title: Does the timing of parental migration matter for child growth? A life course study on left-behind children in rural China.
abstract: BACKGROUND
  China's unprecedented internal migration has left 61 million rural children living apart from parents. This study investigates how being left behind is associated with children's growth, by examining children's height and weight trajectories by age, testing the accumulation and critical period life course hypotheses.
  
  
  METHODS
  Data were drawn from five waves of the China Health and Nutrition Survey (CHNS). Multiple cohorts of children under 6 years old from 1997-2009 were examined (N = 2,555). Growth curve models investigated whether height and weight trajectories differ for children who were left behind at different stages of the life course: in early childhood (from ages 0-5 but not afterwards), in later childhood (from ages 6 to 17 only), and in both early and later childhood (from ages 0-5 and from ages 6-17), compared to their peers from intact households.
  
  
  RESULTS
  Boys who were left behind at different life stages of childhood differed in height and weight growth compared with boys from intact families. No significant associations were found for girls. As young boys turned into adolescents, those left behind in early childhood tended to have slower height growth and weight gain than their peers from intact households. There was a 2.8 cm difference in the predicted heights of boys who were left behind in early childhood compared to boys from intact households, by the age of 14. Similarly, the difference in weight between the two groups of boys was 5.3 kg by the age of 14.
  
  
  CONCLUSIONS
  Being left behind during early childhood, as compared to not being left behind, could lead to slower growth rates of height and weight for boys. The life course approach adopted in this study suggests that early childhood is a critical period of children's growth in later life, especially for boys who are left behind. The gender paradox in China, where sons are preferred, but being left behind appears to affect boys more than girls, needs further exploration.
authors.affiliation: Room 3.331, The School of Nursing, Midwifery and Social Work, Jean McFarlane Building, The University of Manchester, Oxford Road, Manchester, M13 9 PL, UK. nancytju@gmail.com.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Cathie Marsh Institute for Social Research (CMIST), School of Social Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK. laia.becares@manchester.ac.uk.
authors.forename: Laia
authors.initials: L
authors.lastname: Bécares
authors.affiliation: Cathie Marsh Institute for Social Research (CMIST), School of Social Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK. tarani.chandola@manchester.ac.uk.
authors.forename: Tarani
authors.initials: T
authors.lastname: Chandola
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001827:Body Height; D001835:Body Weight; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D002681:China; D004641:Emigration and Immigration / Q000706:statistics & numerical data*; D005191:Family Characteristics; D005260:Female; D006801:Humans; D008297:Male; D009749:Nutrition Surveys / Q000706:statistics & numerical data; D010290:Parents; D012424:Rural Population; D012737:Sex Factors; D015430:Weight Gain