title: The Cohort for Childhood Origin of Asthma and allergic diseases (COCOA) study: design, rationale and methods.
abstract: BACKGROUND
  This paper describes the background, aim, and design of a prospective birth-cohort study in Korea called the COhort for Childhood Origin of Asthma and allergic diseases (COCOA). COCOA objectives are to investigate the individual and interactive effects of genetics, perinatal environment, maternal lifestyle, and psychosocial stress of mother and child on pediatric susceptibility to allergic diseases.
  
  
  METHODS
  The participants in COCOA represents a Korean inner-city population. Recruitment started on 19 November, 2007 and will continue until 31 December, 2015. Recruitment is performed at five medical centers and eight public-health centers for antenatal care located in Seoul. Participating mother-baby pairs are followed from before birth to adolescents. COCOA investigates whether the following five environmental variables contribute causally to the development and natural course of allergic diseases: (1) perinatal indoor factors (i.e. house-dust mite, bacterial endotoxin, tobacco smoking, and particulate matters 2.5 and 10), (2) perinatal outdoor pollutants, (3) maternal prenatal psychosocial stress and the child's neurodevelopment, (4) perinatal nutrition, and (5) perinatal microbiome. Cord blood and blood samples from the child are used to assess whether the child's genes and epigenetic changes influence allergic-disease susceptibility. Thus, COCOA aims to investigate the contributions of genetics, epigenetics, and various environmental factors in early life to allergic-disease susceptibility in later life. How these variables interact to shape allergic-disease susceptibility is also a key aim.The COCOA data collection schedule includes 11 routine standardized follow-up assessments of all children at 6 months and every year until 10 years of age, regardless of allergic-disease development. The mothers will complete multiple questionnaires to assess the baseline characteristics, the child's exposure to environmental factors, maternal pre- and post-natal psychological stress, and the child's neurodevelopment, nutritional status, and development of allergic and respiratory illnesses. The child's microbiome, genes, epigenetics, plasma cytokine levels, and neuropsychological status, the microbiome of the residence, and the levels of indoor and outdoor pollutants are measured by standard procedures.
  
  
  CONCLUSIONS
  The COCOA study will improve our understanding of how individual genetic or environmental risk factors influence susceptibility to allergic disease and how these variables interact to shape the phenotype of allergic diseases.
authors.forename: Hyeon-Jong
authors.initials: HJ
authors.lastname: Yang
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Lee
authors.forename: Dong In
authors.initials: DI
authors.lastname: Suh
authors.forename: Youn Ho
authors.initials: YH
authors.lastname: Shin
authors.forename: Byoung-Ju
authors.initials: BJ
authors.lastname: Kim
authors.forename: Ju-Hee
authors.initials: JH
authors.lastname: Seo
authors.forename: Hyoung Yoon
authors.initials: HY
authors.lastname: Chang
authors.forename: Kyung Won
authors.initials: KW
authors.lastname: Kim
authors.forename: Kangmo
authors.initials: K
authors.lastname: Ahn
authors.forename: Yee-Jin
authors.initials: YJ
authors.lastname: Shin
authors.forename: Kyung-Sook
authors.initials: KS
authors.lastname: Lee
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Lee
authors.forename: Se-Young
authors.initials: SY
authors.lastname: Oh
authors.forename: Ho
authors.initials: H
authors.lastname: Kim
authors.forename: Jong-Han
authors.initials: JH
authors.lastname: Leem
authors.forename: Hwan-Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Eun-Jin
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Childhood Asthma Atopy Center, Research Center for Standardization of Allergic Diseases, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, 760, Korea. jooshil@korea.kr.
authors.forename: Joo-Shil
authors.initials: JS
authors.lastname: Lee
authors.forename: Soo-Jong
authors.initials: SJ
authors.lastname: Hong
mesh_terms: D000393:Air Pollutants; D001249:Asthma / Q000453:epidemiology / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000032:analysis; D003876:Dermatitis, Atopic / Q000453:epidemiology; D004198:Disease Susceptibility / Q000453:epidemiology; D004781:Environmental Exposure; D044127:Epigenesis, Genetic; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005512:Food Hypersensitivity / Q000453:epidemiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology* / Q000209:etiology*; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D018811:Maternal Exposure; D064307:Microbiota; D015596:Nutrition Assessment; D018812:Paternal Exposure; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology; D011446:Prospective Studies; D056910:Republic of Korea; D012107:Research Design; D012135:Respiratory Sounds; D065631:Rhinitis, Allergic / Q000453:epidemiology; D012867:Skin / Q000382:microbiology; D013315:Stress, Psychological / Q000453:epidemiology; D014505:Urban Population
chemical_list: D000393:Air Pollutants; D004247:DNA