Does long-term lactation protect premenopausal women against hypertension risk? A Korean women's cohort study

Association of Hypertension and Breast Cancer: Antihypertensive Drugs as an Effective Adjunctive in Breast Cancer Therapy

Breast cancer (BC) is the most common malignancy affecting women, and its incidence in younger women is rising worldwide. Early-onset of BC is a multi-step process involving various biological aggressive tumors such as triple negative and human epidermal growth factor 2 (HER2)-positive cancers. BC prevention is still arduous across the globe. A series of observational studies have established a conclusive non-genetic clinical link between hypertension (HTN) and the development of invasive BC. Those clinical associations have driven a pharmacological seek to use the anti-hypertension (AHTN) drugs as an effective adjunctive in BC therapy. The use of AHTN, especially beta-blockers and thiazides, has been recognized as a potent anti-tumor drug to mitigate BC progression, reduce the side effects of cancer treatment, and stop the reoccurrence of cancer in the survivors. Considering the dire need to disseminate the research on how AHTN drugs can be opted as the effective adjunctive therapy to cure the BC, the current review aimed to provide an update on novel understandings on association and mechanisms of AHTN-drugs against BC as an additional cancer therapy.

Adverse Pregnancy Outcomes and Cardiovascular Disease Risk: Unique Opportunities for Cardiovascular Disease Prevention in Women: A Scientific Statement From the American Heart Association

This statement summarizes evidence that adverse pregnancy outcomes (APOs) such as hypertensive disorders of pregnancy, preterm delivery, gestational diabetes, small-for-gestational-age delivery, placental abruption, and pregnancy loss increase a woman's risk of developing cardiovascular disease (CVD) risk factors and of developing subsequent CVD (including fatal and nonfatal coronary heart disease, stroke, peripheral vascular disease, and heart failure). This statement highlights the importance of recognizing APOs when CVD risk is evaluated in women, although their value in reclassifying risk may not be established. A history of APOs is a prompt for more vigorous primordial prevention of CVD risk factors and primary prevention of CVD. Adopting a heart-healthy diet and increasing physical activity among women with APOs, starting in the postpartum setting and continuing across the life span, are important lifestyle interventions to decrease CVD risk. Lactation and breastfeeding may lower a woman's later cardiometabolic risk. Black and Asian women experience a higher proportion APOs, with more severe clinical presentation and worse outcomes, than White women. More studies on APOs and CVD in non-White women are needed to better understand and address these health disparities. Future studies of aspirin, statins, and metformin may better inform our recommendations for pharmacotherapy in primary CVD prevention among women who have had an APO. Several opportunities exist for health care systems to improve transitions of care for women with APOs and to implement strategies to reduce their long-term CVD risk. One proposed strategy includes incorporation of the concept of a fourth trimester into clinical recommendations and health care policy.

Lactation Patterns in Women with Hypertensive Disorders of Pregnancy: An Analysis of Illinois 2012-2015 Pregnancy Risk Assessment Monitoring System (PRAMS) Data

BACKGROUND

Hypertensive disorders of pregnancy have lifelong implications on maternal cardiovascular health. Breastfeeding has a variety of maternal benefits, including improved lifelong maternal cardiovascular outcomes, with longer periods of lactation resulting in further improvement. Women with hypertensive disorders of pregnancy encounter many barriers to breastfeeding. Little is known about lactation initiation and duration rates in women with hypertensive disorders of pregnancy. The purpose of this study is to describe lactation patterns in women with HDP, hypertensive disorders of pregnancy, compared to normotensive controls using data from the phase 7 Illinois Pregnancy Risk Assessment Monitoring System (PRAMS).

SUBJECTS AND METHODS

Illinois PRAMS 2012-2015 (Phase 7) data was used to assess lactation patterns as well as rationale for not initiating breastfeeding or earlier cessation. Women who delivered during this time period were eligible to participate in the PRAMS survey, 5285 were included the analysis.

RESULTS

Overall, 17.6% of all women in the study reported their healthcare provider did not speak with them prenatally about breastfeeding. Women who reported they had HDP, were significantly less likely (p ≤ 0.001) to ever breastfeed or pump breast milk to feed their baby, even for a short period, than those women without an HDP. At the time the PRAMS survey was completed, more women without an HDP were still breastfeeding or providing their baby with pumped milk (54.9 v. 48%; p = 0.002). More women with HDP reported stopping breastfeeding because they got sick or had to stop for medical reasons (p = 0.002) and/or because their baby was jaundiced (p = 0.007).

CONCLUSION

Cardiovascular disease remains the leading cause of death among women and women with a history of HDP are at increased risk for cardiovascular related morbidity and mortality. Obstetrical providers and nurses caring for this high-risk population should ensure they educate women about the increased cardiovascular risk associated with HDP and the maternal cardiovascular benefits associated with lactation in order to promote and support lactation in this population of women.

Lactation and Maternal Subclinical Atherosclerosis Among Women With and Without a History of Hypertensive Disorders of Pregnancy

Background: We evaluated subclinical cardiovascular disease in relation to lactation history among women with normotensive pregnancies and women with hypertensive pregnancies, a distinction not previously examined. Materials and Methods: The POUCHmoms study included 678 women from a pregnancy cohort who were followed 7-15 years after delivery. We measured blood pressure, lipid levels, carotid intima-media thickness (CIMT), and lactation duration for each live birth (LB) at follow-up. We categorized lactation as never, <6 months/LB, or ≥6 months/LB. We analyzed associations between lactation and cardiometabolic risk factors and CIMT by using analysis of variance and multivariable linear regression (adjusted for age, race, socioeconomic status, smoking, time from last pregnancy, and total parity), which produced adjusted least square mean differences (LSMdiff) between groups. Results: In the normotensive pregnancies group with women who never lactated as the referent (n = 157): Women with some lactation but <6 months/LB (n = 284) had higher high density lipoprotein (HDL) (LSMdiff = +4.47 mg/dL, p = 0.013), lower triglycerides (LSMdiff = -38.1 mg/dL, p = 0.02), and thinner mean CIMT (LSMdiff = -0.03 mm, p = 0.005); women who lactated for ≥6 months/LB (n = 133) also had higher HDL (LSMdiff = +7.59 mg/dL, p < 0.001), lower triglycerides (LSMdiff = -41.6 mg/dL, p = 0.01), and thinner mean CIMT (LSMdiff = -0.03 mm, p = 0.003). After further adjustment for body mass index, associations between lactation and HDL, triglycerides, and mean CIMT persisted. These associations were not detected in women with prior hypertensive pregnancies. Conclusions: Women with a history of normotensive pregnancies and lactation for any duration had a more favorable cardiometabolic profile and were at decreased risk of subclinical atherosclerosis compared with those who never lactated.

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

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.

Breastfeeding and maternal cardiovascular risk factors: 1982 Pelotas Birth Cohort

This study evaluated the association of breastfeeding duration with maternal metabolic cardiovascular risk factors among women who have been prospectively followed since birth in a southern Brazilian city. In the unadjusted analysis, total cholesterol was higher among women who never breastfed in relation to those who breastfed ≥12 months. Among women with one livebirth, a shorter duration of breastfeeding was associated with lower HDL, while those with two or more livebirths and that breastfed for shorter time presented lower pulse wave velocity, glycaemia and non-HDL measures. After controlling for confounding variables, the magnitude of these associations decreased, and the confidence intervals included the reference. Concerning the duration of breastfeeding of the last child, the analysis was stratified by time since last birth. After controlling for confounders, systolic blood pressure was lower among women who breastfed 3 to <6 months and had a child within the last five years in relation to those who breastfed ≥6, but no clear trend was observed (p = 0.17). In conclusion, our findings suggest that there is no association between lactation and maternal cardiometabolic risk factors.

Breastfeeding Duration and the Risk of Coronary Artery Disease

BACKGROUND

Previous studies have suggested that prolonged breastfeeding has beneficial effects on the health of the mother including the reduction of long-term risk of coronary artery disease (CAD). The mechanism of this association remains unclear.

METHODS

We surveyed 643 women aged 40-65 years receiving outpatient care at Stanford University Hospital on their reproductive/lactation history, including 137 women (cases) with clinically confirmed CAD. Survey data were supplemented with traditional risk factor data for CAD obtained from the participant's medical record. We then conducted logistic regression analyses to assess the relationship between breastfeeding duration and case-control status for each of the two separate definitions of duration. The first was based on the participant's single longest duration of breastfeeding considering all live births reported and the second was based on a participant's total duration of breastfeeding summed over all live births. For each of these two definitions, we ran three sequential models each with a different reference group-(1) nulliparous women, (2) parous women that never breastfed, and (3) parous women with a short duration of breastfeeding-successively excluding women in the reference group of the previous model(s).

RESULTS

Just over one-half (51.6%) of the women surveyed reported a history of breastfeeding. We found nominally significant associations (p = 0.04-0.12) for our multivariate analyses that modeled maximum duration of breastfeeding. When compared with nulliparous women, parous women who either never breastfed or always breastfed for <5 months had approximately double the risk of CAD. Among parous women, women who breastfeed for ≥5 months at least once in their lifetime had a ∼30% decrease risk of CAD compared with those who did not initiate breastfeeding. Among parous women who breastfed ≥1 month, women who breastfed ≥5 months had ∼50% decreased risk of CAD. We found similar point estimates of effect for analogous analyses modeling maximum breastfeeding duration but p-values for these analyses were not significant. Unadjusted analyses demonstrated higher valued odds ratios and lower p-values suggesting the presence of some confounding by traditional risk factors.

CONCLUSIONS

Parous women who breastfeed ≥5 months in at least one pregnancy seem to be at decreased risk of CAD later in their life, whereas parous women who either never breastfed or discontinued breastfeeding early seem to be at increased risk. More research is needed to more reliably quantify and determine the nature of the relationship between parity, breastfeeding duration, and risk of CAD.

Effect of Lactation on Maternal Hypertension: A Systematic Review

INTRODUCTION

Hypertension is relatively common in pregnancy, and pregnancy may unmask hypertension among women who are predisposed to it. Lactation may be a means through which to mitigate pregnancy-related vascular risk. The impact of lactation on maternal blood pressure, and the duration of any effect, remains unclear. This study aimed at systematically reviewing the literature evaluating the impact of lactation on the development of hypertension.

MATERIALS AND METHODS

We searched PubMed, including EMBASE and MEDLINE, for studies that reported on the association between breastfeeding and maternal risk of hypertension that were published in a peer-reviewed source. The quality of the studies included was assessed by using the Newcastle-Ottawa Scale.

RESULTS

Nineteen studies met all inclusion criteria for this review. Of the four studies with short-term follow-up, 50% showed a protective association. The fifteen studies with longer-term follow-up were stratified by outcome assessed. Sixty-seven percent of the studies that evaluated for elevated blood pressure and 100% of the studies evaluating for an outcome of hypertension showed a protective association. The minimum duration of lactation associated with a benefit was 1 month. This association was demonstrated in follow-up periods as long as two to three decades. Studies that showed a protective association had overall higher quality ratings.

DISCUSSION

Lactation is associated with a beneficial effect on maternal blood pressure that persists for decades. These results add to the growing body of literature demonstrating the protective association of lactation on maternal cardiovascular risk. Providers may incorporate the decreased risk of hypertension into their counseling on the maternal benefits of lactation.

Breastfeeding and later maternal risk of hypertension and cardiovascular disease - The role of overall and abdominal obesity

In this study, we examined how any, full, and partial breastfeeding durations were associated with maternal risk of hypertension and cardiovascular disease (CVD), and how prepregnancy body mass index (BMI) and waist circumference 7 years postpartum influenced these associations. A total of 63,260 women with live-born singleton infants in the Danish National Birth Cohort (1996-2002) were included. Interviews during pregnancy and 6 and 18 months postpartum provided information on prepregnancy weight, height, and the duration of full and partial breastfeeding. Waist circumference was self-reported 7 years postpartum. Cox regression models were used to estimate hazard ratios of incident hypertension and CVD, registered in the National Patient Register from either 18 months or 7 years postpartum through 15 years postpartum. Any breastfeeding ≥4 months was associated with 20-30% lower risks of hypertension and CVD compared to <4 months in both normal/underweight and overweight/obese women. At follow-up starting 7 years postpartum, similar risk reductions were observed after accounting for waist circumference adjusted for BMI. Partial breastfeeding >2 months compared to ≤2 months, following up to 6 months of full breastfeeding, was associated with 10-25% lower risk of hypertension and CVD. Compared with short breastfeeding duration, additional partial breastfeeding was as important as additional full breastfeeding in reducing risk of hypertension and CVD. Altogether, longer duration of breastfeeding was associated with lower maternal risk of hypertension and CVD irrespective of prepregnancy BMI and abdominal adiposity 7 years after delivery. Both full and partial breastfeeding contributed to an improved cardiovascular health in mothers.

Association Between Duration of Breastfeeding and Maternal Hypertension: A Systematic Review and Meta-Analysis

OBJECTIVES

Recently, an increasing number of studies have implied that breastfeeding has a protective effect on maternal hypertension, but it remains controversial. The aim of this study is to evaluate the effect of breastfeeding on maternal hypertension through meta-analysis.

MATERIALS AND METHODS

Eligible studies were searched and identified in various databases. Meta-analysis was conducted to assess the association between the duration of breastfeeding and maternal hypertension.

RESULTS

Seven eligible studies that contained 444,759 participants were included in our study. Meta-analysis of these seven studies showed a significant protective effect of breastfeeding on maternal hypertension. Specifically, pooled odds ratios (ORs) of hypertension for >0-6, >6-12, and >12 months of breastfeeding were 0.92 (95% confidence interval [CI]: 0.88-0.96, I² = 67.5%), 0.89 (95% CI: 0.86-0.92, I² = 0), and 0.88 (95% CI: 0.84-0.93, I² = 43.9%), respectively, compared with nonbreastfeeding mothers, and the pooled OR of hypertension was 0.93 (95% CI: 0.91-0.95, I² = 40.8%) for women who breastfed compared with women who had not. Furthermore, the pooled hazard ratio of hypertension was 1.34 (95% CI: 1.17-1.52, I² = 58.7%) for women who did not breastfeed compared with women who breastfed for more than 12 months for their first child.

CONCLUSION

Different durations of breastfeeding have different protective effects against the development of maternal hypertension, and breastfeeding for >12 months has a better effect than <12 months.

Association of breastfeeding duration with dyslipidemia in women aged over 20 years: Korea National Health and Nutrition Examination Survey 2010-2014

BACKGROUND

The prevalence of dyslipidemia, particularly hypercholesterolemia, has been reported to increase after pregnancy and menopause in Korea. This suggests the importance of the management of dyslipidemia in women for preventing cardiovascular diseases.

OBJECTIVE

This study aimed to examine the association of breastfeeding with 5 subtypes of dyslipidemia in Korean women aged over 20 years, by using the nationally representative Korea National Health and Nutrition Examination Survey 2010-2014.

METHODS

Ordinary least square regression and ordered logistic regression analyses were used to determine the association between breastfeeding duration and dyslipidemia.

RESULTS

The likelihood of having low-density lipoprotein cholesterol (LDL-C) disorder decreased by 16% in the group that breastfed for more than 24 months (odds ratio, 0.84; 95% confidence interval, 0.75-0.95) compared with the group that did not breastfeed. The likelihood of having non-high-density lipoprotein cholesterol (non-HDL-C) disorder was significantly reduced by 25% when the breastfeeding duration was more than 24 months (odds ratio, 0.75; 95% confidence interval, 0.64-0.87). The tendency toward developing disorders of total cholesterol (TC), LDL-C, and non-HDL-C decreased as the duration of breastfeeding increased, particularly among women aged 30-39 years.

CONCLUSION

Breastfeeding duration was negatively correlated with dyslipidemia in terms of TC, LDL-C, non-HDL-C, and triglycerides. Long-term breastfeeding was associated with the prevalence of dyslipidemia-TC, LDL-C, non-HDL-C, and TG disorders, in particular.

Breastfeeding and maternal cardiovascular risk factors and outcomes: A systematic review

Background

There is growing evidence that breastfeeding has short- and long-term cardiovascular health benefits for mothers. The objectives of this systematic review were to examine the association between breastfeeding and maternal cardiovascular risk factors and outcomes that have not previously been synthesized systematically, including metabolic syndrome, hypertension and cardiovascular disease.

Methods and findings

This systematic review meets PRISMA guidelines. The MEDLINE, EMBASE and CINAHL databases were systematically searched for relevant publications of any study design from the earliest publication date to March 2016. The reference lists from selected articles were reviewed, and forward and backward referencing were conducted. The methodological quality of reviewed articles was appraised using validated checklists.

Twenty-one studies meeting the inclusion criteria examined the association between self-reported breastfeeding and one or more of the following outcomes: metabolic syndrome/metabolic risk factors (n = 10), inflammatory markers/adipokines (n = 2), hypertension (n = 7), subclinical cardiovascular disease (n = 2), prevalence/incidence of cardiovascular disease (n = 3) and cardiovascular disease mortality (n = 2). Overall, 19 studies (10 cross-sectional/retrospective, 9 prospective) reported significant protective effects of breastfeeding, nine studies (3 cross-sectional/retrospective, 5 prospective, 1 cluster randomized controlled trial) reported non-significant findings and none reported detrimental effects of breastfeeding. In most studies reporting significant associations, breastfeeding remained associated with both short- and long-term maternal cardiovascular health risk factors/outcomes, even after covariate adjustment. Findings from several studies suggested that the effects of breastfeeding may diminish with age and a dose-response association between breastfeeding and several metabolic risk factors. However, further longitudinal studies, including studies that measure exclusive breastfeeding, are needed to confirm these findings.

Conclusions

The evidence from this review suggests that breastfeeding is associated with cardiovascular health benefits. However, results should be interpreted with caution as the evidence gathered for each individual outcome was limited by the small number of observational studies. Additional prospective studies are needed.

PROSPERO registration number

CRD42016047766.

Cumulative Lactation and Onset of Hypertension in African-American Women

Hypertension affects nearly 1 of 3 women and contributes to cardiovascular disease, the leading cause of death in the United States. Breastfeeding leads to metabolic changes that could reduce risks of hypertension. Hypertension disproportionately affects black women, but rates of breastfeeding among black women lag behind those in the general population. In the Black Women's Health Study (n = 59,001), we conducted a nested case-control analysis using unconditional logistic regression to estimate the association between breastfeeding and incident hypertension at ages 40-65 years using data collected from 1995 to 2011. Controls were frequency-matched 2:1 to 12,513 hypertensive women by age and questionnaire cycle. Overall, there was little evidence of association between ever breastfeeding and incident hypertension (odds ratio = 0.97, 95% confidence interval: 0.92, 1.02). However, age modified the relationship (P = 0.02): Breastfeeding was associated with reduced risk of hypertension at ages 40-49 years (odds ratio = 0.92, 95% confidence interval: 0.85, 0.99) but not at older ages. In addition, risk of hypertension at ages 40-49 years decreased with increasing duration of breastfeeding (P for trend = 0.08). Our results suggest that long-duration breastfeeding may reduce the risk of incident hypertension in middle age. Addressing breastfeeding as a potential preventative health behavior is particularly compelling because it is required for only a discrete period of time.

Breastfeeding and the Risk of Maternal Cardiovascular Disease: A Prospective Study of 300 000 Chinese Women

BACKGROUND

Breastfeeding confers substantial benefits to child health and has also been associated with lower risk of maternal cardiovascular diseases (CVDs) in later life. However, the evidence on the effects of CVD is still inconsistent, especially in East Asians, in whom the frequency and duration of breastfeeding significantly differ from those in the West.

METHODS AND RESULTS

In 2004-2008, the nationwide China Kadoorie Biobank recruited 0.5 million individuals aged 30 to 79 years from 10 diverse regions across China. During 8 years of follow-up, 16 671 incident cases of coronary heart disease and 23 983 cases of stroke were recorded among 289 573 women without prior CVD at baseline. Cox regression yielded adjusted hazard ratios (HRs) and 95% CIs for incident CVD by breastfeeding. Overall, ≈99% of women had given birth, among whom 97% reported a history of breastfeeding, with a median duration of 12 months per child. Compared with parous women who had never breastfed, ever breastfeeding was associated with a significantly lower risk of CVD, with adjusted HRs of 0.91 (95% CI, 0.84-0.99) for coronary heart disease and 0.92 (95% CI, 0.85-0.99) for stroke. Women who had breastfed for ≥24 months had an 18% (HR, 0.82; 0.77-0.87) lower risk of coronary heart disease and a 17% (HR, 0.83; 0.79-0.87) lower risk of stroke compared with women who had never breastfed. Among women who ever breastfed, each additional 6 months of breastfeeding per child was associated with an adjusted HR of 0.96 (95% CI, 0.94-0.98) for coronary heart disease and 0.97 (95% CI, 0.96-0.98) for stroke.

CONCLUSIONS

Among Chinese women, a history of breastfeeding was associated with an ≈10% lower risk of CVD in later life and the magnitude of the inverse association was stronger among those with a longer duration of breastfeeding.

Preterm Delivery and Maternal Cardiovascular Disease in Young and Middle-Aged Adult Women

BACKGROUND

Preterm delivery has been shown to be associated with increased risk of cardiovascular disease (CVD), but it is unknown whether this risk remains after adjustment for prepregnancy lifestyle and CVD risk factors.

METHODS

We examined the association between history of having delivered an infant preterm (<37 weeks) and CVD in 70 182 parous women in the Nurses' Health Study II. Multivariable Cox proportional-hazards models were used to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) for CVD events (myocardial infarction and stroke, n=949); we also adjusted for intermediates to determine the proportion of the association between preterm and CVD accounted for by postpartum development of CVD risk factors.

RESULTS

After adjusting for age, race, parental education, and prepregnancy lifestyle and CVD risk factors, preterm delivery in the first pregnancy was associated with an increased risk of CVD (HR, 1.42; 95% CI, 1.16-1.72) in comparison with women with a term delivery (≥37 weeks) in the first pregnancy. When preterm delivery was split into moderate preterm (≥32 to <37 weeks) and very preterm (<32 weeks), the HRs were 1.22 (95% CI, 0.96-1.54) and 2.01 (95% CI, 1.47-2.75), respectively. The increased rate of CVD in the very preterm group persisted even among women whose first pregnancy was not complicated by hypertensive disorders of pregnancy (HR, 2.01; 95% CI, 1.38-2.93). In comparison with women with at least 2 pregnancies, all of which were delivered at term, women with a preterm first birth and at least 1 later preterm birth had a HR of CVD of 1.65 (95% CI, 1.20-2.28). The association between moderate preterm first birth and CVD was accounted for in part by the development of postpartum chronic hypertension, hypercholesterolemia, type 2 diabetes mellitus, and changes in body mass index (proportion accounted for, 14.5%; 95% CI, 4.0-41.1), as was the very-preterm-CVD relationship (13.1%; 95% CI, 9.0-18.7).

CONCLUSIONS

Preterm delivery is independently predictive of CVD and may be useful for CVD prevention efforts. Because only a modest proportion of the preterm-CVD association was accounted for by development of conventional CVD risk factors, further research may identify additional pathways.

Parity, breastfeeding and risk of coronary heart disease: A pan-European case-cohort study

OBJECTIVE

There is uncertainty about the direction and magnitude of the associations between parity, breastfeeding and the risk of coronary heart disease (CHD). We examined the separate and combined associations of parity and breastfeeding practices with the incidence of CHD later in life among women in a large, pan-European cohort study.

METHODS

Data were used from European Prospective Investigation into Cancer and Nutrition (EPIC)-CVD, a case-cohort study nested within the EPIC prospective study of 520,000 participants from 10 countries. Information on reproductive history was available for 14,917 women, including 5138 incident cases of CHD. Using Prentice-weighted Cox regression separately for each country followed by a random-effects meta-analysis, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for CHD, after adjustment for age, study centre and several socioeconomic and biological risk factors.

RESULTS

Compared with nulliparous women, the adjusted HR was 1.19 (95% CI: 1.01-1.41) among parous women; HRs were higher among women with more children (e.g., adjusted HR: 1.95 (95% CI: 1.19-3.20) for women with five or more children). Compared with women who did not breastfeed, the adjusted HR was 0.71 (95% CI: 0.52-0.98) among women who breastfed. For childbearing women who never breastfed, the adjusted HR was 1.58 (95% CI: 1.09-2.30) compared with nulliparous women, whereas for childbearing women who breastfed, the adjusted HR was 1.19 (95% CI: 0.99-1.43).

CONCLUSION

Having more children was associated with a higher risk of CHD later in life, whereas breastfeeding was associated with a lower CHD risk. Women who both had children and breastfed did have a non-significantly higher risk of CHD.

Effects of lactation on postpartum blood pressure among women with gestational hypertension and preeclampsia

BACKGROUND

Women with a history of hypertensive disorders of pregnancy are at an increased risk of hypertension and cardiovascular disease in later life. Lactation has been associated with a reduced risk of maternal hypertension, both in the postpartum period and later life. However, little is known about whether lactation is also cardioprotective in women with hypertensive disorders of pregnancy such as preeclampsia or gestational hypertension.

OBJECTIVE

This study aimed to characterize the relationship between lactation and postpartum blood pressure among women with preeclampsia and gestational hypertension.

STUDY DESIGN

Data were obtained from women who participated in the Prenatal Exposures and Preeclampsia Prevention study (n = 379; 66% African American; 85% overweight or obese). Women enrolled during pregnancy and attended a postpartum visit (on average, 9.1 months after delivery) during which data on lactation duration and blood pressure were collected. The significance of the associations between postpartum blood pressure and lactation among women who remained normotensive during pregnancy, developed gestational hypertension, or developed preeclampsia were assessed with an analysis of variance. Linear regression models were used to adjust for maternal age, race, education, prepregnancy weight, and time since delivery.

RESULTS

Gestational hypertension affected 42 subjects (11%) and preeclampsia affected 33 (9%). Lactation was reported by 217 (57%) with 78 (21%) reporting ≥ 6 months of lactation. Women who lactated were somewhat older, more educated, and had higher socioeconomic status. Among women who had gestational hypertension, lactation was associated with lower systolic blood pressure (P = .02) and diastolic blood pressure (P = .02). This association persisted after adjustment for age, race, education, prepregnancy weight, and time since delivery. However, for women who had preeclampsia and women who remained normotensive during pregnancy, lactation was not associated with postpartum blood pressure in either bivariate or multivariate analyses.

CONCLUSION

This study found that lactation is associated with lower postpartum blood pressure among overweight women who develop gestational hypertension but not among women who develop preeclampsia. Future studies are needed to explore the association of lactation and blood pressure in later life for women with hypertensive disorders of pregnancy.

Lactation and Maternal Cardio-Metabolic Health

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.

Physiological mechanisms, behavioral and psychological factors influencing the transfer of milk from mothers to their young

This article is part of a Special Issue "Parental Care".Producing milk to support the growth of their young is a central element of maternal care in mammals. In spite of the facts that ecological constraints influence nursing frequency, length of time until weaning and the composition of milk, there is considerable similarity in the anatomy and physiology of milk production and delivery across mammalian species. Here we provide an overview of cross species variation in nursing patterns and milk composition as well as the mechanisms underlying mammary gland development, milk production and letdown. Not all women breastfeed their infants, thus in later sections we review studies of factors that facilitate or impede the initiation and duration of breastfeeding. The results of these investigations suggest that the decisions to initiate and maintain breastfeeding are influenced by an array of personal, social and biological factors. Finally, studies comparing the development of breastfed and formula fed infants as well as those investigating associations between breastfeeding, maternal health and mother/infant interaction are reviewed. Leading health agencies including the World Health Organization and CDC advocate breastfeeding for at least the first 6months postpartum. To achieve these rates will require not only institutional support but also a focus on individual mother/infant dyads and their experience.

Associations Among Lactation, Maternal Carbohydrate Metabolism, and Cardiovascular Health

In mammalian reproductive physiology, lactation follows pregnancy; growing evidence suggests that disruption of this physiology affects a woman's lifetime risk of metabolic disease. These differences may reflect lactation-induced mobilization of fat stores and modulation of maternal stress reactivity. In addition, confounders may play a role: women who breastfeed for long durations are more likely to engage in other healthy behaviors, and obesity and insulin resistance may interfere with breastfeeding physiology. These findings underscore the importance of evidenced-based care to enable women to achieve their infant feeding goals.

Reproductive factors and risk of mortality in the European Prospective Investigation into Cancer and Nutrition; a cohort study

BACKGROUND

Reproductive events are associated with important physiologic changes, yet little is known about how reproductive factors influence long-term health in women. Our objective was to assess the relation of reproductive characteristics with all-cause and cause-specific mortality risk.

METHODS

The analysis was performed within the European Investigation into Cancer and Nutrition prospective cohort study, which enrolled >500,000 women and men from 1992 to 2000, who were residing in a given town/geographic area in 10 European countries. The current analysis included 322,972 eligible women aged 25-70 years with 99 % complete follow-up for vital status. We assessed reproductive characteristics reported at the study baseline including parity, age at the first birth, breastfeeding, infertility, oral contraceptive use, age at menarche and menopause, total ovulatory years, and history of oophorectomy/hysterectomy. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for mortality were determined using Cox proportional hazards regression models adjusted for menopausal status, body mass index, physical activity, education level, and smoking status/intensity and duration.

RESULTS

During a mean follow-up of 12.9 years, 14,383 deaths occurred. The HR (95 % CI) for risk of all-cause mortality was lower in parous versus nulliparous women (0.80; 0.76-0.84), in women who had ever versus never breastfed (0.92; 0.87-0.97), in ever versus never users of oral contraceptives (among non-smokers; 0.90; 0.86-0.95), and in women reporting a later age at menarche (≥15 years versus <12; 0.90; 0.85-0.96; P for trend = 0.038).

CONCLUSIONS

Childbirth, breastfeeding, oral contraceptive use, and a later age at menarche were associated with better health outcomes. These findings may contribute to the development of improved strategies to promote better long-term health in women.

Trends in breastfeeding initiation, continuation, and exclusivity by maternal prepregnancy weight: 2004-2011

OBJECTIVE

To examine trends in breastfeeding initiation, continuation, and exclusivity by prepregnancy weight from 2004 to 2011 and the associations between these outcomes and prepregnancy weight.

METHODS

Data from the 2004 to 2011 Pregnancy Risk Assessment Monitoring System, a survey of women with a recent live birth from 34 states and New York City, were used. Trends in breastfeeding initiation, continuation, and exclusivity at 12 weeks postpartum were evaluated by prepregnancy BMI. Logistic regression was used to identify the association between prepregnancy BMI and the breastfeeding outcomes.

RESULTS

Among 244,196 women, with increasing BMI, a decreasing number of women initiated, continued, and breastfed exclusively. From 2004 to 2011, the rates of breastfeeding initiation increased significantly for women of all weight classes (P < 0.01), and the disparity between normal-weight women and women with obesity class III narrowed. Among all women, breastfeeding continuation increased significantly for women of almost all weight classes (P < 0.01), although the disparity between normal-weight women and women with obesity class III worsened. From 2009 to 2011, among all women, exclusive breastfeeding increased significantly among women with normal and overweight BMI (P < 0.01) but decreased among obese class III; the disparity between women with normal and obese class III BMI worsened.

CONCLUSIONS

Our results highlight the need for more concentrated efforts on breastfeeding continuation and exclusivity, particularly for women with obesity.

Invited Commentary: Breastfeeding and Maternal Cardiovascular Health--Weighing the Evidence

Recently, there has been growing interest in understanding the ways in which lactation affects maternal health. The accompanying article by Palmer et al. (Am J Epidemiol. 2015;181(12):932-939), particularly their finding that prepregnancy obesity modifies the relationship between lactation and postpartum weight gain, makes an important contribution to this field. In this commentary, I discuss these findings within the context of other recent literature which indicates that whether or not a mother breastfeeds her newborn appears to be a powerful predictor of the mother's future risk of developing diabetes, hypertension, and cardiovascular disease, independent of maternal weight or body mass index in later life.

Does breastfeeding prevent the metabolic syndrome, or does the metabolic syndrome prevent breastfeeding?

In mammalian physiology, lactation follows pregnancy. Disruption of this physiology is associated with long-term adverse maternal health outcomes, including higher risks of later-life obesity, type 2 diabetes, metabolic syndrome, hypertension, and cardiovascular disease. Multiple mechanisms likely contribute to these associations, including the metabolic demands of breastfeeding, modulation of stress reactivity, and confounding by other health behaviors. At the same time, evidence suggests that maternal metabolic health entering pregnancy affects lactation performance. In this paradigm, adverse lactation outcomes may be a marker for underlying maternal disease risk. Understanding these relationships has important clinical and policy implications for women's health.

Breastfeeding and maternal hypertension and diabetes: a population-based cross-sectional study

OBJECTIVE

This study aimed to assess the association of breastfeeding and maternal hypertension and diabetes in Beijing, China.

SUBJECTS AND METHODS

A cross-sectional study was conducted in four urban communities of Beijing, China, with 9,128 parous women 40-81 years of age who had had only one lifetime birth. Each participant completed a detailed survey and accepted blood pressure measurement and blood glucose testing. Moreover, self-reported hypertension and diabetes were confirmed by review of medical records.

RESULTS

After the analysis was adjusted for the potential confounders, including age, body mass index (BMI), waist to hip ratio (WHR), working status, educational level, drinking, smoking, family history of hypertension, age of menarche, menopause, oral contraceptive use, age of child-bearing, and postpartum BMI, the odd ratio (OR) of hypertension was 1.18 (95% confidence interval [CI], 1.05-1.32) for women who did not breastfeed, compared with women who did. In addition, the ORs for >0 to 6 months, >6 to 12 months, and >12 months of breastfeeding were 0.87 (95% CI, 0.76-0.99), 0.83 (95% CI, 0.68-1.00), and 0.79 (95% CI, 0.65-0.97), respectively, compared with women who did not breastfeed. With adjustment for age, WHR, working status, educational level, family history of diabetes, and postpartum BMI, women who did not breastfeed increased the risk of diabetes (OR=1.30; 95% CI, 1.11-1.53) compared with women who did. Moreover, women who breastfed for >0 to 6 months (OR=0.81; 95% CI, 0.67-0.98) and >6 to 12 months (OR=0.46; 95% CI, 0.26-0.84) had a lower risk of diabetes, compared with women who did not breastfeed.

CONCLUSIONS

Chinese mothers who did not breastfeed were more likely to develop hypertension and diabetes in later life.

Self-soothing behaviors with particular reference to oxytocin release induced by non-noxious sensory stimulation

Oxytocin, a hypothalamic nonapeptide, is linked to increased levels of social interaction, well-being and anti-stress effects. The effects of oxytocin that is released by sensory stimulation during different kinds of interactive behaviors are often underestimated or even forgotten. In fact, many of the positive effects caused during interaction, such a wellbeing, stress reduction and even health promotion, are indeed linked to oxytocin released in response to activation of various types of sensory nerves. Oxytocin is released in response to activation of sensory nerves during labor, breastfeeding and sexual activity. In addition oxytocin is released in response to low intensity stimulation of the skin, e.g., in response to touch, stroking, warm temperature, etc. Consequently oxytocin is not only released during interaction between mothers and infants, but also during positive interaction between adults or between humans and animals. Finally oxytocin is also released in response to suckling and food intake. Oxytocin released in the brain in response to sensory stimulation as a consequence of these types of interactive behaviors, contributes to every day wellbeing and ability to handle stress. Food intake or sex may be used or even abused to achieve oxytocin-linked wellbeing and stress relief to compensate for lack of good relationships or when the levels of anxiety are high. The present review article will summarize the role played by oxytocin released by sensory (in particular somatosensory) stimulation, during various kinds of interactive behaviors. Also the fact that the anti-stress effects of oxytocin are particularly strong when oxytocin is released in response to “low intensity” stimulation of the skin will be highlighted.

Breastfeeding status and maternal cardiovascular variables across the postpartum

BACKGROUND

There have been recent reports that lactational history is associated with long-term women's health benefits. Most of these studies are epidemiological. If particular cardiometabolic changes that occur during lactation ultimately influence women's health later is unknown.

METHODS

Seventy-one healthy women participated in a prospective postpartum study that provided an opportunity to study anthropometric, endocrine, immune, and behavioral variables across time. Variables studied were heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), C-reactive protein, body mass index (BMI), perceived stress, and hormones. A cohort of women without a change in breastfeeding (N=22) or formula feeding (N=23) group membership for 5 months was used for analysis of effects of feeding status. The data were analyzed using factorial repeated measures analysis of variance and analysis of covariance.

RESULTS

SBP and HR declined across the postpartum and were significantly lower in breastfeeding compared to formula feeding mothers (p<0.05). These differences remained statistically significant when BMI was added to the model. Other covariates of income, stress, marital status, and ethnicity were not significantly associated with these variables over time. DBP was also lower, but the significance was reduced by the addition of BMI as a covariate. Stress also was lower in breastfeeders, but this effect was reduced by the addition of income as a covariate.

CONCLUSIONS

These data suggest that there are important physiological differences in women during months of breastfeeding. These may have roles in influencing or programming later risks for a number of midlife diseases.

Effect of lactation on maternal postpartum cardiac function and adiposity: a murine model

OBJECTIVE

Lactation is associated with reduction in maternal metabolic disease and hypertension later in life; however, findings in humans may be confounded by socioeconomic factors. We sought to determine the independent contribution of lactation on cardiovascular parameters and adiposity in a murine model.

STUDY DESIGN

Following delivery, CD-1 female mice were randomly divided into 2 groups: lactated (L; nursed pups for 3 weeks, n = 10), and nonlactated (NL; pups were removed after birth, n = 12). Blood pressure (BP) was assessed prepregnancy and at 1 and 2 months' postpartum. Visceral and subcutaneous adipose tissue determined by computed tomography and left ventricular ejection fraction, cardiac output, and the E/A ratio determined by microultrasound were evaluated at 1 and 2 months' postpartum. The results were analyzed using a Student t test (significance at P < .05).

RESULTS

We observed a significantly different maternal BP at 2 months' postpartum with relatively greater BP in NL (systolic BP: NL, 122.2 ± 7.2 vs L, 96.8 ± 9.8 mm Hg; P = .04; diastolic BP: NL, 87.0 ± 6.8 vs L, 65.9 ± 6.2 mm Hg; P = .04). Visceral adipose tissue was significantly increased in NL mice at 1 (22.0 ± 4.1% vs 10.7 ± 1.8%, P = .04) and 2 months' postpartum (22.9 ± 3.5% vs 11.2 ± 2.2%, P = .02), whereas subcutaneous adipose tissue did not differ between the groups. At 2 months' postpartum, ejection fraction (51.8 ± 1.5% vs 60.5 ± 3.8%; P = .04), cardiac output (14.2 ± 1.0 vs 18.0 ± 1.3 mL/min; P = .02) and mitral valve E/A ratio (1.38 ± 0.06 vs 1.82 ± 0.13; P = .04) were significantly lower in NL mice than L mice.

CONCLUSION

Our data provide evidence that interruption of lactation adversely affects postpartum maternal cardiovascular function and adiposity.

A prospective population-based cohort study of lactation and cardiovascular disease mortality: the HUNT study

Background

Recent studies suggest that lactation has long-term effects on risk for cardiovascular disease in women, but the effects on cardiovascular mortality are less well known.

Method

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. Adjusted hazard ratios (HR) for death from all causes and cardiovascular disease were calculated using Cox regression.

Results

During follow-up, 1,246 women died from cardiovascular disease. 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). There was some evidence of a U-shaped association, where women who reported lactating 7–12 months had a HR of 0.55 (95% CI: 0.27, 1.09). No clear associations were observed among women 65 years or older.

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.

Infant feeding in America: enough to break a mother's heart?

Cardiovascular disease is a leading cause of death of women around the world. Diet, exercise, smoking cessation, and blood pressure control are all recognized as key elements of preventing cardiovascular disease. Infant feeding has received less attention, but the studies reviewed here indicate that lactation may also play an important role in determining women's future risk of heart disease. A growing body of literature indicates that mothers who prematurely discontinue lactation face increased risk of visceral adiposity, hypertension, hyperlipidemia, diabetes, and subclinical cardiovascular disease, as well as cardiovascular morbidity and mortality. Breastfeeding is not always easy, but neither is dieting, exercise, smoking cessation, or treating hypertension. In order to effectively fight heart disease, efforts are needed to promote all aspects of a healthy lifestyle, which for women includes breastfeeding their babies.

Cost analysis of maternal disease associated with suboptimal breastfeeding

OBJECTIVE

To estimate the U.S. maternal health burden from current breastfeeding rates both in terms of premature death as well as economic costs.

METHODS

Using literature on associations between lactation and maternal health, we modeled the health outcomes and costs expected for a U.S. cohort of 15-year-old females followed to age 70 years. In 2002, this cohort included 1.88 million individuals. Using Monte Carlo simulations, we compared the outcomes expected if 90% of mothers were able to breastfeed for at least 1 year after each birth with outcomes under the current 1-year breastfeeding rate of 23%. We modeled cases of breast cancer, premenopausal ovarian cancer, hypertension, type 2 diabetes mellitus, and myocardial infarction considering direct costs, indirect costs, and cost of premature death (before age 70 years) expressed in 2011 dollars.

RESULTS

If observed associations between breastfeeding duration and maternal health are causal, we estimate that current breastfeeding rates result in 4,981 excess cases of breast cancer, 53,847 cases of hypertension, and 13,946 cases of myocardial infarction compared with a cohort of 1.88 million U.S. women who optimally breastfed. Using a 3% discount rate, suboptimal breastfeeding incurs a total of $17.4 billion in cost to society resulting from premature death (95% confidence interval [CI] $4.38-24.68 billion), $733.7 million in direct costs (95% CI $612.9-859.7 million), and $126.1 million indirect morbidity costs (95% CI $99.00-153.22 million). We found a nonsignificant difference in number of deaths before age 70 years under current breastfeeding rates (4,396 additional premature deaths, 95% CI -810-7,918).

CONCLUSIONS

Suboptimal breastfeeding may increase U.S. maternal morbidity and health care costs. Thus, investigating whether the observed associations between suboptimal breastfeeding and adverse maternal health outcomes are causal should be a research priority.

Lactation, female hormones and age-related macular degeneration: the Tromsø Study

OBJECTIVE

Some risk factors for age-related macular degeneration (AMD) have been shown to act differently in women and men. The present study aims to investigate this disparity by examining associations between female hormones, reproductive history and AMD.

METHODS

Women aged 65-87 years were invited to this cross-sectional, population-based study in Norway. Participants underwent physical examination, retinal photography, answered questionnaires and had blood samples taken.

RESULTS

The sample included 1512 women, of whom 48 (3.2%) had late AMD and 378 (25%) had large drusen >125 μm phenotype. Length of breast feeding per child was significantly associated with late AMD (OR per month 0.80, 95% CI 0.68 to 0.94) in multivariable regression analysis. We observed no associations between late AMD or drusen >125 μm and contraceptives, oral hormonal replacement therapy, parity, age at first childbirth, age of menarche, age of menopause, number of menstruating years or the reason for menopause.

CONCLUSIONS

Longer duration of lactation was associated with lower frequency of maternal late AMD when controlled for confounders. Other reproductive factors and hormone replacement therapy were not significantly associated with AMD.

Association between parity and breastfeeding with maternal high blood pressure

OBJECTIVE

The objective of this study was to determine how parity and breastfeeding were associated with maternal high blood pressure, and how age modifies this association.

STUDY DESIGN

Baseline data for 74,785 women were sourced from the 45 and Up Study, Australia. These women were 45 years of age or older, had an intact uterus, and had not been diagnosed with high blood pressure before pregnancy. Odds ratios (ORs) and 99% confidence intervals (CIs) for the association between giving birth, breastfeeding, lifetime breastfeeding duration, and average breastfeeding per child with high blood pressure were estimated using logistic regression.

RESULTS

The combination of parity and breastfeeding was associated with lower odds of having high blood pressure (adjusted OR, 0.89; 99% CI, 0.82-0.97; P < .001), compared with nulliparous women, whereas there was no significant difference between mothers who did not breastfeed and nulliparous women (adjusted OR, 1.06; 99% CI, 0.95-1.18; P = .20). Women who breastfed for longer than 6 months in their lifetime, or greater than 3 months per child, on average, had significantly lower odds of having high blood pressure when compared with parous women who never breastfed. The odds were lower with longer breastfeeding durations and were no longer significant in the majority of women over the age of 64 years.

CONCLUSION

Women should be encouraged to breastfeed for as long as possible and a woman's breastfeeding history should be taken into account when assessing her likelihood of high blood pressure in later life.

Influence of breastfeeding on maternal blood pressure at one month postpartum

BACKGROUND

The benefits of breastfeeding for improved health and developmental outcomes in mothers and their infants have been widely recognized. The purpose of the present study was to assess whether feeding modes influence maternal blood pressure at one month postpartum.

METHODS

The pregnancy charts of 407 women who delivered at a birthing center in rural Japan between August 1998 and September 2007 were analyzed. The criteria for inclusion were low-risk, full-term pregnancy (duration, 37-42 weeks) resulting in spontaneous vaginal deliveries, intrapartum hemorrhage < 500 mL, and a healthy infant (Apgar score ≥ 8 at one minute).

RESULTS

The subjects were classified into three groups based on feeding modes. The proportion of each mode was 28.3% in the breastfeeding group, 56.5% in the mixed-feeding group, and 15.2% in the formula-feeding group. The systolic blood pressure (SBP) in mothers at one month postpartum for each feeding mode was 118.4 ± 8.7 mmHg in the breastfeeding group, 120.6 ± 9.3 mmHg in the mixed-feeding group, and 122.0 ± 9.9 mmHg in the formula-feeding group. SBP at one month postpartum in the breastfeeding group was significantly lower than that in the other groups. No significant differences were observed in diastolic blood pressure in the three groups at one month postpartum.

CONCLUSION

Breastfeeding resulted in lower SBP in mothers at one month postpartum compared with those using other feeding modes, thus indicating an effect of breastfeeding on maternal blood pressure.

Lactation and maternal subclinical cardiovascular disease among premenopausal women

OBJECTIVE

The objective of the study was to examine the association between lactation and maternal subclinical cardiovascular disease.

STUDY DESIGN

The Women and Infants Study of Healthy Hearts enrolled 607 mothers who delivered a singleton between 1997 and 2002. In 2007, participating mothers underwent measurements of carotid intima-media thickness, lumen diameter, adventitial diameter, and carotid-femoral pulse wave velocity. Multivariable linear and logistic regressions were used to estimate the associations between lactation and subclinical cardiovascular disease.

RESULTS

Compared with mothers who breastfed for 3 or more months after every birth, mothers who never breastfed exhibited a 0.13 mm larger lumen diameter (95% confidence interval, 0.04-0.22) and a 0.12 mm larger adventitial diameter (95% confidence interval, 0.02-0.22) in models adjusting for age, parity, birth outcome, sociodemographic variables, health-related behaviors, family history, gestational weight gain, early adult body mass index, current body mass index, C-reactive protein, blood pressure, cholesterol, triglyceride, high-density lipoprotein, glucose, and insulin levels.

CONCLUSION

Mothers who do not breastfeed have vascular characteristics associated with a greater risk of cardiovascular disease.

Lactation and cardiovascular risk factors in mothers in a population-based study: the HUNT-study

Background

Lactation has beneficial short term effects on maternal metabolic health, but the long term effects are less well known.

Methods

We studied the association between lifetime duration of lactation and cardiovascular risk factors in mothers later in life among 21,368 parous women aged 20 to 85 years attending the second Nord-Trøndelag Health Study (HUNT2) in 1995–1997, Norway, a cross-sectional population-based study. General linear modelling was used to calculate mean values of known cardiovascular risk factor levels in five categories of lifetime duration of lactation. Logistic regression was conducted to estimate odds ratios of hypertension, obesity and diabetes.

Results

Among women aged 50 years or younger, lifetime duration of lactation was significantly and inversely associated with body mass index (P-trend, < 0.001), waist circumference (P-trend, < 0.001), systolic and diastolic blood pressure (both P-trends, < 0.001), and serum levels of triglycerides, total cholesterol and low density lipoprotein cholesterol (all P-trends, < 0.001) after adjustment for covariates. Parous women aged 50 years or younger who had never lactated had higher prevalence of hypertension, obesity and diabetes. In this age group, compared to women who had lactated for 24 months or more, parous women who had never lactated had an OR for hypertension of 1.88 (95% CI 1.41, 2.51), an OR for obesity of 3.37 (95% CI 2.51, 4.51) and an OR for diabetes of 5.87 (95% CI 2.25, 15.3). Among women older than 50 years there were no clear associations.

Conclusion

Lifetime duration of lactation was associated with long term reduced cardiovascular risk levels in mothers aged 50 years or younger.

Duration of lactation and maternal metabolism at 3 years postpartum

OBJECTIVE

Lactation has been associated with reduced risk of type 2 diabetes and the metabolic syndrome in mothers. We examined the relation between breastfeeding duration and metabolic markers at 3 years postpartum.

METHODS

We used linear regression to relate duration of lactation to maternal glucose and lipid metabolism, inflammatory markers, and anthropometry at 3 years postpartum among 570 participants with 3-year blood samples (175 fasting) in Project Viva, a cohort study of mothers and children.

RESULTS

Among the participants, 88% had initiated breastfeeding, and 26% had breastfed >or=12 months. In multivariate analyses, we observed no consistent trends relating duration of lactation to maternal metabolism at 3 years postpartum. Women who exclusively breastfed for >6 months had lower postpartum weight retention at 3 years than women with shorter durations of exclusive breastfeeding (multivariate adjusted predicted mean -0.5, -3.6-2.6 kg vs. 4.8, 2.0-7.6 kg for those who never exclusively breastfed, partial F p = 0.03).

CONCLUSIONS

In this prospective cohort study, we did not observe a dose-response relationship between duration of lactation and metabolic risk at 3 years postpartum.

Duration of lactation and incidence of maternal hypertension: a longitudinal cohort study

Never or curtailed lactation has been associated with an increased risk for incident hypertension, but the effect of exclusive breastfeeding is unknown. The authors conducted an observational cohort study of 55,636 parous women in the US Nurses' Health Study II. From 1991 to 2005, participants reported 8,861 cases of incident hypertension during 660,880 person-years of follow-up. Never or curtailed lactation was associated with an increased risk of incident hypertension. Compared with women who breastfed their first child for ≥12 months, women who did not breastfeed were more likely to develop hypertension (hazard ratio (HR) = 1.27, 95% confidence interval (CI): 1.18, 1.36), adjusting for family history and lifestyle covariates. Women who never breastfed were more likely to develop hypertension than women who exclusively breastfed their first child for ≥6 months (HR = 1.29, 95% CI: 1.20, 1.40). The authors found similar results for women who had never breastfed compared with those who had breastfed each child for an average of ≥12 months (HR = 1.22, 95% CI: 1.13, 1.32). In conclusion, never or curtailed lactation was associated with an increased risk of incident maternal hypertension, compared with the recommended ≥6 months of exclusive or ≥12 months of total lactation per child, in a large cohort of parous women.

Duration of lactation and maternal adipokines at 3 years postpartum

OBJECTIVE

Lactation has been associated with reduced maternal risk of type 2 diabetes, the metabolic syndrome, and cardiovascular disease. We examined the relationship between breastfeeding duration and maternal adipokines at 3 years postpartum.

RESEARCH DESIGN AND METHODS

We used linear regression to relate the duration of lactation to maternal leptin, adiponectin, ghrelin, and peptide YY (PYY) at 3 years postpartum among 570 participants with 3-year postpartum blood samples (178 fasting), prospectively collected lactation history, and no intervening pregnancy in Project Viva, a cohort study of mothers and children.

RESULTS

A total of 88% of mothers had initiated breastfeeding, 26% had breastfed ≥ 12 months, and 42% had exclusively breastfed for ≥ 3 months. In multivariate analyses, we found that duration of total breastfeeding was directly related to PYY and ghrelin, and exclusive breastfeeding duration was directly related to ghrelin (predicted mean for never exclusively breastfeeding: 790.6 pg/mL vs. ≥ 6 months of exclusive breastfeeding: 1,008.1 pg/mL; P < 0.01) at 3 years postpartum, adjusting for pregravid BMI, gestational weight gain, family history of diabetes, parity, smoking status, and age. We found a nonlinear pattern of association between exclusive breastfeeding duration and adiponectin in multivariate-adjusted models.

CONCLUSIONS

In this prospective cohort study, we found a direct relationship between the duration of lactation and both ghrelin and PYY at 3 years postpartum.

The risks and benefits of infant feeding practices for women and their children

Infant feeding decisions affect maternal and child health outcomes, worldwide. Even in settings with clean water and good sanitation, infants who are not breast-fed face an increased risk of infectious, as well as non-infectious morbidity and mortality. The decision not to breast-feed can also adversely affect mothers' health by increasing the risk of pre-menopausal breast cancer, ovarian cancer, type II diabetes, hypertension, hyperlipidemia and cardiovascular disease. Clinicians who counsel mothers about the health impact of infant feeding and provide evidence-based care to maximize successful breast-feeding, can improve the short and long-term health of both mothers and infants.

Lactation and maternal measures of subclinical cardiovascular disease

OBJECTIVE

To examine the relationship between lactation and subclinical cardiovascular disease in a population free of clinical cardiovascular disease.

METHODS

We conducted a cross-sectional analysis of 297 women who reported at least one live birth on enrollment in the Study of Women Across the Nation-Heart Study. Participants were mothers aged 45-58 years who were free of clinical cardiovascular disease. History of lactation was self-reported. Electron beam tomography was used to assess coronary and aortic calcification. B-mode ultrasonography was used to assess carotid adventitial diameter, intima-media thickness, and carotid plaque. Multivariable linear and logistic regression models were used to estimate whether lactation was independently associated with markers of subclinical cardiovascular disease.

RESULTS

In unadjusted models, compared with mothers who had breastfed all of their children for at least 3 months, mothers who had not breastfed were more likely to have coronary artery calcification (17% compared with 32%), aortic calcification (17% compared with 39%), carotid plaque (10% compared with 18%), and larger carotid adventitial diameters (mean+/-standard deviation 6.63+/-0.59 compared with 6.87+/-0.60 mm). After adjusting for measures of socioeconomic status and lifestyle and family history variables, mothers who had not breastfed remained more likely to have aortic calcification (odds ratio [OR] 3.85, 95% confidence interval [CI] 1.47-10.00) and coronary artery calcification (OR 2.78, 95% CI 1.05-7.14) than mothers who had consistently breastfed. After further adjustment for body mass index and traditional risk factors for cardiovascular disease, mothers who had not breastfed remained more likely to have aortic calcification than mothers who had consistently breastfed (OR 5.26, 95% CI 1.47-20.00).

CONCLUSION

Mothers who do not breastfeed their infants seem to be at increased risk of vascular changes associated with future cardiovascular disease.

LEVEL OF EVIDENCE

II.

Duration of lactation and risk factors for maternal cardiovascular disease

OBJECTIVE

To examine dose-response relationships between the cumulative number of months women lactated and postmenopausal risk factors for cardiovascular disease.

METHODS

We examined data from 139,681 postmenopausal women (median age 63 years) who reported at least one live birth on enrolling in the Women's Health Initiative observational study or controlled trials. Multivariable models were used to control for sociodemographic (age, parity, race, education, income, age at menopause), lifestyle, and family history variables when examining the effect of duration of lactation on risk factors for cardiovascular disease, including obesity (body mass index [BMI] at or above 30), hypertension, self-reported diabetes, hyperlipidemia, and prevalent and incident cardiovascular disease.

RESULTS

Dose-response relationships were seen; in fully adjusted models, women who reported a lifetime history of more than 12 months of lactation were less likely to have hypertension (odds ratio [OR] 0.88, P<.001), diabetes (OR 0.80, P<.001), hyperlipidemia (OR 0.81, P<.001), or cardiovascular disease (OR 0.91, P=.008) than women who never breast-fed, but they were not less likely to be obese. In models adjusted for all above variables and BMI, similar relationships were seen. Using multivariate adjusted prevalence ratios from generalized linear models, we estimate that among parous women who did not breast-feed compared with those who breast-fed for more than 12 months, 42.1% versus 38.6% would have hypertension, 5.3% versus 4.3% would have diabetes, 14.8% versus 12.3% would have hyperlipidemia, and 9.9% versus 9.1% would have developed cardiovascular disease when postmenopausal. Over an average of 7.9 years of postmenopausal participation in the Women's Health Initiative, women with a single live birth who breast-fed for 7-12 months were significantly less likely to develop cardiovascular disease (hazard ratio 0.72, 95% confidence interval 0.53-0.97) than women who never breast-fed.

CONCLUSION

Among postmenopausal women, increased duration of lactation was associated with a lower prevalence of hypertension, diabetes, hyperlipidemia, and cardiovascular disease.

Duration of lactation and incidence of myocardial infarction in middle to late adulthood

OBJECTIVE

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

During 1,350,965 person-years of follow-up, 2540 cases of coronary heart disease were diagnosed. 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.

Short- and long-term decrease of blood pressure in women during breastfeeding

BACKGROUND AND AIMS

The benefits of breastfeeding for infants are well known. Recently data have started to emerge showing that breastfeeding may also induce positive effects in the mother. This study aimed to investigate the pattern of maternal blood pressure before, during, and after a breastfeed 2 days postpartum. Additionally, blood pressure during the following 25-week breastfeeding period was investigated.

METHODS

Sixty-six primiparae with normal deliveries were consecutively recruited. Blood pressure was measured at -5, 10, 30, and 60 minutes in connection with a morning breastfeed. Thirty-three women continued to measure blood pressure before and after breastfeeding for 25 weeks.

RESULTS

Blood pressure fell significantly in response to breastfeeding 2 days after birth. The fall in systolic and diastolic blood pressure amounted to 8.8 (SD = 11.00) and 7.7 (SD = 9.3) mm Hg, respectively. During the 25-week follow-up period a significant fall of basal blood pressure (systolic, df = 3, F = 7.843, p < 0.001; diastolic, df = 3, F = 5.453, p = 0.002) was observed. The total fall in systolic and diastolic blood pressure amounted to a mean of 15 (SD = 10.4) mm Hg and 10 (SD = 9.7) mm Hg, respectively. In addition, blood pressure fell significantly in response to individual breastfeeding sessions during the entire observation period.

CONCLUSIONS

In conclusion, both systolic and diastolic blood pressures fall during a breastfeeding session, and pre-breastfeeding blood pressure decreases during at least the first 6 months of a breastfeeding period in a homelike environment. This study lends further support to the health-promoting effects of breastfeeding.