Lactation and maternal risk of diabetes: Evidence from the Mexican Teachers' Cohort

Barriers to promoting breastfeeding in primary health care in Mexico: a qualitative perspective

Objective

This article aimed to identify the main barriers related to promoting and counseling breastfeeding (BF) at the Primary Health Care (PHC) in Mexico.

Methodology

A qualitative study with a phenomenological approach was carried out in 88 health centers of the Ministry of Health in the states of Chihuahua, Oaxaca, Chiapas, Veracruz, Mexico, and Yucatan. From September to November 2021, we interviewed 88 key health professionals (HPs) (physicians, nurses, nutritionists, and others) from the PHC of the Ministry of Health in Mexico and 80 parents of children under 5 years old. In addition, nine focus groups were conducted with parents and caregivers. The data obtained were triangulated with information from focus groups and semi-structured interviews.

Results

Of the total interviews, 43.2% (n = 38) were nurses, 29.5% (n = 26) were physicians, 19.3% (n = 17) were nutritionists, and the rest were other health professionals. In the group of users, 97.6% (n = 121) were women. We identified contextual barriers, such as the lack of well-trained health professionals and the scarcest nutrition professionals, as material resources in the health units, without mentioning the low user attendance at their control consultations. Furthermore, we identified barriers related to the orientation and promotion of breastfeeding in health units, including a lack of specific strategies, ineffective communication, and the recommendations of commercial milk formulas.

Conclusion

The results presented reflect the reality of Mexico in relation to BF, making it urgent to take immediate action to improve the quality of nutritional care related to the promotion and orientation of BF at the PHC.

Breastfeeding is associated with the intelligence of school-age children in Mexico

Breastfeeding has been consistently associated with higher intelligence since childhood. However, this relation could be confounded due to maternal selection bias. We estimated the association between predominant breastfeeding and intelligence in school-age children considering potential selection bias and we simulated the intelligence gap reduction between low versus higher socioeconomic status children by increasing breastfeeding. We analysed predominant breastfeeding practices (breastmilk and water-based liquids) of children 0-3 years included in the Mexican Family Life Survey (MxFLS-1). Intelligence was estimated as the z-score of the abbreviated Raven score, measured at 6-12 years in the MxFLS-2 or MxFLS-3. We predicted breastfeeding duration among children with censored data with a Poisson model. We used the Heckman selection model to assess the association between breastfeeding and intelligence, correcting for selection bias and stratified by socioeconomic status. Results show after controlling for selection bias, a 1-month increase in predominant breastfeeding duration was associated with a 0.02 SD increase in the Raven z-score (p < 0.05). The children who were predominantly breastfed for 4-6 months versus <1 month had 0.16 SD higher Raven z-score (p < 0.05). No associations were found using multiple linear regression models. Among low socioeconomic status children, increasing predominantly breastfeeding duration to 6 months would increase their mean Raven z-score from -0.14 to -0.07 SD and reduce by 12.5% the intelligence gap with high socioeconomic status children. In conclusion, predominant breastfeeding duration was significantly associated with childhood intelligence after controlling for maternal selection bias. Increased breastfeeding duration may reduce poverty-driven intelligence inequities.

The Effects of Breastfeeding on Maternal Mental Health: A Systematic Review

Background: Breastfeeding has many positive effects on the health of infants and mothers, however, the effect of breastfeeding on maternal mental health is largely unknown. The goal of this systematic review was to (1) synthesize the existing literature on the effects of breastfeeding on maternal mental health, and (2) inform breastfeeding recommendations. Materials and Methods: A literature search was conducted in electronic databases using search terms related to breastfeeding (e.g., breastfeeding, infant feeding practices) and mental health conditions (e.g., mental illness, anxiety, depression), resulting in 1,110 records. After reviewing article titles and abstracts, 339 articles were advanced to full-text review. Fifty-five articles were included in the final analysis. Results: Thirty-six studies reported significant relationships between breastfeeding and maternal mental health outcomes, namely symptoms of postpartum depression and anxiety: 29 found that breastfeeding is associated with fewer mental health symptoms, one found it was associated with more, and six reported a mixed association between breastfeeding and mental health. Five studies found that breastfeeding challenges were associated with a higher risk of negative mental health symptoms. Conclusions: Overall, breastfeeding was associated with improved maternal mental health outcomes. However, with challenges or a discordance between breastfeeding expectations and actual experience, breastfeeding was associated with negative mental health outcomes. Breastfeeding recommendations should be individualized to take this into account. Further research, specifically examining the breastfeeding experiences of women who experienced mental health conditions, is warranted to help clinicians better personalize breastfeeding and mental health counseling.

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.

A comparative study of bilateral and unilateral early sucking within 2 hours of delivery on lactation

OBJECTIVE

This study explored and analyzed the effects of bilateral and unilateral early sucking within 2 h after delivery on lactation.

METHODS

From August 2019 to August 2020, 392 primiparas with full-term, singleton, natural delivery, and normal breast conditions were submitted to the Obstetrics Department of our hospital and were enrolled as the research subjects. The subjects were randomly divided into an experimental group and a control group, with 196 in each group. Both groups implemented early sucking with the assistance of a midwife within 2 h after delivery. The experimental group conducted bilateral breast sucking and the control group received unilateral sucking. The onset time of colostrum, the lactation volume, and the prolactin levels at 6 h, 24 h, 48 h, and 72 h after delivery, including neonatal urination and incidence of complications were compared between the two groups.

RESULTS

The onset time of colostrum in the experimental group was much earlier than that in the control group with a statistically significant difference (P<0.05). The postpartum filling time of the experimental group was shorter than that of the control group, with a statistically significant difference (P<0.05). There was a statistically insignificant difference in the distribution of lactation yield between the two groups at 6 h of postpartum (P>0.05). The lactation yield distribution in the experimental group at 24 h, 48 h, and 72 h was critically superior to that in control group, with statistically significant difference (P<0.05). The degree of prolactin in the experimental group was higher than that in the control group (P<0.05). There was no significant difference in urination frequency and the incidence of complications between the two groups of neonates at 24 h, 48 h, and 72 h (P>0.05).

CONCLUSION

The effect of bilateral early lactation within 2 h after delivery is superior to that of unilateral early lactation, which is worthy of clinical application.

Association of lactation with maternal risk of type 2 diabetes: A systematic review and meta-analysis of observational studies

AIM

To investigate the association between lactation and maternal risk of type 2 diabetes, including a potential graded association according to lactation duration.

METHODS

A systematic review and meta-analysis of observational studies that investigated the reported association between lactation (irrespective of duration, intensity or mode) and maternal risk of type 2 diabetes was conducted.

RESULTS

A total of 22 studies (17 cohort studies and five cross-sectional studies) were included in this systematic review, and 16 contributed to the meta-analysis. Studies that investigated the association of lactation with risk of type 2 diabetes in the first months after birth in women with gestational diabetes reported conflicting results. Studies with a longer follow-up showed a graded protective association for lactation and the risk of type 2 diabetes, with a potentially larger risk reduction in women with gestational diabetes than in those without gestational diabetes. Overall, ever versus never lactation was associated with a 27% lower risk of type 2 diabetes (RR 0.73, 95% CI [0.65, 0.83]). Each additional month of lactation was associated with a 1% lower risk of type 2 diabetes (RR 0.99, 95% CI [0.98, 0.99]). However, the overall quality of the studies was modest.

CONCLUSIONS

Lactation is associated with a significantly reduced risk of maternal type 2 diabetes over the life course, particularly in women with gestational diabetes. The protective effect seems to increase with longer duration of lactation. Further research is warranted to understand whether this association is modified by exposure to other risk factors.

Breastfeeding practices in Mexico: Results from the National Demographic Dynamic Survey 2006-2018

Although actions have been taken to improve breastfeeding in Mexico, trends over the last decade and their associated factors have not been analysed. We estimated trends in breastfeeding practices at the national, rural/urban, and regional level indigenous ethnicity and socio-economic level, and their associated factors using the National Demographic Dynamics Survey (2006, 2009, 2014 and 2018). We assessed breastfeeding indicators of women with children <24 months according to The World Health Organization recommendations. Logistic regressions models of pooled data were used to estimate trends and associations with biological and sociodemographic characteristics. Between 2006 and 2018, the prevalence of ever breastfed increased from 91.8% to 94.2% (p < 0.001), whereas early initiation of breastfeeding increased from 40.8% to 59.7% (p < 0.001), with similar increments by urban/rural level. Between 2009 and 2018, the prevalence of exclusive breastfeeding in children <6 months increased from 13.0% to 20.7% (p < 0.001). The largest increase was seen in Mexico City, in nonindigenous women and those with a high socio-economic status, whereas indigenous women and those from the South had the lowest or no improvements. Breastfeeding education during pregnancy [odds ratio (OR) 1.3; 95% confidence interval (CI) 1.1-1.5] was positively associated with exclusive breastfeeding, whereas being employed (OR 0.8; 95% CI 0.6-0.9) was negatively associated. Breastfeeding practices improved but are still far from recommendations. Implementing strategies like breastfeeding counselling and programmes and policies that promote and support breastfeeding for poor, indigenous, single and working mothers should be a priority for the government to ensure that all children have the best start in life.

Lactation and maternal risk of diabetes: Evidence from the Mexican Teachers' Cohort

One postpartum behaviour that may be protective against diabetes is lactation due to its potential role in resetting maternal metabolism after pregnancy. However, the role of lactation in maternal risk of diabetes has not been investigated in Latin American populations, where rates of breastfeeding are suboptimal and diabetes incidence is increasing. Therefore, our aim was to estimate the association between mean duration of lactation per child and maternal incidence of diabetes. We followed 66,573 women from the Mexican Teachers' Cohort free of diabetes at baseline. Incident diabetes was ascertained through triennial questionnaires and lactation history was asked in baseline questionnaire. We used Cox proportional hazards regression models to estimate the hazard ratio (HR) for diabetes by mean duration of lactation per child. We examined the dose-response association between lactation per child and diabetes with restricted cubic splines. We found that 3,168 incident cases of diabetes were diagnosed during 157,510 person years of follow-up. In comparison with women who did not breastfed, women with a mean lactation per child of 3 to <6 months and 6 to <12 months had HRs of 0.81 (95% CI [0.65, 0.99]) and 0.73 (95% CI [0.59, 0.91]), respectively (p for quadratic term 0.004). There was no further decline in risk of diabetes after ≥12 months of lactation per child. The dose-response association between lactation and diabetes was linear up to 9 months of lactation. Our findings suggest that lactation is associated with reduced incidence of diabetes, indicating considerable potential for diabetes prevention on a population level.