Self-Regulation as a Protective Factor for Diabetes Distress and Adherence in Youth with Type 1 Diabetes During the COVID-19 Pandemic.

OBJECTIVE: The COVID-19 pandemic increased economic, social, and health stressors for families, yet its impacts on families of youth with chronic conditions, such as type 1 diabetes (T1D), are not well understood. Self-regulation (SR)-or the capacities to control emotions, cognition, and behavior in response to challenge-is known to support T1D management and coping in the face of stress. Strong SR may have protected youth with T1D from the impacts of pandemic-related stressors. This study compared youth and parent emotional functioning and T1D management before and after the pandemic's onset in relation to family pandemic-related stress and youth SR. METHODS: Parents of youth with T1D (N = 88) and a subset of these youth (N = 43; Mean age 15.3 years [SD 2.2]) completed surveys regarding SR, stress, emotional functioning, and T1D-related functioning prior to and after March 2020. Outcomes were compared using mixed effects models adjusting for covariates. Family pandemic-related stress experiences and youth SR were tested as moderators of change. RESULTS: Parents' responsibility for T1D management increased across pandemic onset and their diabetes-related distress decreased. Family pandemic-related stress was associated with decreased emotional functioning over time. Youth SR, particularly emotional and behavioral aspects, predicted better emotional and T1D-related functioning. DISCUSSION: While youth with T1D whose families experienced higher pandemic-related stress had poorer adjustment, strong emotional and behavioral SR appeared to protect against worsening youth mood and adherence across pandemic onset. Both social-contextual and individual factors are important to consider when working with families managing T1D.

Contribution of iron status at birth to infant iron status at 9 months: data from a prospective maternal-infant birth cohort in China.

BACKGROUND/OBJECTIVES: The contribution of iron status at birth to iron status in infancy is not known. We used a physiologic framework to evaluate how iron status at birth related to iron status at 9 months, taking iron needs and sources into account. SUBJECTS/METHODS: In a longitudinal birth cohort in China, iron status measures in cord blood and venous blood in infancy (9 months) and clinical data were prospectively collected in 545 healthy term maternal-infant dyads. We used structural equation modeling (SEM) to create a 9-month iron composite and to assess direct and indirect contributions of multiple influences on 9-month iron status. Logistic regression was used to calculate odds ratios for iron deficiency (ID), iron deficiency anemia (IDA), and anemia. RESULTS: Approximately 15% (78/523) of infants were born with cord SF <75 µg/l, suggesting fetal-neonatal ID. At 9 months, 34.8% (186/535) and 19.6% (105/535) of infants had ID and IDA, respectively. The following factors were independently associated with poorer 9-month iron status: higher cord zinc protoporphyrin/heme (ZPP/H) (adjusted estimate -0.18, P < 0.001) and serum transferrin receptor (sTfR) (-0.11, P = 0.004), lower cord hemoglobin (Hb) (0.13, P = 0.004), lower birth weight (0.15, P < 0.001), male sex (0.10, P = 0.013), older age at testing (-0.26, P < 0.001), higher 9-month weight (-0.12, P = 0.006) and breastfeeding (0.38, P < 0.001). Breastfeeding at 9 months showed the strongest association, adjusting for all other factors. Compared to formula-fed infants, the odds of IDA were 19.1 (95% CI: 6.92, 52.49, P < 0.001) and 3.6 (95% CI: 1.04, 12.50, P = 0.043) times higher in breastfed and mixed-fed infants, respectively. CONCLUSIONS: Indicators of iron status at birth, postnatal iron needs, and iron sources independently related to iron status at 9 months. Sex was an additional factor. Public health policies to identify and protect infants at increased risk of ID should be prioritized.

Adolescent Interventions to Manage Self-Regulation in Type 1 Diabetes (AIMS-T1D): randomized control trial study protocol.

BACKGROUND: Self-regulation (SR), or the capacity to control one's thoughts, emotions, and behaviors in order to achieve a desired goal, shapes health outcomes through many pathways, including supporting adherence to medical treatment regimens. Type 1 Diabetes (T1D) is one specific condition that requires SR to ensure adherence to daily treatment regimens that can be arduous and effortful (e.g., monitoring blood glucose). Adolescents, in particular, have poor adherence to T1D treatment regimens, yet it is essential that they assume increased responsibility for managing their T1D as they approach young adulthood. Adolescence is also a time of rapid changes in SR capacity and thus a compelling period for intervention. Promoting SR among adolescents with T1D may thus be a novel method to improve treatment regimen adherence. The current study tests a behavioral intervention to enhance SR among adolescents with T1D. SR and T1D medical regimen adherence will be examined as primary and secondary outcomes, respectively. METHODS: We will use a randomized control trial design to test the impact of a behavioral intervention on three SR targets: Executive Functioning (EF), Emotion Regulation (ER), and Future Orientation (FO); and T1D medical regimen adherence. Adolescents with T1D (n = 94) will be recruited from pediatric endocrinology clinics and randomly assigned to treatment or control group. The behavioral intervention consists of working memory training (to enhance EF), biofeedback and relaxation training (to enhance ER), and episodic future thinking training (to enhance FO) across an 8-week period. SR and treatment regimen adherence will be assessed at pre- and post-test using multiple methods (behavioral tasks, diabetes device downloads, self- and parent-report). We will use an intent-to-treat framework using generalized linear mixed models to test our hypotheses that: 1) the treatment group will demonstrate greater improvements in SR than the control group, and 2) the treatment group will demonstrate better treatment regimen adherence outcomes than the control group. DISCUSSION: If successful, SR-focused behavioral interventions could improve health outcomes among adolescents with T1D and have transdiagnostic implications across multiple chronic conditions requiring treatment regimen adherence. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03688919; registered September 28, 2018.

Child, Caregiver, Family, and Social-Contextual Factors to Consider when Implementing Parent-Focused Child Feeding Interventions.

PURPOSE OF REVIEW: Interventions that aim to alter child eating behaviors often focus on parents as a proximal influence. Yet, parents can be difficult to engage. Therefore, intervention recommendations are often not implemented as designed. The goal of this review is to highlight factors at multiple contextual levels that are important to consider when developing interventions to address child eating, due to their implications for overcoming parent engagement challenges. RECENT FINDINGS: Intervention studies suggest that parents are often the key to successfully changing child eating behaviors, and many interventions focus on feeding. Factors such as child eating phenotypes, parent stress, family system dynamics, and sociodemographic constraints have also been identified as shaping food parenting. Challenges at multiple contextual levels can affect the likelihood of parent engagement. Addressing factors at the child-, parent-, family-, and broader social-contextual levels of influence is essential in order to promote best practices for parent-focused feeding interventions.

Breastfeeding, Mixed, or Formula Feeding at 9 Months of Age and the Prevalence of Iron Deficiency and Iron Deficiency Anemia in Two Cohorts of Infants in China.

OBJECTIVE: To assess associations between breastfeeding and iron status at 9 months of age in 2 samples of Chinese infants. STUDY DESIGN: Associations between feeding at 9 months of age (breastfed as sole milk source, mixed fed, or formula fed) and iron deficiency anemia (IDA), iron deficiency, and iron sufficiency were determined in infants from Zhejiang (n = 142) and Hebei (n= 813) provinces. Iron deficiency was defined as body iron < 0 mg/kg, and IDA as iron deficiency + hemoglobin < 110 g/L. Multiple logistic regression assessed associations between feeding pattern and iron status. RESULTS: Breastfeeding was associated with iron status (P < .001). In Zhejiang, 27.5% of breastfed infants had IDA compared with 0% of formula-fed infants. The odds of iron deficiency/IDA were increased in breastfed and mixed-fed infants compared with formula-fed infants: breastfed vs formula-fed OR, 28.8 (95% CI, 3.7-226.4) and mixed-fed vs formula-fed OR, 11.0 (95% CI, 1.2-103.2). In Hebei, 44.0% of breastfed infants had IDA compared with 2.8% of formula-fed infants. With covariable adjustment, odds of IDA were increased in breastfed and mixed-fed groups: breastfed vs formula-fed OR, 78.8 (95% CI, 27.2-228.1) and mixed-fed vs formula-fed OR, 21.0 (95% CI, 7.3-60.9). CONCLUSIONS: In both cohorts, the odds of iron deficiency/IDA at 9 months of age were increased in breastfed and mixed-fed infants, and iron deficiency/IDA was common. Although the benefits of breastfeeding are indisputable, these findings add to the evidence that breastfeeding in later infancy identifies infants at risk for iron deficiency/IDA in many settings. Protocols for detecting and preventing iron deficiency/IDA in breastfed infants are needed. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00642863 and NCT00613717.

Low-Dose Iron Supplementation in Infancy Modestly Increases Infant Iron Status at 9 Mo without Decreasing Growth or Increasing Illness in a Randomized Clinical Trial in Rural China.

BACKGROUND: Previous trials of iron supplementation in infancy did not consider maternal iron supplementation. OBJECTIVE: This study assessed effects of iron supplementation in infancy and/or pregnancy on infant iron status, illnesses, and growth at 9 mo. METHODS: Enrollment occurred from December 2009 to June 2012 in Hebei, China. Infants born to women in a pregnancy iron supplementation trial were randomly assigned 1:1 to iron [∼1 mg Fe/(kg · d) as oral iron proteinsuccynilate] or placebo from 6 wk to 9 mo, excluding infants with cord ferritin <35 µg/L. Study groups were pregnancy placebo/infancy placebo (placebo/placebo), pregnancy placebo/infancy iron (placebo/iron), pregnancy iron/infancy placebo (iron/placebo), and pregnancy iron/infancy iron (iron/iron). The primary outcome was 9-mo iron status: iron deficiency (ID) by cutoff (≥2 abnormal iron measures) or body iron <0 mg/kg and ID + anemia (hemoglobin <110 g/L). Secondary outcomes were doctor visits or hospitalizations and weight or length gain from birth to 9 mo. Statistical analysis by intention to treat and dose-response (between number of iron bottles received and outcome) used logistic regression with concomitant RRs and general linear models, with covariate control as applicable. RESULTS: Of 1482 infants randomly allocated, 1276 had 9-mo data (n = 312-327/group). Iron supplementation in infancy, but not pregnancy, reduced ID risk: RRs (95% CIs) were 0.89 (0.79, 0.998) for placebo/iron compared to placebo/placebo, 0.79 (0.63, 0.98) for placebo/iron compared to iron/placebo, 0.87 (0.77, 0.98) for iron/iron compared to placebo/placebo, and 0.86 (0.77, 0.97) for iron/iron compared to iron/placebo. However, >60% of infants still had ID at 9 mo. Receiving more bottles of iron in infancy was associated with better infant iron status at 9 mo but only among iron-supplemented infants whose mothers were also iron supplemented (i.e., the iron/iron group). There were no group differences in hospitalizations or illnesses and no adverse effects on growth overall or among infants who were iron sufficient at birth. CONCLUSIONS: Iron supplementation in Chinese infants reduced ID at 9 mo without adverse effects on growth or illness. Effects of iron supplementation in pregnancy were observed only when higher amounts of iron were distributed in infancy. This trial was registered at clinicaltrials.gov as NCT00613717.

Iron deficiency (ID) at both birth and 9 months predicts right frontal EEG asymmetry in infancy.

This study considered effects of timing and duration of iron deficiency (ID) on frontal EEG asymmetry in infancy. In healthy term Chinese infants, EEG was recorded at 9 months in three experimental conditions: baseline, peek-a-boo, and stranger approach. Eighty infants provided data for all conditions. Prenatal ID was defined as low cord ferritin or high ZPP/H. Postnatal ID was defined as ≥ two abnormal iron measures at 9 months. Study groups were pre- and postnatal ID, prenatal ID only, postnatal ID only, and not ID. GLM repeated measure analysis showed a main effect for iron group. The pre- and postnatal ID group had negative asymmetry scores, reflecting right frontal EEG asymmetry (mean ± SE: -.18 ± .07) versus prenatal ID only (.00 ± .04), postnatal ID only (.03 ± .04), and not ID (.02 ± .04). Thus, ID at both birth and 9 months was associated with right frontal EEG asymmetry, a neural correlate of behavioral withdrawal and negative emotions.

Prenatal Iron Supplementation Reduces Maternal Anemia, Iron Deficiency, and Iron Deficiency Anemia in a Randomized Clinical Trial in Rural China, but Iron Deficiency Remains Widespread in Mothers and Neonates.

BACKGROUND: Previous trials of prenatal iron supplementation had limited measures of maternal or neonatal iron status. OBJECTIVE: The purpose was to assess effects of prenatal iron-folate supplementation on maternal and neonatal iron status. METHODS: Enrollment occurred June 2009 through December 2011 in Hebei, China. Women with uncomplicated singleton pregnancies at ≤20 wk gestation, aged ≥18 y, and with hemoglobin ≥100 g/L were randomly assigned 1:1 to receive daily iron (300 mg ferrous sulfate) or placebo + 0.40 mg folate from enrollment to birth. Iron status was assessed in maternal venous blood (at enrollment and at or near term) and cord blood. Primary outcomes were as follows: 1) maternal iron deficiency (ID) defined in 2 ways as serum ferritin (SF) <15 µg/L and body iron (BI) <0 mg/kg; 2) maternal ID anemia [ID + anemia (IDA); hemoglobin <110 g/L]; and 3) neonatal ID (cord blood ferritin <75 µg/L or zinc protoporphyrin/heme >118 µmol/mol). RESULTS: A total of 2371 women were randomly assigned, with outcomes for 1632 women or neonates (809 placebo/folate, 823 iron/folate; 1579 mother-newborn pairs, 37 mothers, 16 neonates). Most infants (97%) were born at term. At or near term, maternal hemoglobin was significantly higher (+5.56 g/L) for iron vs. placebo groups. Anemia risk was reduced (RR: 0.53; 95% CI: 0.43, 0.66), as were risks of ID (RR: 0.74; 95% CI: 0.69, 0.79 by SF; RR: 0.65; 95% CI: 0.59, 0.71 by BI) and IDA (RR: 0.49; 95% CI: 0.38, 0.62 by SF; RR: 0.51; 95% CI: 0.40, 0.65 by BI). Most women still had ID (66.8% by SF, 54.7% by BI). Adverse effects, all minor, were similar by group. There were no differences in cord blood iron measures; >45% of neonates in each group had ID. However, dose-response analyses showed higher cord SF with more maternal iron capsules reported being consumed (ß per 10 capsules = 2.60, P < 0.05). CONCLUSIONS: Prenatal iron supplementation reduced anemia, ID, and IDA in pregnant women in rural China, but most women and >45% of neonates had ID, regardless of supplementation. This trial was registered at clinicaltrials.gov as NCT02221752.

Iron supplementation in infancy contributes to more adaptive behavior at 10 years of age.

Most studies of behavioral/developmental effects of iron deficiency anemia (IDA) or iron supplementation in infancy have found social-emotional differences. Differences could relate to behavioral inhibition or lack of positive affect and altered response to reward. To determine long-term behavioral effects, the study was a follow-up of a randomized controlled trial of behavioral/developmental effects of preventing IDA in infancy. Healthy Chilean infants free of IDA at age 6 mo were randomly assigned to iron supplementation or no added iron (formula with iron/powdered cow milk, vitamins with/without iron) from ages 6 to 12 mo. At age 10 y, 59% (666 of 1123) and 68% (366 of 534) of iron-supplemented and no-added-iron groups were assessed. Social-emotional outcomes included maternal-reported behavior problems, self-reported behavior, examiner ratings, and video coding of a social stress task and gamelike paradigms. Examiners rated the iron-supplemented group as more cooperative, confident, persistent after failure, coordinated, and direct and reality-oriented in speech and working harder after praise compared with the no-added-iron group. In a task designed to elicit positive affect, supplemented children spent more time laughing and smiling together with their mothers and started smiling more quickly. In the social stress task they smiled and laughed more and needed less prompting to complete the task. All P values were <0.05; effect sizes were 0.14-0.36. There were no differences in behaviors related to behavioral inhibition, such as anxiety/depression or social problems. In sum, iron supplementation in infancy was associated with more adaptive behavior at age 10 y, especially in affect and response to reward, which may improve performance at school and work, mental health, and personal relationships.

Functional significance of early-life iron deficiency: outcomes at 25 years.

OBJECTIVE: To evaluate adulthood function following chronic iron deficiency in infancy. STUDY DESIGN: At 25 years, we compared 33 subjects with chronic iron deficiency in infancy to 89 who were iron-sufficient before and/or after iron therapy. Outcomes included education, employment, marital status, and physical and mental health. RESULTS: Adjusting for sex and socioeconomic status, a higher proportion of the group with chronic iron deficiency did not complete secondary school (58.1% vs 19.8% in iron-sufficient group; Wald value = 8.74; P = .003), were not pursuing further education/training (76.1% vs 31.5%; Wald value = 3.01; P = .08; suggestive trend), and were single (83.9% vs 23.7%, Wald value = 4.49; P = .03). They reported poorer emotional health and more negative emotions and feelings of dissociation/detachment. Results were similar in secondary analyses comparing the chronic iron-deficient group with subjects in the iron-sufficient group who had been iron-deficient before treatment in infancy. Path analysis showed direct paths for chronic iron deficiency in infancy and being single and more detachment/dissociation at 25 years. There were indirect paths for chronic iron deficiency and not completing secondary school via poorer cognitive functioning in early adolescence and more negative emotions via behavior problems in adolescence, indicating a cascade of adverse outcomes. CONCLUSION: The observational nature of this study limits our ability to draw causal inference, even when controlling for background factors. Nonetheless, our results indicate substantial loss of human potential. There may be broader societal implications, considering that many adults worldwide had chronic iron deficiency in infancy. Iron deficiency can be prevented or treated before it becomes chronic or severe.

Iron-fortified vs low-iron infant formula: developmental outcome at 10 years.

OBJECTIVE: To assess long-term developmental outcome in children who received iron-fortified or low-iron formula. DESIGN: Follow-up at 10 years of a randomized controlled trial (1991-1994) of 2 levels of formula iron. Examiners were masked to group assignment. SETTING: Urban areas around Santiago, Chile. PARTICIPANTS: The original study enrolled healthy, full-term infants in community clinics; 835 completed the trial. At 10 years, 473 were assessed (56.6%). INTERVENTION: Iron-fortified (mean, 12.7 mg/L) or low-iron (mean, 2.3 mg/L) formula from 6 to 12 months. MAIN OUTCOME MEASURES: We measured IQ, spatial memory, arithmetic achievement, visual-motor integration, visual perception, and motor functioning. We used covaried regression to compare iron-fortified and low-iron groups and considered hemoglobin level before randomization and sensitivity analyses to identify 6-month hemoglobin levels at which groups diverged in outcome. RESULTS: Compared with the low-iron group, the iron-fortified group scored lower on every 10-year outcome (significant for spatial memory and visual-motor integration; suggestive for IQ, arithmetic achievement, visual perception, and motor coordination; 1.4-4.6 points lower; effect sizes, 0.13-0.21). Children with high 6-month hemoglobin levels (> 12.8 g/dL [to convert to grams per liter, multiply by 10]) showed poorer outcome on these measures if they received iron-fortified formula (10.7-19.3 points lower; large effect sizes, 0.85-1.36); those with low hemoglobin levels (< 10.5 g/dL) showed better outcome (2.6-4.5 points higher; small but significant effects, 0.22-0.36). High hemoglobin levels represented 5.5% of the sample (n = 26) and low hemoglobin levels represented 18.4% (n = 87). CONCLUSION: Long-term development may be adversely affected in infants with high hemoglobin levels who receive 12.7 mg/L of iron-fortified formula. Optimal amounts of iron in infant formula warrant further study.

Home intervention improves cognitive and social-emotional scores in iron-deficient anemic infants.

BACKGROUND: Iron-deficiency anemia (IDA) is associated with alterations in infant behavior and development that may not be corrected with iron therapy. OBJECTIVE: To determine if a home-based intervention to foster child development improves behavior and development of infants with IDA. METHODS: Infants with IDA and nonanemic infants aged 6 and 12 months were treated with oral iron and randomly assigned to a year of surveillance or intervention. Infants in the surveillance group were visited weekly, and information on iron intake, feeding, and health were recorded. Infants in the intervention were visited weekly, and the home visits included an hour-long program to foster child development by providing support to the mother-infant relationship. The number of infants enrolled was 128 (66 who received intervention) and 149 (70 intervention) at 6 and 12 months, respectively. Psychologists who were unaware of iron status and intervention assignment assessed infants' cognitive, motor, and social-emotional development (Bayley Scales) at the beginning, midpoint, and end of the year; 116 6-month-olds and 134 12-month-olds had at least 2 assessments. Hierarchical linear modeling was used to analyze change over time. RESULTS: Infants with IDA, regardless of enrollment age, were rated as less positive in social-emotional behavior at baseline. There were significant interactions between iron status and intervention associated with change in cognitive performance and positive social-emotional behavior. Infants with IDA who received intervention had developmental trajectories comparable to those of nonanemic infants in the intervention and surveillance groups, but these infants did not catch up in social-emotional behavior. Infants with IDA who received surveillance showed less increase in cognitive scores and had declines in positive social-emotional ratings. CONCLUSIONS: Home-based intervention to foster child development improved cognitive and social-emotional scores in infants with IDA, but social-emotional differences remained between infants with IDA and those without IDA.

Depressed mood and speech in Chilean mothers of 5½-year-old children.

Previous research on maternal speech and depression has focused almost exclusively on how depressed mothers talk to their infants and toddlers in the U.S. and U.K., two English-speaking countries. This study considered how depressed Spanish-speaking mothers from a Latin American country talk about their preschool-age children. Five-minute speech samples were provided by 178 Chilean mothers who were asked to talk about their 5½-year-old children to a project psychologist. Maternal depressive symptomatology was measured by the Spanish-language version of the Center for Epidemiologic Studies Depression Scale (CES-D). In multivariate analysis of covariance (MANCOVA), higher maternal depressed mood showed statistically significant associations with the following maternal speech characteristics: more criticisms, less laughter, fewer medium pauses, less positive satisfaction with the child's behavior or characteristics, a rating of a negative overall relationship with the child, and more crying (suggestive trend). A structural equation model confirmed these findings and found an indirect effect between laughter and criticisms: mothers with higher depressed mood who laughed less criticized their children less. The findings illustrate that depressed mood adversely affects how a group of Chilean mothers speak about their children.

Higher infant blood lead levels with longer duration of breastfeeding.

OBJECTIVE: To determine whether longer breastfeeding is associated with higher infant lead concentrations. STUDY DESIGN: Data were analyzed from 3 studies of developmental effects of iron deficiency in infancy: Costa Rica (1981-1984), Chile (1991-1996), and Detroit (2002-2003). The relation between duration of breastfeeding and lead levels was assessed with Pearson product-moment or partial correlation coefficients. RESULTS: More than 93% of the Costa Rica and Chile samples was breastfed (179 and 323 breastfed infants, respectively; mean weaning age, 8-10 months), as was 35.6% of the Detroit sample (53 breastfed infants; mean weaning age, 4.5 months). Lead concentrations averaged 10.8 microg/dL (Costa Rica, 12-23 months), 7.8 microg/dL (Chile, 12 months), and 2.5 microg/dL (Detroit, 9-10 months). Duration of breastfeeding as sole milk source and total breastfeeding correlated with lead concentration in all samples (r values = 0.14-0.57; P values = .06-<.0001). CONCLUSIONS: Longer breastfeeding was associated with higher infant lead concentration in 3 countries, in 3 different decades, in settings differing in breastfeeding patterns, environmental lead sources, and infant lead levels. The results suggest that monitoring lead concentrations in breastfed infants be considered.

Dose-response relationships between iron deficiency with or without anemia and infant social-emotional behavior.

OBJECTIVE: To assess dose-response relationships between severity of iron deficiency (ID) and infant social-emotional behavior. STUDY DESIGN: The study group was a cohort of 9- to 10-month-old African-American infants (n = 77 with final iron status classification). The infants were given oral iron for 3 months. Social-emotional outcomes included mother and examiner ratings at 9 and 12 months and quantitative behavioral coding from videotape at 12 months. General linear model analyses tested for linear effects of iron status group (ordered from worst to best: iron-deficient anemia [IDA], nonanemic iron-deficient [NA ID], iron-sufficient [IS]) and determined thresholds for effects. RESULTS: There were significant (P <.05) linear effects of poorer iron status for shyness (increasing, maternal rating), orientation-engagement, and soothability (decreasing, examiner ratings), and the following quantitatively coded behaviors: positive affect (decreasing) and latencies to engage with the examiner (increasing) and move away from the examiner (decreasing). The threshold for all but 1 effect was ID with or without anemia versus IS. CONCLUSIONS: Infant social-emotional behavior appears to be adversely affected by ID with or without anemia. ID without anemia is not detected by common screening procedures and is more widespread than IDA. Infant social-emotional behavior can profoundly influence the care-giving environment, with repercussions for overall development.

Breast-feeding and mental and motor development at 51/2 years.

OBJECTIVE: Breast-feeding is associated with better child development outcomes, but uncertainty remains primarily due to the close relationship between breast-feeding and socioeconomic status. This study assesses the issue in a low socioeconomic status sample where breast-feeding was close to universal. METHODS: Seven hundred eighty-four Chilean children were followed longitudinally from infancy. All but four were initially breastfed, 40% nursed beyond 12 months, and infant growth was normal. Child development was assessed at 5(1/2) years by a cognitive, language, and motor test battery. The duration of breast-feeding as the sole milk source was analyzed as a continuous variable, adjusting for a comprehensive set of background factors. RESULTS: The relationship between breast-feeding and most 5(1/2)-year developmental outcomes was nonlinear, with poorer outcome for periods of breast-feeding as the sole milk source for <2 months or >8 months--statistically significant for language, motor, and one comprehensive cognitive test, with a suggestive trend for IQ. CONCLUSIONS: The observed nonlinear relationships showed that breast-feeding as the sole milk source for <2 months or >8 months, compared with 2-8 months, was associated with poorer development in this sample. The latter finding requires replication in other samples where long breast-feeding is common and socioeconomic status is relatively homogeneous.