Lactation and Progression to Type 2 Diabetes Mellitus After Gestational Diabetes Mellitus

A Prospective Cohort Study

Gunderson, Erica P. PhD, MPH, MS, RD
Hurston, Shanta R. MPA
Ning, Xian MS
Lo, Joan C. MD
Crites, Yvonne MD
Walton, David MD
Dewey, Kathryn G. PhD
Azevedo, Robert A. MD
Young, Stephen MD
Fox, Gary MD
Elmasian, Cathie C. MD
Salvador, Nora MD
Lum, Michael MD
Sternfeld, Barbara PhD
Quesenberry, Charles P. Jr. PhD

From Kaiser Permanente Northern California and the Permanente Medical Group, Oakland, and University of California, Davis, Davis, California.

Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Grant Support: By the National Institute of Child Health and Human Development (R01 HD050625 to Dr. Gunderson); the National Center for Research Resources, National Institutes of Health (UCSF-CTSI UL1 RR024131); the Kaiser Permanente Northern California Community Benefit Program; and the W.K. Kellogg Foundation.

Disclosures: Dr. Gunderson reports grants from the National Institute of Child Health and Human Development, Kaiser Permanente Community Benefit Program, W.K. Kellogg Foundation, National Institutes of Health National Center for Research Resources, and American Diabetes Association during the conduct of the study. Dr. Lo reports grants from the National Institutes of Health during the conduct of the study and grants from Sanofi outside the submitted work. Dr. Fox reports grants from the National Institute of Child Health and Human Development, Kaiser Permanente Community Benefit Program, W.K. Kellogg Foundation, National Institutes of Health National Center for Research Resources, and the American Diabetes Association during the conduct of the study. Dr. Quesenberry reports grants from the National Institute of Child Health and Human Development during the conduct of the study and grants from Takeda, Merck, Sanofi–Aventis, Lilly, Genentech, Valeant, and Pfizer outside the submitted work. Authors not named here have disclosed no conflicts of interest. Forms can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M15-0807.

Reproducible Research Statement:Study protocol, statistical code, and data set: Available from Dr. Gunderson (e-mail, [email protected]).

Requests for Single Reprints: Erica P. Gunderson, PhD, MPH, MS, RD, Senior Research Scientist, Division of Research, Cardiovascular and Metabolic Conditions Section, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA 94612; e-mail, [email protected].

Current author addresses and author contributions are available at www.annals.org.

For author affiliations, see end of text.

This article was published online first at www.annals.org on 24 November 2015.

* For a list of the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy investigators, see the Appendix (available at www.annals.org).

Current Author Addresses: Drs. Gunderson, Lo, Sternfeld, and Quesenberry; Ms. Hurston; and Ms. Ning: Division of Research, Kaiser Permanente Northern California, 2000 Broadway, Oakland, CA 94612.

Dr. Crites: Maternal-Fetal Medicine, Perinatology, Kaiser Permanente, 710 Lawrence Expressway, Santa Clara, CA 95051.

Dr. Walton: Director of Perinatal Services, Kaiser Foundation Hospital, Oakland Medical Center, 3779 Piedmont Avenue, Oakland, CA 94611.

Dr. Dewey: Distinguished Professor, Department of Nutrition, University of California, Davis, 1 Shields Avenue, Davis, CA 95616-8669.

Dr. Azevedo: Physician-in-Chief, Sacramento Medical Center, Kaiser Permanente, 2025 Morse Avenue, Sacramento, CA 95825.

Dr. Young: Senior Consultant, Department of Obstetrics and Gynecology, Union City Medical Offices, Kaiser Permanente, 3555 Whipple Road, Building A, Union City, CA 94587.

Dr. Fox: Chief, Department of Obstetrics and Gynecology, South Sacramento Medical Center, Kaiser Permanente, 6600 Bruceville Road, Sacramento, CA 95823.

Dr. Elmasian: Folsom Medical Offices, Kaiser Permanente, 2155 Iron Point Road, Folsom, CA 95630.

Dr. Salvador: Richmond Medical Center, Kaiser Permanente, 901 Nevin Avenue, Richmond, CA 94801.

Dr. Lum: Department of Obstetrics and Gynecology, San Jose Medical Center, Kaiser Permanente, 276 International Circle, San Jose, CA 95119.

Author Contributions: Conception and design: E.P. Gunderson, C.P. Quesenberry.

Analysis and interpretation of the data: E.P. Gunderson, S.R. Hurston, X. Ning, J.C. Lo, D. Walton, B. Sternfeld, C.P. Quesenberry.

Drafting of the article: E.P. Gunderson.

Critical revision of the article for important intellectual content: E.P. Gunderson, J.C. Lo, D. Walton, K.G. Dewey, B. Sternfeld.

Final approval of the article: E.P. Gunderson, S.R. Hurston, X. Ning, J.C. Lo, Y. Crites, D. Walton, K.G. Dewey, R.A. Azevedo, S. Young, G. Fox, C.C. Elmasian, N. Salvador, M. Lum, B. Sternfeld, C.P. Quesenberry.

Provision of study materials or patients: E.P. Gunderson, Y. Crites, D. Walton, S. Young, C.C. Elmasian, N. Salvador, M. Lum.

Statistical expertise: C.P. Quesenberry.

Obtaining of funding: E.P. Gunderson, C.P. Quesenberry.

Administrative, technical, or logistic support: S.R. Hurston, J.C. Lo, K.G. Dewey, G. Fox, C.C. Elmasian.

Collection and assembly of data: E.P. Gunderson, S.R. Hurston, J.C. Lo.

Annals of Internal Medicine 163(12):p 889-898, December 15, 2015.

Background:

Lactation improves glucose metabolism, but its role in preventing type 2 diabetes mellitus (DM) after gestational diabetes mellitus (GDM) remains uncertain.

Objective:

To evaluate lactation and the 2-year incidence of DM after GDM pregnancy.

Design:

Prospective, observational cohort of women with recent GDM. (ClinicalTrials.gov: NCT01967030)

Setting:

Integrated health care system.

Participants:

1035 women diagnosed with GDM who delivered singletons at 35 weeks' gestation or later and enrolled in the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy from 2008 to 2011.

Measurements:

Three in-person research examinations from 6 to 9 weeks after delivery (baseline) and annual follow-up for 2 years that included 2-hour, 75-g oral glucose tolerance testing; anthropometry; and interviews. Multivariable Weibull regression models evaluated independent associations of lactation measures with incident DM adjusted for potential confounders.

Results:

Of 1010 women without diabetes at baseline, 959 (95%) were evaluated up to 2 years later; 113 (11.8%) developed incident DM. There were graded inverse associations for lactation intensity at baseline with incident DM and adjusted hazard ratios of 0.64, 0.54, and 0.46 for mostly formula or mixed/inconsistent, mostly lactation, and exclusive lactation versus exclusive formula feeding, respectively (P trend = 0.016). Time-dependent lactation duration showed graded inverse associations with incident DM and adjusted hazard ratios of 0.55, 0.50, and 0.43 for greater than 2 to 5 months, greater than 5 to 10 months, and greater than 10 months, respectively, versus 0 to 2 months (P trend = 0.007). Weight change slightly attenuated hazard ratios.

Limitation:

Randomized design is not feasible or desirable for clinical studies of lactation.

Conclusion:

Higher lactation intensity and longer duration were independently associated with lower 2-year incidences of DM after GDM pregnancy. Lactation may prevent DM after GDM delivery.

Primary Funding Source:

National Institute of Child Health and Human Development.