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.

Breastfeeding and growth during infancy among offspring of mothers with gestational diabetes mellitus: a prospective cohort study.

BACKGROUND: Breastfeeding (BF) may protect against obesity and type 2 diabetes mellitus in children exposed to maternal diabetes in utero, but its effects on infant growth among this high-risk group have rarely been evaluated. OBJECTIVES: The objective of this study was to evaluate BF intensity and duration in relation to infant growth from birth through 12 months among offspring of mothers with gestational diabetes mellitus (GDM). METHODS: Prospective cohort of 464 GDM mother-infant dyads (28% White, 36% Hispanic, 26% Asian, 8% Black, 2% other). Weight and length measured at birth, 6-9 weeks, 6 months and 12 months. Categorized as intensive BF or formula feeding (FF) groups at 6-9 weeks (study baseline), and intensity from birth through 12 months as Group 1: consistent exclusive/mostly FF, Group 2: transition from BF to FF within 3-9 months and Group 3: consistent exclusive/mostly BF. Multivariable mixed linear regression models estimated adjusted mean (95% confidence interval) change in z-scores; weight-for-length (WLZ), weight-for-age and length-for-age. RESULTS: Compared with intensive BF at 6-9 weeks, FF showed greater increases in WLZ-scores from 6 to 9 weeks to 6 months [+0.38 (0.13 to 0.62) vs. +0.02 (-0.15 to 0.19); p = 0.02] and birth to 12 months [+1.11 (0.87 to 1.34) vs. +0.53 (0.37 to 0.69); p < 0.001]. For 12-month intensity and duration, Groups 2 and 3 had smaller WLZ-score increases than Group 1 from 6 to 9 weeks to 6 months [-0.05 (-0.27 to 0.18) and +0.07 (-0.19 to 0.23) vs. +0.40 (0.15 to 0.64); p = 0.01 and 0.07], and birth to 12 months [+0.60 (0.39 to 0.82) and +0.59 (0.33 to 0.85) vs. +0.97 (0.75 to 1.19); p < 0.05]. CONCLUSIONS: Among offspring of mothers with GDM, high intensity BF from birth through 1 year is associated with slower infant ponderal growth and lower weight gain.

Cardiorespiratory fitness, exercise haemodynamics and birth outcomes: the Coronary Artery Risk Development in Young Adults Study.

OBJECTIVE: Determine associations of cardiorespiratory fitness, exercise systolic blood pressure (SBP) and heart rate recovery (HRR) following a maximal exercise test performed years preceding pregnancy with odds of preterm birth (PTB; <37 weeks' gestation) and small for gestational age (SGA; birthweight <10th percentile) delivery. DESIGN: Prospective, longitudinal. SETTING: Multi-site, observational cohort study initially consisting of 2787 black and white women aged 18-30 at baseline (1985-86) and followed for 25 years (Y25; 2010-2011). POPULATION: 768 nulliparous women at baseline who reported ≥1 live birth by the Y25 exam. METHODS: We used Poisson regression to determine associations of exposures with PTB/SGA. MAIN OUTCOME MEASURES: PTB and/or SGA births. RESULTS: Women with PTB (n = 143) and/or SGA (n = 88) were younger, had completed fewer years of education and were more likely to be black versus women without PTB/SGA (n = 546). Women with PTB/SGA had lower fitness (501 ± 9 versus 535 ± 6 seconds, P < 0.002) and higher submaximal SBP than women without PTB/SGA (144 ± 1 versus 142 ± 1 mmHg, P < 0.04). After adjustment, no exercise test variables were associated with PTB/SGA, though the association with HRR and submaximal SBP approached significance in the subset of women who completed the exercise test <5 years before the index birth. CONCLUSIONS: Neither fitness nor haemodynamic responses to exercise a median of 5 years preceding pregnancy, were associated with PTB/SGA. These findings indicate excess likelihood of PTB/SGA is not detectable by low fitness or exercise haemodynamic responses 5 years preceding pregnancy, but exercise testing, especially HRR and submaximal SBP, may be more useful when conducted closer to the onset of pregnancy. TWEETABLE ABSTRACT: Exercise testing conducted >5 years before pregnancy may not detect women likely to have PTB/SGA.

The Kaiser Permanente Northern California research program on genes, environment, and health (RPGEH) pregnancy cohort: study design, methodology and baseline characteristics.

BACKGROUND: Exposures during the prenatal period may have lasting effects on maternal and child health outcomes. To better understand the effects of the in utero environment on children's short- and long-term health, large representative pregnancy cohorts with comprehensive information on a broad range of environmental influences (including biological and behavioral) and the ability to link to prenatal, child and maternal health outcomes are needed. The Research Program on Genes, Environment and Health (RPGEH) pregnancy cohort at Kaiser Permanente Northern California (KPNC) was established to create a resource for conducting research to better understand factors influencing women's and children's health. Recruitment is integrated into routine clinical prenatal care at KPNC, an integrated health care delivery system. We detail the study design, data collection, and methodologies for establishing this cohort. We also describe the baseline characteristics and the cohort's representativeness of the underlying pregnant population in KPNC. METHODS: While recruitment is ongoing, as of October 2014, the RPGEH pregnancy cohort included 16,977 pregnancies (53 % from racial and ethnic minorities). RPGEH pregnancy cohort participants consented to have blood samples obtained in the first trimester (mean gestational age 9.1 weeks ± 4.2 SD) and second trimester (mean gestational age 18.1 weeks ± 5.5 SD) to be stored for future use. Women were invited to complete a questionnaire on health history and lifestyle. Information on women's clinical and health assessments before, during and after pregnancy and women and children's health outcomes are available in the health system's electronic health records, which also allows long-term follow-up. DISCUSSION: This large, racially- and ethnically-diverse cohort of pregnancies with prenatal biospecimens and clinical data is a valuable resource for future studies on in utero environmental exposures and maternal and child perinatal and long term health outcomes. The baseline characteristics of RPGEH Pregnancy Cohort demonstrate that it is highly representative of the underlying population living in the broader community in Northern California.

Central obesity and increased risk of dementia more than three decades later.

BACKGROUND: Numerous reports show that a centralized distribution of adiposity is a more dangerous risk factor for cardiovascular disease and diabetes than total body obesity. No studies have evaluated whether the same pattern exists with dementia. The objective was to evaluate the association between midlife central obesity and risk of dementia three decades later. METHODS: A longitudinal analysis was conducted of 6,583 members of Kaiser Permanente of Northern California who had their sagittal abdominal diameter (SAD) measured in 1964 to 1973. Diagnoses of dementia were from medical records an average of 36 years later, January 1, 1994, to June 16, 2006. Cox proportional hazard models adjusted for age, sex, race, education, marital status, diabetes, hypertension, hyperlipidemia, stroke, heart disease, and medical utilization were conducted. RESULTS: A total of 1,049 participants (15.9%) were diagnosed with dementia. Compared with those in the lowest quintile of SAD, those in the highest had nearly a threefold increased risk of dementia (hazard ratio, 2.72; 95% CI, 2.33-3.33), and this was only mildly attenuated after adding body mass index (BMI) to the model (hazard ratio, 1.92; 95% CI, 1.58-2.35). Those with high SAD (>25 cm) and normal BMI had an increased risk (hazard ratio, 1.89; 95% CI, 0.98-3.81) vs those with low SAD (<25 cm) and normal BMI (18.5-24.9 kg/m(2)), whereas those both obese (BMI >30 kg/m(2)) and with high SAD had the highest risk of dementia (HR, 3.60; 95% CI, 2.85-4.55). CONCLUSIONS: Central obesity in midlife increases risk of dementia independent of diabetes and cardiovascular comorbidities. Fifty percent of adults have central obesity; therefore, mechanisms linking central obesity to dementia need to be unveiled.

Excess gains in weight and waist circumference associated with childbearing: The Coronary Artery Risk Development in Young Adults Study (CARDIA).

OBJECTIVE: To examine the association of childbearing with weight and waist circumference (WC) changes, we compared women with and without pregnancies or births during follow-up. STUDY DESIGN: A multicenter, longitudinal observational study over 10 years. Comparison groups defined by the number of pregnancies and births during follow-up: P0 (0 pregnancies; nongravid), P1 (1+ miscarriages or abortions; 'short' pregnancies), B1 (1 birth), and B2 (2+ births). Mean changes in weight and WC for P1, B1 and B2 groups vs P0 were examined separately by race (black and white), baseline parity (nulliparous and parous) and baseline weight status (normal weight; BMI <25 kg/m(2) and overweight; BMI >/=25 kg/m(2)). SUBJECTS: A population-based sample of 2070 women aged 18-30 y at baseline (1053 black subjects and 1017 white subjects) from Birmingham, Alabama, Chicago, Illinois, Minneapolis, Minnesota, and Oakland, California were examined five times between 1985-1986 and 1995-1996. MEASUREMENTS: Weight and WC measurements were obtained using standardized protocol at baseline and examinations at years 2, 5, 7 and 10. Sociodemographic, reproductive, and behavioral attributes were assessed at baseline and follow-up examinations. RESULTS: Gains in weight and WC associated with pregnancy and childbearing varied by race (P<0.001), baseline parity (P<0.05) and overweight status (P<0.001). Among overweight nulliparas, excess gains in weight (black subjects: 3-5 kg, white subjects: 5-6 kg) and WC (black subjects: 3-4 cm, white subjects: 5-6 cm) were associated with 'short' pregnancies and one or more birth(s) during follow-up compared to no pregnancies (P<0.01 and 0.001). Among normal weight nulliparas, excess gains in weight (about 1 kg) and WC (2-3 cm) were associated with follow-up birth(s) (P<0.05). Among women parous at baseline, no excess weight gains were found, but excess WC gains (2-4 cm) were associated with follow-up births. CONCLUSION: Substantial excess weight gain is associated with both short pregnancies and a first birth in women overweight prior to initiation of childbearing. Excess weight gain was not associated with higher order births. Increases in waist girth were cumulative with both first and higher order births among overweight as well as normal weight women. Interventions to prevent obesity should be targeted at women who are overweight prior to initiation of childbearing. The impact of excess WC gains associated with childbearing on women's future health risk should be evaluated further.

Does the pattern of postpartum weight change differ according to pregravid body size?

OBJECTIVES: To examine differences in the pattern of weight changes during and after pregnancy among four pregravid body mass index (BMI) groups. STUDY DESIGN: Prospective cohort study of women who had two consecutive births at the University of California, San Francisco (UCSF) between 1980 and 1990. MEASUREMENTS: Maternal body weights were available before conception and delivery, and at 6 weeks postpartum for the first (index) pregnancy, and before conception for the second study pregnancy. Height and two pregravid weights were self-reported. Weights at delivery and 6 weeks postpartum were measured. Net delivery weight was defined as delivery weight minus infant birth weight. Three non-overlapping sequential weight changes were constructed: (1) net gestational gain (net delivery weight minus pregravid weight at the index pregnancy); (2) early net postpartum weight change (6-week postpartum weight minus net delivery weight); and (3) late postpartum weight change (pregravid weight at the second pregnancy minus 6-week postpartum weight). SUBJECTS: A total of 985 healthy women (age 18-41 y) from four race/ethnicity groups (Asian, Hispanic, black and white) who had a singleton, full-term, live birth for the index pregnancy followed by a second consecutive birth. RESULTS: Four race/ethnicity groups were combined (no interaction) to contrast average weight changes among pregravid BMI groups. Means adjusted for eight covariates (parity, race/ethnicity, education, mode of delivery, smoking, hypertension of pregnancy, age, height) and time intervals were not altered appreciably. Early net postpartum weight losses were similar for all pregravid BMI groups. Late (median of 2 y) postpartum weight losses were 4 kg higher in the low and average BMI groups compared with the highest BMI group. About half of the net gestational gain was lost by 6 weeks postpartum, and the percentage that was lost decreased over time. CONCLUSIONS: This study suggests that early postpartum weight loss does not vary by maternal pregravid BMI group, but late postpartum weight change does. Serial weight measurements are needed in epidemiologic studies to differentiate retention of gestational gain from weight gain during the late postpartum period.

The relative importance of gestational gain and maternal characteristics associated with the risk of becoming overweight after pregnancy.

OBJECTIVES: To assess the relationships between gestational gain, race/ethnicity, reproductive history, age, education and the risk of becoming overweight after pregnancy. STUDY DESIGN: Prospective cohort study of adult women from four race/ethnicity groups who had two consecutive births between 1980 and 1990 at the University of California, San Francisco (UCSF). MEASUREMENTS: Height and pregravid weights for each pregnancy were self-reported. Women were classified as overweight or not overweight according to the Institute of Medicine (IOM) criteria for pregnancy. Gestational gain was defined as the difference between the pregravid weight and the last weight before delivery of the first study pregnancy. SUBJECTS: 1300 healthy women aged 18-41 y who had a singleton, full-term, live birth (index or first study pregnancy) followed by a second birth. Self-reported pregravid weights and heights were used to calculate body mass index (BMI). Women with a pregravid BMI below 26.0 kg/m2 before the index pregnancy were classified as not overweight (n = 1128). Overweight status following the index pregnancy was based on pregravid BMI for the second pregnancy. RESULTS: Seventy-two women (6.4%) became overweight following the index pregnancy. Statistically significant independent predictors of the risk of becoming overweight included: maternal age 24-30 vs above 30 y, high gestational gain, short interval from menarche to first ever birth ( < 8 y), and young age at menarche ( < 12 y). The risk of becoming overweight was increased 2.5-3 times for each of these risk factors. Whites were 4.5 times more likely to become overweight than Asians, but blacks and Hispanics did not appear to differ from whites. Parity, time interval, smoking habit, education, marital status and other factors were not associated with the risk of becoming overweight. CONCLUSIONS: These findings suggest that young age at menarche, maternal age and short time from menarche to first ever birth may be as important as high gestational weight gain in determining the risk of becoming overweight after pregnancy.

Iron stores in users of oral contraceptive agents.

A comparison of serum ferritin and other parameters of iron status was made between 46 women taking oral contraceptive agents (OCAs) for two or more years continuously and 71 women who never took OCAs. The mean serum ferritin level for the OCA users was 39.5 +/- 21.5 ng/ml and the control group mean level was 25.4 +/- 15.96 ng/ml, which is significantly different at p less than 0.001. Serum transferrin, serum iron, TIBC, MCH and MCHC levels were significantly greater for the OCA users group. Significantly lower RBC and hematocrit levels were found for OCA users while other parameters, hemoglobin, MCV and percent transferrin saturation, were not significantly different. No major differences in subject characteristics and dietary traits were evidenced, except a difference in reported menstrual cycle losses and a higher heme iron content in the diet of the OCA users.

PIP: A comparison of serum ferritin and other parameters of iron status was made between 46 women taking oral contraceptives (OCs) for 2 or more years continuously and 71 women who never took them. The mean serum ferritin level for OC users was 39.5 +or- 21.5 ng/ml and the control group mean level was 25.4 +or- 15.96 ng/ml which is significantly different at P0.001. Serum transferrin, serum iron, TIBC, MCH, and MCHC levels were significantly greater for the group using OCs. Significantly lower RBD and hematocrit levels were found for OC users while other parameters, hemoglobin, MCV, and percent transferrin saturation were not significantly different. No major differences in subject characteristics and dietary traits were in evidence, except for a difference in reported menstrual cycle losses and a higher heme iron content in the diet of OC users.