Association of Maternal Lactation With Diabetes and Hypertension: A Systematic Review and Meta-analysis

Rabel Misbah Rameez; Divyajot Sadana; Simrat Kaur; Taha Ahmed; Jay Patel; Muhammad Shahzeb Khan; Sarah Misbah; Marian T Simonson; Haris Riaz; Haitham M Ahmed

doi:10.1001/jamanetworkopen.2019.13401

Postpartum Infant Feeding

Association of Maternal Lactation With Diabetes and Hypertension: A Systematic Review and Meta-analysis

Rameez RM, Sadana D, Kaur S, Ahmed T, Patel J, Khan MS, Misbah S, Simonson MT, Riaz H, Ahmed HM

Published October 2, 2019 JAMA network open, 2(10), e1913401

DOI 10.1001/jamanetworkopen.2019.13401 PMID 31617928 PMC PMC6806428

RRM Academy Synopsis

Breastfeeding over a year is linked to lower maternal diabetes risk

Breastfeeding for longer than 12 months was linked to 30% lower diabetes risk in a meta-analysis of six observational studies of adult women. Breastfeeding for longer than 12 months was also linked to 13% lower hypertension risk. The studies included more than 200 000 participants.

Study at a glance, systematic review and meta-analysis: Breastfeeding over a year linked to lower diabetes risk — Study at a glance, systematic review and meta-analysis of six observational studies: Breastfeeding over a year linked to lower diabetes risk. Source: Rameez RM et al., 2019, PMID 31617928.

Key Findings

Women who breastfed for longer than 12 months had 30% lower diabetes risk (pooled odds ratio, 0.70 [95% CI, 0.62-0.78]; I2 = 33%; P < .001), pooled across 4 studies.
Women who breastfed for longer than 12 months had 13% lower hypertension risk (pooled odds ratio, 0.87 [95% CI, 0.78-0.97]; I2 = 60.6%; P = .01), pooled across 5 studies.
A July 2018 database search returned 1558 records. Twenty-two studies went through qualitative analysis, and 6 of them met full inclusion criteria for the meta-analysis.
Pooling studies that reported relative risks or hazard ratios alongside odds ratios showed no difference in the results for diabetes or hypertension.
The authors report Egger test P values of .51 and .93 for hypertension and diabetes, respectively, and conclude that publication bias did not alter the results.

Interpretation

The paper is a systematic review and meta-analysis, which pools results from earlier studies into one estimate. The six studies were observational and enrolled adult women in China, Korea, Australia, and the United States. The estimates compare breastfeeding for longer than 12 months with breastfeeding for less than 12 months. The analysis used each study's adjusted odds ratios. Results varied more between studies for hypertension than for diabetes. The authors note that none of the studies was a randomized trial, so an element of confounding bias may be present.

RRM Context

Restorative reproductive medicine follows a woman's health across her whole life. That span runs from ovulatory cycles through pregnancy, birth, and lactation. The authors write that pregnancy and the time after birth come with unique stresses on the heart and metabolism. They also cite the view that lactation works as a reset for the adverse effects of pregnancy.

Our editorial summary of this paper, not the article's abstract.

Abstract

Importance

Lactation has been shown to be associated with lower rates of diabetes and hypertension in mothers. However, the strength of association has varied between studies, and sample sizes are relatively small.

Objective

To conduct a systematic review and meta-analysis to determine whether lactation is associated with a lower risk of diabetes and hypertension.

Data Sources

Ovid MEDLINE, Ovid Embase, Cochrane CENTRAL, and CINAHL databases were searched from inception to July 2018 with manual search of the references.

Study Selection

Studies of adult women that specified duration of breastfeeding for at least 12 months, evaluated primary hypertension and diabetes as outcomes, were full-text articles in English, and reported statistical outcomes as odds ratios were included.

Data Extraction and Synthesis

Study characteristics were independently extracted using a standard spreadsheet template and the data were pooled using the random-effects model. The Meta-analysis of Observational Studies in Epidemiology (MOOSE) guideline for reporting was followed.

Main Outcomes and Measures

Diabetes and hypertension.

Results

The search yielded 1558 articles, from which a total of 6 studies met inclusion criteria for association between breastfeeding and diabetes and/or hypertension. The 4 studies included in the meta-analysis for the association between lactation and diabetes had a total of 206 204 participants, and the 5 studies included in the meta-analysis for the association between lactation and hypertension had a total of 255 271 participants. Breastfeeding for more than 12 months was associated with a relative risk reduction of 30% for diabetes (pooled odds ratio, 0.70 [95% CI, 0.62-0.78]; P < .001) and a relative risk reduction of 13% for hypertension (pooled odds ratio, 0.87 [95% CI, 0.78-0.97]; P = .01).

Conclusions and Relevance

This study suggests that education about the benefits of breastfeeding for prevention of diabetes and hypertension in women is a low-risk intervention that can be easily included in daily practice and may have a positive impact on cardiovascular outcomes in mothers.

Topics

Postpartum › Infant Feeding › Breastfeeding Support · Lifestyle and Environment › Nutrition and Metabolic Health › Blood Sugar and Insulin

Rabel Misbah Rameez, Divyajot Sadana, Simrat Kaur, Taha Ahmed, Jay Patel, Muhammad Shahzeb Khan, Sarah Misbah, Marian T Simonson, Haris Riaz, Haitham M Ahmed

R Rameez, D Sadana, S Kaur, T Ahmed, J Patel, M Khan, S Misbah, M Simonson, H Riaz, H Ahmed

PMID 31617928 31617928 DOI 10.1001/jamanetworkopen.2019.13401 10.1001/jamanetworkopen.2019.13401 Rameez et al. 2019, Rameez 2019

Association of Maternal Lactation With Diabetes and Hypertension: A Systematic Review and Meta-analysis

Breastfeeding over a year is linked to lower maternal diabetes risk

Key Findings

Interpretation

RRM Context

Abstract

Topics

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