Prospective association of family members’ sugar-sweetened beverages intake with children’s sugar-sweetened beverages consumption in China

Over the last 20 years, epidemiological studies have indicated a 24.4% increment of sugar-sweetened beverage (SSB) consumption among Chinese children [1]. Higher SSB consumption is an established risk factor for childhood obesity and dental caries [2] and is suggested to be associated with cancer [3], cardiovascular disease and metabolic syndrome later in life [4]. Thus, to protect children from health problems and health hazards, more attention is required to address the causes and factors influencing children’s SSB consumption.

Family factors have been proved to be one of the main influencing factors affecting children’s SSB consumption, and associations between family members’ SSB consumption and children’s diet with high SSB intake have been found in cross-sectional studies [1, 5‐13]. While the correlation is strong, it is not possible to unequivocally determine the direction of causality. A bidirectional relationship may exist between adolescents and family members [14]. Thus, prospective studies with a clearly defined temporal relationship are more convincing than cross-sectional studies in elucidating potentially causal links between family members’ SSB consumption and children’s SSB intake. Moreover, sex differences in intergenerational relationships between parents and offspring were found in alcohol consumption [15] and physical activity [16], and sex difference also exists in SSB drinking behavior [17]. These lead us to speculate on the possible sex differences in the association for SSB intake between parents and children, which did not attract widespread attention yet.

Among family members, an important area of study is the extent to which the SSB consumption patterns of adults influence those of children in their households. Most studies that describe SSB consumption within families assess one child with one parent [5, 6, 8, 10‐12] or guardian [7, 9]. It is argued that fathers and mothers provided different experiences for adolescents’ health status [18]. Only conducted in one parent may induce selection bias. In addition to parents, siblings could be another influencing factor for children to establish health attitudes toward physical activity[19] and dietary habits [20], such as eating frequency and food diversity. To date, there is only one cross-sectional study in Great Britain that indicated the role of siblings on children’s SSB consumption [13]. And this association, to our knowledge, has never been explored thus far in China.

Considering the secular trend of increasing SSB intake in Chinese children and its short- and long-term health concerns, this study aimed to investigate whether family members’ SSB consumption was prospectively associated with children’s SSB intake, including: (1) parental impact on children’s SSB consumption, and potential sex difference; (2) sibling’s impact on children’s SSB intake.

In the present study, higher parental SSB consumption was prospectively associated with higher children’s SSB intake, and this association was more pronounced in boys than in girls, and fathers had a stronger impact than mothers. Additionally, children’s SSB consumption was influenced prospectively by their older siblings’ SSB intake rather than younger siblings’.

In the present study, children with parents who drink SSB were more likely to consume SSB, which was in line with the studies in 2–17 years old children and adolescents from the US [6, 9, 12], and 8–12 years old children from New Zealand [8]. Parents serve as role models for children’s behavior [5], and parental intake of vegetables and fruit, red meat, dairy and dairy products can directly affect children’s consumption of these foods and beverages [35, 36]. In addition, foods are mainly prepared and purchased by parents at home [37], and those with a diet rich in SSB might often store SSBs at home and may be less apt to restrict or have rules on their children’s SSB consumption. The availability and consumption of SSB for these children would, thus, be higher than those with parents who seldom drink SSB. Other than parental dietary behavior, previous researchers examined parental educational levels were examined as a factor in children’s SSB consumption [38]. Higher-educated parents tended to be well-off economically [39]. In this study, 88.2% of parents were high school graduates or below and two-thirds of households have a monthly personal income of less than 3200 Yuan (488.7 $). When parents consume SSB, the odds of children consuming SSB were lower in this study (OR:5.3; 95%CI: 1.4, 14.2) than in the US study (OR:8.9; 95%CI:4.6, 17.3) with a higher parental education level and a good socioeconomic status [12]. This contradiction might be explained by different SSB market prices. In developing countries, SSBs were usually less affordable than in western countries [40], and Chinese parents of better economic status may be the ones who regularly buy SSBs for their children, while in the United States, low-income parents often choose to feed their children with low-priced SSB [8]. Additionally, this study included a relatively large number of rural children. Supermarkets are far from their places of residence, and these families may go to the supermarket once in a very long time to make purchases. Some rural areas in China are located in mountainous areas with inconvenient transportation[41], and parents living in these areas would buy more household necessities rather than expensive and heavy SSBs. These would decrease the accessibility of SSB to children. Different amounts of SSB intake may also have contributed to the difference. In our study, the median SSB consumption of Chinese children was 70.3 ml/day, which was much lower than the mean SSB consumption of children in the USA (419.2 ml/day) [32].

Potential sex differences were found in intergenerational relationships between parents and their offspring [15, 16]. In this analysis, we paid special attention to the sex differences and found that boys’ SSB consumption was more susceptible to their parents' SSB intake than girls’, and fathers seemed to have a greater influence on whether children consume SSB than mothers. These differences may be explained by different attitudes towards consuming SSB between males and females, and diverse parenting styles in sons and daughters. First, different attitudes have been shown to produce different patterns of behavior [42]. In adults, the prevalence of sweetened soft drink consumption for men was higher by at least 5% than for women [17]. In children, boys tend to link the behavior of consuming SSB, especially carbonated beverages, with “popular”, “cool”, and “risky”, and have a positive attitude toward SSB [43‐45]. When they witness others drinking SSB, to make themselves look cool and popular, they are more inclined to choose SSB rather than plain water. Girls, however, tend to link the behavior of consuming healthy beverages with good body shape and are more inclined to choose plain water and 100% juice instead of SSB [44, 46, 47]. Secondly, different parenting styles would lead to different parent–child intimacy communication styles [48]. In China, authoritative parenting styles were often found in boys’ families [49]. Boys in these families are more likely to imitate their parents’ behavior to reduce the possibility of being scolded for making mistakes. When witnessing parents drinking SSB, to imitate their behavior, boys may choose SSB. Democratic styles were often found in girls’ families [49], they are less likely to drink SSB to imitate parental behavior.

In this study, fathers seemed to have a greater influence on whether children consume SSB than mothers, which was inconsistent with a recent cross-sectional study in Chinese population [1]. The studies were of the same population, and socio-demographic parameters were relatively similar. The discrepancy between studies may be related to the different methodologies and different selections of participants. Selection of study participants and detained processing of children with multiple surveys were unknown in that study, the same child could be included as a study participant more than once. In Chinese population, fathers instead of mothers were proved to have an impact on children’s dietary protein intake [50], implying that a similar role may exist in SSB consumption. This hypothesis requires further investigation in longitudinal studies. While we do find that boys were 1.3–1.7 times more likely to be influenced by their parental SSB consumption than girls, the bias due to inevitable limitations challenges the validity of these findings, including observational nature of the study, selection bias, missing data and measurement error. However, this is the first study to focus on sex differences in SSB consumption in intergenerational relationships, these findings still provide an interesting perspective for future research in other populations, including a larger sample across Chinese general population.

In our study, children's SSB intake would be affected by older siblings’ SSB consumption rather than that of younger brothers or sisters, which was consistent with a recent cross-sectional study in England [13]. O’Leary et al. [13] only found a correlation of intrahousehold SSB consumption between children of different ages, and because of the methodological limitations, the direction of causality is difficult to assess. The results of this study further determined the direction of the association. In the present study, the older children were already in adolescence (median age: 12 years), and younger children were still in prepubertal period (median age: 8 years). Adolescents have considerable autonomy and decision-making power regarding their dietary behavior [51]. Compared to their younger siblings, they prefer spending lots of time with their friends [52] and get pocket money [8] which may be used to purchase unhealthy food. For younger children, they tend to imitate older siblings to develop their dietary behavior [53]. In 2016, China officially ended the one-child policy, and in 2021, the government even encouraged reproductive-age women to have three births. More than 8 million second child were born in 2016, and 59.5% of newborns were second child in 2019 [54]. With the increasing number of multiple-child families in China, the influence of sibling’s effect cannot be ignored. For second child’s parents, who were likely raised in a single-child family and have little experience with siblings, and this makes education for multiple children has become a critical social issue requiring immediate attention. However, due to limitations imposed by the small sample size, our estimation results for sex differences in the relationships between siblings and children in SSB consumption were not reliably available (Table S5), still, our findings provided an interesting new direction for future research in dietary consumption.

Our study has several strengths, including its prospective nature to establish causal order, and the ability to adjust for a number of potential confounders both in children and in parents. A further advantage lies in the detailed exploration of SSB consumption in both fathers and mothers. Moreover, unlike other studies of children or adolescents, we noted sex differences in SSB intergenerational relationships, which may require more attention in the development of SSB reduction policies for children.

Nevertheless, some limitations should also be mentioned. First, though the amount of SSB intake in this study is consistent with that obtained in other studies of Chinese children and adults, the dietary assessment method of SSB has not been validated yet. And self-report of dietary data and the unavailability of energy intake data obtained through the food frequency questionnaire introduced the possibility of bias and underreporting. Second, as the CHNS has not regularly tested the consistency in the operation of investigators, there might be inadequacies with the quality of basic anthropometric measurements (height and weight). Third, though acceptance of initial invitation for study participants varied by area, we excluded participants who refused participation, which may have resulted in the selection of a more “health-conscious” study sample. Fourth, the sample size limited the extent of analysis which makes us unable to analyze the sex difference in siblings’ impact and in families with only one parent drinking SSB.

In conclusion, our study illustrated that parental SSB consumption and older siblings’ SSB intake, not younger siblings’ SSB intake, were prospectively associated with Chinese children’s SSB consumption. And in Chinese families, boys were more susceptible to their parents' SSB intake than girls, and fathers seemed to have more influence on children’s SSB consumption than mothers.