Methods for the year 6 follow-up study of children in the Infant Feeding Practices Study II.

OBJECTIVE: We describe methods used in the Year 6 Follow-Up (Y6FU) of children who participated in the Infant Feeding Practices Study II (IFPSII). This study consists of a questionnaire administered 6 years after the IFPSII to characterize the health, development, and diet quality of the children. METHODS: The Y6FU sample was a subset of those who participated in IFPSII. The IFPSII participants were drawn from a national consumer opinion panel; neither the IFPSII nor the Y6FU sample is nationally representative. The Y6FU sampling frame included all qualified participants who answered at least the first postnatal questionnaire. One questionnaire was administered by mail in 2012, and nonrespondents were contacted for a telephone interview. Survey topics included measures of health, development, diet, physical activity, screen time, and family medical history. We attempted to contact 2958 mothers and obtained completed questionnaires from 1542, a response rate of 52.1%. We conducted 2 sample evaluations, 1 comparing respondents and nonrespondents on data from IFPSII and the other comparing Y6FU respondents with 6-year-old participants in the National Survey of Children's Health. RESULTS: Y6FU mothers are more likely to be white, married, older, and of higher education and income than both nonresponders and nationally representative mothers. Comparisons also revealed health-related differences and similarities. CONCLUSIONS: Although not nationally representative, the Y6FU provides a valuable database because of its wide coverage of diet and health issues and its unique ability to link early feeding patterns with outcomes at age 6 years.

Influence of bedsharing activity on breastfeeding duration among US mothers.

IMPORTANCE: Some professional associations advocate bedsharing to facilitate breastfeeding, while others recommend against it to reduce the risk of sudden infant death syndrome and suffocation deaths. A better understanding of the quantitative influence of bedsharing on breastfeeding duration is needed to guide policy. OBJECTIVE: To quantify the influence of bedsharing on breastfeeding duration. DESIGN, SETTING, AND PARTICIPANTS: Longitudinal data were from the Infant Feeding Practices Study II, which enrolled mothers while pregnant and followed them through the first year of infant life. Questionnaires were sent at infant ages 1 to 7, 9, 10, and 12 months, and 1846 mothers answered at least 1 question regarding bedsharing and were breastfeeding at infant age 2 weeks. EXPOSURES: Bedsharing, defined as the mother lying down and sleeping with her infant on the same bed or other sleeping surfaces for nighttime sleep or during the major sleep period. MAIN OUTCOMES AND MEASURES: Survival analysis to investigate the effect of bedsharing on duration of any and exclusive breastfeeding. RESULTS: Longer duration of bedsharing, indicated by a larger cumulative bedsharing score, was associated with a longer duration of any breastfeeding but not exclusive breastfeeding, after adjusting for covariates. Breastfeeding duration was longer among women who were better educated, were white, had previously breastfed, had planned to breastfeed, and had not returned to work in the first year postpartum. CONCLUSIONS AND RELEVANCE: Multiple factors were associated with breastfeeding, including bedsharing. Given the risk of sudden infant death syndrome related to bedsharing, multipronged strategies to promote breastfeeding should be developed and tested.

The association of prenatal media marketing exposure recall with breastfeeding intentions, initiation, and duration.

BACKGROUND: Infant formula marketing, either directly to consumers or through health care providers, may influence women's breastfeeding intentions, initiation, and duration. However, little is known about the impact of different types of media marketing on infant feeding intentions and behavior. OBJECTIVE: This study investigated whether different types of recalled prenatal media marketing exposure to formula and breastfeeding information are related to breastfeeding intentions and behavior. METHODS: Data were from the Infant Feeding Practices Study II, a longitudinal study from pregnancy through the infants' first year. Sample sizes ranged from 1384 to 2530. Negative binomial, logistic regression, and survival models were used to examine associations between recalled prenatal exposure to formula or breastfeeding information and breastfeeding intentions and behavior. RESULTS: Exposure to infant formula information from print media was associated with shorter intended duration of exclusive breastfeeding, and formula information from websites was related to lower odds of both intended and actual initiation. Exposure to breastfeeding information from websites was related to higher odds of both intended and actual initiation and longer intended duration of any breastfeeding. Breastfeeding information from print media was associated with longer duration of any breastfeeding, but information from broadcast media was associated with shorter duration of any breastfeeding. CONCLUSION: Mothers who recall exposure to formula information from print or websites are more likely to intend to use formula or to intend to use formula earlier and are less likely to initiate breastfeeding than mothers who do not recall seeing such information.

How US mothers store and handle their expressed breast milk.

BACKGROUND: Many mothers express and store their milk to later feed to their infant. Health organizations provide recommendations on expressed milk storage and handling because these practices can affect milk quality and safety. However, little information exists on US mothers' practices. OBJECTIVE: To describe how US mothers of healthy infants store and handle their expressed milk and to compare their practices with recommendations. METHODS: Mothers participating in the Infant Feeding Practices Study II from 2005-2006 who were expressing milk formed the cohort for this analysis (n = 436-1060, depending on infant age). Participants in this longitudinal mail survey were drawn from a consumer opinion panel and answered questions about milk expression around 2, 5, and 7 months postpartum. Data were analyzed cross sectionally using frequency procedures, and the analysis compared mothers who fed expressed milk with and without also feeding formula. RESULTS: Few mothers stored their milk longer than recommended. Among mothers of the youngest infants in this analysis, 12% heated their milk in a microwave and 17% rinsed bottle nipples with only water before reuse; percentages were similar as infants aged. These practices may pose risks to infant health. Compared with those who fed no formula, mothers who fed both expressed milk and formula were more likely to heat milk in a microwave and, among those with the youngest infants, to rinse bottle nipples with only water between uses. CONCLUSION: Consumer education should emphasize safe warming and cleaning practices for feeding expressed milk.

Association of health profession and direct-to-consumer marketing with infant formula choice and switching.

BACKGROUND: Infant formula is marketed by health professionals and directly to consumers. Formula marketing has been shown to reduce breastfeeding, but the relation with switching formulas has not been studied. Willingness to switch formula can enable families to spend less on formula. METHODS: Data are from the Infant Feeding Practices Study II, a United States national longitudinal study. Mothers were asked about media exposure to formula information during pregnancy, receiving formula samples or coupons at hospital discharge, reasons for their formula choice at infant age 1 month, and formula switching at infant ages 2, 5, 7, and 9 months. Analysis included 1,700 mothers who fed formula at infant age 1 month; it used logistic regression and longitudinal data analysis methods to evaluate the association between marketing and formula choice and switching. RESULTS: Most mothers were exposed to both types of formula marketing. Mothers who received a sample of formula from the hospital at birth were more likely to use the hospital formula 1 month later. Mothers who chose formula at 1 month because their doctor recommended it were less likely to switch formula than those who chose in response to direct-to-consumer marketing. Mothers who chose a formula because it was used in the hospital were less likely to switch if they had not been exposed to Internet web-based formula information when pregnant or if they received a formula sample in the mail. CONCLUSIONS: Marketing formula through health professionals may decrease mothers' willingness to switch formula.

Risk of bottle-feeding for rapid weight gain during the first year of life.

OBJECTIVE: To better understand the mechanisms behind breastfeeding and childhood obesity, we assessed the association of weight gain with the mode of milk delivery aside from the type of milk given to infants. DESIGN: A longitudinal study of infants followed up from birth to age 1 year. Multilevel analyses were conducted to estimate infant weight gain by type of milk and feeding mode. SETTING: Pregnant women were recruited from a consumer mail panel throughout the United States between May 2005 and June 2007. PARTICIPANTS: One thousand eight hundred ninety nine infants with at least 3 weight measurements reported during the first year. MAIN EXPOSURES: Six mutually exclusive feeding categories and proportions of milk feedings given as breastmilk or by bottle. MAIN OUTCOME MEASURES: Weight measurements reported on 3-, 5-, 7-, and 12-month surveys. RESULTS: Compared with infants fed at the breast, infants fed only by bottle gained 71 or 89 g more per month when fed nonhuman milk only (P < .001) or human milk only (P = .02), respectively. Weight gain was negatively associated with proportion of breastmilk feedings, but it was positively associated with proportion of bottle-feedings among those who received mostly breastmilk. Among infants fed only breastmilk, monthly weight gain increased from 729 g when few feedings were by bottle to 780 g when most feedings were by bottle. CONCLUSIONS: Infant weight gain might be associated not only with type of milk consumed but also with mode of milk delivery. Regardless of milk type in the bottle, bottle-feeding might be distinct from feeding at the breast in its effect on infants' weight gain.

Awareness of methylmercury in fish and fish consumption among pregnant and postpartum women and women of childbearing age in the United States.

In 2004, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) reissued joint advice recommending that pregnant women, nursing mothers, young children, and women who may become pregnant not consume fish high in mercury such as shark, swordfish, king mackerel, and tilefish, and not consume more than 12 ounces (340.2g) of other lower mercury fish per week. These groups were encouraged to eat up to 12 ounces (340.2g) of low mercury fish per week to get the health benefits of fish. Using a survey of 1286 pregnant women, 522 postpartum women, and a control group of 1349 non-pregnant/non-postpartum women of childbearing age, this study evaluated awareness of mercury as a problem in food and examined fish consumption levels across groups using regression analysis. We also compared awareness of mercury as a problem in food to awareness of Listeria, dioxins and PCBs. We found that the majority of all 3 groups of women were aware of mercury and that nearly all women in all 3 groups limited consumption consistent with the advice; they ate less than 340.2g (12 oz) of fish per week and no high mercury fish. Compared with the control group, pregnant and postpartum women were more likely to be aware of mercury as a problem in food, and pregnant women ate less total fish and were less likely to eat fish, to eat more than 340.2g (12 oz) of fish, and to eat high mercury fish. However, all groups ate much less than the recommended 340.2g (12 oz) of low mercury fish per week for optimum health benefits. Among women who ate fish, the median intake of total fish was 51.6 g/wk (1.8 oz/wk), 71.4 g/wk (2.5 oz/wk), and 85.3 g/wk (3.0 oz/wk) for the pregnant, postpartum, and control groups, respectively. Thus, it appears that the targeted groups of women were more aware of mercury and were eating fish within the FDA/EPA guidelines, but these women may be missing the health benefits to themselves and their children of eating a sufficient amount of fish.

Trends in U.S. consumers' safe handling and consumption of food and their risk perceptions, 1988 through 2010.

Although survey results measuring the safety of consumers' food handling and risky food consumption practices have been published for over 20 years, evaluation of trends is impossible because the designs of published studies are not comparable. The Food Safety Surveys used comparable methods to interview U.S. adults by telephone in 1988, 1993, 2001, 2006, and 2010 about food handling (i.e., cross-contamination prevention) and risky consumption practices (eating raw or undercooked foods from animals) and perceived risk from foodborne illness. Sample sizes ranged from 1,620 to 4,547. Responses were analyzed descriptively, and four indices measuring meat, chicken, and egg cross-contamination, fish cross-contamination, risky consumption, and risk perceptions were analyzed using generalized linear models. The extent of media coverage of food safety issues was also examined. We found a substantial improvement in food handling and consumption practices and an increase in perceived risk from foodborne illness between 1993 and 1998. All indices were stable or declined between 1998 and 2006. Between 2006 and 2010, the two safe food handling practice indices increased significantly, but risk perceptions did not change, and safe consumption declined. Women had safer food handling and consumption practices than men. The oldest and youngest respondents and those with the highest education had the least safe food handling behaviors. Changes in safety of practices over the survey years are consistent with the change in the number of media stories about food safety in the periods between surveys. This finding suggests that increased media attention to food safety issues may raise awareness of food safety hazards and increase vigilance in food handling by consumers.

Feeding of dietary botanical supplements and teas to infants in the United States.

OBJECTIVES: To describe the use of dietary botanical supplements and teas among infants, the characteristics of mothers who give them the specific botanical supplements and teas used, reasons for use, and sources of information. METHODS: We used data from the Infant Feeding Practices Study II, a longitudinal survey of women studied from late pregnancy through their infant's first year of life conducted by the US Food and Drug Administration and the Centers for Disease Control and Prevention between 2005 and 2007. The sample was drawn from a nationally distributed consumer opinion panel and was limited to healthy mothers with healthy term or near-term singleton infants. The final analytical sample included 2653 mothers. Statistical techniques include frequencies, χ² tests, and ordered logit models. RESULTS: Nine percent of infants were given dietary botanical supplements or teas in their first year of life, including infants as young as 1 month. Maternal herbal use (P < .0001), longer breastfeeding (P < .0001), and being Hispanic (P = .016) were significantly associated with giving infants dietary botanical supplements or teas in the multivariate model. Many supplements and teas used were marketed and sold specifically for infants. Commonly mentioned information sources included friends or family, health professionals, and the media. CONCLUSIONS: A substantial proportion of infants in this sample was given a wide variety of supplements and teas. Because some supplements given to infants may pose health risks, health care providers need to recognize that infants under their care may be receiving supplements or teas.

Effect of components of a workplace lactation program on breastfeeding duration among employees of a public-sector employer.

The purpose of this study was to evaluate the impact of the individual services offered via a workplace lactation program of one large public-sector employer on the duration of any breastfeeding and exclusive breastfeeding. Exclusive breastfeeding was defined as exclusive feeding of human milk for the milk feeding. A cross-sectional mailed survey approach was used. The sample (n = 128) consisted of women who had used at least one component of the lactation program in the past 3 years and who were still employed at the same organization when data were collected. Descriptive statistics included frequency distributions and contingency table analysis. Chi-square analysis was used for comparison of groups, and both analysis of variance (ANOVA) and univariate analysis of variance from a general linear model were used for comparison of means. The survey respondents were primarily older, white, married, well-educated, high-income women. More of the women who received each lactation program service were exclusively breastfeeding at 6 months of infant age in all categories of services, with significant differences in the categories of telephone support and return to work consultation. After adjusting for race and work status, logistic regression analysis showed the number of services received was positively related to exclusive breastfeeding at 6 months and participation in a return to work consultation was positively related to any breastfeeding at 6 months. The study demonstrated that the workplace lactation program had a positive impact on duration of breastfeeding for the women who participated. Participation in the telephone support and return to work consultation services, and the total number of services used were related to longer duration of exclusive and/or any breastfeeding.

Do infants fed from bottles lack self-regulation of milk intake compared with directly breastfed infants?

OBJECTIVE: How breastfeeding reduces the risk of childhood obesity is unclear, and 1 hypothesis pertains to the ability of breastfed infants to self-regulate. We studied whether infants' self-regulation of milk intake is affected by feeding mode (bottle versus breast) and the type of milk in the bottle (formula versus expressed breast milk). PATIENTS AND METHODS: Participants in the 2005-2007 Infant Feeding Practices Study II received monthly questionnaires during their infant's first year, and compete data were available for 1250 infants. We tested the impact of feeding mode and type of milk during early infancy on self-regulation during late infancy. RESULTS: Although only 27% of infants fed exclusively at the breast in early infancy emptied the bottle or cup in late infancy, 54% of infants who were fed both at the breast and by bottle did so, and 68% of those who were fed only by bottle did so. Multivariate regression analysis indicated that infants who were bottle-fed more intensively early in life were approximately 71% or 2 times more likely to empty the bottle or cup later in life than those who were bottle-fed less intensively ((1/3)-(2/3) or (2/3) of milk feeds given by bottle versus < (1/3) of milk feeds). When feeding formula and expressed milk were considered separately, similar dose-response relationships were observed. CONCLUSIONS: Infants who are bottle-fed in early infancy are more likely to empty the bottle or cup in late infancy than those who are fed directly at the breast. Bottle-feeding, regardless of the type of milk, is distinct from feeding at the breast in its effect on infants' self-regulation of milk intake.

Maternally reported food allergies and other food-related health problems in infants: characteristics and associated factors.

OBJECTIVE: Our goal was to identify the frequency, demographics, and diagnostic characteristics associated with maternally reported food allergies and other food-related health problems among infants aged < or = 1 year. METHODS: We analyzed data from the 2005-2007 Infant Feeding Practices Study II, a longitudinal survey of 2441 US mothers of healthy singletons from pregnancy through their infant's first year. Doctor diagnosis and symptoms-based criteria were used to identify a probable-food-allergic group from maternal reports of infant health problems with food. RESULTS: More than one fifth of the 2441 mothers reported that their infant had a food-related problem; 6% (n = 143) had a probable food allergy, and 15% (n = 359) had other food-related problems. Forty percent of the infants with a food-related health problem were evaluated by a doctor. Gastrointestinal symptoms were more commonly reported in early infancy compared with skin-related symptoms, which were reported in later infancy, and 27% received medical treatment for the symptoms. Characteristics associated with increased incidence of probable food allergy included family histories of food allergy and type 1 diabetes, gestational diabetes, living in rural or urban areas, being black, and being male. Among all infants with a food-related health problem, the majority experienced their first problem by 6 months of age. Foods recognized to be major allergens were most commonly reported as the source of an allergy. CONCLUSIONS: Food-related problems occurred at a high frequency in the first year of life. A better understanding of the demographics, family history, disease manifestations, and diagnoses may provide insight into public health efforts to minimize or prevent food allergies in infancy and to help differentiate food-allergic problems from nonallergic food problems in this age group.

Infant sleeping arrangements and practices during the first year of life.

OBJECTIVES: Our goal was to examine the sleeping arrangements for infants from birth to 1 year of age and to assess the association between such arrangements and maternal characteristics. METHODS: Responses to the 3-, 6-, 9-, and 12-month questionnaires from the Infant Feeding Practices Study II were analyzed to assess sleep arrangements, including bed sharing, the latter defined as mother ever (in a given time frame) slept with the infant on the same sleeping surface for nighttime sleep. Women were also asked about the reasons for bed sharing or not bed sharing. RESULTS: Approximately 2300 women responded at 3 months, and 1800 at 12 months. At 3 months, 85% of the infants slept in the same room as their mother, and at 12 months that rate was 29%. At 3 months, 26% of the mothers did not use the recommended supine position for their infant's nighttime sleep. The rate of noncompliance increased to 29% by 6 months and 36% by 12 months. The bed-sharing rates were 42% at 2 weeks, 34% at 3 months, and 27% at 12 months. Approximately two thirds of those who bed shared with their infant also shared the bed with their husband or partner, and 5% to 15% shared it with other children. The major reasons for bed sharing were to calm a fussy infant, facilitate breastfeeding, and help the infant and/or mother sleep better. The major reasons for not lying down with the infant were safety concerns. Non-Hispanic black mothers were more likely than non-Hispanic white mothers to use nonsupine infant sleep positions and to bed share. CONCLUSIONS: More than one third of the women in this cohort were noncompliant with safe-sleeping guidelines when their infant was 3 months old. Health care providers need to advise parents of current recommendations and discuss the risks and benefits of their choices for infant sleeping practices.

Infant Feeding Practices Study II: study methods.

OBJECTIVE: Our goal is to describe the methods used in the Infant Feeding Practices Study II (IFPS II), a study of infant feeding and care practices throughout the first year of life. Survey topics included breastfeeding, formula and complementary feeding, infant health, breast-pump use, food allergies, sleeping arrangements, mother's employment, and child care arrangements. In addition, mothers' dietary intake was measured prenatally and postnatally. PARTICIPANTS AND METHODS: The IFPS II sample was drawn from a nationally distributed consumer opinion panel of 500,000 households. All questionnaires were administered by mail, 1 prenatally and 10 postpartum. Qualifying criteria were used to achieve the sample goals of mothers of healthy term and late preterm singleton infants. In addition to the questionnaires about the infants, women were sent a diet-assessment questionnaire prenatally and at approximately 4 months after delivery; this questionnaire was also sent to members of a comparison group who were neither pregnant nor postpartum. RESULTS: A sample of 4902 pregnant women began the study, and approximately 2000 continued through their infant's first year. Response rates ranged from 63% to 87% for the different questionnaires. Compared with adult mothers of singletons from the nationally representative sample of the National Survey of Family Growth, IFPS II participants had a higher mean education level; were older; were more likely to be middle income, white, and employed; were less likely to smoke; and had fewer other children. Compared with women who participated in the National Immunization Survey who gave birth in 2004, IFPS II mothers were more likely to breastfeed and to breastfeed longer. CONCLUSIONS: The IFPS II provides a valuable database because of its large sample size, the frequency of its questionnaires, and its wide coverage of issues salient to infant feeding.

Infant feeding and feeding transitions during the first year of life.

OBJECTIVE: Infancy is a time of rapid transition from a diet of virtually nothing but milk (either breast milk or infant formula) to a varied diet from nearly all food groups being consumed on a daily basis by most infants. Despite various recommendations about infant feeding, little is known about actual patterns of feeding among US infants. This article documents transitions in infant feeding patterns across the first year of life and determinants of key aspects of infant feeding. METHODS: Using data from the Infant Feeding Practices Study II, we analyzed responses to a 7-day food-recall chart that was administered every month. The sample size declined from 2907 at birth to 1782 at 12 months of age. RESULTS: Although 83% of survey respondents initiated breastfeeding, the percentage who breastfed declined rapidly to 50% at 6 months and to 24% at 12 months. Many of the women who breastfed also fed their infants formula; 52% reported that their infants received formula while in the hospital. At 4 months, 40% of the infants had consumed infant cereal, 17% had consumed fruit or vegetable products, and <1% had consumed meat. Compared with infants who were not fed solid foods at 4 months, those who were fed solid foods were more likely to have discontinued breastfeeding at 6 months (70% vs 34%) and to have been fed fatty or sugary foods at 12 months (75% vs 62%). CONCLUSIONS: Supplementing breast milk with infant formula while infants were still in the hospital was very common. Despite recommendations that complementary foods not be introduced to infants aged 4 months or younger, almost half of the infants in this study had consumed solid foods by the age of 4 months. This early introduction of complementary foods was associated with unhealthful subsequent feeding behaviors.

Effect of maternity-care practices on breastfeeding.

OBJECTIVE: Our goal was to assess the impact of "Baby-Friendly" hospital practices and other maternity-care practices experienced by mothers on breastfeeding duration. METHODS: This analysis of the Infant Feeding Practices Study II focused on mothers who initiated breastfeeding and intended prenatally to breastfeed for >2 months, with complete data on all variables (n = 1907). Predictor variables included indicators of 6 "Baby-Friendly" practices (breastfeeding initiation within 1 hour of birth, giving only breast milk, rooming in, breastfeeding on demand, no pacifiers, fostering breastfeeding support groups) along with several other maternity-care practices. The main outcome measure was breastfeeding termination before 6 weeks. RESULTS: Only 8.1% of the mothers experienced all 6 "Baby-Friendly" practices. The practices most consistently associated with breastfeeding beyond 6 weeks were initiation within 1 hour of birth, giving only breast milk, and not using pacifiers. Bringing the infant to the room for feeding at night if not rooming in and not giving pain medications to the mother during delivery were also protective against early breastfeeding termination. Compared with the mothers who experienced all 6 "Baby-Friendly" practices, mothers who experienced none were approximately 13 times more likely to stop breastfeeding early. Additional practices decreased the risk for early termination. CONCLUSIONS: Increased "Baby-Friendly" hospital practices, along with several other maternity-care practices, improve the chances of breastfeeding beyond 6 weeks. The need to work with hospitals to implement these practices continues to exist, as illustrated by the small proportion of mothers who reported experiencing all 6 of the "Baby-Friendly" hospital practices measured in this study.