Are parents’ education levels associated with either their oral health knowledge or their children’s oral health behaviors? A survey of 8446 families in Wuhan

Funded by the Hongshan District Government, the Hongshan Longitudinal Study on Pit and Fissure Sealants Application (HoLSPA) project aimed to provide free oral examination and pit and fissure sealants (PFS) for the first and second graders in Hongshan District, Wuhan, China, and at the same time carry out relevant research through oral examinations, data collection and online surveys.

As part of the HoLSPA project, the present study was conducted via an online questionnaire survey targeted at all families of those first and second graders involved in HoLSPA. As determined a priori, responses from 1) single-parent families, 2) parents who had psychiatric or cognitive dysfunctions, 3) parents who did not provide informed consent, or 4) parents who did not fill out the questionnaire completely were excluded from this study.

Electronic questionnaires were sent by the Education Bureau of Hongshan District to parents of 11,000 eligible families through WeChat (a Chinese multi-purpose messaging and social media app) by head teachers. Each family was required to fill out one questionnaire (either by the father or the mother) and return it via WeChat. The survey was completed before the clinical part of HoLSPA project started. In the survey, information on children’s family situation, COB, POK and parents’ PFS-related choice were collected. Full text of the questionnaire can be found in the Additional file 1.

This study was approved by the Medical Ethics Committee of Hospital of Stomatology, Wuhan University (2018. B13). Written informed consents were obtained from all participants of this study.

Since the HoLSPA project was free, families from all social backgrounds could participate in the project. The HoLSPA was supervised by Education Bureau and the Health Commission of Hongshan District, which guaranteed an adequate response rate. The questionnaire questions mainly came from the Fourth National Oral Survey of China (2015–2016), which was developed according to the WHO guidelines [22] by Chinese Stomatological Association. A class of students in the Wuhan Primary School was randomly selected for pilot study one week prior to the launch of the main trial to test the repeatability of the questionnaire. There were no significant differences between the results of the pilot study and the main study, suggesting the repeatability of this questionnaire was convincing.

We first assessed the crude associations between family characteristics, COB, POK, parents’ PFS-related choices and parental education levels using Chi-square tests. Then, logistic regression analyses were performed to examine the association between COB and parents’ education levels. Associations between children’s oral health and parents’ education levels were not always consistent for the father and the mother [23]. Thus, we conducted univariate analyses to investigate the association between COB and mother’s and father’s education level independently, and then assessed the educational effects of both parents simultaneously in the multivariate model.

Next, we examined the association between POK and parental education levels using logistic regression analysis. Finally, logistic regression analyses were performed to examine the association between parental education and their understanding of PFS as a proxy of parents’ choices of oral health care. We stratified all analysis by parent’s gender to control the confounding effect of gender. EpiData 3.0 was used for data entry and SPSS 25.0 was used for data analysis. A significant level of 0.05 was used to determine statistical significance. Additionally, histograms were drawn by SPSSAU to demonstrate the relationship between the determinants of PFS location choice and parents’ education separately.

Our questionnaire was sent to a total of 11,000 families, 2459 of which did not participate in this survey. Among the 8541 responses that we received, 95 were either incomplete or from single-parent families and were therefore excluded. Finally, 8446 eligible responses from 8446 families (with children from 43 primary schools in Hongshan District, Wuhan) were included in this analysis, resulting in a response rate of 76.78% (8446/11000).

The distribution of family characteristics, COB, POK, and parents’ PFS-related choices by parental education levels were presented in Table 1. The number of families that had only one child (50.82%) was slightly higher than those with two or more children (49.18%). As shown in Table 1, parents with a lower level of education were more likely to have more than one child. According to the results of the chi-square test, the responses of all questions were significantly related to both parents’ academic backgrounds (P < 0.001). Overall, parents in higher education groups had better oral health knowledge and their children reported more favorable behaviors than their counterparts.

Table 2 demonstrated logistic regression results of the effects of mother’s and father’s educational attainments on COB. In the univariate model, mother’s and father’s education levels were all associated with children’s tooth-brushing behaviors. When adjusted for education level of counterpart parent, children’s tooth-brushing behavior can be predicted by mother’s education level rather than father’s education level. Participants whose mother had college degree (Odds Ratio [OR] = 2.62, 95% Confidential Interval [CI] = 1.57–4.35) and undergraduate degree or above (OR = 1.72, 95%CI = 1.03–2.85) were more likely to brush their teeth than those whose mother with middle school education or below. A clear increased gradient in the effects of parental education levels on tooth-brushing frequency was found, showing that children whose parents with higher education levels were more likely to brush their teeth twice a day or more. For example, children whose mother with university degree were 2.47 (95%CI = 2.01–3.02) more likely to brush teeth at least twice a day than those whose mother in the lowest education group, and the effect size of father’s education level (OR = 2.05, 95%CI = 1.68–2.51) was slightly smaller than that of mother’s. Similarly, the proportion of children ever had dental visit was steadily increasing as the parental education levels rose. The odds of children ever had dental visit was 1.79 (95%CI = 2.45–3.32) times and 1.52 (95%CI = 1.24–1.87) times higher among mothers with university degrees and fathers with university degrees than their counterparts with middle school education or lower, respectively. When further exploring the last dental visit, participants whose father ever attended university were 1.41 (95CI% = 1.09–1.83) times more likely to had dental visit in the past 12 months than those whose father with lowest educational background. Additionally, those whose mother with higher education levels were more likely to visit dentists for dental treatment (OR = 1.28, 95%CI = 1.02–1.61 for high school degree; OR = 1.61, 95%CI = 1.22–2.11 for college degree; OR = 1.70, 95%CI = 1.35–2.37 for university degree or above). The reason for dental visit was associated with father’s education level in the univariate model, however, this association was eliminated after adjusted for mother’s education level.

Table 3 showed the relationship between parental education levels and correctness rates to true-false oral health-related statements. The multivariate logistic regression results showed that correctness rates of seven oral health-related statements were significantly related to mother’s academic qualification, and correctness rates of four statements were significantly related to father’s education level.

The correctness rates of answers to “bleeding gums are normal when brushing teeth”, “tooth-brushing is helpful in preventing gingivitis”, “dental caries is mainly caused by pathogenic bacteria”, “sugar intake is associated with dental caries”, “fluoride protects teeth from decay”, “PFS help in preventing dental caries” and “oral diseases is essential to general health” were significantly lower among mothers with lower education than those of higher education. Regarding to fathers’ responses, the correctness rates of answers to “fluoride protects teeth from decay”, “PFS help in preventing dental caries” and “oral diseases is essential to general health” were significantly higher among fathers with undergraduate degrees or above than fathers with lowest educational background (OR = 1.30, 95%CI = 1.06–1.58; OR = 2.03, 95%CI = 1.49–2.76; OR = 2.03, 95%CI = 1.43–2.89, respectively). Moreover, fathers ever attended high schools or colleges were 1.19 (95%CI = 1.01–1.40) and 1.26 (95%CI = 1.03–1.55) times more likely to report correct answer to “bleeding gums are normal when brushing teeth” than those with lowest level of education.

Table 4 presented the results of logistic regression analysis between parents’ education levels and their PFS-related choices. The odds of PFS awareness rate increased with both mother’s and father’s education level. Compared with mothers attended nine-year education or less, having high school, college and undergraduate degrees or above yielded ORs of 1.29 (95% CI = 1.09–1.53), 1.65 (95% CI = 1.31–2.08), and 2.15 (95% CI = 1.67–2.78), respectively. The effect size of father’s education level on PFS awareness was similar to mother’s.

Regarding to the preference of PFS location for children, the proportion of choosing dental hospitals increased as the higher academic qualifications gained among both mothers and fathers. The effect size of education levels on PFS location preference was stronger among fathers than mothers.

Figure 1 A and B presented the distribution of parental education levels and conditions that will be considered when selecting the location of PFS. The trends shown in the two figures were generally alike, showing that the proportions of parents who considered “completeness of medical facilities” and “distance to PFS sites” rose with increase in their education levels. In contrast, the proportion of parents who listened to “children’s willingness” decreased with increase academic achievements