title: Potential protective effect of lactation against incidence of type 2 diabetes mellitus in women with previous gestational diabetes mellitus: A systematic review and meta-analysis.
abstract: Lactation may protect women with previous gestational diabetes mellitus (GDM) from developing type 2 diabetes mellitus, but the results of existing studies are inconsistent, ranging from null to beneficial. We aimed to conduct a systematic review to gather available evidence. Databases MEDLINE, CINAHL, PubMed, and EMBASE were searched on December 15, 2015, without restriction of language or publication year. A manual search was also conducted. We included observational studies (cross-sectional, case-control, and cohort study) with information on lactation and type 2 diabetes mellitus incidence among women with previous GDM. We excluded case studies without control data. Data synthesis was conducted by random-effect meta-analysis. Fourteen reports of 9 studies were included. Overall risk of bias using RoBANS ranged from low to unclear. Longer lactation for more than 4 to 12 weeks postpartum had risk reduction of type 2 diabetes mellitus compared with shorter lactation (OR 0.77, 95% CI 0.01-55.86; OR 0.56, 95% CI 0.35-0.89; OR 0.22, 95% CI 0.13-0.36; type 2 diabetes mellitus evaluation time < 2 y, 2-5 y, and >5 y, respectively). Exclusive lactation for more than 6 to 9 weeks postpartum also had lower risk of type 2 diabetes mellitus compared with exclusive formula (OR 0.42, 95% CI 0.22-0.81). The findings support the evidence that longer and exclusive lactation may be beneficial for type 2 diabetes mellitus prevention in women with previous GDM. However, the evidence relies only on observational studies. Therefore, further studies are required to address the true causal effect.
authors.affiliation: Division of Maternal Medicine, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Tanase-Nakao
authors.affiliation: Division of Maternal Medicine, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Naoko
authors.identifier: 0000-0003-2667-7653
authors.initials: N
authors.lastname: Arata
authors.affiliation: Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Kawasaki
authors.affiliation: Department of Obstetrics and Gynecology, National Hospital Organization Nagasaki Medical Center, Nagasaki, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yasuhi
authors.affiliation: Department of Hematology, Endocrinology and Metabolism, Niigata University Faculty of Medicine, Niigata, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Sone
authors.affiliation: Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Rintaro
authors.initials: R
authors.lastname: Mori
authors.affiliation: Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan.|Department of Global Health Nursing, Graduate School of Nursing Sciences, St. Luke's International University, Tokyo, Japan.
authors.forename: Erika
authors.initials: E
authors.lastname: Ota
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000517:prevention & control*; D016640:Diabetes, Gestational / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007774:Lactation; D011247:Pregnancy
keywords: gestational diabetes mellitus; lactation; meta-analysis; prevention; systematic review; type 2 diabetes mellitus