Association of Socioeconomic Factors and Infant Nutrition Decisions: Breastfeeding and Type of Formula

Abstract

Objective:

Breastfeeding is considered the gold standard of infant feeding during the first year of life. However, many women experience difficulty breastfeeding and do not breastfeed to the extent that they initially planned. Our aims were to present factors influencing parents' choices of infant nutrition and to examine whether these choices are influenced by socioeconomic status (SES).

Materials and Methods:

We conducted a cross-sectional survey by interviewing mothers attending family health centers in various areas of Tel Aviv, Israel.

Results:

A total of 239 mothers participated in the survey. The choice of source of their infants' nutrition up to the age of 6 months was divided between exclusive breastfeeding, a combination of infant formula (IF) and breastfeeding, and exclusive IF (36%, 34%, and 30%, respectively). Exclusive breastfeeding was related to a higher SES (p = 0.02). The leading cause for combining IF in the infant's diet was maternal difficulty in breastfeeding (60%). The leading factors that influenced the choice of a specific IF product were continuation from the IF given in the hospital nursery (20%), advice from friends or family (20%) and cost (10%). There was a significant difference based on SES. A greater proportion of responders in a higher SES continued the IF that was supplied in the hospital, whereas lower SES parents tended to choose a formula according to its price (p < 0.05 for both).

Conclusion:

There is an overall lower prevalence of exclusive breastfeeding among low-income families. The maternal choice of the type of IF is associated with parental SES, with the choice of high SES mothers what was fed in the hospital and the choice of low SES related to price.

Introduction

Breastfeeding is considered the gold standard of infant feeding during the first year of life.^1,2 Many guidelines have been provided by various organizations, with some even recommending the continuation of breastfeeding much beyond the first year of life.^3–5 Unfortunately, in both industrialized and developing world, many women do not breastfeed their infant, and most who breastfeed do so for less than the recommended period of 1 year.^6–9 According to the latest data from the Center for Disease Control and Prevention report on breastfeeding, although most infants born in 2017 were started on breastfeeding (84.1%), only 58.3% of them were still breastfeeding at 6 months. The percentage of breastfed infants supplemented with infant formula (IF) before 2 days of age was 19.2% among infants born in 2017, an increase from 16.9% among infants born in 2016.¹⁰ A previous U.S. survey revealed that approximately one-half of women breastfed as long as they had planned.¹¹ There was a strong correlation between family income and reaching the goals of breastfeeding duration. In addition to the socioeconomic status (SES), many other factors impeded breastfeeding, including babies “having difficulty nursing,” “convenience of formula feeding” and “lack of environmental support”.¹¹ Many women in that survey claimed that they experienced discomfort, infections, or other problems that were important deterring factors in their choices of infant nutrition.

We conducted this study to determine contemporary reasons for changing modes of infant nutrition in the first 6 months of life and to assess the effect of SES on infant breastfeeding patterns in the Tel Aviv area. Our hypothesis was that a low SES would negatively affect desirable breastfeeding patterns.

Materials and Methods

Setting and subjects

The study was conducted in public well-baby clinics of family health centers (FHCs) of six diverse sociodemographic areas of Tel Aviv, Israel. The treatment at the clinic that was standardized and included guidance and weighing by a nurse once a month and a doctor`s evaluation once every 6 months, irrespective of the FHC clinic location or the SES level of the population served. Participants were mothers of healthy infants aged 6 months or less, who were born not earlier than gestation week 36. Excluded from the study were mothers of infants who were born earlier and infants who were diagnosed as having medical condition, that can influence nutritional choice, such as gastroesophageal reflux disease or cow`s milk protein allergy. Data were collected through a questionnaire administered by two interviewers (S.B. and A.F.) during personal interviews.

SES was estimated according to several proxy measurements for each infant. We assumed that the location of the FHCs would be a good proxy marker for the SESs of the mothers who attend them.^12–14 FHCs were chosen for the study according to location and classified into low, intermediate, and high SESs as defined by the municipality social services administration. Additional proxy measurements for SES were the number of years of education of the infant's parents, which is another reportedly good marker for SES,^12,13 as well as the ratio between the number of family members in the household, and the number of rooms in the family residence (residence index).¹⁴ We chose not to relate directly to income as a marker of SES to avoid bias of responses to questions on this subject that has been previously described.¹⁴

Measurements

The questionnaire was divided into three parts: demographic characteristics, clinical parameters on pregnancy and delivery, and an infant nutritional questionnaire. Demographic parameters for all infant–mother dyads included characteristics of the parents (age, marital status, and ethnic origin) and maternal body mass index (BMI) before pregnancy and before labor. Clinical data included medical history of the pregnancy (gravidity, parity, prenatal care, gestational age at delivery, and mode of delivery), and the infant's birth weight. The nutritional questionnaire included items on the type of nutrition of previous children, nutrition of the index child, reason for not exclusively breastfeeding, type and brand of formula that was used, and the reasons for choosing the specific type of formula.

Data analysis

The statistical analysis was performed with SPSS (IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp.). Descriptive statistics were examined for all variables. Continuous variables were expressed as mean ± standard deviation. Categorical variables were presented as number and percentage. Differences in all variables between the three SES groups were examined by one-way analysis of variance (ANOVA) for continuous variables and the chi-square test for categorical variables. A p-value ≤0.05 was considered significant.

Ethical considerations

The study protocol was approved by the institutional review board of the medical center (TLV-0597-12). Signed informed consent was obtained from the parents of all the participants.

Results

Participants

Demographic characteristics of the participants in this study are presented in Table 1. In brief, we recruited 239 mothers with a mean age of 33.2 ± 5.6 years. According to their residential location, 93 (39%) mothers were assigned to a high SES FHC, 85 (35%) to an intermediate SES FHC, and 61 (26%) to a low SES FHC. As expected, both parents had significantly more years of education and a lower residence index in the FHCs that were located in areas of higher SESs (p < 0.001 and p = 0.003, respectively). Women from a higher SES had a significantly lower BMI before pregnancy compared with woman from a lower SES. There was no significant difference in BMI before labor associated with SES. Since the main characteristics of the high and intermediate SES groups were comparable, we merged them and compared the combined two groups with the low SES group.

Table 1.

Maternal and Neonatal Characteristics

Variable	High SES (n = 93)	Intermediate SES (n = 85)	Low SES (n = 61)	p
Maternal age (range)	34.7 ± 4.5 (27–45)	33.7 ± 4.4 (22–44)	30 ± 5.9 (21–46)	<0.001^a
Paternal age (years)	36.9 ± 5.2 (29–57)	35.8 ± 5.2 (24–52)	32.5 ± 5.1 (29–57)	<0.001^a
Maternal years of education	16.6 ± 2.5 (12–26)	15.7 ± 2.4 (12–23)	13.7 ± 2.5 (10–20)	<0.001^b
Paternal years of education	15.9 ± 2.6 (6–22)	15.2 ± 2.7 (10–24)	12.9 ± 1.9 (9–18)	<0.001^b
Marital status, n (%)
Single	15 (16.1)	10 (11.7)	5 (8.2)
Married	78 (83.9)	75 (88.3)	56 (91.8)	NS
Residence index	1.05 ± 0.3 (0.4–3)	1.2 ± 0.4 (0.6–3)	1.3 ± 0.5 (0.5–3.3)	<0.001^b
Maternal dietary habits
Omnivorous	83 (89.4)	76 (89.5)	60 (98.4)	0.05^a
Vegetarian	9 (9.6)	7 (8.2)	0 (0)
Vegan	1 (1)	2 (2.3)	1 (1.6)
Maternal BMI prepregnancy	22.07 ± 3.8 (16–37)	22.3 ± 4.2 (15–39)	23.5 ± 3.9 (16–36.7)	0.01^a
Maternal BMI before labor	27 ± 4 (20–37.6)	27.3 ± 4.03 (20.9–40.6)	27.9 ± 4 (19.5–39.3)	NS
Pregnancy monitoring, yes/no, n (%)	93 (100)	85 (100)	60 (98.4)	NS
Number of ultrasound scans				<0.001^b
0	0	1	2
1	1	0	8
2	66	72	51
3	17	3	0
4	9	3	0
Mode of delivery
Vaginal	80 (86)	69 (81.2)	51 (83.6)	NS
Cesarean section	13 (14)	16 (18.8)	10 (16.4)
Birth weight, g	3,267.8 ± 531.8 (1,426–4,190)	3,093.1 ± 489 (2,100–4,200)	3,183.5 ± 465.5 (1,800–4,415)	NS
Gestational age at birth, weeks	39.3 ± 1.5 (35–42.2)	38.9 ± 1.4 (35–42)	39 ± 1.9 (35–41.4)	NS

Difference between high/intermediate and low SES.

Difference between three groups.

BMI, body mass index; NS, no significant; SES, socioeconomic status.

Source of infant nutrition

The choices of the infant's sources of nutrition were exclusive breastfeeding, a combination of IF and breastfeeding, and exclusive IF [n = 86, (36%), n = 81 (34%), and n = 72, (30%), respectively]. Exclusive breastfeeding was related to a higher SES (43% versus 22% for a lower SES, p = 0.01). Thirty-two percent of parents combined breastfeeding with IF. IF was added to infant nutrition due to maternal factors in the majority of cases: specifically, maternal discomfort (49.3%), impression of insufficient milk (8.2%), wish to share milk with other feeding caregivers (2.7%), and return to work or school (6.8%), with no significant differences between the SES groups (Fig. 1).

FIG. 1.

Reasons for adding formula to infant nutrition.

The leading factors influencing the choice of a certain IF product were continuation of the same IF that had been given in the hospital nursery (n = 30, 20%), advice from friends or family members (n = 30, 20%), infant compliance (n = 24, 16%), and financial considerations (n = 16, 10%). Only 17 mothers (11%) used a formula according to the advice of a health care professional. Higher SES parents tended to continue nutrition with the IF that was supplied in the hospital nursery, whereas lower SES parents tended to choose a formula according to its price (p = 0.02 and p = 0.01, respectively, Table 2).

Table 2.

Reasons for Choice of Infant Formula in All Participants and Difference Between High and Low Socioeconomic Status

Reasons N (%)	All participants who combine IF in infant nutrition N = 153	High SES N = 105	Low SES N = 48	p
Availability	16 (10)	13 (12.3)	3 (6.4)	NS
Advertisement	6 (3.9)	4 (3.8)	2 (4.3)	NS
Professional advice	17 (11)	10 (9.4)	7 (14.9)	NS
Continuation from nursery	30 (19.6)	26 (24.5)	4 (8.5)	0.02
Friends advice	30 (19)	21 (19.8)	9 (19.1)	NS
Infant compliance	24 (15.7)	18 (17)	6 (12.8)	NS
Experience with previous child	13 (8.5)	5 (4.7)	8 (17)	NS
Price	4 (2.6)	0 (0)	4 (100)	0.01
Other^a	15 (10)	9 (8)	6 (12)	NS

Kashrut, Preference of international or Israeli brand, random decision.

IF, infant formula; NS, no significant; SES, socioeconomic status.

Discussion

Evidence-based clinical practices are pivotal for establishing breastfeeding. To help mothers reach their breastfeeding goals, individualized assistance in the first few days of the infant's life is important. Our results on infant nutrition showed that only one-third of our study cohort exclusively breastfed their infant, and that the remaining used formula exclusively or in combination with breastfeeding during the first 6 months of life. They also confirmed our hypothesis that exclusive breastfeeding correlated with a higher SES. The considerations for formula integration in infant nutrition were mostly (60%) due to maternal factors, regardless of SES. The leading factor influencing the choice of a specific IF brand was continuation of the same IF that had been given in the hospital nursery.

There is growing body of evidence that shows that the addition of formula to breastfeeding reduces the well-known advantages of exclusive breastfeeding, such as reduction on the rate of infectious episodes¹⁵ and a beneficial effect on infant body weight.^16,17 Therefore, in view of all the obvious benefits of exclusive breastfeeding, it is important to improve breastfeeding support and education in FHCs and hospitals to increase the acceptance of exclusive breastfeeding. Importantly, the prevalence of exclusive breastfeeding in our study was higher than that reported by Nevo et al., who studied feeding patterns in the first 6 months of life of babies born at term one decade ago (36% exclusively breastfeeding rates in this study versus 15% in the previous study).¹⁸ However, our study finding highlights that still in 60% of cases IF was added to infant nutrition due to maternal difficulties in breastfeeding. Efforts should be focused upon locating mothers who experience difficulties in breastfeeding at both hospitals and community levels.

We found a significant correlation between the maternal SES status and the choice and type of IF. The impact of maternal SES on dietary choices for their child is well known, from the breastfeeding rates and duration to the complementary food choices.^10,19–21 This study demonstrated that beyond the effect of SES status on breastfeeding rates, the SES also influences formula choices. Higher SES parents tended to continue nutrition with the IF that was supplied in the hospital nursery, whereas lower SES parents tended to choose a formula according to its relatively lower price. Moreover, we demonstrated a predominant effect of nonprofessional data sources on IF selection (advice of friends and family members, advertisements). Only 11% of the parents chose a formula according to a pediatrician's advice. Providing formulas only to mothers with medical indications, in accordance with the Baby Friendly Hospital Initiative steps^22,23 may improve overall exclusive breastfeeding rates.

The uniqueness of this study is that it reflects a contemporary insight into the parents' choice of infant nutrition in the first few months of the baby's life. The strengths of this study is its heterogeneous population of parents from different SESs, and the inclusion of several indicators for assessing SES. Its limitations are the use of a survey questionnaire as a single measurement tool and the reliance on the subjects' memory of events that began 9–15 months before the interview. These limitations may have impaired the accuracy and reliability of the data, although they do not appear to have created differential information bias among the various research groups (low, intermediate, and high SESs).

Conclusion/Implications

This study demonstrated association of socioeconomic factors and infant nutrition decisions. There is an overall lower prevalence of exclusive breastfeeding among low-income families. The maternal choice of the type of IF is associated with parental SES with the choice of high SES mothers what was fed in the hospital and the choice of low SES related to price.

Footnotes

Disclosure Statement

No competing financial interests exist.

Funding Information

The study was supported by a grant from the Israel Ambulatory Pediatric Association.

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