Lactation and maternal cardiovascular disease risk in later life

Age at Menopause and Development of Type 2 Diabetes in Korea

Importance

There is limited evidence regarding the association between age at menopause and incident type 2 diabetes (T2D).

Objective

To investigate whether age at menopause and premature menopause are associated with T2D incidence in postmenopausal Korean women.

Design, Setting, and Participants

This population-based cohort study was conducted among a nationally representative sample from the Korean National Health Insurance Service database of 1 125 378 postmenopausal women without T2D who enrolled in 2009. The median (IQR) follow-up was 8.4 (8.1-8.7) years. Data were analyzed in March 2024.

Exposures

Age at menopause and premature menopause (menopause onset at age <40 years).

Main Outcomes and Measures

The primary outcome was incident T2D. Multivariable Cox proportional hazards regression analysis was used to estimate hazard ratios (HRs) and 95% CIs for incident T2D by age at menopause, adjusting for potential confounders.

Results

Of 1 125 378 participants (mean [SD] age at enrollment, 61.2 [8.4] years), 113 864 individuals (10.1%) were diagnosed with T2D at least 1 year after enrollment. Women with menopause onset at ages younger than 40 years (premature menopause; HR, 1.13; 95% CI, 1.08-1.18) and ages 40 to 44 years (HR, 1.03; 95% CI, 1.00-1.06) had increased risk of T2D compared with those with onset at age 50 years or older, with adjustment for sociodemographic, lifestyle, cardiometabolic, psychiatric, and reproductive factors; a younger age at menopause was associated with increased risk of developing T2D (P for trend <.001). Body mass index, depressive disorder, and prediabetes modified the association in subgroup analyses; for example, for individuals with premature menopause vs those with menopause at ages 50 years or older, HRs were 1.54 (95% CI, 1.14-2.06) for a BMI less than 18.5 and 1.14 (95% CI, 1.00-1.30) for a BMI of 30 or greater (P < .001), 1.28 (95% CI, 1.12-1.45) for individuals with depression and 1.11 (95% CI, 1.07-1.16) for those without depression (P = .01), and 1.25 (95% CI, 1.18-1.33) for individuals who were not prediabetic and 1.04 (95% CI, 0.99-1.11) those who were prediabetic (P < .001).

Conclusions and Relevance

In this study, premature and early menopause were associated with a higher risk of T2D, highlighting the need for targeted public health strategies aimed at preventing or delaying T2D among postmenopausal women.

Maternal heart exhibits metabolic and redox adaptations post-uncomplicated pregnancy

Pregnancy may be a challenging period for the maternal systems and has been regarded as a stress test, as imperceptible/mild dysfunctions eventually present may be exacerbated during this period. The cardiovascular system is no exception, and several morphological and functional adaptations accompanying pregnancy have been described. However, long-term pregnancy-induced cardiac molecular alterations remain highly unexplored. The postpartum is marked by reverse remodeling of the pregnancy-induced cardiovascular adaptations, representing a possible critical period for assessing future maternal cardiovascular health. The current study explored the molecular and metabolic alterations in the cardiac tissue eight weeks after a physiological uncomplicated pregnancy. Female Sprague-Dawley rats were fed a chow diet through pregnancy, lactation, and weaning and compared to their non-pregnant counterparts. Eight weeks postpartum, increased levels of the phosphorylated form of AMPKα (Thr172) and its ratio to total AMPKα indicated possible alterations in cardiac metabolic flexibility, accompanied by increased Pparα and Hif1α transcripts levels. Additionally, postpartum hearts exhibited higher mitochondrial ATP and NADH levels without major changes in mitochondrial respiratory function. Elevated Nrf2 levels in the cardiac tissue suggested potential implications for cardiac redox balance, further supported by increased levels or activity of proteins directly regulated by Nrf2. The findings herein reported suggest that at eight weeks postpartum, molecular alterations induced by pregnancy, especially regarding redox balance, are still observed in the mothers' heart. These alterations present at late postpartum may open new avenues to understand the different risk for cardiovascular complications development after normal pregnancies.

Prospective associations between breast feeding, metabolic health, inflammation and bone density in women with prior gestational diabetes mellitus

INTRODUCTION

The aim of the study is to investigate prospective associations between breastfeeding and metabolic outcomes, inflammation, and bone density in women with prior gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

We prospectively included 171 women with GDM from the MySweetheart trial. Women were followed during pregnancy (from 24 up to 32 weeks' gestational age) up to 1 year postpartum. Outcomes included weight, weight retention, body composition, insulin resistance and secretion indices, C reactive protein (CRP), and bone density. We compared differences in the associations between breastfeeding and health outcomes between women who breast fed <6 months vs ≥6 months. Analyses were adjusted for potential medical and sociodemographic confounders.

RESULTS

Breastfeeding initiation was 94.2% (n=161) and mean breastfeeding duration was 6.6 months. Breastfeeding duration was independently associated with lower weight, weight retention, body fat, visceral adipose tissue, lean mass, CRP, insulin resistance (Homeostatic Model Assessment for Insulin Resistance), and insulin secretion (Homeostatic Model Assessment of β-cell index) at 1 year postpartum (all p≤0.04) after adjusting for confounders. Breastfeeding was associated with higher insulin resistance-adjusted insulin secretion (Insulin Secretion-Sensitivity Index-2) in the unadjusted analyses only. There was no association between breastfeeding duration and bone density. Compared with <6 months, breastfeeding duration ≥6 months was associated with lower weight, weight retention, body fat, fat-free mass as well as lower CRP at 1 year postpartum (all p<0.05) after adjusting for confounders.

CONCLUSIONS

Longer breastfeeding duration among women with prior GDM was associated with lower insulin resistance, weight, weight retention, body fat and inflammation, but not lower bone density at 1 year postpartum. Breastfeeding for ≥6 months after GDM can help to improve cardiometabolic health outcomes 1 year after delivery.

Cardiac mitochondrial metabolism during pregnancy and the postpartum period

The goal of the present study was to characterize changes in mitochondrial respiration in the maternal heart during pregnancy and after birth. Timed pregnancy studies were performed in 12-wk-old female FVB/NJ mice, and cardiac mitochondria were isolated from the following groups of mice: nonpregnant (NP), midpregnancy (MP), late pregnancy (LP), and 1-wk postbirth (PB). Similar to our previous studies, we observed increased heart size during all stages of pregnancy (e.g., MP and LP) and postbirth (e.g., PB) compared with NP mice. Differential cardiac gene and protein expression analyses revealed changes in several mitochondrial transcripts at LP and PB, including several mitochondrial complex subunits and members of the Slc family, important for mitochondrial substrate transport. Respirometry revealed that pyruvate- and glutamate-supported state 3 respiration was significantly higher in PB vs. LP mitochondria, with respiratory control ratio (RCR) values higher in PB mitochondria. In addition, we found that PB mitochondria respired more avidly when given 3-hydroxybutyrate (3-OHB) than mitochondria from NP, MP, and LP hearts, with no differences in RCR. These increases in respiration in PB hearts occurred independent of changes in mitochondrial yield but were associated with higher abundance of 3-hydroxybutyrate dehydrogenase 1. Collectively, these findings suggest that, after birth, maternal cardiac mitochondria have an increased capacity to use 3-OHB, pyruvate, and glutamate as energy sources; however, increases in mitochondrial efficiency in the postpartum heart appear limited to carbohydrate and amino acid metabolism.NEW & NOTEWORTHY Few studies have detailed the physiological adaptations that occur in the maternal heart. We and others have shown that pregnancy-induced cardiac growth is associated with significant changes in cardiac metabolism. Here, we examined mitochondrial respiration and substrate preference in isolated mitochondria from the maternal heart. We show that following birth, cardiac mitochondria are "primed" to respire on carbohydrate, amino acid, and ketone bodies. However, heightened respiratory efficiency is observed only with carbohydrate and amino acid sources. These results suggest that significant changes in mitochondrial respiration occur in the maternal heart in the postpartum period.

Impaired hypoglycaemia awareness in early pregnancy increases risk of severe hypoglycaemia in the mid-long term postpartum irrespective of breastfeeding status in women with type 1 diabetes

INTRODUCTION

Information regarding the postpartum period in women with type 1 diabetes (T1D) is scarce. We aim to evaluate the relation of impaired hypoglycaemia awareness (IAH) in early pregnancy and breastfeeding status (its presence and duration) with severe postpartum hypoglycaemia (SH).

MATERIALS AND METHODS

Retrospective cohort study of women with T1D followed during pregnancy between 2012 and 2019. Data on SH were recorded before and during pregnancy. IAH was evaluated at the first antenatal visit. Data on breastfeeding and the long-term postpartum period were collected by questionnaire and from medical records.

RESULTS

A total of 89 women with T1D were included with a median follow-up after pregnancy of 19.2 [8.7-30.5] months. Twenty-eight (32%) women had IAH at the first antenatal visit. At discharge, 74 (83%) started breastfeeding during a median of 8 [4.4-15] months. A total of 18 (22%) women experienced ≥1 SH during postpartum. The incidence of SH significantly increased from pregestational to the gestational and post-partum period (0.09, 0.15 and 0.25 episodes/patient-year, respectively). Postpartum SH rates were comparable in breastfeeding and non-breastfeeding women (21.4% vs. 25%, respectively, p>0.05). Clarke test score at the first antenatal visit was associated with postpartum SH (for each 1-point increase: OR 1.53; 95% CI, 1.06-2.21) adjusted for confounders. No other diabetes and pregnancy-related variables were identified as predictors of SH in this period.

CONCLUSIONS

SH are common in the long-term postpartum period independently of breastfeeding. Assessing IAH in early pregnancy could identify those at an increased risk of SH in the postpartum period.

The mothers' breastfeeding behaviour within six weeks postpartum: new scale development and psychometric validation study

BACKGROUND

The evaluation of mothers' breastfeeding behaviour within 6 weeks postpartum could help health workers comprehensively identify maternal breastfeeding shortcomings, clarify nursing problems, and provide targeted interventions. However, no prior study was found, therefore this study aimed to develop and validate the reliability and validity of the mothers' breastfeeding behaviour scale within 6 weeks postpartum.

METHODS

A main two-step approach was used: (1) a qualitative pilot study using the purposive sampling method was adopted to test the fitness, simplicity, and clarity of items with 30 mothers; (2) a cross-sectional survey using the convenient sampling method was conducted for item analysis and psychometric validation with 600 mothers.

RESULTS

The final version of the scale consisted of 36 items with seven dimensions, explaining 68.852% of the total variance. The Cronbach's α, split-half, and retest coefficients were 0.958, 0.843, and 0.753, respectively. The validity of the scale: (1) Content validity: content validity index (CVI) range of items was between 0.882 and 1.000. The scale-level-CVI was 0.990. (2) Structure validity: The fitting indices were as follows: χ²/ⅆf =2.239, RMR = 0.049, RMSEA = 0.069, TLI = 0.893, CFI = 0.903, IFI = 0.904, PGFI = 0.674, and PNFI = 0.763. (3) Convergent validity: The composite reliability and average variance extracted (AVE) of the seven dimensions were between 0.876 and 0.920 and between 0.594 and 0.696. (4) Distinguish validity: The correlation coefficients were less than the square root of the AVE, except for self-decision behaviour, self-coping behaviour, and self-control behaviour. However, the fit index of the original three-factor model was better than that of the other new models, with significant differences (P < 0.001). (5) Calibration validity: The area under the curve was 0.860 or 0.898 when the scale was used to predict exclusive or any breastfeeding at 42 days. The correlation coefficients of the maternal breasting feeding evaluation scale, breastfeeding self-efficacy short-form scale, and the scale were 0.569 and 0.674, respectively.

CONCLUSION

The newly developed mothers' breastfeeding behaviour scale within 6 weeks postpartum consists of 36 items belonging to seven dimensions with good reliability and validity and is a reliable and valid instrument to be used in future maternal breastfeeding behaviour assessments and interventions.

Lactation Duration and the Risk of Subtypes of Stroke Among Parous Postmenopausal Women From the China Kadoorie Biobank

IMPORTANCE

Previous studies have reported favorable associations between lactation and cardiovascular diseases. Various stroke subtypes are caused by different pathological processes; however, to date, the associations of lactation duration with different stroke subtypes are less well established.

OBJECTIVE

To examine the associations of lactation duration with stroke and its subtypes in parous postmenopausal women.

DESIGN, SETTING, AND PARTICIPANTS

This population-based prospective cohort study included parous postmenopausal women aged 45 to 79 years in the China Kadoorie Biobank (CKB) study at baseline (2004-2008). Lactation duration was counted as lifetime, mean per child, and for the first child. New-onset stroke and its subtypes (ischemic stroke, intracerebral hemorrhage [ICH], and subarachnoid hemorrhage [SAH]) were assessed via disease registries and national health insurance claim databases during follow-up (2008-2015). Data were analyzed from June to December 2021.

EXPOSURES

Lactation duration (lifetime, mean per child, and for the first child).

MAIN OUTCOMES AND MEASURES

The main outcomes were total stroke, ischemic stroke, ICH, and SAH. Multivariable Cox regression was applied to calculate the adjusted hazard ratios (aHRs) with 95% CIs for stroke and subtypes.

RESULTS

Of 129 511 parous postmenopausal women (median [IQR] age, 58.3 [54.0-64.6] years) without prior stroke at baseline, 15 721 developed stroke, with median (IQR) lifetime lactation duration of 42.0 (24.0-70.0) months among 13 427 women who had ischemic stroke, 54.0 (36.0-84.0) months among 2567 women who had ICH, and 36.0 (24.0-64.5) months among 284 women with SAH. Compared with parous postmenopausal women who had never lactated, those with lifetime lactation duration of at least 7 months had lower risks of ischemic stroke (aHRs varying from 0.52 [95% CI, 0.50-0.55] to 0.64 [95% CI, 0.59-0.69]) and ICH (aHRs, 0.56 [95% CI, 0.49-0.63] to 0.78 [95% CI, 0.64-0.96]). However, for SAH, such associations were found only in participants with lifetime lactation duration longer than 24 months (aHR, 0.61 [95% CI, 0.47-0.79]). Additionally, women with mean lactation duration per child or lactation duration for the first child of 7 months or longer were less likely to develop stroke (aHRs varying from 0.53 [95% CI, 0.52-0.54] to 0.65 [95% CI, 0.63-0.67]) and its subtypes (aHRs varying from 0.51 [95% CI, 0.30-0.87] to 0.75 [95% CI, 0.69-0.81]).

CONCLUSIONS AND RELEVANCE

In this cohort study, lactation was significantly associated with a lower risk of stroke, especially ischemic stroke, emphasizing the importance of promoting breastfeeding as a targeted prevention strategy of stroke.

Association of breastfeeding duration with carotid intima-media thickness in later life: a systematic review and meta-analysis

OBJECTIVE

To assess the relationship of breastfeeding duration with maternal ultrasound carotid intima-media thickness (CIMT) in later life.

METHODS

PubMed, Scopus, Web of Science, Embase, and Cochrane Central database searching up to December 15, 2020, for eligible studies that reported on the breastfeeding duration and ultrasound measurement of CIMT in later life. The exposed group corresponded to breastfeeding duration ≥ 6 months whereas the control group was women with breastfeeding of shorter duration or nil breastfeeding. The methodological quality of reviewed articles was appraised using the Newcastle-Ottawa Scale (NOS). Results are reported as the mean difference (MD) or the standardized MD (SMD) and their 95% confidence intervals (CIs). The study was registered in the PROSPERO database.

RESULTS

Of 532 unique studies, three studies met inclusion criteria including 1721 women with a mean age ranging between 36.6 ± 6.9 and 55.7 ± 5.3 years, comparing breastfeeding duration ≥ 6 months versus 1-5 months (NOS: 7-8). Common CIMT was lower in women who breastfed for a longer duration (SMD = -0.10, 95% CI -0.20 to -0.00). Circulating HDL-cholesterol was higher in women with longer breastfeeding duration (MD = 3.25, 95% CI 0.88-5.61). There were no significant differences for total cholesterol, LDL-cholesterol, triglycerides, glucose, and blood pressure between breastfeeding 6 or more months and the control group.

CONCLUSIONS

The available studies showed lower CIMT and higher HDL-cholesterol levels in women who breastfed for 6 or more months as compared to controls.

The Association of Lactation Duration with Visceral and Pericardial Fat Volumes in Parous Women: The CARDIA Study

BACKGROUND

Lactation is associated with lower risks for cardiovascular disease in women. Organ-related adiposity, which plays significant roles in the development of cardiometabolic diseases, could help explain this observation. We evaluated the association of lactation duration with visceral (VAT) and pericardial (PAT) fat volumes in women.

METHODS

Data were obtained from 910 women enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study (1985-1986) without diabetes prior to pregnancy who had ≥1 birth during 25 years of follow-up and had VAT and PAT measured from computed tomographic scans in 2010-2011. Cumulative lactation duration across all births since baseline was calculated from self-reports collected at periodic exams.

RESULTS

At baseline, the average age of women (48% black, 52% white) was 24 ± 3.7 years. After controlling for baseline age, race, smoking status, body mass index, fasting glucose, family history of diabetes, fat intake, total cholesterol, physical activity, and follow-up covariates (parity, gestational diabetes), the mean fat volumes across categories of lactation [none (n = 221), 1-5 months (n = 306), 6-11 months (n = 210), and ≥12 months (n = 173)] were 122.0, 113.7 105.0, and 110.1 cm3 for VAT and 52.2, 46.7, 44.5, and 43.4 cm3 for PAT, respectively. Changes in body weight from the first post-baseline birth to the end of follow-up mediated 21% and 18% of the associations of lactation with VAT and PAT, respectively.

CONCLUSIONS

In this prospective study, longer cumulative lactation duration was associated with lower VAT and PAT volumes, with weight gain partially mediating these associations.

Antioxidative Molecules in Human Milk and Environmental Contaminants

Breastfeeding provides overall beneficial health to the mother-child dyad and is universally recognized as the preferred feeding mode for infants up to 6-months and beyond. Human milk provides immuno-protection and supplies nutrients and bioactive compounds whose concentrations vary with lactation stage. Environmental and dietary factors potentially lead to excessive chemical exposure in critical windows of development such as neonatal life, including lactation. This review discusses current knowledge on these environmental and dietary contaminants and summarizes the known effects of these chemicals in human milk, taking into account the protective presence of antioxidative molecules. Particular attention is given to short- and long-term effects of these contaminants, considering their role as endocrine disruptors and potential epigenetic modulators. Finally, we identify knowledge gaps and indicate potential future research directions.

Duration of Lactation and Maternal Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis

Cardiovascular disease (CVD) is the leading cause of death of women across all ages, and targeting modifiable risk factors, such as those comprised in metabolic syndrome (MetS) (e.g., waist circumference, lipid profile, blood pressure, and blood glucose), is of great importance. An inverse association between lactation and CVD has been suggested, and lactation may decrease the risk of MetS. This systematic review and meta-analysis examined how lactation may affect the development and prevalence of MetS in women. A literature search was performed using Cinahl, Embase, Web of Science, and PubMed. A total of 1286 citations were identified, and finally, ten studies (two prospective and eight cross-sectional) were included. Seven studies (two prospective and five cross-sectional) revealed associations between lactation and MetS, suggesting that breastfeeding might prevent or improve metabolic health and have a protective role in MetS prevention. This protective role might be related to the duration of lactation; however, a lack of controlling for potential confounders, such as parity, might inflict the results. The pooled effect was non-conclusive. Additional research is required to further explore the duration of lactation and its potential role in improving or reversing MetS and its components.

Breastfeeding is associated with lower subclinical atherosclerosis in postmenopausal women

Objective: To evaluate the association between a personal history of lactation and indices of subclinical atherosclerosis in postmenopausal women.Methods: We evaluated the association between a history of breastfeeding and indices of subclinical atherosclerosis (pulse wave velocity, PWV; intima-media thickness [IMT]; atherosclerotic plaque presence) in 197 parous postmenopausal women with history of breastfeeding.Results: Women who reported breastfeeding ≥6 months when compared with women who reported breastfeeding for 1-5 months exhibited significantly lower values of common carotid artery IMT (Model R²=15.7%, b-coefficient = -0.170, 95% CI: -0.208-0.001, p-value = .019) and lower odds of subclinical atherosclerosis (Model X²=28.127, OR = 0.491, 95% CI 0.318-0.999, p-value = .049), adjusting for traditional cardiovascular risk factors.Conclusions: Postmenopausal women with a history of breastfeeding for at least 6 months have a lower prevalence of subclinical atherosclerosis, independently of traditional cardiovascular risk factors. A longer duration of breastfeeding may have a beneficial effect on subclinical atherosclerosis later in life.

Association Between Serum Lipid Levels in Greek Children with Dyslipidemia and Mediterranean Diet Adherence, Dietary Habits, Lifestyle and Family Socioeconomic Factors

Background: Childhood dyslipidemia is an important risk factor for developing cardiovascular disease in adulthood. Our study aimed to investigate a possible correlation between nutritional, lifestyle, behavioral and socioeconomic factors and serum lipid levels in children with dyslipidemia. Methods: In this retrospective, observational study, in 31 children with dyslipidemia, aged 3–14 years, dietary habits, physical activity, hours watching television or playing video games, family’s socioeconomic status, weight of children and parents, and duration of breastfeeding were recorded. The children’s adherence to the Mediterranean diet was also evaluated by KidMed index. Statistical analysis was performed using SPSS.22. Results: Children with increased physical activity had lower triglyceride levels, compared to those with lower physical activity (p = 0.001). Children who consumed only one meal per day, had increased levels of total cholesterol (p = 0.01), LDL-cholesterol (p = 0.01), ApoB (p = 0.001) and lipoprotein (a) (p = 0.018), compared to those who consumed more than 3 meals per day (p < 0.05). Children who were breastfed less than 6 months had significantly increased LDL-C levels (p = 0.022), compared to children who were breastfed more than 6 months. All other parameters investigated did not differ significantly. Conclusions: This study showed association between lipid profile of children with dyslipidemia and specific nutritional and socioeconomic factors, such as increased physical activity, increased meals consumption during the day, and exclusive breastfeeding for more than 6 months. Nevertheless, further research is needed, in order to confirm these findings.

O-GlcNAcylation, a sweet link to the pathology of diseases

O-linked N-acetylglucosamine (O-GlcNAc) is a dynamic post-translational modification occurring on myriad proteins in the cell nucleus, cytoplasm, and mitochondria. The donor sugar for O-GlcNAcylation, uridine-diphosphate N-acetylglucosamine (UDP-GlcNAc), is synthesized from glucose through the hexosamine biosynthetic pathway (HBP). The recycling of O-GlcNAc on proteins is mediated by two enzymes in cells-O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), which catalyze the addition and removal of O-GlcNAc, respectively. O-GlcNAcylation is involved in a number of important cell processes including transcription, translation, metabolism, signal transduction, and apoptosis. Deregulation of O-GlcNAcylation has been reported to be associated with various human diseases such as cancer, diabetes, neurodegenerative diseases, and cardiovascular diseases. A better understanding of the roles of O-GlcNAcylation in physiopathological processes would help to uncover novel avenues for therapeutic intervention. The aim of this review is to discuss the recent updates on the mechanisms and impacts of O-GlcNAcylation on these diseases, and its potential as a new clinical target.