a randomized controlled trial

Background

Despite Australia’s sunny climate, low vitamin D levels are increasingly prevalent. Sun exposure is limited by long working hours, an increase in time spent indoors, and sun protection practices, and there is limited dietary vitamin D fortification. While the importance of vitamin D for bone mineralization is well known, its role as a protective agent against chronic diseases, such as type 2 diabetes and cardiovascular disease, is less understood. Observational and limited intervention studies suggest that vitamin D might improve insulin sensitivity and secretion, mainly via its anti-inflammatory properties, thereby decreasing the risk of development and progression of type 2 diabetes. The primary aim of this trial is to investigate whether improved plasma concentrations of 25-hydroxyvitamin D (25(OH)D), obtained through vitamin D supplementation, will increase insulin sensitivity and insulin secretion. A secondary aim is to determine whether these relationships are mediated by a reduction in underlying subclinical inflammation associated with obesity.

Methods/Design

Fifty overweight but otherwise healthy nondiabetic adults between 18 and 60 years old, with low vitamin D levels (25(OH)D < 50 nmol/l), will be randomly assigned to intervention or placebo. At baseline, participants will undergo a medical review and anthropometric measurements, including dual X-ray absorptiometry, an intravenous glucose tolerance test, muscle and fat biopsies, a hyperinsulinemic euglycemic clamp, and questionnaires assessing diet, physical activity, sun exposure, back and knee pain, and depression. The intervention group will receive a first dose of 100,000 IU followed by 4,000 IU vitamin D (cholecalciferol) daily, while the placebo group will receive apparently identical capsules, both for a period of 16 weeks. All measurements will be repeated at follow-up, with the primary outcome measure expressed as a change from baseline in insulin sensitivity and secretion for the intervention group compared with the placebo group. Secondary outcome measures will compare changes in anthropometry, cardiovascular risk factors, and inflammatory markers.

Discussion

The trial will provide much needed clinical evidence on the impact of vitamin D supplementation on insulin resistance and secretion and its underlying mechanisms, which are relevant for the prevention and management of type 2 diabetes.

Trial registration

Clinicaltrials.gov ID: NCT02112721.

Vitamin D supplementation reduces depressive symptoms in patients with chronic liver disease

BACKGROUND AND AIMS

Vitamin D deficiency and depression frequently occur in patients with chronic liver diseases (CLD). Depression has recently been inversely associated with vitamin D in a meta-analysis, and vitamin D receptor is expressed in brain. This pilot study investigates whether vitamin D replacement ameliorates depressive symptoms in CLD patients and consists of a cross-sectional and an interventional analysis.

METHODS

Overall, 111 patients with CLD were included in the cross-sectional analysis. The Beck Depression Inventory II (BDI-II) was used to assess depression. Chemiluminescence immunoassay and LC-MS/MS quantified serum 25-hydroxyvitamin D levels. For the interventional analysis, 77 patients with inadequate vitamin D concentrations received 20,000 IU vitamin D per week for six months. The final follow-up was carried out six months post supplementation.

RESULTS

In the cross-sectional analysis, 81% of patients (median age 55 years, 47% women) had inadequate baseline vitamin D levels (<30 ng/ml), and 31% presented with depressive symptoms (BDI-II score ≥14). Depression severity correlated inversely with vitamin D level in depressed patients (β = -0.483, P = 0.004). Depression scores improved significantly from baseline in depressed patients after three and six months (P = 0.003 and P = 0.004, respectively) of supplementation, with vitamin D levels increasing to normal (P < 0.0001). Subgroup analyses revealed this anti-depressant effect of vitamin D to occur predominantly in women. The final follow-up showed increases in median BDI-II scores in the setting of decreased vitamin D levels.

CONCLUSIONS

Vitamin D levels correlated with BDI-II scores, and vitamin D replacement significantly improved depressive symptoms in women with CLD. Adjuvant vitamin D may be considered in these patients.

REGISTRATION NO

DRKS00007782 German Clinical Trials Registry (DRKS).

Low serum 25-hydroxyvitamin D concentrations are associated with increased likelihood of having depressive symptoms among Japanese workers

BACKGROUND

Accumulating evidence suggests a protective role of vitamin D against mood disorders; however, epidemiologic studies are scarce in working populations.

OBJECTIVE

We investigated cross-sectionally the association of serum vitamin D status and depressive symptoms among Japanese workers.

METHODS

Participants were 1786 employees (9% women), aged 19-69 y, who received health check-ups and participated in a nutrition and health survey. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured with the use of a competitive protein binding assay. Depressive symptoms were assessed by using the Center for Epidemiologic Studies Depression (CES-D) scale. Logistic regression was used to estimate ORs with adjustment for potential confounding variables including dietary factors.

RESULTS

Overall, 92% of study participants had suboptimal vitamin D status [25(OH)D <30 μg/L]. Depressive symptoms were inversely associated with 25(OH)D. Compared with those with a 25(OH)D concentration of <20 μg/L, multivariable-adjusted ORs (95% CIs) for depressive symptoms (CES-D scale score ≥16) were 0.75 (0.59, 0.95) and 0.66 (0.41, 1.06) for those with a 25(OH)D concentration of 20-29 μg/L and ≥30 μg/L, respectively (P-trend = 0.01). After further adjustment for leisure-time physical activity and shift work (factors closely related to photo-initiated vitamin D production), the OR (95% CI) for the highest category of 25(OH)D was 0.70 (0.43, 1.14). The association between 25(OH)D and depressive symptoms appears to be linear, according to restricted cubic spline regression.

CONCLUSION

Results suggest that lower concentrations of circulating vitamin D are associated with increased likelihood of having depressive symptoms among apparently healthy workers.

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.