Association of Occupational Factors and Dementia or Cognitive Impairment: A Systematic Review and Meta-Analysis

2020 ◽  
Vol 78 (1) ◽  
pp. 217-227 ◽  
Author(s):  
Liang-Yu Huang ◽  
He-Ying Hu ◽  
Zuo-Teng Wang ◽  
Ya-Hui Ma ◽  
Qiang Dong ◽  
...  

Background: Several existing studies have reported that occupational factors might play an important part in cognitive function with aging. Objective: We aim to explore the associations between modifiable occupational factors and risk of dementia or mild cognitive impairment (MCI). Methods: Adopting random-effect models, this study conducted primary analyses for all occupational factors and subgroup analyses for the effect of occupation type based on prospective cohort and case-control studies searched from PubMed and EMBASE databases up to March 2020. Results: Among the 38,111 identified literatures, 9 studies on occupation type, 4 studies on work complexity, and 30 studies on occupational exposure were included. In terms of occupation type, mental work conferred a 44% reduced risk (95% CI = 0.34–0.94, I² = 85.00%, p < 0.01) for MCI. In terms of work complexity, higher work complexity conferred a 5% reduced risk (95% CI = 0.91–1.00, I² = 57.00%, p < 0.01) for dementia. In terms of occupational exposure, high strain and passive job in the longest-held job conferred a 1.21- and 1.15-fold excess risk (95% CI = 1.05–1.39 I² = 62.00%, p < 0.05; 95% CI = 1.05–1.26 I² = 31.00%, p = 0.23; respectively) of cognitive decline. Besides, magnetic field exposure conferred a 1.26-fold excess risk (95% CI = 1.01–1.57, I² = 69.00%, p < 0.01) for dementia. Conclusion: Novel prevention strategies based on occupational factors may hold promise against dementia and MCI.

Author(s):  
X.-T. Wang ◽  
Z.-T. Wang ◽  
H.-Y. Hu ◽  
Y. Qu ◽  
M. Wang ◽  
...  

Background: Subjective cognitive decline (SCD) as an early pathological manifestation of brain aging has become more prevalent among older adults. Objectives: We aimed to investigate the associations of subjective cognitive decline (SCD) with the combined risk of cognitive impairment and dementia. Design: We performed a systematic review and meta-analysis via searching Embase, PubMed and Cochrane electronic databases from January 1 st 1970 to June 4th, 2020. Setting: Prospective cohort studies Participants: Healthy individuals were recruited from community, clinics and population. Measurements: Healthy individuals with SCD were classified into exposure groups, while those without were considered as the reference group. Adjusted relative risks (RR) were estimated in a random-effects model. Both primary and subgroup analyses were conducted. Results: Of 28,895 identified studies, 21 studies containing 22 cohorts were eligible for inclusion in the meta-analysis. SCD increased the risk of subsequent cognitive disorders (RR=2.12, 95% confidence intervals [CI] =1.75-2.58, I2=87%, P<0.01). To be specific, SCD conferred a 2.29-fold excess risk for cognitive impairment (RR=2.29, 95% CI=1.66-3.17, I2=83%, P<0.01) and a 2.16-fold excess risk for dementia (RR=2.16, 95% CI=1.63-2.86, I2=81%, P<0.01). In subgroup analyses, participants with SCD in the subgroup of 65-75 years old, long-education (>15 years) subgroup and subgroup of clinics showed a higher risk of developing objective cognitive disorders. Conclusions: SCD is associated with an increased combined risk of cognitive impairment and incident dementia and should be considered a risk factor for objective cognitive disorders.


2021 ◽  
Vol 55 (2) ◽  
pp. 79-91
Author(s):  
Yan Deng ◽  
Siqi Zhao ◽  
Guangwen Cheng ◽  
Jiajia Yang ◽  
Benchao Li ◽  
...  

<b><i>Background:</i></b> Mild cognitive impairment (MCI) induced the majority number of dementia patients. The prevalence of MCI in China varied across studies with different screening tools and diagnostic criteria. <b><i>Objective:</i></b> A systematic review and meta-analysis was conducted to estimate the pooled MCI prevalence among the population aged 55 years and older in China. <b><i>Methods:</i></b> PubMed, EMBASE, CNKI, Wanfang, CQVIP, and CBMdisc were searched for studies on prevalence of MCI among Chinese elderly between January 1, 1980, and February 10, 2020. The quality assessment was conducted via external validity, internal validity, and informativity, the pooled prevalence was calculated through the random-effect model, and the homogeneity was evaluated by Cochran’s <i>Q</i> test and <i>I</i><sup>2</sup>. <b><i>Results:</i></b> Fifty-three studies with 123,766 subjects were included. The pooled prevalence of MCI among Chinese elderly was 15.4% (95% CI: 13.5–17.4%). Subgroup analyses indicated that the prevalence calculated with different screening tools was 20.2% (95% CI: 15.1–25.9%) for Montreal Cognitive Assessment (MoCA) and 13.0% (95% CI: 10.7–15.5%) for Mini-Mental State Examination (MMSE). According to different diagnostic criteria, the prevalence was 14.8% (95% CI: 12.2–17.6%) for Petersen criteria, 15.0% (95% CI: 12.7–17.5%) for DSM-IV, and 21.2% (95% CI: 17.5–25.2%) for Chinese Expert Consensus on Cognitive Impairment (CECCI). Besides, women, older adults, illiterate people, rural residents, and those who lived with unhealthy lifestyles and morbidity showed higher prevalence. <b><i>Conclusions:</i></b> The prevalence of MCI in China was 15.4%, which varied by demographics, lifestyles, morbidity, screening tools, and diagnostic criteria. In further studies, screening tools and diagnosis criteria should be considered when estimating MCI prevalence.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Luca Miele ◽  
Cristina Bosetti ◽  
Federica Turati ◽  
Gianlodovico Rapaccini ◽  
Antonio Gasbarrini ◽  
...  

Introduction. Metabolic conditions, including type 2 diabetes, have been related to hepatocellular carcinoma (HCC) risk. We have further analyzed the role of diabetes and antidiabetic treatments on HCC.Methods. Data derived from a hospital-based case-control study (Italy, 2005–2012) on 224 HCC patients and 389 controls. Odds ratios (ORs) were estimated using multiple logistic regression models.Results. Sixty-nine (30.9%) cases versus 52 (13.5%) controls reported a diabetes diagnosis, corresponding to a multivariate OR of 2.25 (95% confidence interval, CI = 1.42–3.56). A stronger excess risk emerged for a longer time since diabetes diagnosis (OR = 2.96 for <10 years and 5.33 for ≥10 years). Oral therapies were inversely, though not significantly, related to HCC risk, OR being 0.44 for metformin and 0.88 for sulfonylureas; conversely, insulin was nonsignificantly directly associated (OR = 1.90). Compared to nondiabetic subjects who were never smokers, those who were diabetics and ever smokers had an OR of 6.61 (95% CI 3.31–13.25).Conclusion. Our study confirms an over 2-fold excess HCC risk in diabetics, with a stronger excess risk in diabetic subjects who are also tobacco smokers. Metformin may decrease the risk of HCC, whereas insulin may increase the risk.


2019 ◽  
Vol 63 (9) ◽  
pp. 1013-1028
Author(s):  
Lucile Migault ◽  
Joseph D Bowman ◽  
Hans Kromhout ◽  
Jordi Figuerola ◽  
Isabelle Baldi ◽  
...  

Abstract Objectives The aim of this work was to build a job-exposure matrix (JEM) using an international coding system and covering the non-thermal intermediate frequency (IF) (3–100 kHz, named IFELF), thermal IF (100 kHz–10 MHz, named IFRF), and radiofrequency (RF) (>10 MHz) bands. Methods Detailed occupational data were collected in a large population-based case–control study, INTEROCC, with occupations coded into the International Standard Classification of Occupations system 1988 (ISCO88). The subjects’ occupational source-based ancillary information was combined with an existing source-exposure matrix and the reference levels of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for occupational exposure to calculate estimates of level (L) of exposure to electric (E) and magnetic (H) fields by ISCO88 code and frequency band as ICNIRP ratios (IFELF) or squared ratios (IFRF and RF). Estimates of exposure probability (P) were obtained by dividing the number of exposed subjects by the total number of subjects available per job title. Results With 36 011 job histories collected, 468 ISCO88 (four-digit) codes were included in the JEM, of which 62.4% are exposed to RF, IFRF, and/or IFELF. As a reference, P values for RF E-fields ranged from 0.3 to 65.0% with a median of 5.1%. L values for RF E-fields (ICNIRP squared ratio) ranged from 6.94 × 10−11 to 33.97 with a median of 0.61. Conclusions The methodology used allowed the development of a JEM for high-frequency electromagnetic fields containing exposure estimates for the largest number of occupations to date. Although the validity of this JEM is limited by the small number of available observations for some codes, this JEM may be useful for epidemiological studies and occupational health management programs assessing high-frequency electromagnetic field exposure in occupational settings.


2017 ◽  
Vol 11 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Felipe Kenji Sudo ◽  
Patricia Amado ◽  
Gilberto Sousa Alves ◽  
Jerson Laks ◽  
Eliasz Engelhardt

ABSTRACT. Background. Subcortical Vascular Cognitive Impairment (SVCI) is a clinical continuum of vascular-related cognitive impairment, including Vascular Mild Cognitive Impairment (VaMCI) and Vascular Dementia. Deficits in Executive Function (EF) are hallmarks of the disorder, but the best methods to assess this function have yet to be determined. The insidious and almost predictable course of SVCI and the multidimensional concept of EF suggest that a temporal dissociation of impairments in EF domains exists early in the disorder. Objective: This study aims to review and analyze data from the literature about performance of VaMCI patients on the most used EF tests through a meta-analytic approach. Methods: Medline, Web of Knowledge and PsycINFO were searched, using the terms: “vascular mild cognitive impairment” OR “vascular cognitive impairment no dementia” OR “vascular mild neurocognitive disorder” AND “dysexecutive” OR “executive function”. Meta-analyses were conducted for each of the selected tests, using random-effect models. Results: Systematic review showed major discrepancies among the results of the studies included. Meta-analyses evidenced poorer performance on the Trail-Making Test part B and the Stroop color test by VaMCI patients compared to controls. Conclusion: A continuum of EF impairments has been proposed in SVCI. Early deficits appear to occur in cognitive flexibility and inhibitory control.


2020 ◽  
Author(s):  
Yeo Jin Kim ◽  
Kyung-Do Han ◽  
Min Seok Baek ◽  
Hanna Cho ◽  
Chul Hyoung Lyoo

Abstract Background Physical activity has been suggested to prevent the conversion of mild cognitive impairment (MCI) to dementia in patients. We investigated the association between the continuance and regularity of physical activity and the risk of developing dementia in patients with MCI. Methods We analyzed data for 247,149 individuals in the National Health Insurance Service (NHIS) cohort who were enrolled between January 1, 2009 and December 31, 2015. The patients were divided into four groups: those who did not engage in physical activity consistently (Never-PA group), those who initiated physical activity (Initiation-PA group), those who ceased physical activity (Withdrawal-PA group), and those who performed physical activity consistently (Maintenance-PA group). We also divided the patients into two groups: those who engaged in physical activity irregularly (Irregular-PA) and those who undertook physical activity regularly (Regular-PA). Results When the risk for the Never-PA group was set as the benchmark (ref=1), the Maintenance-PA group had the lowest incidence of Alzheimer’s disease (AD) compared to the other groups (HR= 0.82, 95% CI 0.79-0.86). The AD risk of Initiation-PA group (HR = 0.89, 95% CI 0.85-0.93) and Withdrawal-PA group (HR = 1, 95% CI 0.96-1.04) was still lower than the Never-PA group. In addition, compared to the Irregular-PA group, the Regular-PA group had a 15% reduced risk for developing AD. Conclusions Continued regular physical activity in patients with MCI is associated with a protective effect against developing AD. Moreover, ceasing physical activity could halt this protective effect.


2020 ◽  
Author(s):  
Yeo Jin Kim ◽  
Kyung-Do Han ◽  
Min Seok Baek ◽  
Hanna Cho ◽  
Eun Joo Lee ◽  
...  

Abstract Background: Physical activity has been suggested to prevent the conversion of mild cognitive impairment (MCI) to dementia in patients. We investigated the association between the continuance and regularity of physical activity and the risk of developing dementia in patients with MCI.Methods: We analyzed 6-year followed up data for 247,149 individuals in the National Health Insurance Service (NHIS) cohort of Korea who were enrolled between January 1, 2009 and December 31, 2015. The patients were divided into four groups: those who did not engage in physical activity consistently (Never-PA group), those who initiated physical activity (Initiation-PA group), those who ceased physical activity (Withdrawal-PA group), and those who performed physical activity consistently (Maintenance-PA group). We also divided the patients into two groups: those who engaged in physical activity irregularly (Irregular-PA) and those who undertook physical activity regularly (Regular-PA).Results: When the risk for the Never-PA group was set as the benchmark (ref=1), the Maintenance-PA group had the lowest incidence of dementia of the Alzheimer type (DAT) compared to the other groups (HR= 0.82, 95% CI 0.79-0.86). The DAT risk of Initiation-PA group (HR = 0.89, 95% CI 0.85-0.93) was lower than the Never-PA group. In addition, compared to the Irregular-PA group, the Regular-PA group had a 15% reduced risk for developing DAT.Conclusions: Although no causal inference could be made, continued regular physical activity in patients with MCI is associated with a protective effect against developing DAT. Moreover, ceasing physical activity could halt this protective effect.


2019 ◽  
Vol 47 (4) ◽  
pp. 478-489 ◽  
Author(s):  
Abdul Razak ◽  
Asif Hussain

Abstract Background Erythropoietin (EPO) appears to confer neuroprotection to the injured brain. Randomized clinical trials (RCTs) have demonstrated its safety in neonates with hypoxic-ischemic encephalopathy (HIE); however, the evidence is unclear. The objective of this study was to examine the role of EPO in perinatal HIE by a systematic review and meta-analysis. Methods Database search included Embase, MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Cochrane Central Register of Controlled Trials (CENTRAL). RCTs reporting a death, neurodevelopmental outcomes or brain injury were included. Two authors extracted the data independently from included studies and assessed the level of evidence (LOE). Results Six RCTs (EPO=5 and darbepoetin α=1) involving 454 neonates were included. A trend toward a lower risk of death was identified in infants treated with EPO [EPO with or without hypothermia: five RCTs, 368 participants, relative risk (RR) 0.74, 95% confidence interval (CI) 0.47–1.19, LOE−low; EPO without hypothermia: four RCTs, 318 participants, RR 0.89, 95% CI 0.49–1.32, LOE−low]. EPO treatment without hypothermia compared to placebo resulted in a reduced risk of cerebral palsy (two RCTs, 230 participants, RR 0.47, 95% CI 0.27–0.80, LOE−moderate) and moderate to severe cognitive impairment (two RCTs, 226 participants, RR 0.49, 95% CI 0.28–0.85, LOE−moderate). A reduced risk of brain injury was identified in EPO treated infants (EPO with or without hypothermia, two RCTs, 148 participants, RR 0.70, 95% CI 0.53–0.92, LOE−moderate). Conclusion EPO administration in neonates with perinatal HIE reduces the risk of brain injury, cerebral palsy and cognitive impairment. The evidence is limited to suggest its role as an adjuvant to hypothermia. Larger powered trials are underway to overcome this limitation.


2021 ◽  
pp. postgradmedj-2021-140432
Author(s):  
Yue Chen ◽  
Xingyu Cheng ◽  
Chenyu Sun ◽  
Na Hyun Kim ◽  
Sujatha Kailas ◽  
...  

ObjectivesStudies on the association between metformin use and the risk of oesophageal cancer (OC) have generated controversial findings. This updated meta-analysis was conducted to reassess the effects of metformin on OC.MethodsA comprehensive search strategy was conducted to select relevant studies from origination to February 2021. Heterogeneity was evaluated through the Q test and I2 statistics. HRs and 95% CIs were pooled through either random-effect or fixed-effect models. Meta-regression, subgroup analyses, sensitivity analysis and publication bias diagnosis were also performed.ResultsSeven studies with 5 426 343 subjects were included. Metformin use was associated with reduced risk of OC (HR=0.69, 95% CI 0.54 to 0.87, p<0.001). Sensitivity analysis suggested that the results were relatively stable.ConclusionMetformin is associated with a reduced risk of OC. More well-designed studies are still needed to further elaborate on these associations.PROSPERO registration numberCRD42021237127.


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