Racial differences in IGF1 methylation and birth weight

Clinical Epigenetics

Vinod K Misra¹  Dawn P Misra²  Monica Uddin³  Levent Sipahi⁵  Jennifer K Straughen⁴ 

[1] Children’s Hospital of Michigan, Division of Genetic and Metabolic Disorders, The Wayne State University School of Medicine, 3950 Beaubien Blvd, Detroit 48201, MI, USA;Department of Family Medicine and Public Health Sciences, The Wayne State University School of Medicine, 3939 Woodward Avenue, Detroit 48201, MI, USA;Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign 61820, IL, USA;Current address: Department of Public Health Sciences, Henry Ford Hospital, One Ford Place, Detroit 48202, MI, USA;Center for Molecular Medicine and Genetics, The Wayne State University School of Medicine, 540 East Canfield, Detroit 48201, MI, USA

关键词: Perinatal;    Disparities;    Race;    Epigenetics;    Methylation;    IGF1;    Birth weight;   

Others  :  1210207
DOI  :  10.1186/s13148-015-0080-6

 received in 2014-12-30, accepted in 2015-04-06,  发布年份 2015

【 摘 要 】

Background

The birth weight of Black neonates in the United States is consistently smaller than that of their White counterparts. Epigenetic differences between the races may be involved in such disparities. The goal of these analyses was to model the role of IGF1 methylation in mediating the association between race and birth weight. Data was collected on a cohort of 87 live born infants. IGF1 methylation was measured in DNA isolated from the mononuclear fraction of umbilical cord blood collected after delivery. Quantitative, loci-specific methylation was assessed using the Infinium HumanMethylation27 BeadArray (Illumina Inc., San Diego, CA). Locus specific methylation of the IGF1 CpG site was validated on a subset of the original sample (N = 61) using pyrosequencing. Multiple linear regression was used to examine relationships between IGF1 methylation, race, and birth weight. A formal mediation analysis was then used to estimate the relationship of IGF1 methylation to race and birth weight.

Results

Black race was associated with a 7.45% decrease in gestational age-adjusted birth weight (aBW) (P = 0.04) and Black infants had significantly higher IGF1 methylation than non-Black infants (P < 0.05). A one standard deviation increase in IGF1 methylation was associated with a 3.32% decrease in aBW (P = 0.02). Including IGF1 methylation as a covariate, the effect of Black race on aBW was attenuated. A formal mediation analysis showed that the controlled direct effect of Black race on aBW was −6.26% (95% CI = −14.15, 1.06); the total effect of Black race on IGF1 methylation was −8.12% (95% CI = −16.08, −0.55); and the natural indirect effect of Black race on aBW through IGF1 methylation was −1.86% (95% CI = −5.22, 0.18)

Conclusion

The results of the mediation analysis along with the multivariable regression analyses suggest that IGF1 methylation may partially mediate the relationship between Black race and aBW. Such epigenetic differences may be involved in racial disparities observed in perinatal outcomes.

【 授权许可】

   
2015 Straughen et al.; licensee BioMed Central.

【 图 表 】

Figure 1.

Figure 2.

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