The Influence of Teacher–Child Relationships on Preschool Children’s Cortisol Levels

  • Bridget E. HatfieldEmail author
Part of the Emerging Issues in Family and Individual Resilience book series (EIIFR)


A central component of the stress response system, the HPA axis, is shaped in part by environmental inputs throughout early childhood. In particular, the relationships children have during this time are associated with levels of cortisol, the hormonal by-product of the HPA axis. High levels or aberrant patterns of cortisol in young children are related to a variety of deleterious outcomes. Encouragingly, sensitive, responsive parent–child relationships support adaptive cortisol levels and can protect the child in the face of adverse life events. For many children, relationships with teachers in early care and education (ECE) settings are also necessary. This chapter outlines the unique role of ECE teachers on preschool children’s developing stress response system. Children with close, supportive relationships with their ECE teachers are more likely to succeed academically and behaviorally. Further, close relationships and responsive, sensitive ECE classrooms support cortisol patterns for children that align with the expected decline across the day. Results from relationship-focused interventions indicate that a focus on these types of supports may lead to positive change in children’s cortisol at child care. Implications for practice, policies, and families are discussed.


Teacher–child relationships Cortisol Preschool Child care quality Early care and education HPA axis Sensitive caregiving 



Classroom relational climate

A construct of classroom process quality that focuses explicitly on responsive, warm, and sensitive teacher–child interactions at the classroom level.

Close teacher–child relationship

A teacher–child relationship that is characterizied by sensitive and warm interactions, children’s use of the teacher as a secure base, and display of positive affection.


A hormone produced by the HPA axis that affords the ability to cope with stressors and daily life. Cortisol is expected to be the highest approximately 30 min after wake and then decline across the day.

Early care and education

A setting (e.g., center, family child care home) that serves children 0–5 years. The focus of these settings is on the care, education, and development of young children.

Hypothalamic pituitary adrenal (HPA) axis

HPA axis provides a more consistent response (compared to the sympathetic and parasympathetic systems) through the release of cortisol that helps the individual return to homeostasis. It primes the individual to be vigilant through the release of the hormone cortisol.

Process quality

A construct of classroom quality that focuses on relationships and interactions between teachers and children and among peers.

School readiness

A set of skills which include cognitive (e.g., language), social (e.g., peer relations), emotional (e.g., regulation of anger), and behavioral (e.g., impulse control) competencies that children should possess to be ready for school. Often refered to as skills children need to be ready for kindergarten/formal schooling.

Secure attachment

An attachment classification coined by Mary Ainsworth that characterizes an adult–child relationship that is sensitive, warm, and responsive. In a secure adult–child attachment, the child uses the adult as a secure base.

Stress response system

Comprised of three distinct structures—parasympathetic, sympathetic, and hypothalamic pituitary adrenal (HPA) axis that react in response to a stressor.

Structural quality

A construct of classroom quality that focuses on largely physical factors such as teacher education level, curriculum, ratio, and classroom materials.


  1. Ahnert, L., Gunnar, M. G., Lamb, M. E., & Barthel, M. (2004). Transition to child care: Associations with infant-mother attachment, infant negative emotion, and cortisol elevations. Child Development, 75, 639–650. Scholar
  2. Ahnert, L., Harwardt-Heinecke, E., Kappler, G., Eckstein-Madry, T., & Milatz, A. (2012). Student-teacher relationships and classroom climate in first grade: How do they relate to students’ stress regulation? Attachment & Human Development, 14, 249–263. Scholar
  3. Alink, L. R. A., van Ijzendoorn, M. H., Bakermans-Kranenburg, M. J., Mesman, J., Juffer, F., & Koot, H. M. (2008). Cortisol and externalizing behavior in children and adolescents: Mixed meta-analytic evidence for the inverse relation of basal cortisol and cortisol reactivity with externalizing behavior. Developmental Psychobiology, 50, 427–450. Scholar
  4. Ansari, A., & Gershoff, E. (2016). Parent involvement in Head Start and children’s development: Indirect effects through parenting. Journal of Marriage and Family, 78, 562–579. Scholar
  5. Badanes, L. S., Dmitrieva, J., & Watamura, S. E. (2012). Understanding cortisol reactivity across the day at child care: The potential buffering role of secure attachments to caregivers. Early Childhood Research Quarterly, 27, 156–165. Scholar
  6. Bassok, D., Fitzpatrick, M., Greenberg, E., & Loeb, S. (2016). Within- and between-sector quality differences in early childhood education and care. Child Development, 87, 1627–1645. Scholar
  7. Bayat, M. (2010). Use of dialogue journals and video-recording in early childhood teacher education. Journal of Early Childhood Teacher Education, 31, 159–172. Scholar
  8. Bernier, A., Beauchamp, M. H., Carlson, S. M., & Lalonde, G. (2015) A secure base from which to regulate: Attachment security in toddlerhood as a predictor of executive functioning at school entry. Developmental Psychology, 51, 1177–1189.
  9. Bernier, A., Carlson, S. M., & Whipple, N. (2010). From external regulation to self-regulation: Early parenting precursors of young children’s executivefunctioning. Child Development, 81, 326–339.
  10. Berry, D., Blair, C., Granger, D. A., & The Family Life Project Key Investigators. (2016). Child care and cortisol across infancy and toddlerhood: Poverty, peers, and developmental timing. Family Relations, 65, 51–72. Scholar
  11. Birch, S. H., & Ladd, G. W. (1997). The teacher-child relationship and children’s early school adjustment. Journal of School Psychology, 35, 61–79. Scholar
  12. Blair, C., & Raver, C. C. (2014). Closing the achievement gap through modification of neurocognitive and neuroendocrine function: Results from a cluster randomized controlled trial of an innovative approach to the education of children in lindergarten. PLoS One, 9(11), e112393. Scholar
  13. Bronfenbrenner, U., & Morris, P. A. (2006). The bioecological model of human development. In W. Damon, & R. M. Lerner (Eds.), Handbook of child psychology (Vol. 1: Theoretical models of human development, 6th ed., pp. 793–828). Hoboken, NJ: Wiley.Google Scholar
  14. Brownell, C. A., & Kopp, C. B. (Eds.). (2007). Socioemotional development in the toddler years: Transitions and transformations. New York, NY: Guilford.Google Scholar
  15. Burchinal, M., Howes, C., Pianta, R., Bryant, D., Early, D., Clifford, R., & Barbarin, O. (2008). Predicting child outcomes at the end of kindergarten from the quality of pre-kindergarten teacher–child interactions and instruction. Applied Developmental Science, 12, 140–153. Scholar
  16. Burchinal, M., Vandergift, N., Pianta, R., & Mashburn, A. (2010). Threshold analysis of association between child care quality and child outcomes for low-income children in pre-kindergarten programs. Early Childhood Research Quarterly, 25, 166–176. Scholar
  17. Burchinal, M. R., Roberts, J. E., Riggins, R., Jr., Zeisel, S. A., Neebe, E., & Bryant, D. (2000). Relating quality of center-based child care to early cognitive and language development longitudinally. Child Development, 71, 339–357. Scholar
  18. Campbell, F., Conti, G., Heckman, J. J., Moon, S. H., Pinto, R., Pungello, E., & Pan, Y. (2014). Early childhood investments substantially boost adult health. Science, 343, 1478–1485. Scholar
  19. Danziger, S. K., Ananat, E. O., & Browning, K. G. (2004). Childcare subsidies and the transition from welfare to work. Family Relations, 53, 219–228. Scholar
  20. Del Giudice, M., Ellis, B. J., & Shirtclif, E. A. (2011). The adaptive calibration model of stress responsivity. Neuroscience and Biobehavioral Reviews, 35, 1562–1592. Scholar
  21. Dettling, A. C., Gunnar, M. R., & Donzella, B. (1999). Cortisol levels of young children in full-day childcare centers: Relations with age and temperament. Psychoneuroendocrinology, 24, 519–536. Scholar
  22. Dettling, A. C., Parker, S. W., Lane, S., Sebanc, A., & Gunnar, M. R. (2000). Quality of care and temperament determine changes in cortisol concentrations over the day for young children in childcare. Psychoneuroendocrinology, 25, 819–836. Scholar
  23. Dozier, M., Peloso, E., Lewis, E., Laurenceau, J. P., & Levine, S. (2008). Effects of an attachment-based intervention on the cortisol production of infants and toddlers in foster care. Development and Psychopathology, 20, 845–859. Scholar
  24. Driscoll, K., & Pianta, R. (2010). Banking time in Head Start: Early efficacy of an intervention designed to promote supportive teacher-child relationships. Early Education and Development, 21, 38–64. Scholar
  25. Driscoll, K. C., Wang, L., Mashburn, A. J., & Pianta, R. C. (2011). Fostering supportive teacher-child relationships: Intervention implementation in a state-funded preschool program. Early Education and Development, 22, 593–619. Scholar
  26. Early, D. M., Maxwell, K. L., Ponder, B. D., & Pan, Y. (2017). Improving teacher-child interactions: A randomized controlled trial of Making the Most of Classroom Interactions and My Teaching Partner professional development models. Early Childhood Research Quarterly, 38, 57–70. Scholar
  27. EarlyEdU Alliance™. (2016). Early EdU - An alliance of Head Start and early learning. Retrieved from
  28. Fisher, P. A., Gunnar, M. R., Chamberlain, P., & Reid, J. B. (2000). Preventive intervention for maltreated preschool children: Impact on children’s behavior, neuroendocrine activity, and foster parent functioning. Journal of the American Academy of Child & Adolescent Psychiatry, 39, 1356–1364. Scholar
  29. Gelber, A., & Isen, A. (2013). Children’s schooling and parents’ behavior: Evidence from the Head Start impact study. Journal of Public Economics, 101, 35–38. Scholar
  30. Gunnar, M., & Quevedo, K. (2007). The neurobiology of stress and development. Annual Review of Psychology, 58, 145–173. Scholar
  31. Gunnar, M. R., & Donzella, B. (2002). Social regulation of the cortisol levels in early human development. Psychoneuroendocrinology, 27, 199–220. Scholar
  32. Gunnar, M. R., Kryzer, E., Van Ryzin, M. J., & Phillips, D. A. (2010). The rise in cortisol in family day care: Associations with aspects of care quality, child behavior, and child sex. Child Development, 81, 851–869. Scholar
  33. Gunnar, M. R., & Vazquez, D. M. (2001). Low cortisol and a flattening of expected daytime rhythm: Potential indices of risk in human development. Development and Psychopathology, 13, 515–538. Scholar
  34. Hamre, B. K. (2014). Teachers’ daily interactions with children: An essential ingredient in effective early childhood programs. Child Development Perspectives, 8, 223–230. Scholar
  35. Hamre, B. K., Hatfield, B. E., Pianta, R. C., & Jamil, F. (2014). Evidence for general and domain specific elements of teacher-child interactions: Associations with preschool children’s development. Child Development, 85, 1257–1274. Scholar
  36. Hatfield, B. E., Burchinal, M. R., Pianta, R. C., & Sideris, J. (2016). Thresholds in the association between quality of teacher-child interactions and preschool children’s school readiness skills. Early Childhood Research Quarterly, 36, 561–571. Scholar
  37. Hatfield, B. E., Hestenes, L. L., Kintner-Duffy, V. L., & O’Brien, M. (2013). Classroom emotional support predicts differences in preschool children’s cortisol and alpha-amylase levels. Early Childhood Research Quarterly, 28, 347–356. Scholar
  38. Hatfield, B. E., & Williford, A. P. (2017). Cortisol patterns for young children displaying disruptive behavior: Effects linked to a teacher-child, relationship-focused intervention. Prevention Science, 18, 40–49. Scholar
  39. Hertsgaard, L., Gunnar, M., Erickson, M. F., & Nachmias, M. (1995). Adrenocortical responses to the strange situation in infants with disorganized/disoriented attachment relationships. Child Development, 66, 1100–1106. Scholar
  40. Hestenes, L., Cassidy, D., Hegde, A., & Lower, J. K. (2007). Quality in inclusive and non-inclusive infant and toddler classrooms. Journal of Research in Childhood Education, 22, 69–84. Scholar
  41. Hirsh-Pasek, K., Adamson, L. B., Bakeman, R., Owen, M. T., Golinkoff, R. M., Pace, A., … Suma, K. (2015). The contribution of early communication quality to low-income children’s language success. Psychological Science, 26, 1071–1083. Scholar
  42. Howes, C. (2000). Social-emotional classroom climate in child care, child–teacher relationships and children’s second grade peer relations. Social Development, 9, 191–204. Scholar
  43. Howes, C., & Hamilton, C. E. (1992). Children’s relationships with caregivers: Mothers and child care teachers. Child Development, 63, 859–866.. Retrieved from Scholar
  44. La Paro, K. M., Maynard, C., Thomason, A., & Scott-Little, C. (2012). Developing teachers’ classroom interactions: A description of a video review process for early childhood education students. Journal of Early Childhood Teacher Education, 33, 224–238. Scholar
  45. Laughlin, L. (2013). Who’s minding the kids? Child care arrangements: Spring 2011. Retrieved from
  46. Legendre, A. (2003). Environmental features influencing toddlers’ bioemotional reactions in day care centers. Environment and Behavior, 35, 523–548. Scholar
  47. Levine, S. (2005). Developmental determinants of sensitivity and resistance to stress. Psychoneuoendocrinology, 30, 939–946. Scholar
  48. Lisonbee, J. A., Mize, J., Lapp Payne, A., & Granger, D. A. (2008). Children’s cortisol and the quality of teacher–child relationships in child care. Child Development, 79, 1818–1832. Scholar
  49. Loman, M. M., Gunnar, M. R., & The Early Experience, Stress, & Neurobehavioral Development Center. (2010). Early experience and the development of stress reactivity and regulation in children. Neuroscience & Biobehavioral Reviews, 34, 867–876. Scholar
  50. Ludwig, J., & Miller, D. L. (2007). Does Head Start improve children’s life chances? Evidence from a regression discontinuity design. The Quarterly Journal of Economics, 122, 159–208. Scholar
  51. Lumian, D. S., Dmitrieva, J., Mendoza, M. M., Badanes, L. S., & Watamura, S. E. (2016). The impact of program structure on cortisol patterning in children attending out-of-home child care. Early Childhood Research Quarterly, 34, 92–103. Scholar
  52. Marshall, N. L., Wagner Robeson, W., Tracy, A. J., Frye, A., & Roberts, J. (2013). Subsidized child care, maternal employment and access to quality, affordable child care. Early Childhood Research Quarterly, 28, 808–819. Scholar
  53. Mashburn, A. J., Downer, J. T., Hamre, B. K., Justice, L. M., & Pianta, R. C. (2010). Consultation for teachers and children’s language and literacy development during pre-kindergarten. Applied Developmental Science, 14, 179–196. Scholar
  54. Mashburn, A. J., Justice, L. M., Downer, J. T., & Pianta, R. C. (2009). Peer effects on children’s language achievement during pre-kindergarten. Child Development, 80, 686–702. Scholar
  55. Mashburn, A. J., Pianta, R. C., Hamre, B. K., Downer, J. T., Barbarin, O. A., Bryant, D., … Howes, C. (2008). Measures of classroom quality in prekindergarten and children’s development of academic, language, and social skills. Child Development, 79, 732–749. Scholar
  56. Meaney, M. J. (2001). Maternal care, gene expression, and the transmission of individual differences in stress reactivity across generations. Annual Review of Neuroscience, 24, 1161–1192. Scholar
  57. Meaney, M. J., Diorio, J., Francis, D., Widdowson, J., La Plante, P., Caldji, C., … Plotsky, P. M. (1996). Early environmental regulation of forebrain glucocorticoids receptor gene expression: Implications for adrenocortical responses to stress. Developmental Neuroscience, 18, 49–60. Scholar
  58. Menting, A. T. A., Orobio de Castro, B., & Matthys, W. (2013). Effectiveness of the incredible years parent training to modify disruptive and prosocial child behavior: A meta-analytic review. Clinical Psychology Review, 33, 901–913. Scholar
  59. Nachmais, M., Gunnar, M. R., Mangelsdorf, S., Parritz, R. H., & Buss, K. (1996). Behavioral inhibition and stress reactivity: The moderating role of attachment security. Child Development, 67, 508–522. Scholar
  60. National Academics of Sciences, Engineering, & Medicine. (2016). Parenting matters: Supporting parents of children ages (pp. 0–8). Washington, DC: The National Academies Press.Google Scholar
  61. Ouellet-Morin, I., Tremblay, R. E., Boivin, M., Meaney, M., Kramer, M., & Côté, S. M. (2010). Diurnal cortisol secretion at home and in child care: A prospective study of 2-year-old toddlers. Journal of Child Psychology and Psychiatry, 51, 295–303. Scholar
  62. Pears, K. C., Graham, A. M., Kim, H. L., & Fisher, P. A. (2013, April). Effects of a school readiness intervention for children in foster care on diurnal cortisol at the start of school. Paper presented at the Society for Research in Child Development, Seattle, WA.Google Scholar
  63. Phillips, D. A., Lipsey, M. W., Dodge, K. A., Haskins, R., Bassok, D., Burchinal, M. R., … Weiland, C. (2017). Puzzling it out: The current state of scientific knowledge on pre-kindergarten effects: A consensus statement. Retrieved from
  64. Pianta, R. C., & Hamre, B. K. (2001). Banking time: Pre-K manual. Charlottesville, VA: The Center for Advanced Study of Teaching and Learning at the University of Virginia. Retrieved from Scholar
  65. Pratt, M., Lipscomb, S. T., & Schmitt, S. A. (2015). The effect of Head Start on parenting outcomes for children living in non-parental care. Journal of Child and Family Studies, 24, 2944–2956. Scholar
  66. Press, J. E., Fagan, J., & Laughlin, L. (2006). Taking pressure off families: Child-care subsidies lessen mothers’ work-hour problems. Journal of Marriage and Family, 68, 155–171. Scholar
  67. Pianta, R. C., La Paro, K. M., & Hamre, B. K. (2008). Classroom Assessment Scoring System [CLASS] manual: Pre-k. Baltimore, MD: Paul H. Brookes.Google Scholar
  68. Reynolds, A. J., & Temple, J. A. (2008). Cost-effective early childhood development programs from preschool to third grade. Annual Review of Clinical Psychology, 4, 109–139. Scholar
  69. Roisman, G. I., Susman, E., Barnett-Walker, K., Booth-LaForce, C., Owen, M. T., Belsky, J., … The NICHD Early Child Care Research Network. (2009). Early family and child-care antecedents of awakening cortisol levels in adolescence. Child Development, 80, 907–920. Scholar
  70. Romano, E., Kohen, D., & Findlay, L. C. (2010). Associations among child care, family, and behavior outcomes in a nation-wide sample of preschool-aged children. International Journal of Behavioral Development, 34, 427–440. Scholar
  71. Roorda, D. L., Koomen, H. M. Y., Split, J. L., & Oort, F. J. (2011). The influence of affective teacher-student relationships on students’ school engagement and achievement: A meta-analytic approach. Review of Educational Research, 81, 493–529. Scholar
  72. Sabol, T. J., & Hoyt, L. T. (2017). The long arm of childhood: Preschool associations with adolescent health. Developmental Psychology, 53, 752–763. Scholar
  73. Sajaniemi, N., Suhonen, E., Hotulainen, R., Tormanen, M., Alijoki, A., Nislin, M., & Kontu, K. (2011). Demographic factors, temperament and the quality of the preschool environment as predictors of daily cortisol changes among Finnish six-year-old children. European Early Childhood Education Research Journal, 22, 286–306. Scholar
  74. Schmidt, M. B., Pentimonti, J. M., & Justice, L. M. (2012). Teacher-child relationships, behavior regulation, and language gain among at-risk preschoolers. Journal of School Psychology, 50, 681–699. Scholar
  75. Schober, P. S., & Spiess, C. K. (2015). Local day care quality and maternal employment: Evidence From East and West Germany. Family Relations, 77, 712–729. Scholar
  76. Shirtcliff, E. A., Granger, D. A., Booth, A., & Johnson, D. (2005). Low salivary cortisol levels and externalizing behavior problems in youth. Development and Pathology, 17, 167–184. Scholar
  77. Silver, R. B., Measelle, J. R., Armstrong, J. M., & Essex, M. J. (2005). Trajectories of classroom externalizing behavior: Contributions of child characteristics, family characteristics, and the teacher-child relationship during the school transition. Journal of School Psychology, 43, 39–60. Scholar
  78. Sims, M., Guilfoyle, A., & Parry, T. S. (2006). Children’s cortisol levels and quality ofchild care provision. Child: Care, Health and Development, 32, 453–466. Scholar
  79. Slatcher, R. B., & Robles, T. F. (2012). Brief report: Preschoolers’ everyday conflict at home and diurnal cortisol patterns. Health Psychology, 31, 834–838. Scholar
  80. Soliday Hong, S. L., Howes, C., Marcella, J., Zucker, E., & Huang, Y. (2015). Quality rating and improvement systems: Validation of a local implementation in LA county and children’s school-readiness. Early Childhood Research Quarterly, 30(part B), 227–240. Scholar
  81. Teachstone. (2016). QRIS and the Classroom Assessment Scoring System. Retrieved from
  82. van Ijzendoorn, M. H., Schuengel, C., & Bakersmans-Kranenburg, M. J. (1999). Disorganized attachment in early childhood: Meta-analysis of precursors, concomitants, and sequelae. Development and Psychopathology, 11, 225–249. Scholar
  83. Vandell, D. L., Belsky, J., Burchinal, M., Steinberg, L., Vandergrist, N., & NICHD Early Child Care Research Network. (2010). Do effects of early child care extend to age 15 years? Results from the NICHD Study of Early Child Care and Youth Development. Child Development, 81, 737–756. Scholar
  84. Vermeer, H. J., Groeneveld, M. G., Larrea, I., van Ijzendoorn, M. H., Barandiaran, A., & Linting, M. (2010). Child care quality and children’s cortisol in Basque Country and the Netherlands. Journal of Applied Developmental Psychology, 31, 339–347. Scholar
  85. Vermeer, H. J., & van Ijzendoorn, M. H. (2006). Children’s elevated cortisol levels at childcare: A review and meta-analysis. Early Childhood Research Quarterly, 21, 390–401. Scholar
  86. Walter, F., Torres, A., & Aldebot-Green, A. (2015). Elevating quality rating and improvement system communications: How to improve outreach to and engagement with providers, parents, policymakers, and the public. Retrieved from
  87. Watamura, S. E., Donzella, B., Alwin, J., & Gunnar, M. R. (2003). Morning-to-afternoon increases in cortisol concentrations for infants and toddlers at child care: Age differences and behavioral correlates. Child Development, 74, 1006–1020. Scholar
  88. Watamura, S. E., Kryzer, E. M., & Robertson, S. S. (2009). Cortisol patterns at home and child care: Afternoon differences and evening recovery in children attending very high quality full-day center-based child care. Journal of Applied Developmental Psychology, 30, 475–485. Scholar
  89. Weiland, C., Ulvestad, K., Sachs, J., & Yoshikawa, H. (2013). Associations between classroom quality and children’s vocabulary and executive function skills in an urban public prekindergarten program. Early Childhood Research Quarterly, 28, 199–209. Scholar
  90. Wener, C. D., Linting, M., Vermeer, H. J., & van IJzeondoorn, M. H. (2016). Do intervention programs in child care promote the quality of caregiver-child Interactions? A meta-analysis of randomized controlled trials. Prevention Science, 17, 259–273. Scholar
  91. Williford, A. P., LoCasale-Crouch, J., Whittaker, J. V., DeCoster, J., Hartz, K. A., Carter, L. M., … Hatfield, B. E. (2017). Changing teacher-child dyadic interactions to improve preschool children’s externalizing behaviors. Child Development, 88, 1544–1553. Scholar
  92. Yudron, M., Jones, S. M., & Raver, C. C. (2014). Implications of different methods for specifying classroom composition of externalizing behavior and its relationship to social-emotional outcomes. Early Childhood Research Quarterly, 29, 682–691. Scholar
  93. Zalewski, M., Lengua, L., Thompson, S., & Kiff, C. (2016). Income, cumulative risk, and longitudinal profiles of hypothalamic–pituitary–adrenal axis activity in preschool-age children. Development and Psychopathology, 28, 341–353. Scholar
  94. Zalewski, M., Lengua, L. J., Kiff, C. J., & Fisher, P. A. (2012). Understanding the relation of low income to HPA-Axis functioning in preschool children: Cumulative family risk and parenting as pathways to disruptions in cortisol. Child Psychiatry & Human Development, 43, 924–942. Scholar
  95. Zhai, F., Waldfogel, J., & Brooks-Gunn, J. (2013). Estimating the effects of Head Start on parenting and child maltreatment. Children and Youth Services Review, 35, 1119–1129. Scholar

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Authors and Affiliations

  1. 1.College of Public Health and Human Sciences, School of Social and Behavioral Health SciencesOregon State UniversityCorvallisUSA

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