title: Maternal psychosocial factors determining the concentrations of transforming growth factor-beta in breast milk.
abstract: BACKGROUND
  Cytokines in breast milk may play crucial roles in the beneficial effects of breastfeeding in protecting against allergic and infectious diseases in infants. In particular, breast milk-borne transforming growth factor-beta (TGF-β) has an important potential role in developing the mucosal immune system in infants. However, little is known about what factors influence TGF-β expression in human milk. We investigated whether the behavioral and psychosocial characteristics of mothers affect breast milk TGF-β levels.
  
  
  METHODS
  We conducted a survey of all 139 mothers who were lactating between February and October 2010 in Koshu City, Japan. Participants completed a questionnaire and provided breast milk at the health checkups for their 3-month-old child (N = 129, 93%). Breast milk was assayed for total TGF-β2 levels by ELISA. We took an exploratory approach based on linear and ordered logistic regressions to model TGF-β2 concentrations with their multiple potential determinants.
  
  
  RESULTS
  Mothers with depression or poor self-rated health had higher TGF-β2 concentrations than mothers without depression (odds ratio for a higher TGF-β2 quartile: 3.11, 95% confidence intervals: 1.03-9.37) or those reporting better health (odds ratio: 2.34, 1.21-4.55). Smoking, drinking alcohol, probiotics supplementation, social support, and maternal history of allergic diseases were not associated with milk TGF-β2 levels. Milk gathered between August and October or later in the afternoon (3-4 pm vs. 12-2 pm) contained less TGF-β2.
  
  
  CONCLUSIONS
  Depression, as the consequence of psychosocial stress, may be a strong determinant of TGF-β levels in breast milk. Seasonal and daily fluctuations in milk TGF-β2 concentrations warrant further study.
authors.affiliation: Department of Health Sciences, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo-Shi, Japan. nkondo@yamanashi.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Kondo
authors.forename: Yuki
authors.initials: Y
authors.lastname: Suda
authors.forename: Atsuhito
authors.initials: A
authors.lastname: Nakao
authors.forename: Kyoko
authors.initials: K
authors.lastname: Oh-Oka
authors.forename: Kohta
authors.initials: K
authors.lastname: Suzuki
authors.forename: Kayoko
authors.initials: K
authors.lastname: Ishimaru
authors.forename: Miri
authors.initials: M
authors.lastname: Sato
authors.forename: Taichiro
authors.initials: T
authors.lastname: Tanaka
authors.forename: Akiko
authors.initials: A
authors.lastname: Nagai
authors.forename: Zentaro
authors.initials: Z
authors.lastname: Yamagata
mesh_terms: D000328:Adult; D000818:Animals; D001942:Breast Feeding / Q000706:statistics & numerical data; D019052:Depression, Postpartum / Q000453:epidemiology / Q000276:immunology* / Q000523:psychology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018928:Immunity, Mucosal; D007223:Infant; D007564:Japan; D016015:Logistic Models; D008297:Male; D008895:Milk, Human / Q000737:chemistry / Q000276:immunology*; D012621:Seasons; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000276:immunology*; D053781:Transforming Growth Factor beta2 / Q000032:analysis*
chemical_list: D053781:Transforming Growth Factor beta2