Table 1.
Summary of included studies.
Fig 1.
PRISMA flow chart of studies inclusion and exclusion.
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(7): e1000097. doi:10.1371/journal.pmed1000097. For more information, visit http://www.prisma-statement.org.
Fig 2.
Funnel plot for the assessment of potential publication bias.
The funnel graphs plot the square root of the effective sample size (1/ESS1/2) against the OR. Each dot represents each study in the meta-analysis. Asymmetry of the dot distribution between regression lines indicates potential publication bias. (A) for the evaluation of average level of mtDNA copy number, (B) for the risk analysis among the group below median mtDNA copy number level, (C) for the evaluation of risk increase by every 1-SD decrease in mtDNA copy number level, (D) for the risk measurement of the population located in the lowest part of quartile division of mtDNA copy number level, and (E) for the association analysis between mtDNA copy number and the risk of SCD. This funnel plot indicates no publication bias with a p value >0.05. OR = odds ratio, ESS = effective sample size.
Fig 3.
Forest plot for comparison of the normalized mtDNA copy number level between CVD and control groups.
Only the first author of each study is given. SMD, the mean standard deviation.
Fig 4.
ORs for CVD associated with every 1-SD below in mtDNA copy number measurement.
Only the first author of each study is given. CI, confidence interval.
Fig 5.
ORs of CVD among the mtDNA copy number lower than median level proportion.
Only the first author of each study is given. CI, confidence interval.
Fig 6.
ORs of the population located in lowest quartile level in mtDNA copy number.
Only the first author of each study is given. CI, confidence interval.
Fig 7.
ORs for the association between mtDNA copy number and SCD.
Only the first author of each study is given. CI, confidence interval.
Fig 8.
In each diagram, the vertical solid line in the middle represents the total merge effect, and the two vertical solid lines on the left and right represent the upper and lower limits of the 95% confidence interval of the total consolidation effect; The cross line corresponding to each study represents the combined effect of the remaining studies after the deletion of the study.
Table 2.
Summary of Newcastle-Ottawa Scale scores in quality evaluation.