Within the UK, people who belonged to non-White groups were less likely to report fillings, dental extractions, and fewer than 20 teeth. These differences were not explained by dental hygiene and dental services, which were generally used less in non-White groups. Non-White groups were more likely to add sugar to drinks or consume fizzy drinks but they were less likely to consume sweets and cakes. The latter appeared to explain most of the reduced risk in Black participants and some of it in South Asian participants. Dental examination of a sub-group demonstrated fewer dental caries among South Asian participants. Thus, our findings show that non-White groups have generally better oral health, defined by the presence of more teeth, and have had correspondingly fewer dental extractions.
Our findings are consistent with previous studies that have reported little impact of dental services on reducing dental caries [27], and inverse relationships between use of dental services and adverse dental health outcomes [28]. A previous USA study on hypothetical patient preference suggested that Black individuals would be more likely to opt for dental extraction than further root canal restorative treatment; mainly explained by preference, treatment acceptability and ability to afford treatment [29]. In a South American study that presented dentists with hypothetical patient scenarios, the dentists were more likely to choose dental extraction for Black, than White, patients irrespective of their disease severity, lifestyle behaviours or personal choice [30]. Other studies have confirmed that the Black population in the USA and Brazil has more dental caries, more dental extractions and fewer teeth [3, 31]. Our findings suggested that British Black participants had significantly fewer fillings and fewer dental extractions; although the latter did not reach statistical significance. These findings do not necessarily conflict with the American findings since fewer fillings and extractions may reflect poorer access to, or use of, dental services among British Black people, rather than better dental health. We were unable to include Black participants in the sub-group analysis of dental caries, due to lack of statistical power. However, Black participants were significantly more likely, than White, to report poor or very poor oral health suggesting that fewer fillings may reflect unmet need rather than less need. However, further studies are required to ascertain whether this is true.
In 1999, Newton et al. published the first study to demonstrate superior oral health among ethnic minority groups in the UK [26]. These findings have since been corroborated by other UK studies of adults [32–34], but have been refuted by some studies conducted on children and adults in the UK and other countries. Conway et al. demonstrated higher rates of caries among UK Pakistani children, compared with White [22]. Selikowitz and Holst studied the periodontal health of Pakistani people living in Norway and showed a higher prevalence of plaque, sub-gingival calculus and gingival bleeding [35]. Similarly, a study in Singapore demonstrated that Indian residents had worse periodontal health than either Chinese or Malay residents [36].
Overall, smoking prevalence is lower in ethnic minority groups [37]. However, this masks large sex differences. In White populations, smoking prevalence is comparable in men and women [38, 39]. South Asian men have a higher prevalence of smoking than White men [37]. In contrast, the self-reported prevalence of smoking among South Asian women is low [38, 39]. However, these figures do not take account of chewing tobacco which is much more common among South Asian people, including women [40]. In a study by Croucher et al., only 4 % of Bangladeshi women smoked cigarettes but 49 % chewed paan quid with tobacco [41]. Therefore, questionnaires that focus on cigarette consumption are likely to underestimate the use of tobacco products in South Asian study participants.
Williams et al. demonstrated lower levels of dental knowledge among Asian parents compared with White (OR 0.43 95 % CI 0.27-0.70, p < 0.05) [42]. Studies conducted in the 1980’s showed that British Asian women were more likely to rub around their mouth with their fingers than use a toothbrush, with some not cleaning their teeth at all [43, 44]. Practices such as the use of chewing sticks, home-made or imported dentifrices were also common. However, it is unclear whether these findings are still relevant.
Risk of caries is increased if the condition of existing fillings, restorations, orthodontic appliances and partial dentures is poorly maintained [45, 46]. Within the ADHS, more than 50 % of participants from ethnic minority groups visited the dentist every six months and 72 % had visited the dentist within the last year. However, a significant proportion of participants in these groups were not undergoing regular dental clinic visits and ethnic minority groups were more likely to restrict dental visits to when symptoms occurred. Our findings are consistent with previous studies on Bangladeshi adults living in the United Kingdom, which showed that 25 % of adults [32] and 58 % of adult women [47] had never visited a dentist. These studies have also highlighted unmet treatment needs in ethnic minority groups with 80 % of Asian adults living in Southampton found to require dental treatment, but only 38.5 % of them perceiving any need [32]. This is consistent with our finding that Pakistani/Banglasdeshi respondents were more likely to report poor oral health but less likely to report having had dental procedures such as fillings and extractions.
In a focus group, conducted by Croucher and Sohanpal [48], members of ethnic minority groups reported difficulties in obtaining dental appointments and longer waiting times. Other barriers identified to using dental services have included language, cultural beliefs and affordability [49]. In a study of Bangladeshi medical care users in the UK [50], language problems were reported by 73 %, with more women facing difficulties than men. Nearly 68 % required an interpreter; resulting in a preference for evening appointments when family members could attend. Indian and Pakistani study participants felt that their inability to explain their dental problems might prolong their dental treatment, thereby increasing treatment costs [50]. In a number of studies, actual cost of dental treatment, or fear of cost, have been reported as major barriers to members of ethnic minority groups accessing dental services [32, 33, 47–50]. Ethnic minority groups perceive dental treatment to be expensive, lacked clarity about the individual treatment fees and reported difficulties in finding a dentist [48]. Other problems reported include fear of dental treatment [32, 48, 49], difficulty obtaining time off work [32], cultural misunderstandings [49], and concerns about hygiene in the dental surgery [49].
The ADHS provided data on a large sample; representative of the general population of England, Wales and Northern Ireland. Whilst the majority of participants were White, there were still sufficient numbers in the main ethnic groups to permit comparisons between ethnic groups within the same study. The survey provided information on a number of potential confounders and mediators, including socio-demographic information, diet, lifestyle, personal dental hygiene and use of dental services, enabling us to explore possible reasons for the observed ethnic differences. We were also able to adjust for both individual level measures of socioeconomic deprivation and an area-based measure. Self-reported oral health was corroborated by clinical examination in the dentate sub-group of participants.
As with all cross-sectional studies, it is impossible to establish temporal relationships. Also, behaviour may change over time and current lifestyle and use of dental services may not equate to those prior to the development of oral health problems. For example, increased use of dental services may be a result of dental problems and, therefore reflect reverse causation. We adjusted for potential confounders but, in common with all observational studies, residual confounding is possible. Whilst overcrowding is a good proxy measure of deprivation among White populations, cultural differences in the acceptability of living with extended families make it a poorer measure of differences in socioeconomic status between ethnic groups. Therefore, the number of household members was not included as a covariate in the models.
As a secondary data study, our analyses were limited to the data and definitions available to us. The ADHS adopted the usual practice in UK surveys and epidemiological studies of using self classification of ethnic group. This is, arguably, a strength since self-identified ethnicity is more likely to reflect health beliefs and behaviours. Both ethnicity and migration influence oral health. Immigrants arrive in the UK with different lifestyle behaviours which, due to assimilation, gradually converge with those of their recipient country over time [50]. However, we were unable to differentiate between the effects of ethnicity and migration since the ADHS collected no information on length of residence in the UK, personal or parental place of birth. Similarly, no information was available on language, religion or beliefs. However, the Survey did provide data on lifestyle risk factors, use of dental services and personal dental hygiene practice all of which are influenced by religion, culture and beliefs and, therefore, ethnicity [51–53]. We also had information on area- and individual-level socioeconomic status which are important confounders in any studies of ethnic differences. However, our study was insufficiently powered for us to investigate area-level differences in outcomes. Therefore, our results may only apply to metropolitan areas. For the three main outcomes, we were able to include all participants and were, therefore, able to include Indian, Pakistani/Bangladeshi and Black participants as three separate groups. Because the clinical examination was undertaken on a sub-group, statistical power was reduced and we had to combine the Indian and Pakistani/Bangladeshi groups into a single, South Asian, group. Since there are some important differences between the three groups in terms of religion, culture, socioeconomic status and education, care should be heeded in interpreting the findings of the sub-group analysis.
