Early life determinants of low IQ at age 6 in children from the 2004 Pelotas Birth Cohort: a predictive approach

BMC Pediatrics

Fernando C Barros³  Alicia Matijasevich²  Iná S Santos⁴  Aluísio JD Barros⁴  Fabio Alberto Camargo-Figuera¹ 

[1] Universidad Industrial de Santander (UIS), Bucaramanga, Colombia;Department of Preventive Medicine, School of Medicine, University of São Paulo, São Paulo, Brazil;Postgraduate Program in Health and Behavior, Catholic University of Pelotas, Pelotas, Brazil;Postgraduate Program in Epidemiology, Federal University of Pelotas, Pelotas, Brazil

关键词: Brazil;    Social determinants of health;    Cognition;    Intelligence;    Birth cohort;    Child development;   

Others  :  1090461
DOI  :  10.1186/s12887-014-0308-1

 received in 2014-04-07, accepted in 2014-12-07,  发布年份 2014

【 摘 要 】

Background

Childhood intelligence is an important determinant of health outcomes in adulthood. The first years of life are critical to child development. This study aimed to identify early life (perinatal and during the first year of life) predictors of low cognitive performance at age 6.

Methods

A birth cohort study started in the city of Pelotas, southern Brazil, in 2004 and children were followed from birth to age six. Information on a broad set of biological and social predictors was collected. Cognitive ability—the study outcome—was assessed using the Wechsler Intelligence Scale for Children (WISC). IQ scores were standardized into z-scores and low IQ defined as z < −1. We applied bootstrapping methods for internal validation with a multivariate logistic regression model and carried out external validation using a second study from the 1993 Pelotas Birth Cohort.

Results

The proportion of children with IQ z-score < −1 was 16.9% (95% CI 15.6–18.1). The final model included the following early life variables: child’s gender; parents’ skin color; number of siblings; father’s and mother’s employment status; household income; maternal education; number of persons per room; duration of breastfeeding; height-for-age deficit; head circumference-for-age deficit; parental smoking during pregnancy; and maternal perception of the child’s health status. The area under the ROC curve for our final model was 0.8, with sensitivity of 72% and specificity of 74%. Similar results were found when testing external validation by using data from the 1993 Pelotas Birth Cohort.

Conclusions

The study results suggest that a child’s and her/his family’s social conditions are strong predictors of cognitive ability in childhood. Interventions for promoting a healthy early childhood development are needed targeting children at risk of low IQ so that they can reach their full cognitive potential.

【 授权许可】

   
2014 Camargo-Figuera et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

【 参考文献 】

• [1]Calvin CM, Deary IJ, Fenton C, Roberts BA, Der G, Leckenby N, Batty GD: Intelligence in youth and all-cause-mortality: systematic review with meta-analysis. Int J Epidemiol 2011, 40:626-644.
• [2]Feinstein L, Bynner J: The importance of cognitive development in middle childhood for adulthood socioeconomic status, mental health, and problem behavior. Child Dev 2004, 75:1329-1339.
• [3]Johnson RC, Schoeni RF: The influence of early-life events on human capital, health status, and labor market outcomes over the life course. B E J Econom Anal Policy 2011, 11:2521.
• [4]Thomas MSC, Johnson MH: New advances in understanding sensitive periods in brain development. Curr Dir Psychol Sci 2008, 17:1-5.
• [5]Thompson RA, Nelson CA: Developmental science and the media. Early brain development. Am Psychol 2001, 56:5-15.
• [6]Fritsch T, McClendon MJ, Smyth KA, Lerner AJ, Friedland RP, Larsen JD: Cognitive functioning in healthy aging: the role of reserve and lifestyle factors early in life. Gerontologist 2007, 47:307-322.
• [7]Kaplan GA, Turrell G, Lynch JW, Everson SA, Helkala EL, Salonen JT: Childhood socioeconomic position and cognitive function in adulthood. Int J Epidemiol 2001, 30:256-263.
• [8]Deary IJ, Johnson W, Houlihan LM: Genetic foundations of human intelligence. Hum Genet 2009, 126:215-232.
• [9]Walker SP, Wachs TD, Gardner JM, Lozoff B, Wasserman GA, Pollitt E, Carter JA: International Child Development Steering Group: Child development: risk factors for adverse outcomes in developing countries. Lancet 2007, 369:145-157.
• [10]Engle PL, Black MM, Behrman JR, Cabral de Mello M, Gertler PJ, Kapiriri L, Martorell R, Young ME: International Child Development Steering Group: Strategies to avoid the loss of developmental potential in more than 200 million children in the developing world. Lancet 2007, 369:229-242.
• [11]Engle PL, Fernald LC, Alderman H, Behrman J, O’Gara C, Yousafzai A, de Mello MC, Hidrobo M, Ulkuer N, Ertem I, Iltus S: Global Child Development Steering Group: Strategies for reducing inequalities and improving developmental outcomes for young children in low-income and middle-income countries. Lancet 2011, 378:1339-1353.
• [12]Hillemeier MM, Morgan PL, Farkas G, Maczuga SA: Perinatal and socioeconomic risk factors for variable and persistent cognitive delay at 24 and 48 months of age in a national sample. Matern Child Health J 2011, 15:1001-1010.
• [13]Lawlor DA, Najman JM, Batty GD, O’Callaghan MJ, Williams GM, Bor W: Early life predictors of childhood intelligence: findings from the Mater-University study of pregnancy and its outcomes. Paediatr Perinat Epidemiol 2006, 20:148-162.
• [14]Batty GD, Victora CG, Lawlor DA: Family-Based Life Course Studies in Low- and Middle-Income Countries. In Family Matters: Designing, Analysing and Understanding Family Based Studies in Life Course Epidemiology. Edited by Lawlor DA, Mishra GD. Oxford University Press, Oxford; 2009:129-150.
• [15]Brion MJ, Lawlor DA, Matijasevich A, Horta B, Anselmi L, Araujo CL, Menezes AM, Victora CG, Smith GD: What are the causal effects of breastfeeding on IQ, obesity and blood pressure? Evidence from comparing high-income with middle-income cohorts. Int J Epidemiol 2011, 40:670-680.
• [16]Lawlor DA, Batty GD, Morton SM, Deary IJ, Macintyre S, Ronalds G, Leon DA: Early life predictors of childhood intelligence: evidence from the Aberdeen children of the 1950s study. J Epidemiol Community Health 2005, 59:656-663.
• [17]Tong S, Baghurst P, Vimpani G, McMichael A: Socioeconomic position, maternal IQ, home environment, and cognitive development. J Pediatr 2007, 151:284-288. e1
• [18]Barros FC, Victora CG, Scherpbier R, Gwatkin D: Socioeconomic inequities in the health and nutrition of children in low/middle income countries. Rev Saude Publica 2010, 44:1-16.
• [19]Walker SP, Wachs TD, Grantham-McGregor S, Black MM, Nelson CA, Huffman SL, Baker-Henningham H, Chang SM, Hamadani JD, Lozoff B, Gardner JM, Powell CA, Rahman A, Richter L: Inequality in early childhood: risk and protective factors for early child development. Lancet 2011, 378:1325-1338.
• [20]Grantham-McGregor S, Cheung YB, Cueto S, Glewwe P, Richter L, Strupp B: International Child Development Steering Group: Developmental potential in the first 5 years for children in developing countries. Lancet 2007, 369:60-70.
• [21]Martin JA, Hamilton BE, Sutton PD, Ventura SJ, Menacker F, Munson ML: Births: final data for 2003. Natl Vital Stat Rep 2005, 54:1-116.
• [22]Fenton TR: A new growth chart for preterm babies: Babson and Benda’s chart updated with recent data and a new format. BMC Pediatr 2003, 3:13. BioMed Central Full Text
• [23]Dubowitz LM, Dubowitz V, Goldberg C: Clinical assessment of gestational age in the newborn infant. J Pediatr 1970, 77:1-10.
• [24]Barros AJ, da Silva dos Santos I, Victora CG, Albernaz EP, Domingues MR, Timm IK, Matijasevich A, Bertoldi AD, Barros FC: The 2004 Pelotas birth cohort: methods and description. Rev Saude Publica 2006, 40:402-413.
• [25]Santos IS, Barros AJ, Matijasevich A, Domingues MR, Barros FC, Victora CG: Cohort profile: the 2004 Pelotas (Brazil) birth cohort study. Int J Epidemiol 2011, 40:1461-1468.
• [26]Wechsler D: WISC-III: Escala de Inteligência Wechsler para crianças (VLM Figueiredo, adaptação e padronização brasileira). Casa do Psicólogo, São Paulo, SP; 2002.
• [27]Kaufman AS, Kaufman JC, Balgopal R, McLean JE: Comparison of three WISC-III short forms: Weighing psychometric, clinical, and practical factors. J Clin Child Psychol 1996, 25:97-105.
• [28]WHO Multicentre Growth Reference Study Group: WHO child growth standards. [http://www.who.int/childgrowth/standards/en/]
• [29]Hanley JA, McNeil BJ: The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology 1982, 143:29-36.
• [30]Hosmer DW, Lemeshow S, Sturdivant RX: Applied Logistic Regression. 3rd edition. John Wiley & Sons, New Jersey; 2013.
• [31]Steyerberg EW, Harrell FE Jr, Borsboom GJ, Eijkemans MJ, Vergouwe Y, Habbema JD: Internal validation of predictive models: efficiency of some procedures for logistic regression analysis. J Clin Epidemiol 2001, 54:774-781.
• [32]Victora CG, Araújo CLP, Menezes AMB, Hallal PC, Vieira M de F, Neutzling MB, Gonçalves H, Valle NC, Lima RC, Anselmi L, Behague D, Gigante DP, Barros FC: Methodological aspects of the 1993 Pelotas (Brazil) birth cohort study. Rev Saude Publica 2006, 40:39-46.
• [33]Wechsle D: Test de Inteligencia Para Preescolares (WPPSI) Manual. Buenos Aires, Paidos; 1991.
• [34]Kaufman AS: A short form of the Wechsler Preschool and Primary Scale of Intelligence. J Consult Clin Psychol 1972, 39:361-369.
• [35]Moons KG, Kengne AP, Grobbee DE, Royston P, Vergouwe Y, Altman DG, Woodward M: Risk prediction models: II. External validation, model updating, and impact assessment. Heart 2012, 98:691-698.
• [36]Wachs TD, Rahman A: The Nature and Impact of Risk and Protective Influences on Childrens Development in Low-Income Countries. In Handbook of Early Childhood Development Research and Its Impact on Global Policy. Edited by Britto PR, Engle PL, Super CM. Oxford University Press, New York; 2013:85-122.
• [37]Fagan J, Lee Y: Effects of fathers’ and mothers’ cognitive stimulation and household income on toddlers’ cognition: variations by family structure and child risk. Fathering 2012, 10(2):140-158.
• [38]Sylva K, Stein A, Leach P, Barnes J, Malmberg L-E: the FCCC-team: Effects of early child-care on cognition, language, and task-related behaviours at 18 months: an english study. Brit J Dev Psychol 2011, 29(1):18-45.
• [39]Brooks-Gunn J, Han W-J, Waldfogel J: IV. First-year maternal employment and child cognitive development. Monogr Soc Res Child Dev 2010, 75:50-58.
• [40]Coley RL, Lombardi CM: Does maternal employment following childbirth support or inhibit low-income children’s long-term development? Child Dev 2013, 84:178-197.
• [41]Santos DN, Assis AM, Bastos AC, Santos LM, Santos CA, Strina A, Prado MS, Almeida-Filho NM, Rodrigues LC, Barreto ML: Determinants of cognitive function in childhood: a cohort study in a middle income context. BMC Public Health 2008, 8:202. BioMed Central Full Text
• [42]Downey DB: Number of siblings and intellectual development. The resource dilution explanation. Am Psychol 2001, 56:497-504.
• [43]Blair C, Granger DA, Willoughby M, Mills-Koonce R, Cox M, Greenberg MT, Kivlighan KT, Fortunato CK, Investigators FLP: Salivary cortisol mediates effects of poverty and parenting on executive functions in early childhood. Child Dev 2011, 82:1970-1984.
• [44]Crosnoe R, Leventhal T, Wirth RJ, Pierce KM, Pianta RC: NICHD Early Child Care Research Network: Family socioeconomic status and consistent environmental stimulation in early childhood. Child Dev 2010, 81:972-987.
• [45]Hackman DA, Farah MJ, Meaney MJ: Socioeconomic status and the brain: mechanistic insights from human and animal research. Nat Rev Neurosc 2010, 11:651-659.
• [46]Horta BL, Victora CG: Performance in intelligence tests. In Long-term effects of breastfeeding: a systematic review. World Health Organization, Geneva, Switzerland; 2013:57-66.
• [47]Quigley MA, Hockley C, Carson C, Kelly Y, Renfrew MJ, Sacker A: Breastfeeding is Associated with Improved Child Cognitive Development: A Population-Based Cohort Study. J Pediat 2012, 160:25-32.
• [48]Pongcharoen T, Ramakrishnan U, DiGirolamo AM, Winichagoon P, Flores R, Singkhornard J, Martorell R: Influence of prenatal and postnatal growth on intellectual functioning in school-aged children. Arch Pediatr Adolesc Med 2012, 166:411-416.
• [49]Yang S, Tilling K, Martin R, Davies N, Ben-Shlomo Y, Kramer MS: Pre-natal and post-natal growth trajectories and childhood cognitive ability and mental health. Int J Epidemiol 2011, 40:1215-1226.
• [50]Heinonen K, Räikkönen K, Pesonen A-K, Andersson S, Kajantie E, Eriksson JG, Wolke D, Lano A: Longitudinal study of smoking cessation before pregnancy and children’s cognitive abilities at 56 months of age. Early Hum Dev 2011, 87:353-359.
• [51]Julvez J, Ribas-Fitó N, Torrent M, Forns M, Garcia-Esteban R, Sunyer J: Maternal smoking habits and cognitive development of children at age 4 years in a population-based birth cohort. Int J Epidemiol 2007, 36:825-832.
• [52]Bee HL, Barnard KE, Eyres SJ, Gray CA, Hammond MA, Spietz AL, Snyder C, Clark B: Prediction of IQ and language skill from perinatal status, child performance, family characteristics, and mother-infant interaction. Child Dev 1982, 53:1134-1156.
• [53]Barros AJ, Matijasevich A, Santos IS, Halpern R: Child development in a birth cohort: effect of child stimulation is stronger in less educated mothers. Int J Epidemiol 2010, 39:285-294.
• [54]de Moura DR, Costa JC, Santos IS, Barros AJ, Matijasevich A, Halpern R, Dumith S, Karam S, Barros FC: Risk factors for suspected developmental delay at age 2 years in a Brazilian birth cohort. Paediatr Perinat Epidemiol 2010, 24:211-221.
• [55]Moura DR, Costa JC, Santos IS, Barros AJ, Matijasevich A, Halpern R, Dumith S, Karam S, Barros FC: Natural history of suspected developmental delay between 12 and 24 months of age in the 2004 Pelotas birth cohort. J Paediatr Child Health 2010, 46:329-336.
• [56]Eriksen H-LF, Kesmodel US, Underbjerg M, Kilburn TR, Bertrand J, Mortensen EL: Predictors of Intelligence at the Age of 5: Family, Pregnancy and Birth Characteristics, Postnatal Influences, and Postnatal Growth. PLoS One 2013, 8:e79200.
• [57]Fonseca ALM, Albernaz EP, Kaufmann CC, Neves IH, de Figueiredo VLM: Impact of breastfeeding on the intelligence quotient of eight-year-old children. J Pediatr (Rio J) 2013, 89:346-353.
• [58]Chor D, Lima CR: [Epidemiologic aspects of racial inequalities in health in Brazil]. Cad Saude Publica 2005, 21:1586-1594.
• [59]Silva LM, Silva RA, Silva AA, Bettiol H, Barbieri MA: Racial inequalities and perinatal health in the southeast region of Brazil. Braz J Med Biol Res 2007, 40:1187-1194.
• [60]Kraemer HC, Lowe KK, Kupfer DJ: Are All Risk Factors Equal? Types of Risk Factors. In To your health: How to understand what research tells us about risk. Oxford University Press, New York; 2005:270.
• [61]Organisation for Economic Co-operation and Development (OECD): PISA 2012 Results in Focus. What 15-year-olds know and what they can do with what they know: Key results from PISA 2012. [http://www.oecd.org/pisa/keyfindings/pisa-2012-results-overview.pdf]
• [62]Bonnier C: Evaluation of early stimulation programs for enhancing brain development. Acta Paediatr 2008, 97:853-858.
• [63]Eickmann SH, Lima AC, Guerra MQ, Lima MC, Lira PI, Huttly SR, Ashworth A: Improved cognitive and motor development in a community-based intervention of psychosocial stimulation in northeast Brazil. Dev Med Child Neurol 2003, 45:536-541.
• [64]Geddes R, Frank J, Haw S: A rapid review of key strategies to improve the cognitive and social development of children in Scotland. Health Policy 2011, 101:20-28.
• [65]Maulik PK, Darmstadt GL: Community-based interventions to optimize early childhood development in low resource settings. J Perinatol 2009, 29:531-542.
• [66]Baker-Henningham H: The role of early childhood education programmes in the promotion of child and adolescent mental health in low- and middle-income countries. Int J Epidemiol 2014, 43:407-433.
• [67]Baker-Henningham H, Lopez-Boo F: Early childhood stimulation interventions in developing countries: a comprehensive literature review. 2010.
• [68]Grantham-McGregor SM, Fernald LCH, Kagawa RMC, Walker S: Effects of integrated child development and nutrition interventions on child development and nutritional status. Ann N Y Acad Sci 2014, 1308:11-32.