Breastfeeding Reduces Long-Term Risk for Diabetes

Here is yet another study showing that breastfeeding long-term decreases the risk for developing diabetes.

In this latest study, breastfeeding for a total of 12 months or more cut the risk for diabetes by about HALF.

That's a pretty significant decrease. It's not an absolute guarantee against diabetes, of course, but there is excellent evidence that breastfeeding strongly reduces the risk for diabetes or delays its presentation. This has obvious benefits for heart health.

This latest study just adds to the accumulating evidence of the importance of breastfeeding for a woman's long-term health. Pregnancy alters the metabolism significantly, increasing insulin resistance and blood sugar in order to divert more energy to the developing baby. This is good in the short term, but bad for the mother long term.

Biologically speaking, lactation was meant to "re-set" the mother's metabolism back to normal after pregnancy. When this doesn't happen, the mother's metabolism remains altered to some extent and more prone to health issues like diabetes and heart problems.

Sometimes breastfeeding doesn't work out, and that's okay. But new mothers should know that biologically, their bodies were meant to lactate, and the longer the better. Moms who do nurse should be encouraged to nurse as long as possible, and given every support to do so. Moms who don't nurse or who stop within a few weeks or months should be alerted to be even more proactive about avoiding/watching for diabetes.


References

JAMA Intern Med. 2018 Jan 16. doi: 10.1001/jamainternmed.2017.7978. [Epub ahead of print] Lactation Duration and Progression to Diabetes in Women Across the Childbearing Years: The 30-Year CARDIA Study. Gunderson EP, Lewis CE, Lin Y, Sorel M, Gross M, Sidney S, Jacobs DR Jr, Shikany JM, Quesenberry CP Jr. PMID: 29340577

...OBJECTIVE: To evaluate the association between lactation and progression to diabetes using biochemical testing both before and after pregnancy and accounting for prepregnancy cardiometabolic measures, gestational diabetes (GD), and lifestyle behaviors. DESIGN, SETTING, AND PARTICIPANTS: For this US multicenter, community-based 30-year prospective cohort study, there were 1238 women from the Coronary Artery Risk Development in Young Adults (CARDIA) study of young black and white women ages 18 to 30 years without diabetes at baseline (1985-1986) who had 1 or more live births after baseline, reported lactation duration, and were screened for diabetes up to 7 times during 30 years after baseline (1986-2016)...RESULTS: Overall 1238 women were included in this analysis (mean [SD] age, 24.2 [3.7] years; 615 black women). There were 182 incident diabetes cases during 27 598 person-years for an overall incidence rate of 6.6 cases per 1000 person-years (95% CI, 5.6-7.6); and rates for women with GD and without GD were 18.0 (95% CI, 13.3-22.8) and 5.1 (95% CI, 4.2-6.0), respectively (P for difference < .001). Lactation duration showed a strong, graded inverse association with diabetes incidence: adjusted RH [relative hazard] for more than 0 to 6 months, 0.75 (95% CI, 0.51-1.09); more than 6 months to less than 12 months, 0.52 (95% CI, 0.31-0.87), and 12 months or more 0.53 (0.29-0.98) vs none (0 days) (P for trend = .01). There was no evidence of effect modification by race, GD, or parity. CONCLUSIONS AND RELEVANCE: This study provides longitudinal biochemical evidence that lactation duration is independently associated with lower incidence of diabetes....

Other Breastfeeding and Diabetes Research

Am J Physiol Endocrinol Metab. 2017 Mar 1;312(3):E215-E223. doi: 10.1152/ajpendo.00403.2016. Epub 2016 Dec 13. Prior lactation reduces future diabetic risk through sustained postweaning effects on insulin sensitivity. Bajaj H, Ye C, Hanley AJ, Connelly PW, Sermer M, Zinman B, Retnakaran R. PMID: 27965206

...in this study, we evaluated the relationships between duration of lactation [≤3 mo (n = 70), 3-12 mo (n = 140), and ≥12 mo (n = 120)] and trajectories of insulin sensitivity/resistance, β-cell function, and glycemia over the first 3 yr postpartum in a cohort of 330 women comprising the full spectrum of glucose tolerance in pregnancy, who underwent serial metabolic characterization, including oral glucose tolerance tests, at 3 mo, 1 yr, and 3 yr postpartum. The prevalence of dysglycemia (pre-diabetes/diabetes) at 3 yr postpartum was lower in women who breastfed for ≥12 mo (12.5%) than in those who breastfed for ≤3 mo (21.4%) or for 3-12 mo (25.7%)(overall P = 0.028). On logistic regression analysis, lactation for ≥12 mo independently predicted a lower likelihood of prediabetes/diabetes at 3 yr postpartum (OR = 0.37, 95% CI 0.18-0.78, P = 0.009). Notably, lactation for ≥12 mo predicted lesser worsening of insulin sensitivity/resistance (P < 0.0001), fasting glucose (P < 0.0001), and 2-h glucose (P = 0.011) over 3 yr compared with lactation ≤3 mo but no differences in β-cell function (P ≥ 0.37)....

Diabetes Care. 2010 Jun;33(6):1239-41. doi: 10.2337/dc10-0347. Epub 2010 Mar 23.Parity, breastfeeding, and the subsequent risk of maternal type 2 diabetes. Liu B, Jorm L, Banks E. PMID: 20332359

...Using information on parity, breastfeeding, and diabetes collected from 52,731 women recruited into a cohort study, we estimated the risk of type 2 diabetes using multivariate logistic regression... Among parous women, there was a 14% (95% CI 10-18%, P < 0.001) reduced likelihood of diabetes per year of breastfeeding... CONCLUSIONS: Compared with nulliparous women, childbearing women who do not breastfeed have about a 50% increased risk of type 2 diabetes in later life. Breastfeeding substantially reduces this excess risk.

JAMA. 2005 Nov 23;294(20):2601-10. Duration of lactation and incidence of type 2 diabetes. Stuebe AM, Rich-Edwards JW, Willett WC, Manson JE, Michels KB. PMID: 16304074

...Prospective observational cohort study of 83,585 parous women in the Nurses' Health Study (NHS) and retrospective observational cohort study of 73,418 parous women in the Nurses' Health Study II (NHS II)...RESULTS: ...Among parous women, increasing duration of lactation was associated with a reduced risk of type 2 diabetes. For each additional year of lactation, women with a birth in the prior 15 years had a decrease in the risk of diabetes of 15% (95% confidence interval, 1%-27%) among NHS participants and of 14% (95% confidence interval, 7%-21%) among NHS II participants, controlling for current body mass index and other relevant risk factors for type 2 diabetes. CONCLUSIONS: Longer duration of breastfeeding was associated with reduced incidence of type 2 diabetes in 2 large US cohorts of women....

Breastfeeding and Cardiovascular Health/Mortality

Annu Rev Nutr. 2016 Jul 17;36:627-45. doi: 10.1146/annurev-nutr-071715-051213. Epub 2016 May 4. Lactation and Maternal Cardio-Metabolic Health. Perrine CG, Nelson JM, Corbelli J, Scanlon KS. PMID: 27146017

Researchers hypothesize that pregnancy and lactation are part of a continuum, with lactation meant to "reset" the adverse metabolic profile that develops as a part of normal pregnancy, and that when lactation does not occur, women maintain an elevated risk of cardio-metabolic diseases. Several large prospective and retrospective studies, mostly from the United States and other industrialized countries, have examined the associations between lactation and cardio-metabolic outcomes. Less evidence exists regarding an association of lactation with maternal postpartum weight status and dyslipidemia, whereas more evidence exists for an association with diabetes, hypertension, and subclinical and clinical cardiovascular disease.

Am J Obstet Gynecol. 2009 Feb;200(2):138.e1-8. doi: 10.1016/j.ajog.2008.10.001. Epub 2008 Dec 25. Duration of lactation and incidence of myocardial infarction in middle to late adulthood. Stuebe AM, Michels KB, Willett WC, Manson JE, Rexrode K, Rich-Edwards JW. PMID: 19110223

We assessed the relation between duration of lactation and maternal incident myocardial infarction. STUDY DESIGN: This was a prospective cohort study of 89,326 parous women in the Nurses' Health Study. RESULTS:... Compared with parous women who had never breastfed, women who had breastfed for a lifetime total of 2 years or longer had 37% lower risk of coronary heart disease (95% confidence interval, 23-49%; P for trend < .001), adjusting for age, parity, and stillbirth history. With additional adjustment for early-adult adiposity, parental history, and lifestyle factors, women who had breastfed for a lifetime total of 2 years or longer had a 23% lower risk of coronary heart disease (95% confidence interval, 6-38%; P for trend = .02) than women who had never breastfed. CONCLUSION: In a large, prospective cohort, long duration of lactation was associated with a reduced risk of coronary heart disease.

BMC Public Health. 2013 Nov 13;13:1070. doi: 10.1186/1471-2458-13-1070. A prospective population-based cohort study of lactation and cardiovascular disease mortality: the HUNT study. Natland Fagerhaug T, Forsmo S, Jacobsen GW, Midthjell K, Andersen LF, Ivar Lund Nilsen T. PMID: 24219620

...In a Norwegian population-based prospective cohort study, we studied the association of lifetime duration of lactation with cardiovascular mortality in 21,889 women aged 30 to 85 years who attended the second Nord-Trøndelag Health Survey (HUNT2) in 1995-1997. The cohort was followed for mortality through 2010 by a linkage with the Cause of Death Registry...RESULTS:...Parous women younger than 65 years who had never lactated had a higher cardiovascular mortality than the reference group of women who had lactated 24 months or more (HR 2.77, 95% confidence interval [CI]: 1.28, 5.99)...CONCLUSIONS: Excess cardiovascular mortality rates were observed among parous women younger than 65 years who had never lactated. These findings support the hypothesis that lactation may have long-term influences on maternal cardiovascular health.