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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.

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Related in: MedlinePlus

Forest plots for ApoE levels in AD and healthy controls controlling for fasting.AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.
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pone-0089041-g003: Forest plots for ApoE levels in AD and healthy controls controlling for fasting.AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.

Mentions: Of eight included studies, six studies reported that ApoE levels were significantly lower in AD patients than controls, whereas two studies found no significant difference. Combined analysis of the relationship between the peripheral blood ApoE level and AD was shown in forest plots (Figure 2). Compared to healthy controls, AD subjects had a lower ApoE level. The pooled WMD from a random-effects model was −5.59 mg/l (95% CI: [−8.12, −3.06]; I2 = 78%; Cochran’s Q = 32.35; P<0.0001); the test for overall effect: Z = 4.32; p<0.0001. To eliminate the influence of non-fasting on blood ApoE levels, we also performed an additional analysis of the 5 studies that collected blood sample from fasting participants. The pooled WMD was −8.69 mg/l (95% CI: [−13.08, −4.3]; I2 = 83%; Cochran’s Q  = 23.14; P = 0.0001) (Figure 3).


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)

Forest plots for ApoE levels in AD and healthy controls controlling for fasting.AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0089041-g003: Forest plots for ApoE levels in AD and healthy controls controlling for fasting.AD, Alzheimer’s disease; SD, standard deviation; CI, confidence interval.
Mentions: Of eight included studies, six studies reported that ApoE levels were significantly lower in AD patients than controls, whereas two studies found no significant difference. Combined analysis of the relationship between the peripheral blood ApoE level and AD was shown in forest plots (Figure 2). Compared to healthy controls, AD subjects had a lower ApoE level. The pooled WMD from a random-effects model was −5.59 mg/l (95% CI: [−8.12, −3.06]; I2 = 78%; Cochran’s Q = 32.35; P<0.0001); the test for overall effect: Z = 4.32; p<0.0001. To eliminate the influence of non-fasting on blood ApoE levels, we also performed an additional analysis of the 5 studies that collected blood sample from fasting participants. The pooled WMD was −8.69 mg/l (95% CI: [−13.08, −4.3]; I2 = 83%; Cochran’s Q  = 23.14; P = 0.0001) (Figure 3).

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