Objective: To evaluate the direct, indirect, and total prospective effects of serum concentrations of 25-hydroxycholecalciferol (25[OH]D) on depressive symptoms in older adults. Methods: Data from the second (2013-2015) and third (2017-2019) waves of the EpiFloripa Aging Cohort Study (≥ 60 years) were analyzed. Depressive symptoms were assessed with the 15-item Geriatric Depression Scale. 25(OH)D levels were measured using the microparticle chemiluminescence method. A directed acyclic graph was constructed to identify the minimum set of adjustments. Structural equation modeling analysis was used to determine the effects of 25(OH)D on depressive symptoms. Results: Data from 574 older adults (63.1% female) were analyzed. In the follow-up (n=390), 16.2% of them presented severe depressive symptoms (≥ 6 points). Structural equation modeling analysis revealed that 25(OH)D had a small direct negative effect (β = -0.11, p < 0.05) and an overall negative effect (β = -0.13; p < 0.05) on depressive symptoms in wave 3 (increased 25[OH]D led to decreased depressive symptoms). No direct or indirect effect on depressive symptoms was found in wave 2. Conclusion: Our findings indicate a prospective association between 25(OH)D and depressive symptoms, suggesting a long-term effect in older adults from southern Brazil. Objective 25hydroxycholecalciferol hydroxycholecalciferol 25 25OHD OHD OH D (25[OH]D Methods 20132015 2013 2015 (2013-2015 20172019 2017 2019 (2017-2019 ≥ ( years analyzed 15item item 15 Scale method adjustments Results 57 63.1% 631 63 1 (63.1 female followup follow up n=390, n390 n n=390 , 390 (n=390) 162 16 2 16.2 points. points . points) β 0.11, 011 0 11 -0.11 0.05 005 05 0.13 013 13 -0.13 increased symptoms) Conclusion longterm long term Brazil 2013201 201 (2013-201 2017201 (2017-201 5 63.1 (63. n39 n=39 39 (n=390 16. 0.11 01 -0.1 0.0 00 0.1 201320 20 (2013-20 201720 (2017-20 63. (63 n3 n=3 (n=39 -0. 0. 20132 (2013-2 20172 (2017-2 (6 n= (n=3 -0 (2013- (2017- (n= - (2013 (2017 (n (201 (20 (2

ABSTRACT OBJECTIVE To estimate the association between vitamin D and the cognitive decline of older adults and evaluate whether this association is mediated by brain-derived neurotrophic factor (BDNF) serum concentration. METHODS Cross-sectional study nested in a population-based cohort. Of the 604 participants in the complementary examination of the EpiFloripa Study, 576 older adults (60 years or older) were eligible for the study. The outcome is cognitive decline evaluated by the Mini-Mental State Examination, the exposure is vitamin D, and BDNF is the mediator. The control variables are age, sex, per capita family income, and educational level. The direct effect of vitamin D and BDNF on cognitive decline and the indirect effect mediated by BDNF was evaluated using path analysis, with the estimation of standardized coefficients. RESULTS Among the participants, we observed a direct and positive effect of vitamin D on cognitive function (Coef: 0.06; 95%CI: 0.02 to 0.11; p < 0.001) and serum BDNF concentration (Coef: 21.55; 95%CI: 9.92 to 33.17; p = 0.002), i.e., the higher the vitamin D, the higher the cognitive function and serum level of BDNF. CONCLUSION There was an association between vitamin D on serum BDNF and on cognitive decline in older adults. Moreover, BDNF did not have an effect on cognitive decline, so BDNF was not a mediator of the vitamin D effect on cognitive decline.

ABSTRACT OBJECTIVE To estimate the association between vitamin D and the cognitive decline of older adults and evaluate whether this association is mediated by brain-derived neurotrophic factor (BDNF) serum concentration. METHODS Cross-sectional study nested in a population-based cohort. Of the 604 participants in the complementary examination of the EpiFloripa Study, 576 older adults (60 years or older) were eligible for the study. The outcome is cognitive decline evaluated by the Mini-Mental State Examination, the exposure is vitamin D, and BDNF is the mediator. The control variables are age, sex, per capita family income, and educational level. The direct effect of vitamin D and BDNF on cognitive decline and the indirect effect mediated by BDNF was evaluated using path analysis, with the estimation of standardized coefficients. RESULTS Among the participants, we observed a direct and positive effect of vitamin D on cognitive function (Coef: 0.06; 95%CI: 0.02 to 0.11; p < 0.001) and serum BDNF concentration (Coef: 21.55; 95%CI: 9.92 to 33.17; p = 0.002), i.e., the higher the vitamin D, the higher the cognitive function and serum level of BDNF. CONCLUSION There was an association between vitamin D on serum BDNF and on cognitive decline in older adults. Moreover, BDNF did not have an effect on cognitive decline, so BDNF was not a mediator of the vitamin D effect on cognitive decline.

RESUMO Objetivo Avaliar o efeito da participação em Grupos de Cooperação Cognitiva mediados por computadores e internet na variação do Mini-Exame de Estado Mental (MEEM) de pacientes ambulatoriais com queixas de memória, participantes de duas clínicas de memória. Métodos Estudo prospectivo de intervenção controlada, realizado em 2006-2013 com 293 idosos. O grupo de intervenção (n = 160) participou de um Grupo de Cooperação Cognitiva (20 sessões de 1,5 horas cada). O grupo controle (n = 133) recebeu acompanhamento médico. O desfecho foi a variação percentual no MEEM. As variáveis de controle incluíram genêro, idade, estado civil, escolaridade, hipertensão, diabetes, dislipidemia, hipotiroidismo, depressão, doenças cardiovasculares, polimedicação, uso de benzodiazepínicos, exposição ao tabaco, sedentarismo, obesidade e capacidade funcional. Todas as variáveis foram coletadas antes e após a intervenção. O modelo multivariado final foi obtido por regressão linear múltipla. Resultados O grupo de intervenção obteve variação positiva independente de 24,39% (IC95% = 14.86/33.91) no MEEM em relação ao grupo controle. Conclusão Os resultados deste estudo sugerem que o grupo de intervenção, mediados por computadores e internet estão associados com melhora do status cognitivo em idosos de clínicas de memória.

ABSTRACT Objective To estimate the effect of participating in cognitive cooperation groups, mediated by computers and the internet, on the Mini-Mental State Examination (MMSE) percent variation of outpatients with memory complaints attending two memory clinics. Methods A prospective controlled intervention study carried out from 2006 to 2013 with 293 elders. The intervention group (n = 160) attended a cognitive cooperation group (20 sessions of 1.5 hours each). The control group (n = 133) received routine medical care. Outcome was the percent variation in the MMSE. Control variables included gender, age, marital status, schooling, hypertension, diabetes, dyslipidaemia, hypothyroidism, depression, vascular diseases, polymedication, use of benzodiazepines, exposure to tobacco, sedentary lifestyle, obesity and functional capacity. The final model was obtained by multivariate linear regression. Results The intervention group obtained an independent positive variation of 24.39% (CI 95% = 14.86/33.91) in the MMSE compared to the control group. Conclusion The results suggested that cognitive cooperation groups, mediated by computers and the internet, are associated with cognitive status improvement of older adults in memory clinics.