Differences in infant feeding practices between Chinese-born and Australian-born mothers living in Australia: a cross-sectional study

In 2010–2011 The Australian Institute of Health and Welfare (AIHW) conducted The Australian National Infant Feeding Survey (NIFS) [31], a large scale, national survey of infant feeding practices and behaviours of infants aged 0–24 months. Access to the data source in this study was approved by the data custodian Australian Data Archive.

Children aged up to 24 months were randomly selected nationwide from the universal Medicare enrolment database [31]. The sampling methodology has been previously described [31], but of note is the oversampling of infants aged up to 6 months in order to obtain quality estimates of breastfeeding intensity and duration for this age period and allow comparisons with future national survey data [31]. A primary approach letter was sent to the primary card holder on the child’s Medicare card inviting them to participate in the study [31]. A survey questionnaire was sent to participants with a reply paid envelope and an option of completing the survey online [31]. The final sample size was 28,759 (response rate = 56%) [31]. The current study utilises data from two groups within the full NIFS dataset – all mothers born in China (n = 602) and a randomly selected sub-sample of mothers born in Australia (n = 602). This random sub-sample was selected using a command in the statistical package Stata which randomly extracted n = 602 mothers born in Australia from the total sample (SE 15; StataCorp, College Station, TX, USA).

A survey was developed by Australian Bureau of Statistics (ABS) for the AIHW to capture the prevalence and duration of breastfeeding, feeding practices, and the barriers to initiating and continuing breastfeeding as reported by mothers/carers of infants [31]. A literature review informed survey question design and was piloted with parents of 1000 randomly selected children drawn from the Medicare Australia enrolment database. The final survey consisted of 101 questions, 39 of which were utilised for this study.

Demographic information collected included mother/infant date of birth, mother/infant country of birth, postcode, the main language spoken at home, questions regarding a spouse/de facto partner, schooling and educational qualifications, employment, total gross household income, medical issues of the mother (e.g. mental health) [31]. Deciles and quintiles describing area level socioeconomic status were calculated by the custodian of the data using Socio-Economic Indexes for Areas (SEIFA) score of relative disadvantage [31]. Ethnicity of mothers was determined by reported country of birth (i.e. China or Australia). Chinese-born mothers were defined as being born in China (excluding Special Administration Regions such as Hong Kong, Macau, Wolong; and Taiwan Province) [32] and now living in Australia. Regarding Australian-born mothers (non-immigrants); participants were excluded from the random selection if the main language spoken at home was not English (n = 6). Mothers reported the recorded birth weight and length of the infant, and self-reported weight and height at the start of their pregnancy and at the date of survey completion [31].

Mothers reported on infant feeding practices (types of liquid and solid consumption), and the ages when these practices first occurred (months). Mothers reported current breastfeeding (yes/no); whether the infant had ever had formula, water, cow’s milk, toddler milk, soy milk, water-based drinks, fruit juice (yes/no for all); and the age that these items were introduced (number of months recorded in an open field, or less than 1 month). Water included any sips of water, and excluded water combined with other liquids (e.g. cordial) or solids (e.g. formula). Cow’s milk and soy milk included any sips of these milks, including flavoured and powdered milks but excluded these milks combined with solid foods (e.g. cereal). Water-based drinks included cordial, soft drink, tea and excluded diluted fruit juice, and infant formula products. Soft, semi-solid and solid foods included custards, mashed food diluted with water, milk or other fluids [31].

Approval for this study was originally provided by the Australian Institute of Health and Welfare’s Ethics Committee. The secondary data analysis conducted in the current project was approved by the Deakin University Human Research Ethics Committee (2014–161).

There is limited data on breastfeeding in Chinese-born immigrants in Australia. It is encouraging that the proportion of Chinese-born mothers still breastfeeding at survey completion when infants were 6–7 months old was higher (66%) in this study compared to older data reporting breastfeeding by only 50% of Chinese mothers living in Australia at 3 months [8] and in another study, 56% of mothers at 6 months [20]. There is international evidence of ethnic variation in breastfeeding practices, however primarily in white compared to Hispanic or Black mothers [33]; Indian, Pakistani, Bangladeshi, Black Caribbean, Black African [34] or a combined Asian group [35]. The higher proportion of any breastfeeding amongst Chinese-born mothers in this study may be attributed to their views that breastfeeding is important to their identity as a mother and beliefs of its superior health benefits to both infant and mother [36, 37]. Qualitative interviews with Chinese born mothers in Victoria showed that mothers favoured breastfeeding for its health, emotional and financial benefits [10]. The current study did not examine prevalence of exclusive breastfeeding, but it is clear that a high proportion of mothers born in both China and Australia will not meet the recommendation of breastfeeding for 12 months given that about one-third of both groups were already not currently breastfeeding at 6-7 months old when the survey was completed. This is concerning given the protective effect of breastfeeding on infant weight status [23] and that even combination feeding under 6 months may increase the risk of being overweight/obese later in life [38].

In the current study, infants of Chinese-born mothers were younger when they first consumed infant formula, and a higher proportion had ever consumed infant formula compared to infants of Australian-born mothers. Comparison of these findings internationally is difficult as the evidence is still emerging, however these data are consistent with data from North America where the preference for formula (alone or in combination) compared to breastfeeding in women of Chinese descent (born in Hong Kong) is becoming a concern [39]. Previous Australian data is quite dated (1997), showing 50% of mothers bottle feeding, and 16% combination feeding at 3 months; with reported reasons for bottle feeding largely being inadequate milk supply and ease of feeding practice [8, 20]. Concerning misconceptions about bottle feeding have also been reported such as a large proportion of Chinese mothers believing Australian infant formula was better quality compared to that in China, and that a fat baby was a healthy baby [8]. Despite believing that breast milk is best, Chinese mothers recently reported that they thought infant formula was a useful addition in infant feeding as other people could be involved in feeding, babies could sleep through the night and they felt assured of knowing how much the baby has drunk [10]. However, high protein formula feeding has been associated with rapid weight gain and risk of adiposity [25, 27, 28]. Formula feeding (alone or in combination) has been shown to increase risk of overweight and obesity in children [38]. Further research is required to ascertain a deeper understanding of the complex influences behind formula feeding in this Chinese-born group, and whether the infant feeding practices reflect combination feeding of breast and formula.

Overall the average age of soft, semi-solid or solid introduction was younger than recommended in the Australian Infant Feeding Guidelines [22] in both groups of mothers. Recent reviews suggest that introducing complementary foods to infants very early (before 4 months of age) may increase the risk of a child being overweight; however findings are not conclusive [17, 30]. Early introduction of solids may also result in less time breastfeeding, a decline in breastmilk production and sometimes under-nutrition and an increased risk of developing allergies [40]. Compared to infants of Australian-born mothers, a lower proportion of infants of Chinese-born mothers had been exposed to solids; in addition to being older when first exposed. This ethnic diversity in the age of solid introduction has not previously been reported for infants of Chinese immigrants. Qualitative work with Chinese-born mothers in Victoria reported that mothers follow healthcare professional advice to introduce solids between 4-6 months because they want to reduce risks in infants developing allergic diseases [10]. Most commented that prior to 6 months of age, solids were introduced for taste rather than as an important source of nutrients in the infant’s diet [10]. Mothers from all ethnic minority groups (e.g. Indian, Pakistani, Bangladeshi, black Caribbean, black African) have been reported to be less likely to introduce solids before the recommended age than white mothers [41]. Further research on infants of Chinese immigrants, including capturing anthropometric data, is required to understand the risk of early introduction of solids in relation to adiposity in this population.

The Australian Infant Feeding Guidelines do not recommend fruit juice for infants under 12 months of age as it is unnecessary and may interfere with consumption of breastmilk or formula and risk damage to emerging teeth; and it is not recommended to offer tea, herbal tea, coffee, soft drinks, cordial or other beverages [22]. In the current study, a large proportion of mothers, regardless of ethnicity, did not adhere to these guidelines. At the time of survey completion when infants were 6-7 months old, almost one fifth of infants had ever consumed water-based drinks (e.g. cordial, soft drink, tea); a higher proportion of infants of Chinese-born mothers had ever consumed fruit juice. Infants of Chinese-born mothers were younger when exposed to water-based drinks and fruit juice. The present findings support and extend the findings of previous qualitative work with Chinese-born mothers in Victoria which reported that mothers faced pressure from grandparents to introduce water-based drinks to their infants prior to 4 months of age [10].

In the US, one quarter of infants had consumed sugar-sweetened beverages (SSBs) during infancy (between 1-12 months of age) [42]. Examination by ethnicity in the UK has shown some variation in consumption of SSBs - compared to white British counterparts, Pakistani infants had increased consumption of SSBs at 12 months; and increased consumption of SSBs and fruit juice at 18 months [43]. Hispanic children have also been found to consume significantly more juice than non-Hispanic white children [44]. Few studies have examined the association between SSB intake during infancy and obesity during early childhood, however recently SSB consumption during infancy was associated with increased odds of obesity at age 6 years [42]. Numerous studies have also revealed fruit juice consumption in early childhood to be associated with unhealthy weight gain in young children [45‐47].

This study contributes important knowledge regarding differences in infant feeding practices of Chinese-born mothers compared to their non-immigrant counterparts living in Australia. A particular strength of the study is that the data was drawn from a large national database which allows good generalisability; and also permitted adjustment for a large number of covariates. However, we do acknowledge several study limitations. Due to the cross-sectional nature of the database, causality cannot be inferred. Other limitations include recall bias and social desirability bias inherent to self-reported surveys, potential unmeasured confounding factors (e.g. lack of physical activity data collected, year of arrival) and an absence of infant anthropometry data for rate of growth.