Roberta Cohen

University of California, Davis | UCD · Program in International and Community Nutrition

The objectives were to describe weight loss in a multiethnic population of first-born, predominantly breastfed, term infants and to identify potentially modifiable risk factors for excess weight loss (EWL). Data on prenatal breastfeeding intentions, demographic characteristics, labor and delivery interventions and outcomes, breastfeeding behaviors,...

Delayed onset of lactogenesis (OL) is most common in primiparas and increases the risk of excess neonatal weight loss, formula supplementation, and early weaning. We examined variables associated with delayed OL among first-time mothers who delivered at term and initiated breastfeeding (n = 431). We conducted in-person interviews during pregnancy a...

Research tools that are comparable across ethnic groups are needed in order to understand sociodemographic disparities in breastfeeding rates. The Infant Feeding Intentions (IFI) scale provides a quantitative measure of maternal breastfeeding intentions. IFI score ranges from 0 (no intention to breastfeed) to 16 (very strong intentions to fully bre...

We evaluated the validity of two potential ‘screening’ questions asked of primiparous mothers about a breastfeeding episode on days 0 and 3 post‐partum (pp) in Peru (n=154) and the US (n=248). A dichotomous measure (suboptimal vs. optimal infant breastfeeding behavior) based on Infant Breastfeeding Assessment Tool scores recorded by trained observe...

We evaluated early lactation success in two cohorts of primiparas who initiated breastfeeding: 448 in Sacramento, CA and 171 in Lima, Peru. Key outcomes were sub‐optimal infant breastfeeding behavior (SIBB), onset of stage II lactogenesis >72 h postpartum (delayed OL) and excess neonatal weight loss (≥ 10% of birth weight by 70–98 h). All adverse o...

Perinatal depressive symptoms (DS) are associated with shorter breastfeeding duration, but the causal direction is not clear. Among 415 Californian primiparae who initiated breastfeeding, we examined if 1) prenatal DS are associated with greater risk for breastfeeding difficulties, and 2) breastfeeding difficulties are associated with worsening DS...

Little is known regarding modifiable factors that may explain sociodemographic disparities in breastfeeding rates among women in the United States. Using a mediation model approach, we examined the relative contributions of breastfeeding and formula feeding psychosocial factors in explaining disparities in breastfeeding intentions. We interviewed 5...

We evaluated early lactation success in a multi‐ethnic cohort of 448 primiparas in Sacramento, CA. Key outcomes were sub‐optimal infant breastfeeding behavior (SIBB), onset of stage II lactogenesis >72 h postpartum (delayed OL) and excess neonatal weight loss ( > 10% of birth weight by 70‐98 h). Prevalence of SIBB was 69% at 2‐46 h, 34% at 3‐4 d, a...

Our objective was to determine factors associated with delayed onset of lactogenesis (delayed OL)‐defined as onset of stage II lactogenesis after 72 h postpartum (pp)‐among a multi‐ethnic sample of primiparae who initiated breastfeeding (N=415). Prevalence of delayed OL was 42%. Variables associated with delayed OL (P < .10, unadjusted) were greate...

Iron deficiency (ID) can occur among exclusively breastfed infants before 6 mo of age. The objective was to determine which subgroups of fully breastfed infants are at highest risk of ID. We assessed the prevalence of ID (ferritin < 12 mug/L) and iron deficiency anemia (IDA; ferritin < 12 mug/L and hemoglobin < 105 g/L) and risk factors associated...

Formula-fed infants gain weight faster than breastfed infants. This study evaluated whether encouraging formula-feeding caregivers to be sensitive to infant satiety cues would alter feeding practices and reduce infant formula intake and weight gain. Double-blind, randomized educational intervention, with intake and growth measured before (at 1 to 2...

Efforts to develop global programs for the control of iron deficiency require simple, low-cost, and accurate indicators of iron status. We aimed to compare estimates of body iron (BI) stores, as calculated from either plasma ferritin concentration alone (BI-ferritin) or the ratio of plasma transferrin receptor (TfR) to ferritin (BI-TfR/ferritin). D...

Using data from 242 exclusively breastfeeding mother-infant pairs, newborn elimination patterns were analyzed. Sensitivity (Se) and Specificity (Sp) of day 4 (72-96 hours) wet and soiled output, in addition to the timing of onset of lactation, in identifying cases of breastfeeding inadequacy (defined as neonatal weight loss >or= 10% of birth weight...

This review addresses the question of whether a short birth interval is associated with adverse nutritional outcomes for the mother or the child. Indices of anthropometric status (maternal weight or body mass index; child growth) and micronutrient status (e.g. iron or vitamin A) were included as outcomes. A computerized search of all relevant paper...

Aim: To describe the WHO Multicentre Growth Reference Study (MGRS) sample with regard to screening, recruitment, compliance, sample retention and baseline characteristics. Methods: A multi-country community-based study combining a longitudinal follow-up from birth to 24 mo with a cross-sectional survey of children aged 18 to 71 mo. Study subpopulat...

Focus groups were used to examine relationships among maternal beliefs, feeding intentions, and infant-feeding behaviors among 65 Women, Infants and Children-eligible (28 English-speaking and 37 Spanish-speaking) mothers. Participants shared common beliefs that breast-feeding was beneficial; nevertheless, many believed that early introduction of fo...

To investigate whether iron supplements compromise copper status in infants. 214 healthy, term, breastfed Swedish and Honduran infants were randomized to (1) iron supplements (1 mg/kg/d) from 4-9 mo of age, (2) iron supplements from 6-9 mo, or (3) placebo. Blood samples were obtained at 4, 6, and 9 mo and analyzed for plasma copper (p-Cu) and, at 9...

Several studies have documented that length gain often lags behind weight gain during infancy and early childhood, suggesting that linear growth is partly regulated by initial body mass or fatness. To investigate this hypothesis, we analysed data from four longitudinal studies on growth of infants in the first 12 months: (1) U.S. breast-fed and for...

The age range from 6 to 24 months is a critical period when malnutrition and infection are particularly common in developing countries. For breastfed children a set of recommendations in the form of 10 Guiding Principles was recently issued regarding complementary feeding within this age range. Many of these Guiding Principles can also be applied t...

There is little information on the risk of micronutrient deficiencies during the period of exclusive breast-feeding. We evaluated this among term, low-birthweight (LBW; 1500-2500 g) infants in Honduras. Mother-infant pairs were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo. At 4 mo, infants were randomly...

The World Health Organization (WHO) Multicentre Growth Reference Study (MRGS) North American site was Davis, California. For the longitudinal cohort (0-24 months), 208 infants were enrolled between January and December 1999 from five area hospitals at which nearly all Davis women give birth. The target sample size was lower in the United States tha...

The World Health Assembly recommends exclusive breastfeeding of infants until 6 months of age and continued breastfeeding with appropriate complementary feeding until 2 years of age (WHA 2001). Iron deficiency as well as zinc deficiency are public health concerns during infancy, especially in developing countries (Domellöf & Hernell 2002). Copper d...

Little is known about the regulation of iron, zinc, and copper in breast milk and the transport of these minerals across the mammary gland epithelium. The objective was to study associations between breast-milk concentrations of iron, zinc, and copper and maternal mineral status. Milk samples from 191 Swedish and Honduran mothers were collected at...

The World Health Organization (WHO) Multicentre Growth Reference Study (MRGS) North American site was Davis, California. For the longitudinal cohort (0–24 months), 208 infants were enrolled between January and December 1999 from five area hospitals at which nearly all Davis women give birth. The target sample size was lower in the United States tha...

Some mothers have difficulty initiating lactation even when highly motivated to breastfeed. The purpose of this study was to determine the incidence of and risk factors for suboptimal infant breastfeeding behavior (SIBB), delayed onset of lactation, and excess neonatal weight loss among mother-infant pairs in a population with high educational leve...

Diagnostic criteria for iron deficiency (ID) and iron deficiency anemia (IDA) in infants are poorly defined. Our aim was to establish appropriate cut-off values for hemoglobin (Hb), plasma ferritin, erythrocyte mean cell volume (MCV), zinc protoporphyrin (ZPP) and soluble transferrin receptors (TfR) in infancy. Exclusively breast-fed infants (n = 2...

Iron supplements are often prescribed during infancy but their benefits and risks have not been well documented. We examined whether iron supplements affect growth or morbidity of breast-fed infants. Full-term infants in Sweden (n = 101) and Honduras (n = 131) were randomly assigned to three groups at 4 mo of age: 1) placebo from 4 to 9 mo; 2) plac...

It is commonly assumed that there is no difference in iron status between male and female infants, despite a lack of studies addressing this question. To study sex differences in different measures of iron status in infants. At 4 months of age, 263 term, breastfed infants (121 Swedish and 142 Honduran) were randomized to receive iron supplements or...

Breastfeeding success depends greatly on what occurs during the first week or two postpartum. This is the time when lactogenesis stage II takes place and both the mother and the infant are learning how to breastfeed. It is also the peak period for breastfeeding problems. Early supplementation with non breast milk fluids during this time often leads...

The objective was to study the effects of iron supplementation on hemoglobin and iron status in 2 different populations. Study design: In a randomized, placebo-controlled, masked clinical trial, we assigned term Swedish (n = 101) and Honduran (n = 131) infants to 3 groups at 4 months of age: (1) iron supplements, 1 mg/kg/d, from 4 to 9 months, (2)...

To examine whether the duration of exclusive breastfeeding affects maternal nutrition or infant motor development, we examined data from two studies in Honduras: the first with 141 infants of low-income primiparous women and the second with 119 term, low birth weight infants. In both studies, infants were exclusively breastfed for 4 mo and then ran...

Unlabelled: Breast milk intake, urine volume and urine-specific gravity (USG) of exclusively breastfed, low birthweight (LBW) term male infants in Honduras were measured during 8-h periods at 2 (n = 59) and 8 (n = 68) wk of age. Ambient temperature was 22-36 degrees C and relative humidity was 37-86%. Maximum USG ranged from 1.001 to 1.012, all wi...

Previous research has suggested that there may be significant within-subject variability, both site-to-site and over time, in hemoglobin concentrations in capillary blood. This study examined the reliability of the portable hemoglobinometer (PHM) system with use of capillary blood and the implications of errors of the magnitude found for the classi...

Prospective and retrospective data on maternal attitudes and obstacles to exclusive breastfeeding (EBF) were collected from Honduran mothers of low birthweight (1500-2500 g), term infants who were enrolled in an intervention study to compare infant outcomes in those who were randomly assigned to breastfeed exclusively for either 4 or 6 months. Perc...

The optimal age at which to introduce complementary foods is a topic of considerable debate. This study was designed to evaluate this issue in a nutritionally vulnerable population in Honduras. Mothers of low-birth-weight (1500-2500 g) term (ie, small-for-gestational-age) infants were recruited in the hospital and assisted with exclusive breast-fee...

To evaluate the effect of introducing complementary foods before 6 mo of age, we randomly assigned 164 infants who had been exclusively breast-fed for 4 mo to continue being exclusively breast-fed until 6 mo (EBF group) or to receive iron-fortified foods in addition to breast milk from 4 to 6 mo (BF+SF group). At 6 mo, the BF+SF group had higher me...

To evaluate the optimal timing of introducing complementary foods to full-term, low birthweight (1500-2500 g) infants, 119 infants exclusively breastfed for 4 mo were randomly assigned to continue exclusive breastfeeding until 6 mo (EBF) or receive iron-fortified foods (rice cereal, chicken, fruits & vegetables, in jars) in addition to breast milk...

Lactational amenorrhea (LA) is associated with postpartum infertility and is known to be related to breast-feeding frequency and duration, but the exact role of complementary feeding of the infant has not been clearly defined. Data on LA were collected during and after a 2-mo intervention trial in which low-income Honduran women who had breast-fed...

It has been argued that the growth rate of exclusively breast-fed infants may be limited by their protein intake. This issue was examined using data from an intervention study in Honduras in which infants were randomly assigned to be exclusively breast-fed for the first 6 mo (EBF; n = 50), or to receive preprepared solid foods (including egg yolk)...

Low income, primiparous mothers who had exclusively breast-fed for 4 mo were randomly assigned to one of three groups: 1) continued exclusive breast-feeding to 6 mo (EBF), 2) introduction of complementary foods at 4 mo, with ad libitum nursing 4-6 mo (SF), and 3) introduction of complementary foods at 4 mo, with maintenance of base-line nursing fre...

To evaluate the impact of introducing complementary foods to exclusively breast-fed infants at 4 vs 6 months on growth from 6 to 12 months, and to compare growth patterns of Honduran infants with those of breast-fed infants in the United States. Randomized intervention trial from 4 to 6 months and longitudinal study of infants from birth to 12 mont...

Although exclusive breastfeeding for 6 months is likely to be beneficial for infant health, mothers often cite time pressures as a reason to introduce other foods. Using 12-hr in-home observations at 19 and 24 wk postpartum, we compared maternal activity budgets and time spent breastfeeding among low-income, urban mothers not employed outside the h...

As part of a study on the optimal timing of complementary feeding in Honduras, we assessed breast milk volume and composition at 4, 5, and 6 mo in 141 low-income women who were randomly assigned to exclusively breast-feed for the first 6 mo or to complement breast milk with prepared solid foods beginning at 4 mo. Milk volume averaged 797 +/- 139 g/...

In developing countries, the age at which breastfed infants are first given complementary foods is of public health importance because of the risk of diarrhoeal disease from contaminated weaning foods, and the potential risk of growth faltering if foods are inappropriately delayed. To evaluate whether there are any advantage of complementary feedin...