Breast-feeding has a limited long-term effect on anthropometry and body composition of Brazilian mothers

Maternal obesity and its determinants: A neglected issue?

Maternal obesity is a global public health concern that affects every aspect of maternity care. It affects the short-term and long-term health of the mother and her offspring. Obese pregnant mothers are at an increased risk of developing complications during antenatal, intrapartum, and postnatal periods. Maternal complications include gestational diabetes mellitus, hypertensive disorder in pregnancy, pre-eclampsia and eclampsia, increased rate of cesarean delivery, pulmonary embolism, and maternal mortality; fetal complications include congenital malformation, stillbirth, and macrosomia. Moreover, both mother and infant are at an increased risk of developing subsequent non-communicable diseases and cardiovascular problems later in life. Several factors are associated with the likelihood of maternal obesity, including sociodemographic characteristics, obstetric characteristics, knowledge, and perception of health-promoting behavior. Gaining a sound understanding of these factors is vital to reaching the targets of Sustainable Developmental Goal 3-to reduce global maternal mortality and end preventable deaths of children under 5 years of age-by 2030. It is essential to identify pregnant women who are at risk of maternal obesity in order to plan and implement effective and timely interventions for optimal pregnancy outcomes. Importantly, maternal obesity as a significant pregnancy risk factor is largely modifiable.

Association of breastfeeding, maternal anthropometry and body composition in women at 30 years of age

This study aimed at assessing the association of breastfeeding with maternal body mass index (BMI), waist circumference, fat mass index, fat free mass index, android/gynoid fat ratio and bone mineral density. In 1982, the maternity hospitals in Pelotas, Rio Grande do Sul State, Brazil, were daily visited and all live births were identified and examined. These subjects underwent follow-up for several times. At 30 years of age, the participants were interviewed and examined. Parous women provided information on parity and duration of breastfeeding. Multiple linear regression was used in the multivariate analysis, controlling for genomic ancestry, family income, schooling and smoking at 2004-2005. After controlling for confounding factors, breastfeeding was inversely associated with BMI and fat mass index, whereas breastfeeding per live birth was negatively associated with BMI, waist circumference and fat mass index. Women who had had a child in the last 5 years and had breastfed, showed lower BMI (β = -2.12, 95%CI: -4.2; -0.1), waist circumference (β = -4.46, 95%CI: -8.3; -0.6) and fat mass index (β = -1.79, 95%CI: -3.3; -0.3), whereas no association was observed among those whose last childbirth was > 5 years, but the p-value for the tests of interaction were > 0.05. Our findings suggest that breastfeeding is associated with lower BMI and other adiposity measures, mostly in the first years after delivery. Besides that, it has no negative impact on bone mineral density.

Breast-feeding duration for the prevention of excess body weight of mother-child pairs concurrently: a 2-year cohort study

OBJECTIVE

To examine the association between breast-feeding duration and the risk of excess body weight (children >85th percentile, mothers BMI≥25·0 kg/m2) concurrently in mother-child pairs two years after delivery.

DESIGN

Prospective cohort study in Joinville, Brazil. Multivariable logistic regression was used to examine the independent relationship between breast-feeding duration and risk of excess body weight.

SETTING

Brazilian public maternity hospital.

SUBJECTS

Three hundred and five mother-child pairs.

RESULTS

At 2-year follow-up, 23·6 % of mother-child pairs had excess body weight. Children breast-fed for <2 months were more likely to have excess body weight than children breast-fed for ≥6 months (OR=2·4; 95 % CI 1·1, 5·1). Breast-feeding for <2 months was also associated with a greater likelihood of maternal excess body weight compared with those who breast-fed for ≥6 months (OR=2·9; 95 % CI 1·1, 8·1). There was a progressive increase in the likelihood of mother-child pairs having excess body weight as breast-feeding duration decreased. In addition to breast-feeding duration, other independent determinants of excess body weight were pre-pregnancy weight, gestational weight gain and number of pregnancies in mothers, and birth weight in children.

CONCLUSIONS

Breast-feeding for a longer duration has a parallel protective effect on the risk of excess body weight in mother-child pairs two years after birth. Since members of the same family could be influenced by the same risk factors, continued promotion and support of breast-feeding may help to attenuate the rising prevalence of overweight in mother-child pairs.

Factors associated with nutritional outcomes in the mother–child dyad: a population-based cross-sectional study

Objective

To estimate factors associated with double burden of nutritional outcomes in the mother–child dyad at the household level (child stunting and/or maternal overweight).

Design

Cross-sectional study using the Brazilian Demographic and Health Survey. Nutritional outcomes were: mother with normal weight and child with normal height; overweight mother and child with normal height; mother with normal weight and short-stature child; and overweight mother and child with short stature (double burden). The child was classified as short when height-for-ageZ-score was <−2 and the mother as overweight when BMI was ≥25·00 kg/m2. Socio-economic status, environment, social vulnerability, maternal characteristics and the child’s food intake were the exposure factors. The hierarchical approach for multinomial logistic regression modelling was used to assess the associations.

Setting

National Demographic and Health Survey of Children and Women conducted in Brazil, 2006–2007.

Subjects

Mother–child dyads (n3676).

Results

After adjustments, lower maternal educational level (OR=3·53; 95 % CI 1·33, 9·33) and inadequate household (non-masonry house; OR=2·54; 95 % CI 1·39, 4·66) were associated with the double burden of malnutrition. Mother’s short stature (OR=3·41; 95 % CI 1·76, 6·61), child’s vegetable intake on less than or equal to 4 d/week (OR=2·21; 95 % CI 1·03, 4·75) and inadequate household (non-masonry house; OR=2·29; 95 % CI 1·36, 3·87) were associated with child’s short stature. The lack of breast-feeding (OR=2·00; 95 % CI 1·07, 3·72) was associated with maternal overweight.

Conclusions

The present findings contribute to establishing strategies promoting health and healthy diets, by considering the growth deficit and overweight/obesity concomitantly.

Breastmilk Output in a Disadvantaged Community with High HIV Prevalence as Determined by the Deuterium Oxide Dose-to-Mother Technique

INTRODUCTION

World Health Organization breastfeeding guidelines for HIV-infected mothers are exclusive breastfeeding for 6 months and then continued breastfeeding for 12 months, provided the mother is receiving antiretroviral prophylaxis. Many African women perceive that breastmilk alone is not sufficient for their infant's nutritional requirements for the first 6 months of life, and mixed feeding is a common practice.

METHODOLOGY

A stable isotope technique was used to determine breastmilk output volumes and maternal body composition objectively at five different time points in the first year of the infant's life.

RESULTS

Breastmilk output volumes were high for HIV-infected mothers: 831 ± 185 g/day at 6 weeks; 899 ± 188 g/day at 3 months; 871 ± 293 g/day at 6 months; 679 ± 281 g/day at 9 months; and 755 ± 287 g/day at 12 months. These high output volumes had no negative impact on the mother's fat-free mass. The breastmilk output volumes for HIV-uninfected mothers were not significantly different to the outputs for HIV-infected mothers at any of the time points (p > 0.05): 948 ± 223 g/day at 6 weeks; 925 ± 227 g/day at 3 months; 902 ± 286 g/day at 6 months; 746 ± 263 g/day at 9 months; and 713 ± 264 g/day at 12 months.

CONCLUSION

This study using objective methodology shows that breastmilk outputs of HIV-infected mothers were relatively high (and within published reference ranges), and mothers are able to provide sufficient breastmilk for their infants without compromising their own fat-free mass.

Breastfeeding and maternal weight changes during 24 months post-partum: a cohort study

The relationship between breastfeeding and the loss of weight gained during pregnancy remains unclear. This study aimed to investigate the association between breastfeeding and maternal weight changes during 24 months post-partum. We studied a dynamic cohort comprising 315 women living in two cities in the state of Bahia, Brazil. The outcome variable was change in the post-partum weight; the exposure variable was the duration and intensity of breastfeeding. Demographic, socio-economic, environmental, reproductive and lifestyle factors were integrated in the analysis as covariates. The data were analysed using multiple linear regression and linear mixed-effects models. The average cumulative weight loss at 6 months post-partum was 2.561 kg (SD 4.585), increasing at 12 months (3.066 kg; SD 5.098) and decreasing at 18 months (1.993 kg; SD 5.340), being 1.353 kg (SD, 5.574) at 24 months post-partum. After adjustment, the data indicated that for every 1-point increase in breastfeeding score, the estimated average post-partum weight loss observed was 0.191 kg at 6 months (P = 0.03), 0.090 kg at 12 months (P = 0.043), 0.123 kg at 18 months (P < 0.001) and 0.077 kg at 24 months (P = 0.001). Based on these results, we concluded that despite the low expressiveness, the intensity and duration of breastfeeding was associated with post-partum weight loss at all stages of the study during the 24-month follow-up.

Breast-feeding and postpartum weight retention: a systematic review and meta-analysis

OBJECTIVE

Weight gained during pregnancy and postpartum weight retention might contribute to obesity in women of childbearing age. Whether breast-feeding (BF) may decrease postpartum weight retention (PPWR) is still controversial. The purpose of our systematic review and meta-analysis was to investigate the relationship between BF and PPWR.

DESIGN

Three databases were systematically reviewed and the reference lists of relevant articles were checked. Meta-analysis was performed to quantify the pooled standardized mean differences (SMD) of BF on PPWR by using a random-effect model. Heterogeneity was tested using the χ 2 test and I 2 statistics. Publication bias was estimated from Egger's test (linear regression method) or Begg's test (rank correlation method).

RESULTS

Among 349 search hits, eleven studies met the inclusion criteria for the meta-analysis. Seven studies were conducted in the USA, one in Brazil, one in France, one in Georgia and one in Croatia. Compared with formula-feeding, BF for 3 to ≤6 months seemed to have a negative influence on PPWR and if BF continued for >6 months had little or no influence on PPWR. In a subgroup meta-analysis, the results did not change substantially after the analysis had been classified by available confounding factors. There was no indication of a publication bias from the result of either Egger's test or Begg's test.

CONCLUSIONS

Although the available evidence held belief that BF decreases PPWR, more robust studies are needed to reliably assess the impact of patterns and duration of BF on PPWR.

Association of breastfeeding with postmenopausal visceral adiposity among three racial/ethnic groups

OBJECTIVE

We examined the association between breastfeeding and postmenopausal visceral adiposity.

METHODS

Participants were community-dwelling women aged 55-80 from the Caucasian Rancho Bernardo Study, the Filipino Women's Health Study, and the Health Assessment Study of African-American Women who had visceral adipose tissue (VAT) measurements by computed tomography between 2000 and 2002. Linear regression was used to determine the association between average breastfeeding duration per child and VAT.

RESULTS

In Caucasian, Filipino, and African-American women, average number of live births was 3, 4, and 3; average breastfeeding duration was 4.3, 1.8, and 5.1 months, respectively. Filipino women had more live births, were more likely to breastfeed, and breastfed shorter durations. African-American women had lower VAT, despite higher subcutaneous adipose tissue (SAT), BMI, and waist girth. Women who breastfed >3 months on average had 8.8 cm(3) lower VAT than women who breastfed ≤3 months, independent of covariates. Women who initiated breastfeeding had lower BMI and waist girth than those who did not, but they did not differ by VAT unless they breastfed >3 months. Associations were independent of race/ethnicity.

CONCLUSIONS

Results suggest breastfeeding initiation is associated with reduced BMI and smaller waist girth, and breastfeeding >3 months is associated with lower postmenopausal VAT.

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.

Duration of lactation, maternal metabolic profile, and body composition in the Norwegian EBBA I-study

OBJECTIVE

There is conflicting evidence as to whether duration of lactation may decrease the risk of subsequent development of an unfavorable maternal metabolic profile, including overweight and obesity. We hypothesized that duration of lactation is associated with a more favorable metabolic profile and healthier anthropometric measurements.

SUBJECTS AND METHODS

Ninety-eight parous women were studied from the Norwegian EBBAI-study (Energy Balance and Breast cancer Aspects-study), a cross-sectional study of healthy premenopausal women 25-35 years old. Historical lactation data were collected, anthropometric measurements were taken, fasting blood samples (for serum glucose, triglycerides, total cholesterol, and high-density lipoprotein cholesterol) were drawn, and women were asked to fill in a precoded food diary.

RESULTS

Mean time since last birth was 4.7 years, mean number of children was 1.9, mean total duration of lactation was 19 months, and average length of lactation per child was 10.3 months. Women who on average lactated for less than 10 months per child had higher mean levels of fasting serum glucose (5.2 mmol/L vs. 5.0 mmol/L, p=0.04), serum triglyceride (0.91 mmol/L vs. 0.66 mmol/L, p=0.001), and serum cholesterol (4.78 mmol/L vs. 4.32 mmol/L, p=0.004) and a higher waist-to-hip ratio (0.81 vs. 0.77, p=0.001) than women who lactated for 10 months or more per child. The inverse association between average length of lactation per child and waist-to-hip ratio persisted after adjustment for potential confounders.

CONCLUSIONS

These results support the hypothesis that duration of lactation may be associated with a healthier metabolic profile and healthier anthropometric measurements, especially lipid levels and waist-to-hip ratio, even years after weaning.

Estado nutricional e qualidade da dieta de nutrizes em amamentação exclusiva

OBJETIVO: Identificar o estado nutricional, o consumo alimentar e a qualidade da dieta de nutrizes em amamentação exclusiva. MÉTODOS: Estudo transversal realizado com nutrizes em aleitamento exclusivo a partir do 28º dia pós-parto. Foram utilizados instrumentos padronizados e foram avaliados o índice de massa corporal, consumo alimentar e qualidade da dieta. RESULTADOS: As nutrizes apresentaram sobrepeso, consumo energético abaixo do recomendado, porcentagens de macronutrientes adequadas exceto para proteína, que foi elevada. A dieta foi classificada como "precisando de melhorias", conforme o Índice de Alimentação Saudável. CONCLUSÃO: Os resultados mostraram que o sobrepeso associado a uma qualidade inadequada da dieta, indicou possíveis carências de micronutrientes.

Maternal visceral adiposity by consistency of lactation

The purpose of this study was to examine the assocation between lactation and maternal visceral adiposity among US women who were on average 7 years postpartum. This cross-sectional analysis included 89 women who gave birth between 1997 and 2002, who did not have preeclampsia, prepregnancy hypertension or prepregnancy diabetes, and enrolled in The Women and Infant Study of Healthy Hearts (WISH). Computed tomography was used to assess abdominal adiposity. History of lactation was self-reported. Visceral adiposity was greater by 36.96 cm(2) (95% CI: 20.92,53.01) among mothers who never breastfed than mothers who breastfed for ≥3 months after every birth, even after adjustment for age, parity, years since last birth, site, socioeconomic, lifestyle, psychological, and family history variables, early adult BMI, and current BMI. Similarly, in fully adjusted models, mothers who breastfed any of their children for less than 3 months had 20.38 cm(2) (95% CI: 2.70, 38.06) greater visceral adiposity than mothers who consistently breastfed all their children for 3 or more months. This study found that 7 years postpartum visceral fat depots are significantly greater among mothers who lactated for less than 3 months after the birth of each of their children. These results provide a potential physiologic basis for prior findings that women who do not consistently breastfeed are at an increased risk of diabetes, cardiovascular disease, and the metabolic syndrome.

Breastfeeding and subsequent maternal visceral adiposity

Women gain visceral fat during pregnancy. Studies examining the impact of breastfeeding on maternal body composition are inconclusive. We examined the extent to which breastfeeding was associated with visceral adiposity in a sample of US women. This was a cross-sectional analysis of 351 women aged 45-58 years, who were free of clinical cardiovascular disease and had not used oral contraceptives or hormone replacement therapy in the 3 months prior to enrollment in the Study of Women's Health Across the Nation (SWAN)-Heart Study (2001-2003). History of breastfeeding was self-reported. Computed tomography was used to assess abdominal adiposity. Among premenopausal/early-peri-menopausal mothers, those who never breastfed had 28% greater visceral adiposity (95% confidence interval (CI): 11-49, P = 0.001), 4.7% greater waist-hip ratio (95% CI: 1.9-7.4, P < 0.001), and 6.49 cm greater waist circumference (95% CI: 3.71-9.26, P < 0.001) than mothers who breastfed all of their children for ≥3 months in models adjusting for study site; age; parity; years since last birth; socioeconomic, lifestyle, and family history variables; early adult BMI; and current BMI. In comparison to women who were nulliparous, mothers who breastfed all of their children for ≥3 months had similar amounts of visceral fat (P > 0.05). In contrast, premenopausal/early-peri-menopausal mothers who had never breastfed had significantly greater visceral adiposity (42% (95% CI: 17-70), P < 0.001), waist circumference (6.15 cm (95% CI: 2.75-9.56), P < 0.001), and waist-hip ratio (3.7% (95% CI: 0.69-6.8), P = 0.02) than nulliparous women. No significant relationships were observed among late peri-menopausal/postmenopausal women. In conclusion, until menopause, mothers who did not breastfeed all of their children for ≥3 months exhibit significantly greater amounts of metabolically active visceral fat than mothers who had breastfed all of their children for ≥3 months.

Prolonged breast-feeding protects mothers from later-life obesity and related cardio-metabolic disorders

Objective

To investigate the long-term effects of duration of postpartum lactation on maternal body composition and risk for cardio-metabolic disorders in later life.

Design

Retrospective study. Body composition was measured using dual-energy X-ray absorptiometry and serum glucose, insulin and lipids were analysed using enzymatic photometric methods 16–20 years after the last pregnancy. Medical history and lifestyle factors were collected via a self-administered questionnaire. Detailed information regarding weight change patterns during each pregnancy was obtained from personal maternity tracking records.

Setting

City of Jyväskylä and surroundings in Central Finland.

Subjects

Two hundred and twelve women (mean age 48, range 36–60 years).

Results

At 16–20 years after their last pregnancy, women who had breast-fed for less than 6 months had higher total body fat mass and fat mass percentage, particularly in the android region (46·5 (sd8·2) %) than mothers who had breast-fed for longer than 6 months (39·0 (sd10·2) %) or for longer than 10 months (38·4 (sd10·9) %,P< 0·01). These differences were independent of pre-pregnancy weight and BMI, menopausal status, smoking status, level of education, participation in past and present leisure-time physical activity, and current dietary energy intake. Higher body fat mass was also associated with higher fasting serum glucose concentration and insulin resistance, TAG, LDL cholesterol and total cholesterol concentrations, as well as higher systolic and diastolic blood pressure (P< 0·05 for all).

Conclusions

Short duration of breast-feeding may induce weight retention and fat mass accumulation, resulting in increased risk of cardio-metabolic disorders in later life.

Effect of breastfeeding on weight retention from one pregnancy to the next: results from the North Carolina WIC program

OBJECTIVES

Pregnancy-related weight retention can contribute to obesity, and breastfeeding may facilitate postpartum weight loss. We investigated the effect of breastfeeding on long-term postpartum weight retention.

METHODS

Using data from the North Carolina Special Supplemental Nutrition Program for Women, Infants, and Children (WIC; 1996-2004), weight retention was assessed in women aged 18 years or older who had more than one pregnancy available for analysis (n=32,920). Using multivariable linear regression, the relationship between duration of breastfeeding after the first pregnancy and change in pre-pregnancy weight from the first pregnancy to the second pregnancy was estimated, controlling for demographic and weight-related covariates.

RESULTS

Mean time between pregnancies was 2.8 years (standard deviation (SD) 1.5), and mean weight retention from the first to the second pregnancy was 4.9kg (SD 8.7). In covariate-adjusted analyses, breastfeeding for 20 weeks or more resulted in 0.39kg (standard error (SE) 0.18) less weight retention at the beginning of the second pregnancy relative to no breastfeeding (p=0.025).

CONCLUSION

In this large, racially diverse sample of low-income women, long-term weight retention was lower among those who breastfed for at least 20 weeks.

Effect of breast-feeding on weight retention at 3 and 6 months postpartum: data from the North Carolina WIC Programme

OBJECTIVE

Pregnancy-related weight retention can contribute to obesity, and breast-feeding may facilitate postpartum weight loss. We investigated the effect of breast-feeding on postpartum weight retention.

DESIGN

A retrospective follow-up study of weight retention, compared in women who were fully breast-feeding, combining breast-feeding with formula-feeding (mixed feeding), or formula-feeding at 3 months (n 14 330) or 6 months (n 4922) postpartum, controlling for demographic and weight-related covariates using multiple linear regression.

SETTING

The North Carolina Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).

SUBJECTS

Participants in the North Carolina WIC Programme who delivered a baby between 1996 and 2004.

RESULTS

In covariate-adjusted analyses, there was no association between breast-feeding and weight retention at 3 months postpartum. At 6 months postpartum, as compared to formula-feeders, mean weight retention was 0·84 kg lower in mixed feeders (95 % CI 0·39, 1·29; P = 0·0002) and 1·38 kg lower in full breast-feeders (95 % CI 0·89, 1·87; P ≤ 0·0001).

CONCLUSIONS

Breast-feeding was inversely associated with weight retention at 6 months postpartum in this large, racially diverse sample of low-income women. Further, full breast-feeding had a larger protective effect than did breast-feeding combined with formula-feeding.

Determinantes nutricionais e sóciodemográficos da variação de peso no pós-parto: uma revisão da literatura

Trata-se de um estudo de revisão sobre os fatores nutricionais e sócio-demográficos da variação de peso no pós-parto. Foi realizada uma busca bibliográfica nas bases de dados eletrônicas Scientific Eletronic Library On-line (SciELO), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) e Medical Literature Analysis and Retrieval System Online (MEDLINE) referente a literatura publicada na última década (1997-2008). Treze artigos, um informe técnico e dois livros considerados relevantes sobre o assunto e publicados anteriormente ao ano 1997 foram citados na revisão. A revisão priorizou estudos de ensaios clínicos randomizados e de seguimento realizados com gestantes e mulheres no pós-parto. Os resultados obtidos mostram como principais fatores associados com a variação de peso no pós-parto o ganho de peso gestacional acima das recomendações do Institute of Medicine, Índice de Massa Corporal Pré-Gestacional > 25 kg/m2, dieta, tempo e intensidade do aleitamento materno e os fatores sócio-demográficos: raça negra, primiparidade, idade materna, baixa renda e baixa escolaridade. A prática regular de atividade física é recomendada como uma estratégia para evitar o ganho de peso excessivo e melhorar a perda de peso durante o pós-parto. No Brasil não existe uma estratégia nacional para prevenir o ganho de peso excessivo e garantir a adequada perda de peso nesse período. Durante o pós-parto, a maioria das ações de saúde visa basicamente garantir o aleitamento materno.

The reset hypothesis: lactation and maternal metabolism

For maternal metabolism, pregnancy ends not with delivery, but with weaning. In several recent epidemiological studies, authors have reported an association between duration of breast-feeding and reduced maternal risk of metabolic disease. These findings parallel data from animal models showing favorable changes in metabolism associated with lactation. During gestation, visceral fat accumulates, and insulin resistance and lipid and triglyceride levels increase. These changes appear to reverse more quickly, and more completely, with lactation. In this article, we review animal and human studies regarding the effects of lactation on adiposity, lipid, and glucose homeostasis. We hypothesize that lactation plays an important role in "resetting" maternal metabolism after pregnancy.

Duration of breast-feeding and the incidence of type 2 diabetes mellitus in the Shanghai Women's Health Study

AIMS/HYPOTHESIS

The aim of this study was to examine the association between lifetime breast-feeding and the incidence of type 2 diabetes mellitus in a large population-based cohort study of middle-aged women.

METHODS

This was a prospective study of 62,095 middle-aged parous women in Shanghai, China, who had no prior history of type 2 diabetes mellitus, cancer or cardiovascular disease at study recruitment. Breast-feeding history, dietary intake, physical activity and anthropometric measurements were assessed by in-person interviews. The Cox regression model was employed to evaluate the association between breast-feeding and the risk of type 2 diabetes mellitus.

RESULTS

After 4.6 years of follow-up, 1,561 women were diagnosed with type 2 diabetes mellitus. Women who had breastfed their children tended to have a lower risk of diabetes mellitus than those who had never breastfed [relative risk (RR)=0.88; 95% CI, 0.76-1.02; p=0.08]. Increasing duration of breast-feeding was associated with a reduced risk of type 2 diabetes mellitus. The fully adjusted RRs for lifetime breast-feeding duration were 1.00, 0.88, 0.89, 0.88, 0.75 and 0.68 (p trend=0.01) for 0, >0 to 0.99, >0.99 to 1.99, >1.99 to 2.99, >2.99 to 3.99 and >or=4 years in analyses adjusted for age, daily energy intake, BMI, WHR, smoking, alcohol intake, physical activity, occupation, income level, education level, number of live births and presence of hypertension at baseline.

CONCLUSIONS/INTERPRETATION

Breast-feeding may protect parous women from developing type 2 diabetes mellitus later in life.

The effect of number of births on women's mortality: systematic review of the evidence for women who have completed their childbearing

Mortality in women who have completed their childbearing may increase with the number of births experienced because of maternal depletion or a trade-off between reproduction and mortality. We report a systematic review of the evidence on this association. We searched Medline, Embase, Popline, and the Science Citation Index for published and unpublished studies up to September 2003, and the book catalogues of relevant London libraries. Where necessary we also contacted authors for additional information. Mortality declined with increasing numbers of births in twelve historical cohorts, but in eight contemporary cohorts the highest mortality was seen in the nulliparous and in women with more than four births. All effects seen were small and there were few statistically significant results. Studies examining the relationship in other ways (such as by linear trends or by mean number of births by age at death) found inconsistent associations. We discuss methodological, social, and biological factors that may have affected these associations.

Maternal concentration of dichlorodiphenyl dichloroethylene (DDE) and initiation and duration of breast feeding

Dichlorodiphenyl dichloroethylene (DDE) has been shown to reduce the duration of breast feeding in two studies. In addition to duration, we examined whether DDE lowers the initiation of breast feeding. Between 1973 and 1991, the Michigan Department of Community Health conducted three surveys to assess polychlorinated biphenyls (PCBs) and DDE serum concentrations in Michigan anglers. Through telephone interviews with parents, we retrospectively ascertained information on breast feeding. Based on repeated maternal serum measurements between 1973 and 1991, we arrived at the level of exposure at the time of delivery by extrapolating PCB and DDE serum levels. One mother may have contributed more than one child; however, serum concentrations varied between children from the same mother. The maternal DDE and PCB serum concentrations were categorised as follows: 0 to <5 microg/L, 5 to <10 microg/L, >or=10 microg/L. Repeated measurement models and survival analyses were used to determine the relationship between DDE and PCBs and characteristics of breast feeding while controlling for cohort effects, maternal age at delivery, education, and smoking during pregnancy. We focused on 176 pregnancies of 91 mothers who had maternal exposure information and gave birth between 1969 and 1995. Initiation of breast feeding was lowered by 39.5% and duration shortened by 66.4% in children of mothers who smoked during pregnancy. In children of non-smoking mothers, the incidence ratio for breast-feeding initiation was 0.45 [95% CI 0.15, 0.94] and 0.42 [95% CI 0.10, 1.03] when maternal DDE concentrations were 5 to <10 microg/L and >or=10 microg/L respectively, compared with the lowest DDE exposure group. In these offspring (of non-smoking mothers), breast-feeding duration was shorter when DDE concentrations were higher: 13 weeks for >or=10 microg/L DDE, compared with 21.7 weeks for lower DDE. We did not detect any association between PCBs and breast feeding. In the absence of the distorting effects of maternal smoking, DDE exposure may decrease initiation and duration of breast feeding.

Fatores associados com a retenção e o ganho de peso pós-parto: uma revisão sistemática

INTRODUÇÃO: A retenção de peso após o parto é um dos determinantes da obesidade em mulheres. Seu desenvolvimento está relacionado com o ganho de peso gestacional, paridade, idade, situação marital, consumo energético, atividade física e lactação, mas as associações encontradas têm se mostrado inconclusivas e contraditórias. Objetivos: Avaliar estudos que identificaram fatores preditores da retenção e ganho de peso após o parto. MATERIAL E MÉTODOS: Foi realizada uma revisão de literatura na Base de Dados LILACS e MEDLINE, referente aos anos de 1993 a 2003. RESULTADOS: Vinte e oito artigos foram identificados, sendo 23 estudos de coorte, quatro estudos transversais e um estudo caso-controle. A maioria dos estudos foi realizada nos EUA e o tempo de acompanhamento após o parto ocorreu principalmente entre seis semanas e 24 meses. Cerca de 25% dos estudos apresentaram perdas superiores a 30%, 61% incluíram adolescentes na amostra e 75% não aferiram o peso pré-gestacional. Sete estudos foram considerados de melhor qualidade, pois utilizaram o peso pré-gestacional medido, incluíram grupo de comparação, excluíram adolescentes, apresentaram perdas de seguimento inferiores a 30% e controlaram para variáveis de confundimento. CONCLUSÃO: Ganho de peso gestacional, raça negra e paridade estão associados positivamente com a retenção de peso pós-parto. As evidências são contraditórias para a variável lactação e insuficientes para as variáveis consumo alimentar e atividade física. São necessários estudos cuidadosamente desenhados para esclarecer estas questões.

Breastfeeding and postpartum weight retention in a cohort of Brazilian women

BACKGROUND

The relation between postpartum weight retention and breastfeeding practices is controversial.

OBJECTIVE

Defining breastfeeding as the period when a child is exclusively or predominantly breastfed, we studied the association between breastfeeding duration and postpartum weight retention.

DESIGN

We followed 405 women aged 18-45 y who were assessed at 0.5, 2, 6, and 9 mo postpartum. The outcome variable, postpartum weight retention, was expressed as the difference between the observed weight at each follow-up and the reported prepregnancy weight. The main statistical procedure used was the longitudinal mixed-effects model.

RESULTS

Mean postpartum weight retention at the end of the study was 3.1 kg. Single women aged > or = 30 y retained more weight than did younger single women or married women. The combined effect of breastfeeding duration and percentage of body fat at baseline was significant only for women with < 30% body fat. According to the model's prediction, when women who had 22% body fat and breastfed for 180 d were compared with those who had 22% body fat and breastfed for only 30 d, each month of breastfeeding contributed -0.44 kg to postpartum weight retention. When only the percentage of body fat was varied, the total effect was 3.0, 1.7, 1.2, and 0.04 kg in women with 18%, 25%, 28%, and 35% body fat, respectively.

CONCLUSIONS

These results support the hypothesis of an association between breastfeeding and postpartum weight retention and suggest that encouraging prolonged breastfeeding might contribute to decreases in postpartum weight retention.

Postpartum weight retention among women in Rio de Janeiro: a follow-up study

This study presents follow-up results on trends in postpartum weight retention among women in the city of Rio de Janeiro, Brazil, at 0.5, 2, 6, and 9 months postpartum. The outcome variable, weight retention, was calculated by subtracting the reported pre-pregnancy weight from the observed weight at each interview. Statistical analyses used means and a 95% confidence interval for weight retention. Mean weight retention was 4.7, 4.1, 3.4, and 3.1kg at 0.5, 2, 6 and 9 months postpartum, respectively. At completion of the study, the largest weight retention was observed in women over 30 years of age (4.2kg) and with 30% or more of body fat (5.9kg). The rate of reduction in weight retention was 0.4kg/month, 0.2kg/month, and 0.1kg/ month for the periods 0.5-2, 2-6, and 6-9 months, respectively. The largest reductions were observed among young, single women and those with < 30% of body fat at baseline. The results suggest that variables such as age, parity, schooling, and body fat may be important predictors of postpartum weight retention.