The relationship of sleep duration and quality to energy expenditure and physical activity in children

BACKGROUND

Shorter sleep duration has been linked to the risk for obesity in children. The pathways linking sleep duration and quality to the risk of obesity are unclear, particularly the effect of sleep on energetics.

OBJECTIVE

We investigated the relationship between sleep duration, quality and timing in children, to the basal metabolic rate (BMR), total energy expenditure (TEE) and physical activity (PA).

METHODS

Fifty nine children in two age-groups (5-11 and 12-18 years) underwent evaluation of body composition (DXA), BMR in a room calorimeter, free-living TEE by doubly labelled water method, sleep and PA (7-day Actiheart monitor) during school break.

RESULTS

Sleep duration contributed to the variance in BMR (β = 0.11, P = .009) after adjusting for age-group, sex, lean and fat mass, but not to the variance in TEE. Late sleep timing was related to lower PA. In the younger age-group, children who met recommended sleep duration on ≥50% of the 7 days had higher light PA (P = .03) and lower sedentary time (P = .009).

CONCLUSION

Suboptimal sleep is associated with lower BMR, lower PA, and higher sedentary behaviours in young children. Prospective studies are needed to confirm if insufficient sleep duration or late sleep timing contribute to obesity risk by increasing sedentary behaviours and decreasing BMR.

New generation lipid emulsions increase brain DHA and improve body composition, but not short-term neurodevelopment in parenterally-fed preterm piglets

New generation, multicomponent parenteral lipid emulsions provide key fatty acids for brain growth and development, such as docosahexaenoic acid (DHA) and arachidonic acid (AA), yet the content may be suboptimal for preterm infants. Our aim was to test whether DHA and AA-enriched lipid emulsions would increase activity, growth, and neurodevelopment in preterm piglets and limit brain inflammation. Cesarean-delivered preterm pigs were given three weeks of either enteral preterm infant formula (ENT) or TPN with one of three parenteral lipid emulsions: Intralipid (IL), SMOFlipid (SMOF) or an experimental emulsion (EXP). Activity was continuously monitored and weekly blood sampling and behavioral field testing performed. At termination of the study, whole body and tissue metrics were collected. Neuronal density was assessed in sections of hippocampus (HC), thalamus, and cortex. Frontal cortex (FC) and HC tissue were assayed for fatty acid profiles and expression of genes of neuronal growth and inflammation. After 3 weeks of treatment, brain DHA content in SMOF, EXP and ENT pigs was higher (P < 0.01) in FC but not HC vs. IL pigs. There were no differences in brain weight or neuron density among treatment groups. Inflammatory cytokine TNFα and IL-1β expression in brain regions were increased in IL pigs (P < 0.05) compared to other groups. Overall growth velocity was similar among groups, but IL pigs had higher percent body fat and increased insulin resistance compared to other treatments (P < 0.05). ENT pigs spent more time in higher physical activity levels compared to all TPN groups, but there were no differences in exploratory behavior among groups. We conclude that a soybean oil emulsion increased select brain inflammatory cytokines and multicomponent lipid emulsions enriched with DHA and AA in parenteral lipids results in increased cortical DHA and improved body composition without affecting short term neurodevelopmental outcomes.

Using Process Evaluation for Implementation Success of Preschool-Based Programs for Obesity Prevention: The TX Childhood Obesity Research Demonstration Study

BACKGROUND

Through the Texas Childhood Obesity Research Demonstration study, we implemented and evaluated a system-oriented model of primary and secondary prevention approaches to mitigate obesity among low-income Texas children aged 2 to 12 years. Primary prevention included implementing the Coordinated Approach To Child Health Early Childhood (CATCH EC) program in Head Start preschools. In this paper, we describe the methods and results of CATCH EC program process evaluation over 2 years of implementation.

METHODS

We used a quasi-experimental design with serial cross-sectional data collected from Head Start centers across intervention and comparison catchment areas in Houston and Austin, Texas (intervention: N = 12 centers in 2012-2013 [Year 1], N = 12 in 2013-2014 [Year 2]; comparison: N = 13 centers in Year 1, N = 12 in Year 2). Process evaluation included center director and teacher surveys conducted in both years of implementation. We developed indices for implementation of CATCH EC and non-CATCH health events at the centers.

RESULTS

Implementation scores were higher among intervention centers as compared to comparison centers across both years of implementation, and these differences were statistically significant (p < .01). There was also high variability in program implementation in intervention centers across both years ranging from 55% to 95%.

CONCLUSION

These implementation index strategies may inform future evaluation of preschool-based obesity prevention program implementation.

Impact of the Coordinated Approach to Child Health Early Childhood Program for Obesity Prevention among Preschool Children: The Texas Childhood Obesity Research Demonstration Study

BACKGROUND

This study presents the impact of a 2-year implementation of Coordinated Approach to Child Health Early Childhood (CATCH EC), a preschool-based healthy nutrition and physical activity program, on child BMI z-scores, BMI percentiles, diet, physical activity, and sedentary behaviors among 3- to 5-year old children across Head Start centers in Houston and Austin, Texas.

METHODS

We used a quasi-experimental study design with serial cross-sectional data collection (Intervention catchment area: n = 12 centers, 353 parent-child dyads in Year 1; n = 12 centers, 365 parent-child dyads; Comparison catchment area: n = 13 centers in year 1, 319 parent child dyads; and n = 12 centers, 483 parent-child dyads in year 2). Child height and weight were measured and parent self-report surveys were conducted at year 1 (fall 2012) and year 2 (spring 2014).

RESULTS

In year 1, 34.8% of the children were overweight or obese, 74% were Hispanic, and >80% reported an annual household income of <$25,000. In year 2, 32.2% were overweight or obese, 72% were Hispanic, and 82.3% reported an annual income of <$25,000. Results demonstrated significantly lower child BMI z-scores [β = -0.26 (95% confidence interval, CI: -0.50 to -0.01), p = 0.041] and BMI percentiles [β = -6.5 (95% CI: -12.4 to -0.69), p = 0.028] from year 1 to 2 follow-up among those in intervention Head Start centers, compared to those in the comparison centers. There were no significant between-group changes in child dietary, physical activity, or screen time behaviors.

CONCLUSION

Implementation of a preschool-based obesity prevention program can be modestly effective in lowering the prevalence of child overweight in low-income populations.

Calibration of activity-related energy expenditure in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

OBJECTIVES

Usual physical activity (PA) is a complex exposure and typical instruments to measure aspects of PA are subject to measurement error, from systematic biases and biological variability. This error can lead to biased estimates of associations between PA and health outcomes. We developed a calibrated physical activity measure that adjusts for measurement error in both self-reported and accelerometry measures of PA in adults from the US Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a community-based cohort study.

DESIGN

Total energy expenditure (TEE) from doubly labeled water and resting energy expenditure (REE) from indirect calorimetry were measured in 445 men and women aged 18-74years in 2010-2012, as part of the HCHS/SOL Study of Latinos: Nutrition & Physical Activity Assessment Study (SOLNAS). Measurements were repeated in a subset (N=98) 6months later.

METHOD

Calibration equations for usual activity-related energy expenditure (AEE=0.90×TEE-REE) were developed by regressing this objective biomarker on self-reported PA and sedentary behavior, Actical accelerometer PA, and other subject characteristics.

RESULTS

Age, weight and height explained a significant amount of variation in AEE. Actical PA and wear-time were important predictors of AEE; whereas, self-reported PA was not independently associated with AEE. The final calibration equation explained fifty percent of variation in AEE.

CONCLUSIONS

The developed calibration equations can be used to obtain error-corrected associations between PA and health outcomes in HCHS/SOL. Our study represents a unique opportunity to understand the measurement characteristics of PA instruments in an under-studied Hispanic/Latino cohort.

Best Practices and Barriers to Obesity Prevention in Head Start: Differences Between Director and Teacher Perceptions

Introduction

Practices and barriers to promoting healthy eating and physical activity at Head Start centers may influence children’s energy balance behaviors. We examined differences between directors’ and teachers’ perspectives on best practices and barriers to promoting healthy eating and physical activity in Head Start centers.

Methods

We conducted a cross-sectional study of directors (n = 23) and teachers (n = 113) at 23 Head Start centers participating in the baseline assessment of the Texas Childhood Obesity Research Demonstration study. Participants completed surveys about practices and barriers to promoting healthy eating and physical activity. Multilevel regression models examined differences between director and teacher responses.

Results

More than half of directors and teachers reported meeting most best practices related to nutrition and physical activity; few directors or teachers (<25%) reported conducting physical activity for more than 60 minutes a day, and less than 40% of teachers helped children attend to satiety cues. Significantly more directors than teachers reported meeting 2 nutrition-related best practices: “Teachers rarely eat less healthy foods (especially sweets, salty snacks, and sugary drinks) in front of children” and “Teachers talk to children about trying/enjoying new foods” (P < .05). No barrier to healthy eating or physical activity was reported by more than 25% of directors or teachers. Significantly more teachers than directors reported barriers to healthy eating, citing lack of food service staff support, limited time, and insufficient funds (P < .05).

Conclusion

More barriers to healthy eating were reported than were barriers to physical activity indicating that more support may be needed for healthy eating. Differences between responses of directors and teachers may have implications for future assessments of implementation of best practices and barriers to implementation related to nutrition and physical activity in early care and education centers.

Validity of the Remote Food Photography Method Against Doubly Labeled Water Among Minority Preschoolers

OBJECTIVE

The aim of this study was to determine the validity of energy intake (EI) estimations made using the remote food photography method (RFPM) compared to the doubly labeled water (DLW) method in minority preschool children in a free-living environment.

METHODS

Seven days of food intake and spot urine samples excluding first void collections for DLW analysis were obtained on thirty-nine 3- to 5-year-old Hispanic and African American children. Using an iPhone, caregivers captured before and after pictures of each child's intake, pictures were wirelessly transmitted to trained raters who estimated portion size using existing visual estimation procedures, and energy and macronutrients were calculated. Paired t tests, mean differences, and Bland-Altman limits of agreement were performed.

RESULTS

The mean EI was 1,191 ± 256 kcal/d using the RFPM and 1,412 ± 220 kcal/d using the DLW method, resulting in a mean underestimate of 222 kcal/d (-15.6%; P < 0.0001) that was consistent regardless of intake. The RFPM underestimated EI by -28.5% in 34 children and overestimated EI by 15.6% in 5 children.

CONCLUSIONS

The RFPM underestimated total EI when compared to the DLW method among preschoolers. Further refinement of the RFPM is needed for assessing the EI of young children.

Places where preschoolers are (in)active: an observational study on Latino preschoolers and their parents using objective measures

BACKGROUND

To combat the disproportionately higher risk of childhood obesity in Latino preschool-aged children, multilevel interventions targeting physical (in) activity are needed. These require the identification of environmental and psychosocial determinants of physical (in) activity for this ethnic group. The objectives were to examine differences in objectively-measured physical activity and sedentary behavior across objectively-determined types of locations in Latino preschool-aged children; and determine whether the differences in physical activity by location were greater in children of parents with higher neighborhood-safety perceptions and physical activity-supportive parenting practices.

METHODS

An observational field study was conducted in Houston (Texas, USA) from August 2011 to April 2012. A purposive sample of Latino children aged 3-5 years and one of their parents (n = 84) were recruited from Census block groups in Houston (Texas) stratified by objectively-assessed high vs. low traffic and crime safety. Seventy-three children provided valid data. Time spent outdoors/indoors tagged with geographic locations was coded into location types based on objective data collected using Global Positioning Systems units that children wore >8 hr/day for a week. Physical activity parenting practices, perceived neighborhood-safety, and demographics were reported by parents. Time spent in sedentary behavior and moderate-to-vigorous physical activity was measured based on objective data collected using accelerometers (motion sensors) that children wore >8 hr/day for a week.

RESULTS

The odds of children engaging in moderate-to-vigorous physical activity were 43% higher when outdoors than indoors (95% confidence interval: 1.30, 1.58), and the odds of being sedentary were 14% lower when outdoors compared to indoors (95% confidence intervals: 0.81, 0.91). This difference depended on parental neighborhood-safety perceptions and parenting practices. Children were most active in parks/playgrounds (30% of the time spent in moderate-to-vigorous physical activity) and least active in childcare/school settings (8% of the time spent in moderate-to-vigorous physical activity).

CONCLUSIONS

Objectively-assessed time spent in specific locations is correlated with physical activity and sedentary behavior in Latino preschoolers. Interventions and policies should identify ways to engage Latino preschool-aged children in more physical activity and less sedentary behavior while in childcare, and encourage parents to spend more time with their young children in parks/playgrounds and other safe outdoor places.

Feasibility study to objectively assess activity and location of Hispanic preschoolers: a short communication

Both physical and social environmental factors influence young children's physical activity, yet little is known about where Hispanic children are more likely to be active. We assessed the feasibility of simultaneously measuring, then processing objective measures of location and physical activity among Hispanic preschool children. Preschool-aged Hispanic children (n = 15) simultaneously wore QStarz BT100X global positioning system (GPS) data loggers and Actigraph GT3X accelerometers for a 24- to 36-hour period, during which time their parents completed a location and travel diary. Data were aggregated to the minute and processed using the personal activity location measurement system (PALMS). Children successfully wore the GPS data loggers and accelerometers simultaneously, 12 of which yielded data that met quality standards. The average percent correspondence between GPS- and diary-based estimates of types of location was high and Kappa statistics were moderate to excellent, ranging from 0.49-0.99. The between-method (GPS monitor, parent-reported diary) correlations of estimated participant-aggregated minutes spent on vehicle-based trips were strong. The simultaneous use of GPS and accelerometers to assess Hispanic preschool children's location and physical activity is feasible. This methodology has the potential to provide more precise findings to inform environmental interventions and policy changes to promote physical activity among Hispanic preschool children.

The association of cysteine with obesity, inflammatory cytokines and insulin resistance in Hispanic children and adolescents

Context

Plasma total cysteine (tCys) independently relates to fat mass in adults. Dietary cyst(e)ine promotes adiposity and decreases glucose tolerance in some rodent models, but alleviates insulin resistance in others.

Objective

To investigate whether the association of tCys with body fat extends to children at particular risk of obesity, and whether tCys is associated with insulin resistance and obesity-associated inflammation.

Methods

We explored the cross-sectional relations of fasting plasma tCys and related metabolites with body composition measured by dual-energy X-ray absorptiometry in 984 Hispanic children and adolescents aged 4–19 years from the Viva La Familia Study. Linear and logistic regression and dose-response curves were used to evaluate relations of tCys with obesity, insulin resistance and inflammatory markers including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1) and C-reactive protein (CRP).

Results

tCys, methionine and total homocysteine (tHcy) increased with age. Upper tCys quartile was independently associated with a 5-fold increased risk of obesity (95% CI 3.5–8.0, P<0.001), and 2-fold risk of insulin resistance (95% CI: 1.6-5.0, P<0.001; adjusted for body fat%). Within the overweight/obese subgroup, but not in normal-weight children, tCys accounted for 9% of the variability in body fat% (partial r = 0.30, P<0.001; adjusted for age and gender). tCys correlated positively with serum non-esterified fatty acids and leptin, partly independent of body fat, but was not associated with serum IL-6, TNF-α or MCP-1. A positive correlation with CRP disappeared after adjustment for BMI.

Conclusion

tCys is independently associated with obesity and insulin resistance in Hispanic children and adolescents, highlighting a previously underappreciated link between the sulfur amino acid metabolic pathway and obesity and cardiometabolic risk.

Template to improve glycemic control without reducing adiposity or dietary fat

Drugs that improve chronic hyperglycemia independently of insulin signaling or reduction of adiposity or dietary fat intake may be highly desirable. Ad36, a human adenovirus, promotes glucose uptake in vitro independently of adiposity or proximal insulin signaling. We tested the ability of Ad36 to improve glycemic control in vivo and determined if the natural Ad36 infection in humans is associated with better glycemic control. C57BL/6J mice fed a chow diet or made diabetic with a high-fat (HF) diet were mock infected or infected with Ad36 or adenovirus Ad2 as a control for infection. Postinfection (pi), systemic glycemic control, hepatic lipid content, and cell signaling in tissues pertinent to glucose metabolism were determined. Next, sera of 1,507 adults and children were screened for Ad36 antibodies as an indicator of past natural infection. In chow-fed mice, Ad36 significantly improved glycemic control for 12 wk pi. In HF-fed mice, Ad36 improved glycemic control and hepatic steatosis up to 20 wk pi. In adipose tissue (AT), skeletal muscle (SM), and liver, Ad36 upregulated distal insulin signaling without recruiting the proximal insulin signaling. Cell signaling suggested that Ad36 increases AT and SM glucose uptake and reduces hepatic glucose release. In humans, Ad36 infection predicted better glycemic control and lower hepatic lipid content independently of age, sex, or adiposity. We conclude that Ad36 offers a novel tool to understand the pathways to improve hyperglycemia and hepatic steatosis independently of proximal insulin signaling, and despite a HF diet. This metabolic engineering by Ad36 appears relevant to humans for developing more practical and effective antidiabetic approaches.

A quantitative trait locus on chromosome 18q for physical activity and dietary intake in Hispanic children

OBJECTIVE

Genetic components of energy homeostasis contributing to childhood obesity are poorly understood. Genome scans were performed to identify chromosomal regions contributing to physical activity and dietary intake traits in Hispanic children participating in the VIVA LA FAMILIA Study.

RESEARCH METHODS AND PROCEDURES

We report linkage findings on chromosome 18 for physical activity and dietary intake in 1030 siblings from 319 Hispanic families. Measurements entailed physical activity by accelerometry, dietary intake by two 24-hour recalls, and genetic linkage analyses using SOLAR software.

RESULTS

Significant heritabilities were seen for physical activity and dietary intake, ranging from 0.46 to 0.69, except for vigorous activity (h2 = 0.18). Percentage time in sedentary activity mapped to markers D18S1102-D18S64 on chromosome 18 [logarithm of the odds (LOD) score = 4.07], where melanocortin 4 receptor gene (MC4R) resides. Quantitative trait loci (QTLs) for total activity counts, percentage time in light or in moderate activity, and carbohydrate intake and percentage of energy intake from carbohydrates were detected in the same region (LOD = 2.28, 2.79, 2.2, 1.84, and 1.51, respectively). A novel loss of function mutation in MC4R (G55V) was detected in six obese relatives, but not in the rest of the cohort. Removal of these MC4R-deficient subjects from the analysis reduced the LOD score for sedentary activity to 3.94.

DISCUSSION

Given its role in the regulation of food intake and energy expenditure, MC4R is a strong positional candidate gene for the QTL on chromosome 18 detected for physical activity and dietary intake in Hispanic children.

Fat mass in infants and toddlers: comparability of total body water, total body potassium, total body electrical conductivity, and dual-energy X-ray absorptiometry

BACKGROUND

Accurate assessment of body composition in infants and children is fundamental to understanding normal growth and development. Validation of methods applicable to pediatric populations is needed. In the absence of a gold standard, this study was conducted to compare methods using total body water, total body potassium, total body electrical conductivity, and dual-energy x-ray absorptiometry measurements for the estimation of body fat mass in infants and toddlers.

METHODS

Repeated body composition measurements were performed on 76 healthy term infants at 0.5, 3, 6, 9, 12, 18, and 24 months of age. Total body water was determined by deuterium dilution and converted to fat-free mass. Total body electrical conductivity was used to measure fat mass. Total body potassium was estimated by whole-body counting and converted to fat-free mass. Dual-energy x-ray absorptiometry was used to estimate fat mass at 0.5, 12, and 24 months only. Data were analyzed by repeated measures analysis of variance, followed by Bonferroni multiple comparisons at 5%.

RESULTS

Significant differences among methods were encountered at each age (p = 0.001-0.05). The rank order of the methods and the magnitude of the method differences were a function of age, not of gender or infant feeding mode. Wide limits of agreement imply that the methods are not interchangeable for group or individual measurements.

CONCLUSIONS

Methods using total body water, total body potassium, total body electrical conductivity, and dual-energy x-ray absorptiometry to estimate body fat mass in infants and toddlers are not interchangeable and require further development and validation.

Reliability and concurrent validity of Futrex and bioelectrical impedance

Thirty Caucasian males (aged 19-32yr) participated in this study designed to investigate the reliability of multiple bioelectrical impedance analysis (BIA) and near-infrared spectroscopy (Futrex, FTX) measurements and the validity of BIA and FTX estimations of hydrostatically (UW) determined percent body fat (%BF). Two BIA and two FTX instruments were used to make 6 measurements each of resistance (R) and optical density (OD) respectively over a 30 min period on two consecutive days. Repeated measures ANOVA indicated that FTX and BIA, using manufacturer's equations, significantly (p<0.01) under predicted UW by 2.4 and 3.8%BF respectively. Standard error of estimate (SEE) and total error (TE) terms provided by regression analysis for FTX (4.6 and 5.31%BF respectively) and BIA (5.65 and 6.95%BF, respectively) were high. Dependent t-tests revealed no significant differences in either FTX or BIA predictions of %BF using two machines. Intraclass reliabilities for BIA and FTX estimates of UW %BF across trials, days, and machines all exceeded 0.97. A significant random error term associated with FTX and a significant subject-by-day interaction associated with BIA was revealed using the generalizability model. Although FTX and BIA estimates of UW %BF were reliable, due to the significant underestimation of UW %BF and high SEE and TE, neither FTX nor BIA were considered valid estimates of hydrostatically determined %BF.

Postpartum maternal blood helper T (CD3+CD4+) and cytotoxic T (CD3+CD8+) cells: correlations with iron status, parity, supplement use, and lactation status

Iron deficiency reduces T cell counts; however, iron sufficiency is difficult to maintain during pregnancy and to reestablish in the early postpartum period. This cross-sectional study examined relations among postpartum maternal iron status, parity, lactation, supplement use, and maternal blood T cell populations. Sixty lactating and 41 nonlactating postpartum (NLPP) women at 1-2 wk and 1, 2, 4, or 8 mo postpartum and 13 nulliparous women were studied. Among multiparous women, multiple linear regression showed that relative percentages and absolute numbers of CD3+CD8+ cells were correlated positively with maternal serum transferrin saturation. In a separate multiple linear regression model, multiparous NLPP women who did not use multivitamin and mineral supplements had lower CD3+CD4+ cell percentages in the first month postpartum than did nulliparous control women. Lactating women who used supplements, however, had reduced CD3+CD4+ percentages 4-8 mo postpartum compared with control women. CD3+CD4+ percentages did not differ among control women, NLPP women who used supplements, or lactating women who did not use them. These results suggest that nutritional factors such as maternal iron status and use of dietary supplements play a role in a mother's postpartum immune status.

Early growth faltering of rural Mesoamerindian breast-fed infants

Early growth faltering has been described in breast-fed infants 4-6 months of age from less-developed communities. The timing and magnitude of growth faltering, however, depends on the appropriateness or comparability of the reference used to evaluate growth performance. In this paper we compared the growth performance of a group of rural Mesoamerindian breast-fed infants from birth through 6 months of age to that of a reference group of breast-fed infants reared under favourable nutritional and environment conditions in the United States. The validity of this assessment is based upon the comparability of infant feeding mode. Mean weights and lengths and corresponding weight-for-age and length-for-age percentiles and z-scores were significantly lower among the Mesoamerindian (Otomi Indian) infants (p = 0.001). Mean weight-for-length percentiles and z-scores did not differ between groups. Weight gain (g/day) was significantly lower among the Otomi infants throughout the entire 6 months (p = 0.001). Length velocities of the Otomi infants were lower than reference infants at 3-6 months (p = 0.001). The growth pattern of the Otomi infants differed from that of the reference group: decreases in growth velocities and weight-for-age and length-for-age z-scores were significantly more precipitous for the Otomi infants between 4 and 6 months of age (p = 0.001). We conclude that growth faltering was evident among the Otomi infants between 4 and 6 months of age, relative to a reference growth of breast-fed infants.

Relationship between serum prolactin, lactation and changes in maternal blood B-cell (CD19+) percents during the first 8 months post-partum

Lactation is an immunologically unique state when immune factors are produced by the mother for the protection of the infant rather than the mother. While several studies have focused on the immunological composition of human milk, much less information is available on maternal immune status during lactation. Sixty-four lactating and 43 bottle-feeding women at 1-2 weeks, 1, 2, 4 or 8 months post-partum were studied in a cross-sectional design, with 14 nulliparous women as controls. Flow cytometry analysis of peripheral blood lymphocytes showed dynamic, post-partum changes in the B-cell subpopulation. Among lactating women, the relative percents of CD19+ B-cells were significantly lower (P < 0.05) than control levels at 1-2 weeks and 1 month post-partum, but showed a significant, polynomial-linear rise (P < 0.05) over time, reaching control values by 2-4 months post-partum. Bottle-feeding women had an earlier rise in the percentage of CD19+ cells, with relative percents always significantly higher than their lactating counterparts. The differing patterns may be due to changes in serum prolactin concentrations because, among the post-partum women, relative percents of CD19+ cells were negatively correlated with baseline serum prolactin concentrations. These results have implications for maternal immunization programs designed to enhance maternal and/or infant well-being as well as other maternal health effects related to breastfeeding.

A view of the medical and nutritional consequences of the earthquake in Guatemala

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