Limits...
Meta-analysis of peripheral blood apolipoprotein E levels in Alzheimer's disease.

Wang C, Yu JT, Wang HF, Jiang T, Tan CC, Meng XF, Soares HD, Tan L - PLoS ONE (2014)

Bottom Line: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed.The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]).The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong, China.

ABSTRACT

Background: Peripheral blood Apolipoprotein E (ApoE) levels have been proposed as biomarkers of Alzheimer's disease (AD), but previous studies on levels of ApoE in blood remain inconsistent. This meta-analysis was designed to re-examine the potential role of peripheral ApoE in AD diagnosis and its potential value as a candidate biomarker.

Methods: We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane library, and BIOSIS previews for case-control studies measuring ApoE levels in serum or plasma from AD subjects and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between ApoE levels and AD risk.

Results: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed. The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]). The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

Conclusions: Our meta-analysis supports a lowered level of blood ApoE in AD patients, and indicates its potential value as an important risk factor for AD. Further investigation employing standardized assay for ApoE measurement are still warranted to uncover the precise role of ApoE in the pathophysiology of AD.

Show MeSH

Related in: MedlinePlus

Funnel plots for ApoE levels in AD and healthy controls in included studies.Vertical dashed lines represent the summary weighted mean difference (WMD).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3928366&req=5

pone-0089041-g004: Funnel plots for ApoE levels in AD and healthy controls in included studies.Vertical dashed lines represent the summary weighted mean difference (WMD).

Mentions: As sensitivity analyses, we excluded 1 study at a time to assess the stability of the results. There was no significant change in the pooled WMD or 95%CI on excluding any of the studies (WMD lied between −4.80 and −6.38). The study of V.B.Gupta 2011 [28] and Holly D. Soares 2012 [31] which were the only two published after 2003 seemed to have a larger influence, but the result did not change materially after exclusion of these two studies (WMD: −3.54; 95%CI: [−5.00, −2.08]), which suggested that the overall results of this meta-analysis were statistically robust. In addition, the heterogeneity was effectively removed after excluding these two studies (Cochran Q = 7.79; P = 0.17; I2 = 36%). Visual inspection of the funnel plot (Figure 4) indicated asymmetrical distribution of WMD, suggesting publication bias.


Meta-analysis of peripheral blood apolipoprotein E levels in Alzheimer's disease.

Wang C, Yu JT, Wang HF, Jiang T, Tan CC, Meng XF, Soares HD, Tan L - PLoS ONE (2014)

Funnel plots for ApoE levels in AD and healthy controls in included studies.Vertical dashed lines represent the summary weighted mean difference (WMD).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928366&req=5

pone-0089041-g004: Funnel plots for ApoE levels in AD and healthy controls in included studies.Vertical dashed lines represent the summary weighted mean difference (WMD).
Mentions: As sensitivity analyses, we excluded 1 study at a time to assess the stability of the results. There was no significant change in the pooled WMD or 95%CI on excluding any of the studies (WMD lied between −4.80 and −6.38). The study of V.B.Gupta 2011 [28] and Holly D. Soares 2012 [31] which were the only two published after 2003 seemed to have a larger influence, but the result did not change materially after exclusion of these two studies (WMD: −3.54; 95%CI: [−5.00, −2.08]), which suggested that the overall results of this meta-analysis were statistically robust. In addition, the heterogeneity was effectively removed after excluding these two studies (Cochran Q = 7.79; P = 0.17; I2 = 36%). Visual inspection of the funnel plot (Figure 4) indicated asymmetrical distribution of WMD, suggesting publication bias.

Bottom Line: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed.The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]).The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong, China.

ABSTRACT

Background: Peripheral blood Apolipoprotein E (ApoE) levels have been proposed as biomarkers of Alzheimer's disease (AD), but previous studies on levels of ApoE in blood remain inconsistent. This meta-analysis was designed to re-examine the potential role of peripheral ApoE in AD diagnosis and its potential value as a candidate biomarker.

Methods: We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane library, and BIOSIS previews for case-control studies measuring ApoE levels in serum or plasma from AD subjects and healthy controls. The pooled weighted mean difference (WMD) and 95% confidence interval (CI) were used to estimate the association between ApoE levels and AD risk.

Results: Eight studies with a total of 2250 controls and 1498 AD cases were identified and analyzed. The pooled WMD from a random-effect model of AD participants compared with the healthy controls was -5.59 mg/l (95% CI: [-8.12, -3.06]). The overall pattern in WMD was not varied by characteristics of study, including age, country, assay method, publication year, and sample type.

Conclusions: Our meta-analysis supports a lowered level of blood ApoE in AD patients, and indicates its potential value as an important risk factor for AD. Further investigation employing standardized assay for ApoE measurement are still warranted to uncover the precise role of ApoE in the pathophysiology of AD.

Show MeSH
Related in: MedlinePlus