Breastfeeding and long-term maternal metabolic health in the HUNT Study: a longitudinal population-based cohort study

Reproductive factors and metabolic syndrome among Chinese women aged 40 years and older

BACKGROUND

The aim of this study is to explore the relationship between reproductive variables and the prevalence of metabolic syndrome (MetS) and its components among Chinese women aged 40 years and older.

METHODS

A cross-sectional study was conducted among 4453 women aged 40 years and older in Guangxi, China. The associations between women's reproductive factors and MetS were analyzed using a logistic regression model.

RESULTS

The prevalence of MetS was 23.9% in this population. Women with MetS were mostly older, more likely to be postmenopausal, and had higher parity. Compared to women with one prior live birth, those with three or more live births had the highest odds of having MetS (odds ratio [OR] = 1.56; 95% CI, 1.23-1.99). Similarly, compared to premenopausal women, postmenopausal participants had higher odds of having MetS (OR = 1.86; 95% CI, 1.49-2.31). No associations were observed between MetS and abortion or with age at menarche.

CONCLUSIONS

Our study suggests that multiparity and menopausal status may be associated with the development of MetS. The inconsistency seen in epidemiological research to date calls for further investigation.

Pregnancy-related factors may signal additional protection or risk of future cardiovascular diseases

BACKGROUND

Cardiovascular disease (CVD) guidelines recommend using the Pooled Cohort Equation (PCE) to assess 10-year CVD risk based on traditional risk factors. Pregnancy-related factors have been associated with future CVD. We examined the contribution of two pregnancy-related factors, (1) history of a low birthweight (LBW) infant and (2) breastfeeding to CVD risk accounting for traditional risk factors as assessed by the PCE.

METHODS

A nationally representative sample of women, ages 40-79, with a history of pregnancy, but no prior CVD, was identified using NHANES 1999-2006. Outcomes included (1) CVD death and (2) CVD death plus CVD surrogates. We used Cox proportional hazards models to adjust for PCE risk score.

RESULTS

Among 3,758 women, 479 had a LBW infant and 1,926 reported breastfeeding. Mean follow-up time was 12.1 years. Survival models showed a consistent reduction in CVD outcomes among women with a history of breastfeeding. In cause-specific survival models, breastfeeding was associated with a 24% reduction in risk of CVD deaths (HR 0.76; 95% CI 0.45─1.27, p = 0.30) and a 33% reduction in risk of CVD deaths + surrogate CVD, though not statistically significant. (HR 0.77; 95% CI 0.52─1.14, p = 0.19). Survival models yielded inconclusive results for LBW with wide confidence intervals (CVD death: HR 0.98; 95% CI 0.47─2.05; p = 0.96 and CVD death + surrogate CVD: HR 1.29; 95% CI 0.74─2.25; p = 0.38).

CONCLUSION

Pregnancy-related factors may provide important, relevant information about CVD risk beyond traditional risk factors. While further research with more robust datasets is needed, it may be helpful for clinicians to counsel women about the potential impact of pregnancy-related factors, particularly the positive impact of breastfeeding, on cardiovascular health.

Association of Breastfeeding Duration with 12-Month Postpartum Blood Lipids in a Predominately Lower-Income Hispanic Pregnancy Cohort in Los Angeles

Breastfeeding may protect women’s long-term cardiovascular health; however, breastfeeding-related postpartum lipid changes remain unclear. We aim to examine associations of breastfeeding duration with maternal lipids at 12 months postpartum. In a subsample (n = 79) of the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort, breastfeeding status and duration at 3, 6, and 12 months postpartum were self-reported. Serum levels of lipids, including total cholesterol, triglycerides (TG), high-, low-, and very low-density lipoprotein cholesterol (HDL-C, LDL-C, VLDL-C), were measured from blood samples collected at 12 months postpartum. We used linear regression models to compare lipids by breastfeeding duration, adjusting for potential confounders. Women who were breastfeeding at 12 months had higher HDL-C (mean: 41.74 mg/dL, 95% CI: 37.27−46.74 vs. 35.11 mg/dL, 95% CI: 31.42−39.24), lower TG (80.45 mg/dL, 95% CI: 66.20−97.77 vs. 119.11 mg/dL, 95% CI: 98.36−144.25), and lower VLDL-C (16.31 mg/dL, 95% CI: 13.23, 20.12 vs. 23.09 mg/dL, 95% CI: 18.61−28.65) compared to women who breastfed for <6 months. No lipids were significantly different between women who breastfed for 6−11 months and for <6 months. Each month’s increase in breastfeeding duration was significantly, inversely associated with TG and VLDL-C and positively with HDL-C. Adjusting for fasting status, demographics, pre-pregnancy body mass index, breastfeeding frequency, and pregnancy complications did not appreciably change effect estimates. Breastfeeding at 12 months postpartum and a longer duration of breastfeeding in the first year postpartum were both associated with increased HDL-C and decreased TG and VLDL-C at 12 months postpartum.

Breastfeeding and Prevalence of Metabolic Syndrome among Perimenopausal Women

Little is known about the long-term benefits of breastfeeding for mother's metabolic health. This study aimed to investigate the links between breastfeeding duration and the prevalence of metabolic syndrome (MetS) and its components in perimenopausal women. The analysis included a group of 7621 women aged 55.4 ± 5.4 years. MetS and its components were defined according to the International Diabetes Federation guidelines. Women who breastfed for 13-18 months and beyond 18 months were at lower risk of MetS (odds ratio OR) = 0.76, 95% CI 0.60-0.95; p = 0.017 and OR = 0.79, 95% CI 0.64-0.98; p = 0.030, respectively) than those who never breastfed. Meanwhile, women who breastfed for 7-12 months showed increased glucose concentration (OR = 0.77, 95% CI 0.63-0.94; p = 0.012) compared with those who had never breastfed. The additional analysis involving parity showed that women who had given birth to two babies and breastfed them had lower odds of MetS than those who never breastfed (p < 0.05), although there was no significant difference among women who breastfed for >18 months. Women who had given birth to at least three children and breastfed for 1-6 and 13-18 months had lower odds of MetS and increased triglyceride concentration (p < 0.05). Moreover, participants having breastfed for 1-6 months were found to have a reduced risk of abdominal obesity compared with those who had not breastfed (p < 0.05). Breastfeeding is associated with lower prevalence of MetS in perimenopausal women and can be recommended as a way of reducing the risk of MetS and its components.

Prolactin and breast increase during pregnancy in PCOS: linked to long-term metabolic health?

Objective To explore whether gestational prolactin and breast increase are markers of metabolic health in pregnancy and on long-term, in PCOS. Design Follow-up study. Women with PCOS, according to the Rotterdam criteria (n = 239), former participants of the randomized controlled trial (RCT) PregMet were invited, 131 participated in the current follow-up study, at mean 8 years after pregnancy. Methods Metformin 2000 mg/day or placebo from first trimester to delivery in the original RCT. No intervention in the current study. Prolactin was analyzed in the first trimester and at gestational week 32 and metabolic characteristics which are part of the metabolic syndrome and measures of glucose homeostasis were examined. Metabolic health was also evaluated according to breast increase versus lack of breast increase during pregnancy. Results Prolactin increase in pregnancy was negatively correlated to BMI (P = 0.007) and systolic blood pressure (P ≤ 0.001) in gestational week 32. Prolactin at gestational week 32 was negatively correlated to BMI (P = 0.044) and visceral fat area (P = 0.028) at 8-year follow-up in an unadjusted model. Prolactin at gestational week 32 showed no associations to metabolic health at follow-up when baseline BMI was adjusted for. Women who reported lack of breast increase during pregnancy, had higher BMI (P = 0.034), waist-hip ratio (P = 0.004), visceral fat area (P = 0.050), total cholesterol (P = 0.022), systolic (P = 0.027) and diastolic blood pressure (P = 0.011) at 8-year follow-up. Conclusion High prolactin levels and breast increase in pregnancy were associated with a more favorable long-term metabolic health in women with PCOS. Both prolactin and breast increase may be mediated by gestational BMI.