To examine whether delivery by caesarean section is a risk factor for childhood obesity.
Prospective pre-birth cohort study (Project Viva).
Eight outpatient multi-specialty practices based in the Boston, Massachusetts area.
We recruited women during early pregnancy between 1999 and 2002, and followed their children after birth. We included 1255 children with body composition measured at 3 years of age.
Main outcome measures
Body mass index (BMI) z-score, obesity (BMI for age and sex ≥ 95th percentile), and sum of triceps + subscapular skinfold thicknesses, at 3 years of age.
284 children (22.6 percent) were delivered by caesarean section. At age 3, 15.7% of children delivered by caesarean section were obese, compared with 7.5% of children born vaginally. In multivariable logistic and linear regression models adjusting for maternal pre-pregnancy BMI, birth weight, and other covariates, birth by caesarean section was associated with a higher odds of obesity at age 3 (OR 2.10, 95%CI 1.36 to 3.23), higher mean BMI z-score (0.20 units, 95% CI 0.07 to 0.33), and higher sum of triceps + subscapular skinfold thicknesses (0.94 mm, 95% CI 0.36 to 1.51).
Infants delivered by caesarean section may be at increased risk of childhood obesity. Further studies are needed to confirm our findings and to explore mechanisms underlying this association.
Factors influencing excessive weight gain in pregnancy have not been well studied among urban, low-income women.
Prospective cohort study of 94 prenatal care patients at a large university hospital in Philadelphia, examining associations of modifiable mid-pregnancy behaviors and non-modifiable or early pregnancy factors with excessive gestational weight gain. Data were collected through questionnaires and medical record abstraction in 2009-2011.
The majority of women were African-American (83%) and all (100%) received Medicaid. Nearly two-thirds (60%) were overweight or obese in early pregnancy and 41% experienced excessive gain. In multivariable logistic regression analyses, significant predictors of excessive gestational weight gain included high early pregnancy body mass index (odds ratio [OR]: 4.20, 95% confidence interval [CI]: 1.43, 12.34 for overweight/obese vs. normal weight), nulliparity (OR: 3.35, 95% CI: 1.17, 9.62 for nulliparity vs. multiparity), and clinician advice discordant with Institute of Medicine guidelines (OR: 5.88, 95% CI: 1.04, 33.32 for discordant vs. concordant advice). Watching under two hours of television daily (OR: 0.18, 95% CI: 0.03, 1.03) and engaging in regular physical activity during pregnancy (OR: 0.35, 95% CI: 0.11, 1.09) were suggestive of a reduced risk of excessive gain.
In this sample of urban, low-income women, high early pregnancy body mass index, nulliparity, and discordant clinician advice were directly associated with excessive gestational weight gain, with a trend toward decreased risk for viewing fewer hours of television and engaging in regular physical activity. Intervening on these targets may optimize gestational weight gain and promote long-term maternal health.
Short sleep duration is associated with multiple adverse child outcomes. We examined associations of the built environment with infant sleep duration among 1226 participants in a pre-birth cohort. From residential addresses, we used a geographic information system to determine urbanicity, population density, and closeness to major roadways. The main outcome was mother’s report of her infant’s average daily sleep duration at 1 year of age. We ranked urbanicity and population density as quintiles, categorized distance to major roads into 8 categories, and used linear regression adjusted for socio-demographic characteristics, smoking during pregnancy, gestational age, fetal growth, and television viewing at 1 year. In this sample, mean (SD) sleep duration at age 1 year was 12.8 (1.6) hours/day. In multivariable adjusted analyses, children living in the highest quintile of urbanicity slept −19.2 minutes/day (95% CI: −37.0, −1.50) less than those living in the lowest quintile. Neither population density nor closeness to major roadways was associated with infant sleep duration after multivariable adjustment. Our findings suggest that living in more urban environments may be associated with reduced infant sleep.
Sleep; urbanicity; population density; infancy; built environment
Adiponectin is an adipocyte-derived hormone that acts as a marker of insulin sensitivity. Bloodspot sampling by fingerstick onto filter paper may increase the feasibility of large-scale studies of the determinants of insulin sensitivity. We first describe the validation of an enzyme-linked immunoassay (ELISA) for quantifying adiponectin from dried blood spots and then demonstrate its application in a large trial (PROBIT).
We quantified adiponectin from 3-mm diameter discs (≈3 µL of blood) punched from dried blood spots obtained from: i) whole blood standards (validation); and ii) PROBIT trial samples (application) in which paediatricians collected blood spots from 13,879 children aged 11.5 years from 31 sites across Belarus. We examined the distribution of bloodspot adiponectin by demographic and anthropometric factors, fasting insulin and glucose.
In the validation study, mean intra-assay coefficients of variation (n = 162) were 15%, 13% and 10% for ‘low’ (6.78 µg/ml), ‘medium’ (18.18 µg/ml) and 'high’ (33.13 µg/ml) internal quality control (IQC) samples, respectively; the respective inter-assay values (n = 40) were 23%, 21% and 14%. The correlation coefficient between 50 paired whole bloodspot versus plasma samples, collected simultaneously, was 0.87 (95% CI: 0.78 to 0.93). Recovery of known quantities of adiponectin (between 4.5 to 36 µg/ml) was 100.3–133%. Bloodspot adiponectin was stable for at least 30 months at −80°C. In PROBIT, we successfully quantified fasting adiponectin from dried blood spots in 13,329 of 13,879 (96%) children. Mean adiponectin (standard deviation) concentrations were 17.34 µg/ml (7.54) in boys and 18.41 µg/ml (7.92) in girls and were inversely associated with body mass index, fat mass, triceps and subscapular skin-fold thickness, waist circumference, height and fasting glucose.
Bloodspot ELISA is suitable for measuring adiponectin in very small volumes of blood collected on filter paper and can be applied to large-scale studies.
Early life physical activity may help prevent obesity but is difficult to measure. The purpose of this study was to examine associations of age of achievement of gross motor milestones in infancy with adiposity at age 3 years. Seven forty one mother/infant dyads participated in a longitudinal study in Massachusetts. Exposures were age of attainment of 4 gross motor milestones—rolling over, sitting up, crawling, and walking. Outcomes were 3-year sum of subscapular and triceps skinfold thickness (SS + TR) for overall adiposity, their ratio (SS:TR) for central adiposity, and body mass index (BMI) z-score. We used linear regression models adjusted for confounders to examine motor milestone achievement and later adiposity. Rolling over (0.04, 95% CI: 0.008, 0.07) and sitting up (0.02, 95% CI: 0.001, 0.05) at ≥6 months were associated with increased SS:TR compared with attainment before 6 months. Walking at ≥15 months was associated with 0.98 mm higher SS + TR (95% CI: 0.05, 1.91) compared with walking before 12 months. Age at crawling was not associated with the outcomes. None of the milestones were associated with BMI z-score. Age of motor milestone achievement was only a modest predictor of adiposity. Later rolling over and sitting up were associated with greater central adiposity, and later age at walking was associated with greater overall adiposity at age 3 years. Although we controlled for birth weight and 6-month weight-for-length in our models, more detailed assessment of early adiposity prior to achievement of motor milestones is needed to help determine causality.
Infant; Motor development; Obesity; Physical activity
Methyl-donor nutrients are substrates for methylation reactions involved in neurodevelopment processes. The role of maternal intake of these nutrients on cognitive performance of the offspring is poorly understood. We examined the associations of maternal intake of folate, vitamin B12, choline, betaine, and methionine during the first and second trimesters of pregnancy, with tests of cognitive performance in the offspring at 3 y of age using data from 1210 participants in Project Viva, a prospective pre-birth cohort study in Massachusetts. We assessed nutrient intake with the use of food frequency questionnaires. Children’s cognition at age 3 y was evaluated with the Peabody Picture Vocabulary Test III (PPVT-III) and visual-motor skills with the Wide Range Assessment of Visual Motor Abilities (WRAVMA) test. In multivariable models adjusting for potential sociobehavioral and nutritional confounders, for each 600 µg/d increment in total folate intake during the first trimester, PPVT-III score at age 3 y was 1.6 points [95% CI: 0.1, 3.1; P = 0.04] higher. There was a weak inverse association between vitamin B12 intake during the second trimester and PPVT-III scores [−0.4 points per 2.6 µg/d; 95% CI: −0.8, −0.1; P = 0.01]. We did not find associations between choline, betaine, or methionine and cognitive outcomes at this age. Results of this study suggest that higher intake of folate in early pregnancy is associated with higher scores on the PPVT-III, a test of receptive language that predicts overall intelligence, at age 3 y.
folate; vitamin B12; choline; methionine; pregnancy; cognition; children
Given that it is not feasible to use dual x-ray absorptiometry (DXA) or other reference methods to measure adiposity in all pediatric clinical and research settings, it is important to identify reasonable alternatives. Therefore, we sought to determine the extent to which other adiposity measures were correlated with DXA fat mass in school-aged children.
In 1110 children aged 6.5-10.9 years in the pre-birth cohort Project Viva, we calculated Spearman correlation coefficients between DXA (n=875) and other adiposity measures including body mass index (BMI), skinfold thickness, circumferences, and bioimpedance. We also computed correlations between lean body mass measures.
50.0% of the children were female and 36.5% were non-white. Mean (SD) BMI was 17.2 (3.1) and total fat mass by DXA was 7.5 (3.9) kg. DXA total fat mass was highly correlated with BMI (rs=0.83), bioimpedance total fat (rs=0.87), and sum of skinfolds (rs=0.90), and DXA trunk fat was highly correlated with waist circumference (rs=0.79). Correlations of BMI with other adiposity indices were high, e.g., with waist circumference (rs=0.86) and sum of subscapular plus triceps skinfolds (rs=0.79). DXA fat-free mass and bioimpedance fat-free mass were highly correlated (rs=0.94).
In school-aged children, BMI, sum of skinfolds, and other adiposity measures were strongly correlated with DXA fat mass. Although these measurement methods have limitations, BMI and skinfolds are adequate surrogate measures of relative adiposity in children when DXA is not practical.
Adiposity; Obesity; DXA; BMI
Nutritionists advise pregnant women to eat fish to obtain adequate docosahexaenoic acid (DHA), an essential nutrient important for optimal brain development. However, concern exists that this advice will lead to excess intake of methylmercury, a developmental neurotoxicant.
Conduct a pilot intervention to increase consumption of high-DHA, low-mercury fish in pregnancy.
In April-October 2010 we recruited 61 women in the greater Boston, MA area at 12–22 weeks gestation who consumed <=2 fish servings/month, and obtained outcome data from 55. We randomized participants to 3 arms: Advice to consume low-mercury/high-DHA fish (n=18); Advice + grocery store gift cards (GC) to purchase fish (n=17); or Control messages (n=20). At baseline and 12-week follow-up we estimated intake of fish, DHA and mercury using a 1-month fish intake food frequency questionnaire, and measured plasma DHA and blood and hair total mercury.
Baseline characteristics and mean (range) intakes of fish [21 (0–125) g/day] and DHA from fish [91 (0–554) mg/d] were similar in all 3 arms. From baseline to follow-up, intake of fish [Advice: 12 g/day (95% CI: -5, 29), Advice+GC: 22 g/day (5, 39)] and DHA [Advice: 70 mg/d (3, 137), Advice+GC: 161 mg/d (93, 229)] increased in both intervention groups, compared with controls. At follow-up, no control women consumed >= 200mg/d of DHA from fish, compared with 33% in the Advice arm (p=0.005) and 53% in the Advice+GC arm (p=0.0002). We did not detect any differences in mercury intake or in biomarker levels of mercury and DHA between groups.
An educational intervention increased consumption of fish and DHA but not mercury. Future studies are needed to determine intervention effects on pregnancy and childhood health outcomes.
Registered on clinicaltrials.gov as NCT01126762
Fish; Pregnancy; Nutrition; Mercury; Omega-3 fatty acid; Docosahexaenoic acid (DHA)
Pregnancy is now considered to be an important risk factor for new or persistent obesity among women during the childbearing years. High gestational weight gain is the strongest predictor of maternal overweight or obesity following pregnancy. A growing body of evidence also suggests that both high and low gestational weight gains are independently associated with an increased risk of childhood obesity, suggesting that influences occurring very early in life are contributing to obesity onset. In response to these data, the United States Institute of Medicine (IOM) revised gestational weight gain guidelines in 2009 for the first time in nearly two decades. However, less than one-third of pregnant women achieve guideline-recommended gains, with the majority gaining above IOM recommended levels. To date, interventions to optimize pregnancy weight gains have had mixed success. In this paper, we summarize the evidence from human and animal studies linking over-nutrition and under-nutrition in pregnancy to maternal and child obesity. Additionally, we discuss published trials and ongoing interventions to achieve appropriate gestational weight gain as a strategy for obesity prevention in women and their children.
Gestational weight gain; Obesity; Pregnancy; Maternal health; Child health; Postpartum; Fetal growth
Our objective was to examine mothers’ perspectives of obesity-related health behavior recommendations for themselves and their 0–6 month old infants. A health educator conducted 4 motivational counseling calls with 60 mothers of infants during the first 6 months postpartum. Calls addressed 5 behaviors for infants (breastfeeding, introduction of solid foods, sleep, TV, hunger cues), and 4 for mothers (eating, physical activity, sleep, TV). We recorded detailed notes from each call, capturing responsiveness to recommendations and barriers to change. Two independent coders analyzed the notes to identify themes. Mothers in our study were more interested in focusing on their infants’ health behaviors than on their own. While most were receptive to eliminating their infants’ TV exposure, they resisted limiting TV for themselves. There was some resistance to following infant feeding guidelines, and contrary to advice to avoid nursing or rocking babies to sleep, mothers commonly relied on these techniques. Return to work emerged as a barrier to breastfeeding, yet facilitated healthier eating, increased activity, and reduced TV time for mothers. The early postpartum period is a challenging time for mothers to focus on their own health behaviors, but returning to work appears to offer an opportunity for positive changes in this regard. To improve weight-related infant behaviors, interventions should consider mothers’ perceptions of nutrition and physical activity recommendations and barriers to adherence.
Postpartum Women; Infancy; Nutrition; Physical activity; Obesity prevention
To assess the feasibility of a pediatric primary care based intervention to promote healthful behaviors among 0–6 month old infants and their mothers. We enrolled two intervention practices (60 mother-infant pairs) and one usual care control practice (24 pairs) in a non-randomized controlled trial. We completed visits and interviews with 80 (95%) pairs at birth and 6 months. The intervention included (1) brief focused negotiation by pediatricians, (2) motivational counseling by a health educator, and (3) group parenting workshops. We evaluated the intervention effects on infant feeding, sleep duration, TV viewing, and mothers’ responsiveness to satiety cues. Maternal behavioral targets included postpartum diet, physical activity, TV and sleep. At 6 months, fewer intervention than control infants had been introduced to solid foods (57% vs. 82%; P = 0.04), and intervention infants viewed less TV (mean 1.2 vs. 1.5 h/d; P = 0.07). Compared to control infants, intervention infants had larger increases in their nocturnal sleep duration from baseline to follow up (mean increase 1.9 vs. 1.3 h/d; P = 0.05); larger reductions in settling time (mean reduction −0.70 vs. −0.10 h/d; P = 0.02); and larger reductions in hours/day of nighttime wakefulness (mean reduction −2.9 vs. −1.5 h/d; P = 0.08). There were no differences in breastfeeding, response to satiety cues, or maternal health behaviors. A program of brief focused negotiation by pediatricians, individual coaching by health educators using motivational interviewing, and group parenting workshops tended to improve infant feeding, sleep and media exposure, but had less impact on mothers’ own health-related behaviors.
Postpartum women; Infancy; Nutrition; Physical activity; Obesity prevention
In large-scale epidemiology, bloodspot sampling by fingerstick onto filter paper has many advantages, including ease and low costs of collection, processing and transport. We describe the development of an enzyme-linked immunoassay (ELISA) for quantifying insulin from dried blood spots and demonstrate its application in a large trial.
We adapted an existing commercial kit (Mercodia Human Insulin ELISA, 10-1113-01) to quantify insulin from two 3-mm diameter discs (≈6 µL of blood) punched from whole blood standards and from trial samples. Paediatricians collected dried blood spots in a follow-up of 13,879 fasted children aged 11.5 years (interquartile range 11.3–11.8 years) from 31 trial sites across Belarus. We quantified bloodspot insulin levels and examined their distribution by demography and anthropometry.
Mean intra-assay (n = 157) coefficients of variation were 15% and 6% for ‘low’ (6.7 mU/L) and ‘high’ (23.1 mU/L) values, respectively; the respective inter-assay values (n = 33) were 23% and 11%. The intraclass correlation coefficient between 50 paired whole bloodspot versus serum samples, collected simultaneously, was 0.90 (95% confidence interval 0.85 to 0.95). Bloodspot insulin was stable for at least 31 months at −80°C, for one week at +30°C and following four freeze-thaw cycles. Paediatricians collected a median of 8 blood spots from 13,487 (97%) children. The geometric mean insulin (log standard deviation) concentrations amongst 12,812 children were 3.0 mU/L (1.1) in boys and 4.0 mU/L (1.0) in girls and were positively associated with pubertal stage, measures of central and peripheral adiposity, height and fasting glucose.
Our simple and convenient bloodspot assay is suitable for the measurement of insulin in very small volumes of blood collected on filter paper cards and can be applied to large-scale epidemiology studies of the early-life determinants of circulating insulin.
The effect of maternal attempt to lose weight during the postpartum period on later child weight has not been explored. Among 1,044 mother–infant pairs in Project Viva, we estimated longitudinal associations of maternal attempt to lose weight during the postpartum period with child weight and adiposity at age 3 years and examined differences in associations by type of weight loss strategy used. Using covariate-adjusted linear and logistic regression models, we estimated associations before and after adjusting for maternal weight-related variables including prepregnancy BMI. At 6 months postpartum, 53% mothers were trying to lose weight. At age 3 years, mean (s.d.) child BMI z-score was 0.44 (1.01) and 8.9% of children were obese. Children whose mothers were trying to lose weight at 6 months postpartum had higher BMI z-scores (0.30 (95% confidence interval (CI) 0.18, 0.42)) and were more likely to be obese (3.0 (95% CI 1.6, 5.8)) at 3 years of age. Addition of maternal prepregnancy BMI to the models attenuated but did not eliminate the associations seen for BMI z-score (0.24 (95% CI 0.12, 0.36) and obesity (2.4 (95% CI 1.2, 4.7)). Attempting to lose weight by exercising alone was the only weight loss strategy that consistently predicted higher child BMI z-score (0.36 (95% CI 0.14, 0.58)) and odds of obesity (6.0 (95% CI 2.2, 16.5)) at age 3 years. In conclusion, we observed an association between maternal attempt to lose weight at 6 months postpartum, particularly through exercise alone, measured using a single item and child adiposity at age 3 years. This association should be thoroughly examined in future studies.
Fish and shellfish are widely available foods that provide important nutrients, particularly n-3 polyunsaturated fatty acids (n-3 PUFAs), to many populations globally. These nutrients, especially docosahexaenoic acid, confer benefits to brain and visual system development in infants and reduce risks of certain forms of heart disease in adults. However, fish and shellfish can also be a major source of methylmercury (MeHg), a known neurotoxicant that is particularly harmful to fetal brain development. This review documents the latest knowledge on the risks and benefits of seafood consumption for perinatal development of infants. It is possible to choose fish species that are both high in n-3 PUFAs and low in MeHg. A framework for providing dietary advice for women of childbearing age on how to maximize the dietary intake of n-3 PUFAs while minimizing MeHg exposures is suggested.
docosahexaenoic acid; eicosapentaenoic acid; fish; methylmercury; n-3 polyunsaturated fatty acids
Background: Methylmercury (MeHg) is a known neuro-toxicant. Emerging evidence indicates it may have adverse effects on the neuro-logic and other body systems at common low levels of exposure. Impacts of MeHg exposure could vary by individual susceptibility or be confounded by bene-ficial nutrients in fish containing MeHg. Despite its global relevance, synthesis of the available literature on low-level MeHg exposure has been limited.
Objectives: We undertook a synthesis of the current knowledge on the human health effects of low-level MeHg exposure to provide a basis for future research efforts, risk assessment, and exposure remediation policies worldwide.
Data sources and extraction: We reviewed the published literature for original human epidemio-logic research articles that reported a direct biomarker of mercury exposure. To focus on high-quality studies and those specifically on low mercury exposure, we excluded case series, as well as studies of populations with unusually high fish consumption (e.g., the Seychelles), marine mammal consumption (e.g., the Faroe Islands, circumpolar, and other indigenous populations), or consumption of highly contaminated fish (e.g., gold-mining regions in the Amazon).
Data synthesis: Recent evidence raises the possibility of effects of low-level MeHg exposure on fetal growth among susceptible subgroups and on infant growth in the first 2 years of life. Low-level effects of MeHg on neuro-logic outcomes may differ by age, sex, and timing of exposure. No clear pattern has been observed for cardio-vascular disease (CVD) risk across populations or for specific CVD end points. For the few studies evaluating immunologic effects associated with MeHg, results have been inconsistent.
Conclusions: Studies targeted at identifying potential mechanisms of low-level MeHg effects and characterizing individual susceptibility, sexual dimorphism, and non-linearity in dose response would help guide future prevention, policy, and regulatory efforts surrounding MeHg exposure.
birth outcomes; cardio-vascular disease; epidemiology; health outcomes; low-level exposure; metals; methylmercury; neuro-logic outcomes
Background: Diverse perspectives have influenced fish consumption choices.
Objectives: We summarized the issue of fish consumption choice from toxicological, nutritional, ecological, and economic points of view; identified areas of overlap and disagreement among these viewpoints; and reviewed effects of previous fish consumption advisories.
Methods: We reviewed published scientific literature, public health guidelines, and advisories related to fish consumption, focusing on advisories targeted at U.S. populations. However, our conclusions apply to groups having similar fish consumption patterns.
Discussion: There are many possible combinations of matters related to fish consumption, but few, if any, fish consumption patterns optimize all domains. Fish provides a rich source of protein and other nutrients, but because of contamination by methylmercury and other toxicants, higher fish intake often leads to greater toxicant exposure. Furthermore, stocks of wild fish are not adequate to meet the nutrient demands of the growing world population, and fish consumption choices also have a broad economic impact on the fishing industry. Most guidance does not account for ecological and economic impacts of different fish consumption choices.
Conclusion: Despite the relative lack of information integrating the health, ecological, and economic impacts of different fish choices, clear and simple guidance is necessary to effect desired changes. Thus, more comprehensive advice can be developed to describe the multiple impacts of fish consumption. In addition, policy and fishery management inter-ventions will be necessary to ensure long-term availability of fish as an important source of human nutrition.
advisory; economics; fish; methylmercury; nutrition; ocean ecology; poly-chlorinated biphenyls; poly-unsaturated fatty acid; toxicology
Multicenter study designs have several advantages, but the possibility of non-random measurement error resulting from procedural differences between the centers is a special concern. While it is possible to address and correct for some measurement error through statistical analysis, proactive data monitoring is essential to ensure high-quality data collection.
In this article, we describe quality assurance efforts aimed at reducing the effect of measurement error in a recent follow-up of a large cluster-randomized controlled trial through periodic evaluation of intraclass correlation coefficients (ICCs) for continuous measurements. An ICC of 0 indicates the variance in the data is not due to variation between the centers, and thus the data are not clustered by center.
Through our review of early data downloads, we identified several outcomes (including sitting height, waist circumference, and systolic blood pressure) with higher than expected ICC values. Further investigation revealed variations in the procedures used by pediatricians to measure these outcomes. We addressed these procedural inconsistencies through written clarification of the protocol and refresher training workshops with the pediatricians. Further data monitoring at subsequent downloads showed that these efforts had a beneficial effect on data quality (sitting height ICC decreased from 0.92 to 0.03, waist circumference from 0.10 to 0.07, and systolic blood pressure from 0.16 to 0.12).
We describe a simple but formal mechanism for identifying ongoing problems during data collection. The calculation of the ICC can easily be programmed and the mechanism has wide applicability, not just to cluster randomized controlled trials but to any study with multiple centers or with multiple observers.
To examine the association between timing of introduction of solid foods during infancy and obesity at 3 years of age.
We studied 847 children in Project Viva, a prospective pre-birth cohort study. The primary outcome was obesity at 3 years of age (BMI for age and gender ≥95th percentile). The primary exposure was the timing of introduction of solid foods, categorized as <4, 4 to 5, and ≥6 months. We ran separate logistic regression models for infants who were breastfed for at least 4 months (“breastfed”) and infants who were never breastfed or stopped breastfeeding before the age of four months (“formula-fed”), adjusting for child and maternal characteristics, which included change in weight-for-age z score from 0 to 4 months–a marker of early infant growth.
In the first 4 months of life, 568 infants (67%) were breastfed and 279 (32%) were formula-fed. At age 3 years, 75 children (9%) were obese. Among breastfed infants, the timing of solid food introduction was not associated with odds of obesity (odds ratio: 1.1 [95% confidence interval: 0.3–4.4]). Among formula-fed infants, introduction of solid foods before 4 months was associated with a sixfold increase in odds of obesity at age 3 years; the association was not explained by rapid early growth (odds ratio after adjustment: 6.3 [95% confidence interval: 2.3–6.9]).
Among formula-fed infants or infants weaned before the age of 4 months, introduction of solid foods before the age of 4 months was associated with increased odds of obesity at age 3 years.
obesity; infant feeding; complementary foods
Obesity prevalence in the United States has reached an alarming level. Consequently, more young women are entering pregnancy with body mass indices of at least 30 kg/m2. While higher maternal weight entering pregnancy is related to several adverse pregnancy outcomes, some of the strongest and most compelling data to date have linked prepregnancy obesity to gestational diabetes mellitus (GDM). The mechanisms by which excess maternal weight influences metabolic dysfunction in pregnancy are similar to those in obese nonpregnant women; adipocytes are metabolically active and release a number of hormones implicated in insulin resistance. Heavier mothers are also more likely to have higher glucose levels that do not exceed the cutoff for GDM, but nevertheless predict poor perinatal outcomes. Longer-term complications of GDM include increased risk of maternal type 2 diabetes and offspring obesity. Promising intervention studies to decrease the intergenerational cycle of obesity and diabetes are currently underway.
Gestational diabetes mellitus; Obesity; Pregnancy; Postpartum; Maternal health; Child health; Glucose metabolism; Fetal growth; Insulin resistance; Gestational weight gain; Adiposity; Type 2 diabetes mellitus
Few prospective data link early childhood adiposity with asthma-related symptoms.
We sought to examine the associations of weight-for-length (WFL) at age 6 months with incidence of wheezing by age 3 years.
We studied 932 children in a prospective cohort of children. The main outcome was recurrent wheezing, which was defined as parents’ report of wheezing between 2 and 3 years of age plus wheezing in either year 1 or 2 of life. Secondary outcomes included any wheezing from 6 months to 3 years and current asthma. We used multiple logistic regression to examine associations of 6-month WFL z scores with these outcomes.
At 6 months, the infants’ mean WFL z score was 0.68 (SD, 0.94; range −2.96 to 3.24). By age 3 years, 14% of children had recurrent wheezing. After adjustment for a variety of potential confounders, we found that each 1-unit increment in 6-month WFL z score was associated with greater odds of recurrent wheezing (odds ratio [OR], 1.46; 95% CI, 1.11–1.91) and any wheezing (OR, 1.23; 95% CI, 1.03–1.48). We observed a weaker association between 6-month WFL z score and current asthma (OR, 1.22; 95% CI, 0.94–1.59).
Infants with higher WFL z scores at 6 months of age had a greater risk of recurrent wheezing by age 3 years. It is unclear whether the relationship of infant adiposity and early-life wheeze extends to allergic asthma or wheeze that can persist into later childhood. Our findings suggest that early interventions to prevent excess infant adiposity might help reduce children’s risk of asthma-related symptoms.
Asthma; wheeze; adiposity; children; prospective study
To estimate changes over time in birth weight for gestational age and in gestational length among term singleton neonates born from 1990 to 2005.
We used data from the U.S. National Center for Health Statistics for 36,827,828 singleton neonates born at 37–41 weeks of gestation, 1990–2005. We examined trends in birth weight, birth weight for gestational age, large and small for gestational age, and gestational length in the overall population and in a low-risk subgroup defined by maternal age, race or ethnicity, education, marital status, smoking, gestational weight gain, delivery route, and obstetric care characteristics.
In 2005, compared with 1990, we observed decreases in birth weight (−52 g in the overall population, −79 g in a homogenous low-risk subgroup) and large for gestational age birth (−1.4% overall, −2.2% in the homogenous subgroup) that were steeper after 1999 and persisted in regression analyses adjusted for maternal and neonate characteristics, gestational length, cesarean delivery, and induction of labor. Decreases in mean gestational length (−0.34 weeks overall) were similar regardless of route of delivery or induction of labor.
Recent decreases in fetal growth among U.S., term, singleton neonates were not explained by trends in maternal and neonatal characteristics, changes in obstetric practices, or concurrent decreases in gestational length.
LEVEL OF EVIDENCE
To make recommendations for future clinical, public health, and research practices for women with abnormal glucose tolerance during pregnancy, we reviewed the latest evidence regarding rates of postpartum diabetes screening and types of screening tests.
We searched PubMed for journal articles published from January 2008 through December 2010 that reported on postpartum screening and studies designed to prevent progression to type 2 diabetes among women with gestational diabetes mellitus (GDM). Two authors independently reviewed titles and abstracts from 265 articles.
From 34% to 73% of women with GDM completed postpartum glucose screening. Predictors of higher screening rates included older age, nulliparity, and higher income or education. Screening rates varied by race/ethnicity; Asian women were more likely to be screened than were other racial/ethnic minorities. Women who received prenatal care, who were treated with insulin during pregnancy, or who completed a 6-week postpartum visit were also more likely to receive screening. A moderate proportion of women screened had type 2 diabetes (1.2%-4.5%) or prediabetes (12.2%-36.0%).
Rates of postpartum screening among women with a history of GDM are low; only half of women in most populations are screened. Our findings can inform future screening initiatives designed to overcome barriers to screening for both providers and patients. Well-designed lifestyle interventions specific to women with a history of abnormal glucose tolerance during pregnancy and also studies to determine the efficacy and safety of pharmacological interventions will be important to help prevent progression to diabetes among these high-risk women.
Although obesity screening and treatment are recommended by the US Preventive Services Task Force, 1 in 5 women are obese when they conceive. Women are at risk for complications of untreated obesity particularly during the reproductive years and may benefit from targeted screening. Risks of obesity and potential benefits of intervention in this population are well characterized. Rates of adverse pregnancy outcomes including gestational diabetes, preeclampsia, cesarean delivery, and stillbirth increase as maternal body mass index increases. Offspring risks include higher rates of congenital anomalies, abnormal intrauterine growth, and childhood obesity. Observational data suggest that weight loss may reduce risks of obesity-related pregnancy complications. Although obesity screening has not been studied in women of reproductive age, the effect of obesity and the potential for significant maternal and fetal benefits make screening of women during the childbearing years an essential part of the effort to reduce the impact of the obesity epidemic.
The goal of this paper was to determine predictors of having a weight gain goal in early pregnancy. In 2008, we administered a 48-item survey to 249 pregnant women attending obstetric visits. We examined predictors of women having a goal concordant or discordant with 1990 Institute of Medicine (IOM) guidelines, vs. no goal, using binary and multinomial logistic regression. Of the 292 respondents, 116 (40%) had no gestational weight gain goal, 112 (39%) had a concordant goal and 61 (21%) had a goal discordant with IOM guidelines. Predictors of a guideline-concordant goal, vs. no goal, included sugar sweetened beverage consumption < vs. ≥ 1 serving per week (OR = 2.4, 95%CI: 1.1, 5.7), physical activity ≥ vs. <2.5 h per week (OR = 3.6, 95%CI: 1.7, 7.5), agreeing that `I tried to keep weight down not to look pregnant' (OR = 14.3, 95%CI: 1.4, 140.5). Other predictors only of having a discordant goal (vs. no goal) included agreeing that `as long as I am eating well, I don't care how much I gain' (OR = 0.3, 95%CI: 0.2, 0.8) and agreeing that `if I gain too much weight one month, I try to keep from gaining the next' (OR = 4.1, 95%CI: 1.6, 10.4). Women whose doctors recommended weight gains consistent with IOM guidelines were more likely to have a concordant goal (vs. no goal) (OR = 5.3, 95%CI: 1.5, 18.6). Engaging in healthy behaviors and having health providers offer IOM weight gain recommendations may increase the likelihood of having a concordant gestational weight gain goal, which, in turn, is predictive of actual weight gains that fall within IOM guidelines.
Pregnancy; Weight gain goal; Behavioral and maternal characteristics
Background & Aims
The purpose of this study was to determine the effects of total energy intake, macronutrient intake, and maternal adherence to Mediterranean diet or Alternative Healthy Eating Index (AHEI) on cord blood leptin and adiponectin levels, which have been associated with childhood adiposity.
We used multivariable linear regression to assess associations of maternal diet, averaged over 1st and 2nd trimesters, with cord blood adipokines of 780 women from the prospective cohort study Project Viva.
Mean (SD) energy intake during pregnancy was 2135 (596) kcal. Mean (SD) cord blood levels of leptin and adiponectin were 9.0 (6.6) ng/ml and 28.6 (6.7) μg/ml, respectively. Neither closer adherence to a Mediterranean/AHEI pattern diet nor energy intake was associated with either cord blood leptin or adiponectin. Protein intake was associated with both marginally lower leptin (−0.22 ng/ml [95% CI −0.41, −0.02] for each 1% of energy) and adiponectin (−0.25 μg/ml [95% CI −0.48, −0.02]).
Closer adherence to a Mediterranean/AHEI pattern diet during pregnancy was not associated with cord blood leptin or adiponectin. Maternal protein intake was weakly but significantly associated with lower cord blood leptin and adiponectin.
leptin; adiponectin; Mediterranean diet; Alternative healthy eating index (AHEI); Protein intake