Midlife Modifiable Risk Factors for Dementia: A Systematic Review and Meta-analysis of 34 Prospective Cohort Studies

2020 ◽  
Vol 16 (14) ◽  
pp. 1254-1268 ◽  
Author(s):  
Xiao-Ying Li ◽  
Min Zhang ◽  
Wei Xu ◽  
Jie-Qiong Li ◽  
Xi-Peng Cao ◽  
...  

Objective: The aim of this study is to assess the association between midlife risk factors and dementia. Methods: PubMed and Cochrane library were systematically searched on May 24, 2018, to retrieve prospective cohort studies. The summary Relative Risk (RR) and 95% Confidence Interval (CI) were calculated by the random-effect model to explore the association between midlife risk factors and dementia. Sensitivity analysis and meta-regression were conducted to explore the source of heterogeneity. Publication bias was examined using Begg's and Egger's tests. Results: Thirty-four prospective cohort studies were included, among which 24 were eligible for metaanalysis. A total of 159,594 non-demented adults were enrolled at baseline before 65 years and 13,540 people were diagnosed with dementia after follow-up. The pooled results revealed that five factors could significantly increase the dementia risk by 41 to 78%, including obesity (RR, 1.78; 95% CI: 1.31-2.41), diabetes mellitus (RR, 1.69; 95% CI: 1.38-2.07), current smoking (RR, 1.61; 95%, CI: 1.32-1.95), hypercholesterolemia (RR, 1.57; 95% CI: 1.19-2.07), and hypertension (borderline blood pressure RR, 1.41; 95% CI: 1.23-1.62 and high Systolic Blood Pressure (SBP) RR, 1.72; 95% CI: 1.25-2.37). However, the sensitivity analyses found that the results of hypercholesterolemia and high SBP were not reliable, which need to be confirmed by more high-quality studies. No influences due to publication bias were revealed. In the systematic review, another three factors (hyperhomocysteinemia, psychological stress, and heavy drinking) were found to be associated with elevated dementia risk. In addition, physical exercise, a healthy diet, and hormone therapy in middle age were associated with the reduction of dementia risk. Conclusions: Middle-aged people with obesity, diabetes, hypertension, or hypercholesterolemia, and current smokers in midlife are at higher risk of developing dementia later in life.

BMJ Open ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. e024171 ◽  
Author(s):  
Sabrina Ayoub-Charette ◽  
Qi Liu ◽  
Tauseef A Khan ◽  
Fei Au-Yeung ◽  
Sonia Blanco Mejia ◽  
...  

ObjectiveSugar-sweetened beverages (SSBs) are associated with hyperuricaemia and gout. Whether other important food sources of fructose-containing sugars share this association is unclear.DesignTo assess the relation of important food sources of fructose-containing sugars with incident gout and hyperuricaemia, we conducted a systematic review and meta-analysis of prospective cohort studies.MethodsWe searched MEDLINE, Embase and the Cochrane Library (through 13 September 2017). We included prospective cohort studies that investigated the relationship between food sources of sugar and incident gout or hyperuricaemia. Two independent reviewers extracted relevant data and assessed the risk of bias. We pooled natural-log transformed risk ratios (RRs) using the generic inverse variance method with random effects model and expressed as RR with 95% confidence intervals (CIs). The overall certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation system.ResultsWe identified three studies (1 54 289 participants, 1761 cases of gout), comparing the highest with the lowest level of exposure for SSBs, fruit juices and fruits. No reports were found reporting incident hyperuricaemia. Fruit juice and SSB intake showed an adverse association (fruit juice: RR=1.77, 95% CI 1.20 to 2.61; SSB: RR=2.08, 95% CI 1.40 to 3.08), when comparing the highest to lowest intake of the most adjusted models. There was no significant association between fruit intake and gout (RR 0.85, 95% CI 0.63 to 1.14). The strongest evidence was for the adverse association with SSB intake (moderate certainty), and the weakest evidence was for the adverse association with fruit juice intake (very low certainty) and lack of association with fruit intake (very low certainty).ConclusionThere is an adverse association of SSB and fruit juice intake with incident gout, which does not appear to extend to fruit intake. Further research is needed to improve our estimates.Trial registration numberNCT02702375; Results.


2020 ◽  
pp. jech-2020-213842
Author(s):  
Yong-Jae Lee ◽  
Hong-Bae Kim

BackgroundSeveral observational studies have been conducted to investigate the link between anaemia and adult depression but have shown inconsistent results. This systematic review and meta-analysis was performed to investigate this association.MethodsA comprehensive search of four electronic databases (PubMed, EMBASE, PsycINFO and the Cochrane Library) was conducted to identify relevant papers published up to November 2019 for the systematic review and meta-analysis. The Newcastle-Ottawa Scale was used to assess the methodological quality of selected studies. A random-effects model was used to draw metaestimates of the relationship between anaemia and adult depression.ResultsA total of 9706 papers were retrieved, and 14 observational epidemiological studies (9 case–control studies and 5 prospective cohort studies) comprising 10 764 cases of depression were finally included in this meta-analysis. The mean age of the participants ranged from 38.4 to 75.0 years. A significant association was identified between low haemoglobin levels and adult depression (OR or relative risk 1.43; 95% CI 1.23 to 1.65). Subgroup analyses according to study design, mean age, diagnostic criteria of anaemia, geographical region, number of participants, methodological quality and adjustment for various confounding factors such as education, smoking, comorbid disorders, physical activity, alcohol intake and medication use showed similar results.ConclusionsThe current study showed that anaemia was related to an increased risk of adult depression. One of the important limitations of our study was a moderate degree of heterogeneity due to the variety of assessment tools used to identify depression and the existence of publication bias. Another limitation of this meta-analysis was the lack of prospective cohort studies.


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