title: Maternal salivary cortisol levels during pregnancy are positively associated with overweight children.
abstract: BACKGROUND
  Animal and human studies suggest that programing of the hypothalamic-pituitary-adrenal (HPA) axis may be involved in the development of obesity, but human studies of biological indicators of HPA axis activity are lacking. We studied the association between levels of the stress hormone cortisol during pregnancy and overweight offspring during childhood into adolescence.
  
  
  METHODS
  Salivary samples from 655 Danish pregnant women with singleton pregnancies (1989-1991) were collected once in the morning and once in the evening in their second and third trimester. We followed the offspring from two to 16 years of age with at least one measurement of height and weight, and classified their body mass index into overweight and normal weight. The adjusted relative difference in median salivary cortisol (with 95% confidence interval (CI)) during pregnancy (the four samples), in second and third trimester (morning and evening samples) between overweight and normal weight offspring was estimated. Furthermore, the adjusted median ratio between morning and evening maternal salivary cortisol level was estimated for normal weight and overweight children. All the analyses were stratified into the equal age groups: 2-6, 7-11, and 12-16 years.
  
  
  RESULTS
  We found non-significant higher maternal cortisol levels during pregnancy in offspring that were overweight at the age of 2-6, 7-11 and 12-16 years than in normal weight peers; adjusted relative difference in median salivary cortisol 11% (95% CI: -2; 25), 6% (95% CI: -7; 20), and 9% (95% CI: -4; 24), respectively. A statistically significantly higher level of maternal cortisol was found in the second trimester in 2-6-year-old and 12-16-year-old overweight offspring; relative difference 19% (95% CI: 3; 37), and 20% (95% CI: 3; 41), respectively. The median ratio between morning and evening maternal salivary cortisol level was similar for overweight and normal weight children; e.g. at age 2-6 years in third trimester 4.31 (95% CI: 4.05; 4.60)nmol/l and 4.28 (95% CI: 3.60; 5.09)nmol/l, respectively (P=0.93).
  
  
  CONCLUSIONS
  Our findings suggest a relatively consistent association between pregnancy cortisol levels and overweight offspring, especially in the second trimester.
authors.affiliation: Section for General Practice, Institute of Public Health, Aarhus University, Aarhus, Denmark. Electronic address: lena.hohwu@ph.au.dk.
authors.forename: Lena
authors.initials: L
authors.lastname: Hohwü
authors.affiliation: Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Tine B
authors.initials: TB
authors.lastname: Henriksen
authors.affiliation: Section for Biostatistics, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Therese K
authors.initials: TK
authors.lastname: Grønborg
authors.affiliation: Department of Obstetrics, Rigshospitalet, Copenhagen University, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Hedegaard
authors.affiliation: Institute of Preventive Medicine, Bispebjerg and Frederiksbjerg Hospitals, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thorkild I A
authors.initials: TI
authors.lastname: Sørensen
authors.affiliation: Section for General Practice, Institute of Public Health, Aarhus University, Aarhus, Denmark.
authors.forename: Carsten
authors.initials: C
authors.lastname: Obel
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D050177:Overweight / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000378:metabolism*; D012463:Saliva / Q000737:chemistry
chemical_list: D006854:Hydrocortisone
keywords: Body mass index; Children; Cortisol; Overweight; Pregnancy