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Re: Childhood adversity and cell-mediated immunity in young adulthood
Brain, Behavior, and Immunity 34 (2013) 176
Contents lists available at ScienceDirect
Brain, Behavior, and Immunity journal homepage: www.elsevier.com/locate/ybrbi
Letter to the Editor Re: Childhood adversity and cell-mediated immunity in young adulthood
Dear Editor, Slopen, et al. (Feb 2013) examine the association between early adversity and cell-mediated immune function as measured by Epstein-Barr (EBV) antibody titers in the fourth wave of the National Longitudinal Study of Adolescent Health (Add Health). We noted with interest that the study did not exclude any individuals who were EBV seronegative in the analysis of continuous EBV antibodies, though stress-related reactivation of latent herpesvirus infections depends on having been previously infected. Even though a high proportion of this age group is seropositive, the risk of seropositivity in the National Health and Nutrition Examination Survey (NHANES) has been shown to vary significantly according to important sociodemographic variables including race, education, and income Dowd et al., 2013. To explore this issue we examined similar socioeconomic predictors of EBV seropositivity in the Add Health data. Given the absence of information on a seropositivity cut-off in the Add Health documentation, we used an estimated seronegative cut-off of the bottom 10% of continuous EBV antibody values (survey-weighted) based on the estimates from the slightly younger age group in NHANES Dowd et al., 2013. We found that adjusting for race, those with only a high school education had a 5% higher prevalence of EBV compared to those with college or higher (Prevalence Ratio (PR) 1.05, 95% CI 1.02–1.08), and adjusting for education, Blacks and Hispanics had 4% higher prevalence compared to Whites (PR 1.04, 95% CI 1.02–1.06, and PR 1.04, 95% CI 1.01–1.06, respectively.) In light of these results, the failure to exclude those who were EBV seronegative from continuous antibody analysis would result in estimates that are a combination of the association of the risk factors with EBV seropositivity itself as well as continuous antibody response (reflecting subclinical reactivation) among the positive. Since those who are seropositive are more likely to be non-white and socioeconomically less advantaged, they would also be likely to have a higher frequency of physical and sexual abuse, potentially biasing upward the coefficients of abuse on
0889-1591/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.bbi.2013.08.003
EBV antibody titers. The exclusion of seronegatives when examining stress-related reactivation of herpesvirus antibody titers is likely to be especially important when social factors are so strongly associated with both seropositivity and the stressful exposures under investigation. References Slopen, N. et al, 2013. Childhood adversity and cell-mediated immunity in young adulthood: does type and timing matter? Brain. Behav. Immun. 28, 63–71. Dowd, J.B. et al, 2013. Seroprevalence of Epstein-Barr virus infection in U.S. Children ages 6–19, 2003–2010. PLoS One 8 (5), e64921.
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Jennifer B. Dowd CUNY School of Public Health, Hunter College, United States CUNY Institute for Demographic Research (CIDR), United States ⇑ Tel.: +1 203 396 7748. E-mail address: [email protected] Tia Palermo Program in Public Health, Department of Preventive Medicine, Stony Brook University (SUNY), United States Laura Chyu School of Education and Social Policy, Northwestern University, United States Emma Adam School of Education and Social Policy, Northwestern University, United States Cells to Society: The Center on Social Disparities and Health, Institute for Policy Research, Northwestern University, United States Thomas W. McDade Department of Anthropology, Northwestern University, United States Cells to Society: The Center on Social Disparities and Health, Institute for Policy Research, Northwestern University, United States Available online 11 August 2013
Contents lists available at ScienceDirect
Brain, Behavior, and Immunity journal homepage: www.elsevier.com/locate/ybrbi
Letter to the Editor Re: Childhood adversity and cell-mediated immunity in young adulthood
Dear Editor, Slopen, et al. (Feb 2013) examine the association between early adversity and cell-mediated immune function as measured by Epstein-Barr (EBV) antibody titers in the fourth wave of the National Longitudinal Study of Adolescent Health (Add Health). We noted with interest that the study did not exclude any individuals who were EBV seronegative in the analysis of continuous EBV antibodies, though stress-related reactivation of latent herpesvirus infections depends on having been previously infected. Even though a high proportion of this age group is seropositive, the risk of seropositivity in the National Health and Nutrition Examination Survey (NHANES) has been shown to vary significantly according to important sociodemographic variables including race, education, and income Dowd et al., 2013. To explore this issue we examined similar socioeconomic predictors of EBV seropositivity in the Add Health data. Given the absence of information on a seropositivity cut-off in the Add Health documentation, we used an estimated seronegative cut-off of the bottom 10% of continuous EBV antibody values (survey-weighted) based on the estimates from the slightly younger age group in NHANES Dowd et al., 2013. We found that adjusting for race, those with only a high school education had a 5% higher prevalence of EBV compared to those with college or higher (Prevalence Ratio (PR) 1.05, 95% CI 1.02–1.08), and adjusting for education, Blacks and Hispanics had 4% higher prevalence compared to Whites (PR 1.04, 95% CI 1.02–1.06, and PR 1.04, 95% CI 1.01–1.06, respectively.) In light of these results, the failure to exclude those who were EBV seronegative from continuous antibody analysis would result in estimates that are a combination of the association of the risk factors with EBV seropositivity itself as well as continuous antibody response (reflecting subclinical reactivation) among the positive. Since those who are seropositive are more likely to be non-white and socioeconomically less advantaged, they would also be likely to have a higher frequency of physical and sexual abuse, potentially biasing upward the coefficients of abuse on
0889-1591/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.bbi.2013.08.003
EBV antibody titers. The exclusion of seronegatives when examining stress-related reactivation of herpesvirus antibody titers is likely to be especially important when social factors are so strongly associated with both seropositivity and the stressful exposures under investigation. References Slopen, N. et al, 2013. Childhood adversity and cell-mediated immunity in young adulthood: does type and timing matter? Brain. Behav. Immun. 28, 63–71. Dowd, J.B. et al, 2013. Seroprevalence of Epstein-Barr virus infection in U.S. Children ages 6–19, 2003–2010. PLoS One 8 (5), e64921.
⇑
Jennifer B. Dowd CUNY School of Public Health, Hunter College, United States CUNY Institute for Demographic Research (CIDR), United States ⇑ Tel.: +1 203 396 7748. E-mail address: [email protected] Tia Palermo Program in Public Health, Department of Preventive Medicine, Stony Brook University (SUNY), United States Laura Chyu School of Education and Social Policy, Northwestern University, United States Emma Adam School of Education and Social Policy, Northwestern University, United States Cells to Society: The Center on Social Disparities and Health, Institute for Policy Research, Northwestern University, United States Thomas W. McDade Department of Anthropology, Northwestern University, United States Cells to Society: The Center on Social Disparities and Health, Institute for Policy Research, Northwestern University, United States Available online 11 August 2013