Rationale

1. Relation of Iron and Zinc to Child Cognition and Behavior Problems: Moderation by Permissive Parenting and Lead Concentration Laura Hubbs-Tait, AfeworkMulugeta, AlemtsehayBogale, D’Lee Babb, Tay S. Kennedy, TesfayeWogene, Eric R. Baker, Barbara J. Stoecker

2. Rationale Iron and zinc are linked to child cognition and behavior. Some studies report stronger associations than others of these metals with child cognitive and behavioral functioning. One hypothesis for the inconsistencies is that effects of micronutrient deficiencies may be exacerbated or mitigated by parenting practices and neurotoxicant exposures (Hubbs-Tait, Nation, Krebs, & Bellinger, 2005).

3. Placing research on iron and zinc in context of risk Social Environments Child Cognition and Behavior Neurotoxicants Micronutrients Hubbs-Tait, L., Nation, J. R., Krebs, N. F., & Bellinger, D. C. (2005). Neurotoxicants, micronutrients, and social environments: individual and combined effects on children's development. Psychological Science in the Public Interest, 6, 57-121.

4. Background - Iron Circulating iron - hemoglobin (hgb) Hgb < age-appropriate value is indicative of iron deficiency Preschool children: hemoglobin <111 grams per liter [g/L] (CDC, 1998). Tissue iron Measured by soluble transferrin receptors in serum increase with decreasing tissue iron less affected by infection than ferritin > 8.4 mg/L is cutoff for tissue iron deficiency (Schneider et al., 2008)

5. Background - Zinc Less agreement on what constitutes zinc deficiency Previously (Droke et al., 2006) we used a nonfasting low zinc cutoff of 71.2 μg/dL for 3- to 5-year-old children

6. Neurotransmitters as conceptual framework Lower iron or zinc and higher lead affect glutamatergic functioning. Lead causes changes in glutamate receptor, N-methyl-D-aspartate (NMDA), in hippocampus ↓ licking and grooming by rat dams causes Impaired rat pup learning and memory ↓ NMDA receptor mRNA expression and synaptogenesis Zinc = essential ion for zinc finger protein (ZFP) structure found in neuronal receptors like NMDA and functions as an NMDA inhibitor. In vitro and in vivo research (Basha et al., 2003) shows zinc supplementation provided some protection against changes induced by lead in DNA binding of ZFP

7. Parenting Moderates Effects of Iron Cognitive hypothesis Permissive parenting would exacerbate lower iron or zinc Levitsky and Barnes (1972) confirmed a hypothesis proposed by Frankova that environmental isolation exacerbated the effects of early malnutrition in rats. Rats were randomly assigned to both nutritional (malnutrition versus control) and environmental (isolation versus stimulation versus control) conditions.

8. Behavior problems hypothesis Lead Moderates Effects of Iron and Zinc Zinc has previously been reported to be inversely correlated with anxiety or other behavior problems, but usually under circumstances of greater micronutrient deprivation or other risk factors. Zinc would be inversely related to behavior problems for children with lead levels > 2.5 μg/dL Hubbs-Tait et al (2009) found that children with lead levels > 2.5 μg/dL had significantly lower perceptual subscale scores on the McCarthy Scales of Children’s Abilities than children with lead levels < 2.5 μg/dL. Thus, lead level > 2.5 μg/dL constitutes the additional risk.

9. PARTICIPANTS 112 children (mean age = 4.15 ± .55 yr) in Head Start Exclusion criteria reduced total sample of 131 children who provided assent blood lead level above 10 μg/dL (n =1) insufficient blood sampled to measure lead or transferrin receptors (n =5) or C-reactive protein > 10 mg/L indicating infection rendering measurement of nutritional biomarkers questionable or inaccurate (n = 13) (Thurnham et al., 2005; Droke, Kennedy, Hubbs-Tait, 2006). METHOD

10. METHOD Procedure Blood sampling – during a 3-week period in November 2006. Children completed the McCarthy Scales of Children’s Abilities (MSCA) and Peabody Picture Vocabulary Test – III (PPVT-III) prior to blood sampling. Parents completed questionnaires at Head Start centers or home. Teachers completed rating scales at Head Start centers.

11. METHOD Measures Peabody Picture Vocabulary Test – III (PPVT-III) McCarthy Scales of Children’s Abilities (MSCA) Passive-permissive parenting: Parent Behavior Questionnaire-Head Start (PBQ-HS, Coolahan, McWayne, Fantuzzo, & Grim, 2002) “I find it difficult to discipline my child” “I have a hard time saying "no" to my child” “My family says I spoil my child” “When my child doesn't do what I ask, I let it go or do it myself” “I tell my child I'll punish them but don't do it” “If my child resists going to bed, I let them stay up” “When I want my child to stop doing something, I ask many times.” Cronbach’s α for original 11-item scale = .77; for our reduced permissive parenting scale in the current sample, α = .76.

12. METHOD Measures (cont’d) Home literacy items by Senchal et al. (1996) “Please estimate the number of children’sbooks in your home” response choices: 0 (none), 1 (1-5), 2 (2-10), 3 (11-15), 4 (16-20), 5 (21-25), and 6 (more than 25) “How often does your child go to the library?” response choices of 1 (never), 2 (not often), 3 (sometimes), 4 (often), and 5 (very often) Teacher ratings Preschool Behavior Questionnaire (PBQ, Behar, 1977): anxious, aggressive, hyperactive Sociable subscale of Howes (1988) teacher rating scale

13. RESULTS Hemoglobin: 8 children <111 g/L Transferrin receptors: 57 children > 8.4 mg/L Ferritin: 38 < 15 ng/mL Zinc: 6 < 71.2 μg/dL 1 child with low levels of all iron measures: Hgb < 111 g/L + ferritin < 15 and sTfR> 8.4 21 children with low ferritin and sTfR: ferritin < 15 and sTfR> 8.4 Permissive parenting scores of 22 Fe deficient children versus 79 sufficient children:

14. COGNITIVE RESULTS Relation of iron and zinc to child cognitive outcomes

15. COGNITIVE: Hierarchical regressions

16. COGNITIVE RESULTS Hypothesis 1:permissive parenting would exacerbate lower iron Low Permissive, b = -.766 PPVT-III High Permissive, b = - 4.427** ** p < .01 Transferrin receptors

17. BEHAVIOR PROBLEMS Hypothesis 2: Inverse relation for iron and zinc to behavior problems above lead threshold of 2.5 μg/dL Lead > 2.5 μg/dL Lead < 2.5 μg/dL n = 77 n = 28

18. BEHAVIOR PROBLEMS Lead > 2.5 μg/dL Lead < 2.5 μg/dL n = 77 n = 28

19. CONCLUSIONS Permissive parenting exacerbated the negative effects of lower iron. Lead level of 2.5 μg/dL did differentiate relations between micronutrients and teacher reports of behavior problems or social behavior. Significant interactions involving micronutrients were found among relatively well-nourished US preschool children emphasizing importance of interdisciplinary designs. Limitations include correlational design and reliance on parental self-report of styles and behaviors.

20. Acknowledgements and Funding ACKNOWLEDGMENT • I thank Brandy Simmons, Michelle Dickerson, Katey Masri, Rachel Bonnett, Nicole Moore, Beatrice Okwonga, Emily McKenzie, Stephanie Chrisman, Brittany Overstreet, Amber Shelledy, Kelly Shipman, and Allison Fallis for assistance; and the parents and children for their involvement. FUNDING: • United States Department of Agriculture-CREES, Oklahoma Agriculture Experiment Station. USDA-CREES Number OKL0 2605.

21. THANK YOU!You may access these slides at the following address:http://ches.okstate.edu/facultystaff/faculty-documents.php?FacID=24

23. RESULTS