Salivary cortisol mediates effects of poverty and parenting on executive functions in early childhood

May combine two claims.

In this low-income longitudinal sample, higher salivary cortisol measured at 7, 15, and 24 months was uniquely linked to poorer executive function and, less strongly, to lower IQ at age 3.

“higher level of salivary cortisol assessed at ages 7, 15, and 24 months was uniquely associated with lower executive function ability and to a lesser extent IQ at age 3 years.”

May combine two claims.

Positive parenting, negative parenting, and household risk each had unique associations with both executive function and IQ.

“Measures of positive and negative aspects of parenting and household risk were also uniquely related to both executive functions and IQ.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Scores on the executive function tasks were moderately correlated, with r values from .22 to .32 and p < .001.

“Scores were moderately correlated (r = .22 – .32, p < .001).”

Probably not a substantial claim: may not pass S3 (load-bearing).

Executive function and IQ were moderately correlated.

“Executive function and IQ are moderately correlated.”

May combine two claims.

Maternal education, family income, and household density and safety were moderately correlated with parenting and with the cognitive measures.

“Maternal education, family income, and household density and safety are moderately correlated with parenting and with the cognitive measures.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Small significant associations of time since eating and time since sleeping with cortisol at 7 months were accounted for by adjusting for time of day of saliva collection.

“Small significant relations of time since eating and time since sleeping with cortisol at 7 months were accounted for by adjustment for time of day of saliva collection.”

May combine two claims.

Income-to-need was highly correlated across time points (r = .80, p < .0001) and was averaged across ages 7, 15, and 24 months into a single indicator.

“Income-to-need was highly correlated across time points (r = .80, p < .0001) and averaged at child ages 7, 15, and 24 months to create a single indicator.”

May combine two claims.

Cortisol levels were significantly higher at each time point and executive function and IQ were significantly lower for African American participants.

“Levels of cortisol are significantly higher at each time point and child executive function and IQ significantly lower.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

All correlations between latent variables were large and significant at p < .001.

“All correlations between latent variables were large and significant (all p < .001.)”

May combine two claims.

Ratings of positive parenting were significantly lower and ratings of negative parenting significantly higher for African American participants.

“Ratings of positive parenting are significantly lower and negative parenting significantly higher.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Parenting measures, especially positive parenting, had small correlations with cortisol at most time points.

“The measures of parenting at child ages 7, 15, and 24 months, particularly positive parenting, have small correlations with cortisol at most time points.”

May combine two claims.

Income-to-need and maternal education were significantly lower for African American participants, and their homes were significantly more crowded and rated less safe than White participants' homes.

“Income-to-need and maternal education are significantly lower for African Americans and African American families’ homes are significantly more crowded and rated as less safe than are the homes of white participants.”

May combine two claims.

Both executive function and IQ were correlated with the household risk latent variable, with phi = -.44 and -.53 respectively.

“Both executive function and IQ were correlated with the household risk latent variable (φ = −.44 and = − .53, respectively).”

May combine two claims.

Both executive function and IQ were predicted by negative parenting (beta = -.26, p = .003 and beta = -.27, p < .0001), positive parenting (beta = .19, p = .04 and beta = .26, p < .0001), and household risk (marginally for executive function, beta = -.12, p = .07; significantly for IQ, beta = -.25, p < .0001).

“Both executive function and IQ were predicted by negative parenting (β = −.26, p = .003, β = −.27, p < .0001, respectively), positive parenting, (β = .19, p = .04, β = .26, p < .0001), and by household risk (marginally for executive function, β = −.12, p = .07, significantly for IQ, β = −.25, p < .0001).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The correlation between the executive function and IQ latent variables was very high, phi = .92.

“Correlation between EF and IQ latent variables was very high (φ = .92), a finding consistent with numerous studies examining latent variable correlations for these constructs.”

May combine two claims.

Cortisol was negatively related to positive parenting (phi = -.47) and positively related to negative parenting (phi = .37) and household risk (phi = .26).

“Cortisol was negatively related to positive parenting (φ = −.47), and positively related to negative parenting (φ = .37) and household risk (φ = .26).”

May combine two claims.

The executive function latent variable was moderately correlated with positive parenting (phi = .59) and negative parenting (phi = -.59), and IQ showed similar correlations (phi = .61 and -.61).

“The executive function latent variable was moderately correlated with the latent positive (φ = .59) and negative (φ = −.59) parenting variables as was IQ (φ = .61 and −.61).”

May combine two claims.

Executive function and IQ were negatively related to the cortisol latent variable, with a larger relation for executive function (phi = -.56) than for IQ (phi = -.37).

“Executive function and IQ were negatively related to the cortisol latent variable, with a larger relation for executive function (φ = −.56) than for IQ (φ = − .37).”

May combine two claims.

Neither executive function nor IQ was directly predicted by maternal education, income-to-need ratio, African American ethnicity, or age at assessment.

“Neither executive function nor IQ was directly predicted by observed variables maternal education, income-to-need ratio, African American ethnicity, or age at assessment.”

May combine two claims.

Executive function was negatively predicted by cortisol (beta = -.42, p < .0001), while the relation of cortisol to IQ was marginal (beta = -.15, p = .06).

“Direct effects were observed in which executive function was negatively predicted by cortisol, β = −.42, p < .0001, while the relation of cortisol to IQ was marginal, β = −.15, p = .06.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

The conditions of poverty over the child's first two years tend to be stable in this sample.

“The conditions of poverty over the child’s first two years tend to be stable in this sample”

Classified as probably not a substantial claim. May combine two claims.

Early experience influences both cognitive development and the development of the physiological stress response.

“The effect of early experience on cognitive development (Ramey & Ramey, 1998) and on the development of the physiological response to stress (Gunnar & Quevedo, 2007) is well established.”

• cites Ramey & Ramey, 1998Not checked yet

  Not checked in the free run.

• cites Gunnar & Quevedo, 2007Not checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

The physiological stress response, indexed by glucocorticoids and catecholamines, is related to distinct cognitive domains including declarative memory and executive functions.

“It is also well established that the physiological response to stress, as indicated by levels of neuroendocrine hormones, glucocorticoids and catecholamines, is related to distinct aspects of cognition, including declarative memory as well as executive functions (Arnsten, 2000; Diamond, Campbell, Park, Halonen, & Zoladz, 2007).”

• cites Arnsten, 2000 sourceNot checked yet

  Not checked in the free run.

• cites Diamond, Campbell, Park, Halonen, & Zoladz, 2007 sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Under ongoing or persistent stress, basal levels or set points of physiological stress response systems shift upward or downward, a phenomenon called allostasis.

“Importantly, under conditions of ongoing or persistent stress, basal levels or set points of physiological stress response systems are altered either upward or downward, a phenomenon referred to as allostasis (McEwen, 2000).”

• cites McEwen, 2000Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Executive functions contribute substantially to behavioral self-regulation and are central to early academic achievement.

“Executive functions contribute substantially to the self-regulation of behavior (Carlson, Mandell, & Williams, 2004; Hughes & Ensor, 2007) and are central to early academic achievement (Blair & Razza, 2007).”

• cites Carlson, Mandell, & Williams, 2004 sourceNot checked yet

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• cites Hughes & Ensor, 2007Not checked yet

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• cites Blair & Razza, 2007 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

The link between stress hormone levels and executive functions has been shown in naturalistic studies of preschool children and in pharmacological studies with adults.

“In humans the link between stress hormone levels and executive functions has been demonstrated in naturalistic studies with preschool children (Blair, Granger, & Razza, 2005; Davis, Bruce, & Gunnar, 2002) and in pharmacological manipulations with adults (Alexander, Hillier, Smith, Tivarus, & Beversdorf, 2007; Lupien, Gillin, & Hauger, 1999).”

• cites Blair, Granger, & Razza, 2005 sourceNot checked yet

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• cites Davis, Bruce, & Gunnar, 2002Not checked yet

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• cites Alexander, Hillier, Smith, Tivarus, & Beversdorf, 2007 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Prefrontal cortex and executive functions are sensitive indicators of stress effects on development.

“Although by no means the only brain area and cognitive ability affected by stress hormones, PFC and executive functions are sensitive indicators of the effects of stress on development (Cerqueira, Mailliet, Almeida, Jay, & Sousa, 2007).”

• cites Cerqueira, Mailliet, Almeida, Jay, & Sousa, 2007 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

In humans, early sensitive parenting is associated with well-regulated stress physiology and with higher general cognitive and emotion regulation ability.

“In humans, early sensitive parenting is associated with a well regulated stress physiology (Gunnar & Quevedo, 2007) and with higher level of general cognitive (Lugo-Gil & Tamis-Lemonda, 2008) and emotion regulation ability (Sroufe, 1996).”

• cites Gunnar & Quevedo, 2007Not checked yet

  Not checked in the free run.

• cites Lugo-Gil & Tamis-Lemonda, 2008 sourceNot checked yet

  Not checked in the free run.

• cites Sroufe, 1996 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Animal models indicate that early caregiving is a primary influence on HPA axis development and adaptively shapes offspring development for an expected environment.

“Research in animal models indicates early caregiving to be a primary influence on the development of the HPA axis (Champagne et al., 2008; Liu, Diorio, Day, Francis, & Meaney, 2000) and to adaptively shape offspring development to meet an expected environment (Cameron, Champagne, Parent, Fish, Ozaki-Kuroda, & Meaney, 2005).”

• cites Champagne et al., 2008Not checked yet

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• cites Liu, Diorio, Day, Francis, & Meaney, 2000 sourceNot checked yet

  Not checked in the free run.

• cites Cameron, Champagne, Parent, Fish, Ozaki-Kuroda, & Meaney, 2005 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

The environment of poverty is stressful for children and has been associated with higher stress hormone levels.

“The environment of poverty is stressful for children and to date has been associated with increased levels of stress hormones (Evans, 2003).”

• cites Evans, 2003 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Parenting is a primary mechanism through which poverty affects child development and likely mediates the association between poverty and elevated stress in young children.

“Parenting is a primary mechanism through which poverty affects child development (Brody, Murry, Kim, & Brown, 2002; Gershoff, Aber, Raver, & Lennon, 2007; McLoyd, 1998) and likely mediates an association between poverty and elevated stress in young children.”

• cites Brody, Murry, Kim, & Brown, 2002Not checked yet

  Not checked in the free run.

• cites Gershoff, Aber, Raver, & Lennon, 2007 sourceNot checked yet

  Not checked in the free run.

• cites McLoyd, 1998Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Complex sampling procedures were used to recruit a representative sample of 1,292 families in two U.S. regions at the time of the child's birth.

“Complex sampling procedures were used to recruit a representative sample of 1,292 families in two regions of the U.S. at the time that mothers gave birth to a child.”

May combine two claims.

A prior analysis of this sample found that high positive but not negative parenting in infancy was associated with lower basal cortisol and greater cortisol reactivity at 7 and 15 months.

“A prior analysis of the sample reported on here demonstrated that high level of positive but not negative parenting in infancy is associated with lower basal levels of cortisol and greater cortisol reactivity to emotional arousal at age 7 and 15 months (Blair et al., 2008).”

• cites Blair et al., 2008 sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Executive functions are largely distinct from general intelligence.

“Although executive functions are largely distinct from general intelligence (Blair, 2006), the executive function of working memory has been shown to be highly related to general mental ability in a number of studies with adults (Friedman, Miyake, Corley, Young, Defries, & Hewitt, 2006).”

• cites Blair, 2006 sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Two prior studies found no differences in cortisol concentrations between cotton and hydrocellulose saliva collection techniques.

“Two prior studies have indicated no differences in cortisol concentrations associated with the two collection techniques (Granger, Kivlighan, Fortunato, Harmon, Hibel, Schwartz & Whembolua, 2007; Harmon, Granger, Hibel & Rumyantseva, 2007).”

• cites Granger, Kivlighan, Fortunato, Harmon, Hibel, Schwartz & Whembolua, 2007Not checked yet

  Not checked in the free run.

• cites Harmon, Granger, Hibel & Rumyantseva, 2007Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The emotion challenge procedures used to elicit emotional responding had been previously validated.

“All procedures have been previously validated (Stifter & Braungart, 1995).”

• cites Stifter & Braungart, 1995Not checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Prior longitudinal analyses found that risk processes in the context of poverty operate similarly in African American and White families.

“Prior analyses conducted with longitudinal samples have demonstrated that risk processes in the context of poverty work similarly in African American and white families (Conger, Wallace, Sun, Simon, McLoyd, & Brody, 2002; Raver, Gershoff, & Aber, 2007).”

• cites Conger, Wallace, Sun, Simon, McLoyd, & Brody, 2002Not checked yet

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• cites Raver, Gershoff, & Aber, 2007Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Working memory is highly related to general mental ability in adults.

“Although executive functions are largely distinct from general intelligence (Blair, 2006), the executive function of working memory has been shown to be highly related to general mental ability in a number of studies with adults (Friedman, Miyake, Corley, Young, Defries, & Hewitt, 2006).”

• cites Friedman, Miyake, Corley, Young, Defries, & Hewitt, 2006 sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Of 1,105 children given executive function tasks, 764 completed the working memory span task, 795 completed the attention flexibility task, and 866 completed the spatial conflict inhibitory control task.

“Of 1,105 children administered the executive function tasks, 764 successfully completed the working memory span task, 795 successfully completed the attention flexibility task, and 866 successfully completed the spatial conflict inhibitory control task.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

All cortisol samples were assayed in duplicate; samples with more than 20% variation between duplicates were repeated, and the duplicate average was used in analyses.

“All samples were assayed in duplicate. The criterion for repeat testing was variation between duplicates greater than 20%, and the average of the duplicates was used in all analyses.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Few variables showed differences between families present and families missing at each time point.

“Few variables indicated differences between families who were present and those who were missing at each time point.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Salivary cortisol was assayed with a highly sensitive enzyme immunoassay cleared by the FDA for in vitro diagnostic use, with average intra- and inter-assay coefficients of variation below 10% and 15%.

“All samples were assayed for salivary cortisol using a highly-sensitive enzyme immunoassay US FDA 510k cleared for use as an in vitro diagnostic measure of adrenal function (Salimetrics, State College, PA). The test used 25 μl of saliva for singlet determinations, had a range of sensitivity from .007 to 1.8 μg/dl, and average intra-and inter-assay coefficients of variation of less than 10% and 15%”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Inter-rater reliability for parenting ratings was .85 to .91 for positive parenting and .72 to .86 for negative parenting across the 7-, 15-, and 24-month assessments.

“ICCs were .85 – .91 for positive parenting and .72 –.86 across 7, 15, and 24 month assessments.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Children had to pass pretest trials and complete at least 75% of test trials to receive a score, following standard practice for executive function measures in children.

“As is standard for executive function measures with children (Zelazo, 2006), children were required to successfully complete pretest trials for all tasks in which they clearly demonstrated knowledge of the rules for the task and the ability to successfully complete the pretest trials as instructed. Children were also required to complete 75% of test trials in a given task in order to receive a sc”

• cites Zelazo, 2006 sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Executive function was assessed with three tasks modeled on tasks previously used successfully with young children.

“Executive function was assessed with three tasks modeled on tasks previously used successfully with young children. Full details on the executive function tasks are available in Willoughby, Blair, Wirth, & Greenberg (2010).”

• cites Willoughby, Blair, Wirth, & Greenberg (2010) sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

Full information maximum likelihood estimation was used in all analyses to avoid bias from listwise deletion.

“To avoid bias in estimates associated with listwise deletion we used full information maximum likelihood estimation for all analyses.”

May combine two claims.

All factor loadings were statistically significant and in the expected direction, and all latent variances were statistically significant.

“Inspection of parameter estimates indicated that all of the factor loadings were statistically significant and in the expected direction and that all of the latent variances were statistically significant.”

May combine two claims.

Cortisol and both positive and negative parenting mediate associations between poverty conditions and child cognitive ability at age 3 years.

“that cortisol and both positive and negative parenting mediate associations between the conditions of poverty and child cognitive ability at age 3 years”

• AssumptionRests on an assumption: No previous study has examined multiple aspects of poverty in an early childhood sample with the goal of linking poverty, stress physiology, parenting, and cognitive development.

Probably not a substantial claim: may not pass S3 (load-bearing).

Several studies have demonstrated that poverty is associated with increased levels in stress physiology indicators in children.

“several studies have demonstrated that poverty is associated with increased levels in stress physiology indicators in children (Evans, 2003; Fernald & Gunnar, 2009; Lupien, King, Meaney, & McEwen, 2001)”

• cites Evans, 2003 sourceNot checked yet

  Not checked in the free run.

• cites Fernald & Gunnar, 2009Not checked yet

  Not checked in the free run.

• cites Lupien, King, Meaney, & McEwen, 2001Not checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

In biological sensitivity theory, early experience shapes stress response systems to meet expected environments with consequences for behaviors important for regulating behavior in that environment.

“In the biological sensitivity theory, early experience is understood to shape stress response systems to meet expected environments with consequences for behaviors important for regulating behavior in that environment.”

• cites Boyce & Ellis, 2005 sourceNot checked yet

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• cites Ellis, Essex, & Boyce, 2005 sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Mechanisms through which physiological stress affects physical and mental health are well established.

“the mechanisms through which physiological stress affects physical and mental health are well established (McEwen, 2000)”

• cites McEwen, 2000Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The close association between executive function and IQ is consistent with theory and research indicating that executive functions are important building blocks for the development of children's thinking and key contributors to the development of intelligence.

“The close association between the constructs is consistent with theory and research indicating that executive functions are important building blocks for the development of children’s thinking (Zelazo, Muller, Frye, & Marcovitch, 2003) and key contributors to the development of intelligence (Piaget, 1952).”

• cites Zelazo, Muller, Frye, & Marcovitch, 2003 sourceNot checked yet

  Not checked in the free run.

• cites Piaget, 1952 sourceNot checked yet

  Not checked in the free run.

Classified as probably not a substantial claim.

A number of prior studies indicate that executive functions are central to the development of fluid intelligence in children and adults.

“A number of prior studies indicate that executive functions are central to the development of fluid intelligence in children (Fry & Hale, 1996; Kail, 2007) and adults (Engle, Tuholski, Lauglin, & Conway, 1999).”

• cites Fry & Hale, 1996Not checked yet

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• cites Kail, 2007Not checked yet

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• cites Engle, Tuholski, Lauglin, & Conway, 1999 sourceNot checked yet

  Not checked in the free run.

May combine two claims.

Findings here agree with prior studies and indicate that the influence of early experience on executive functions is one pathway through which intelligence develops.

“Findings here are in agreement with these prior studies and indicate the influence of early experience on executive functions as one pathway through which intelligence develops.”

May combine two claims.

In unsupportive environments, increased stress physiology is not well regulated and stress hormones remain elevated, facilitating reactive and inflexible rather than reflective and flexible behavior and cognition.

“In unsupportive environments, however, this increase would not be well regulated and stress hormones would remain elevated, facilitating reactive and inflexible rather than reflective and flexible forms of behavior and cognition.”

Classified as probably not a substantial claim.

The diurnal variation in cortisol necessitates that cortisol levels be adjusted for time of day of saliva collection.

“This variation necessitates that cortisol levels be adjusted for time of day of saliva collection.”

• AssumptionRests on an assumption: Cortisol follows a well-defined diurnal pattern.

May combine two claims.

Work by Fernald and Gunnar (2009) has shown that although there can be some effect of data collectors' presence in the home on child cortisol levels, effects are similar across children and dissipate within one hour.

“work by Fernald and Gunnar (2009) has shown that although there can be some effect of data collectors’ presence in the home on child cortisol levels, effects are similar across children and dissipate within one hour.”

• cites Fernald & Gunnar (2009)Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

Results are consistent with prior studies examining the neurobiology of relations among early experience, the stress response, and cognitive ability.

“Results are consistent with prior studies examining the neurobiology of relations among early experience, the stress response, and cognitive ability.”

Classified as probably not a substantial claim.

Only one aspect of stress physiology, salivary cortisol as an indicator of HPA axis activity, was measured.

“Only one aspect of stress physiology, salivary cortisol as an indicator of the activity of the HPA axis, however, was measured.”

Probably not a substantial claim: may not pass S3 (load-bearing).

By focusing on typical cortisol level, the study did not address questions concerning the relative influence of cortisol and parenting variables at 7, 15, and 24 months on child cognitive ability at age 3 years.

“by focusing on the typical cortisol level or set point over the child’s first two years, we did not address questions concerning the relative influence of cortisol and parenting variables at 7, 15, and 24 months on child cognitive ability at age 3 years.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The approach does not obviate the fact that the HPA axis is a dynamic and reactive system and that measures of HPA reactivity provide meaningful information about effects of stress on development.

“This approach, however, in no way obviates that fact that the HPA axis is a dynamic and reactive system and that measures of HPA reactivity provide meaningful information about effects of stress on development.”

• AssumptionRests on an assumption: The HPA axis is a dynamic and reactive system.

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Saliva samples were collected in the home by data collectors and there may have been some effect of the presence of the data collector on child cortisol.

“Saliva samples were collected in the home by data collectors and there may have been some effect of the presence of the data collector on child cortisol.”