| Abstract|| |
Background: Effects of consanguineous marriage on human population are known. However, the inherited susceptibility to dental caries is unfortunately quite limited. Aim: This study aimed to assess the dental caries status (DMFT/deft [decayed-missed-filling teeth/decayed-extracted-filled teeth] index) in children born out of consanguineous and non-consanguineous marriages. Design: Household survey using a cross-sectional study design was planned, with a sample size of 2000 comprising (1600 non-consanguineous and 400 consanguineous) children, aged 6–9 years. Household survey was also planned using a systematic random sampling. Researcher conducted the study by visiting every 10th household of every 10th ward of Aligarh city, Uttar Pradesh, India. Information of risk factors for dental caries (sociodemographic, birth order, oral hygiene, feeding practices) was recorded on a pretested questionnaire with clinical examination of DMFT/deft index. Analysis: Student t test for equality of means and multivariate logistic regression were used. Results: By Student t test for equality of means, D component (P = 0.003), d component (P < 0.001), and deft score (P < 0.001) were statistically significant in the consanguineous group. Multivariate logistic regression did not deduce any association of either of the study groups, but a significant association of risk factors with dental caries was observed. Conclusion: Dental caries that has multifactorial etiology, both environment and genetic factors, had an influence on the causation of dental caries in this study.
Keywords: Community education, consanguinity, dental caries, inbreeding, risk factor
|How to cite this article:|
Khan SY. Inheritance and susceptibility to dental caries: A community-based study. J Int Soc Prevent Communit Dent 2020;10:148-55
| Introduction|| |
In clinical genetics, a “Consanguineous Marriage” is defined as a union between two individuals who are related as second cousins or closer, where a second cousin consanguineous marriage goes as a marriage between children of first cousins. They share great-grandparents. The first comprehensive study about effects of consanguineous marriage/inbreeding on human population started in the late 1940s with the historical work of Neel and Schull in Hiroshima and Nagasaki, Japan.,, There is evidence of an inherited susceptibility to dental caries, but unfortunately it is quite limited. However, from a preventive aspect, the relative influence of genetics and environment should be known as that would help in modifying and recommending the preventive measures. Therefore, this issue becomes very important and that is why this study was planned with a hypothesis that there is no difference in the occurrence of dental caries in either of the study groups—consanguineous and non-consanguineous.
| Material and Methods|| |
A household survey using a cross-sectional study design was planned. Multilayered sampling method (stratified random sampling) was used. In the first layer, it was assumed that the prevalence of consanguinity itself is around 20% in the study population. At 95% confidence interval (CI) and 80% power and adding for contingency, we went with a sample of 2000 (1600 non-consanguineous and 400 consanguineous). In order to obtain the above calculated sample size in Aligarh city, Uttar Pradesh, India (municipal corporation), which has 70 wards, and to ensure that each ward in the sampling frame has the chance of being selected, the wards were numbered; then a number was selected at random between 1 and 10. For this sampling, ward 4 was picked up and then every 10th ward was selected such as 4, 14, 24, 34, 44, 54, 64, which ended as 7 wards in total by systematic random sampling. The same procedure was adopted for the selection of households by systematic random sampling. The selected ward 4 had 1505 households. Of these households, every 10th household was picked up, which came out to be 150 households in ward 4. The same procedure was adopted in the selection of households in the remaining selected 6 wards (156+481+148+247+306+114), which came out to a total of 1597 households in 7 wards. So, we had a sample size of 2000 (1600 non-consanguineous and 400 consanguineous couples) living in 1597 households in 7 wards of Aligarh city [Figure 1]. The study population included the children aged 6–9 years (1600 non-consanguineous and 400 consanguineous) living in 1597 households in 7 selected wards of Aligarh city. The sampling frame was bound by the following inclusion and exclusion criteria.
- Children aged 6–9 years.
- Permanent residents of Aligarh city; living permanently in Aligarh since birth.
- Healthy children.
- Children living continuously outside Aligarh for a duration exceeding 6 months ever since their birth.
- Non-healthy children.
- Premature births.
- All those not willing to participate in the study.
Permission to carry out the study was obtained from the Institutional Ethics and Research Advisory Committee (D. No. 41/FM/04/08/15). Informed consent was obtained from all the parents of the respondents and they were assured of the confidentiality of the information given by them. All the procedures have been performed as per the ethical guidelines laid down by the Declaration of Helsinki (2008).
To conduct a pilot study and to remove intra-observer bias, the information was recorded on a predesigned questionnaire, which was administered to 20 children. These 20 children were not included in the study sample. The study was conducted by a single examiner. Standardization and validity of the observer was carried out before the conduct of the study. The mean κ value was found to be 0.86. The overall internal reliability of the questionnaire was 0.74 according to Cronbach α. After testing and making necessary corrections in the questionnaire used in the pilot study, the responses were recorded on a self prepared and now a pretested questionnaire. History of risk factors for dental caries was taken (World Health Organization [WHO] Oral health questionnaire for children). Decayed-missed-filling teeth/decayed-extracted-filled teeth (DMFT/deft) index was recorded in accordance with the WHO criteria for epidemiological studies. Oral examination was performed in natural light with children in supine position.
Data were analyzed using IBM, Statistical Package for the Social Sciences (SPSS) (Statistics for Windows software, version 16.0). Descriptive statistics, Student t test, chi-square test, and multivariate logistic regression were used, with a P value of < 0.05 as significant.
| Results|| |
[Table 1] shows the highest number of respondents in non-consanguineous group and consanguineous group as 506 (31.6%) 8-year olds and 136 (34%) 7-year olds, respectively. The difference was statistically highly significant (P < 0.001). Males outnumbered females in both the study groups, that is, 992 males (62%) in non-consanguineous and 276 males (69%) in consanguineous group. Difference was statistically significant (P = 0.009). By religion, majority of respondents in non-consanguineous were Hindus, 1152 (72%), whereas 386 (96.5%) Muslims were in majority in consanguineous group. The difference was statistically highly significant (P < 0.001). [Table 2] presents the DMFT score for the non-consanguineous group and the consanguineous group as 2.02 ± 1.42 and 1.82 ± 0.90, respectively, and the deft score for the non-consanguineous group and the consanguineous group as 3.02 ± 2.13 and 4.06 ± 2.32, respectively. [Table 3] shows the comparison of mean values of DMFT and deft score in consanguineous and non-consanguineous group by Student t test for equality of means; D component (P = 0.003), d component (P < 0.001), and def score (P < 0.001) were statistically significant in the consanguineous group. For multivariate logistic regression analysis, dental caries was the dependent variable, and consanguinity and associated risk factors (demographic, feeding practices, oral hygiene practices) were the independent variables [Table 4]. In this study by multivariate logistic regression, no significant association was deduced between either of the study groups and dental caries. The association of dental caries with risk factors showed the following the results. Under demographic factors, Unemployment (p < 0.001, odd’s ratio (OR) -4.504, CI = 2.512- 8.075), with regard to oral hygiene practices: frequency of teeth cleaning (never, once a day), mode of cleaning (wooden toothpick = 0.051, OR = 0.283, CI= 0.079-1.007), use of tooth paste (p < 0.001, OR = 1.531E7, CI = 1.00E7-2.130E7) and no knowledge of respondents regarding the use of fluoridated tooth paste showed an association with dental caries. In relation to feeding practices, frequency of sweets consumption (every day), milk with sugar (never, several times a month, once a week, every day), tea with sugar (several times a month, several times a week), and nocturnal bottle feeding with milk (P < 0.001; OR = 1.949, CI = 1.307–2.907) had a significant association with dental caries.
|Table 1: Frequency distribution of personal characteristics between consanguineous and non-consanguineous group|
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|Table 2: Decayed-missed-filling teeth and decayed-extracted-filled teeth index of respondents|
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|Table 3: Comparison of means of scores of D, M, F, and DMF, d, e, f and def in two groups by Student t test|
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| Discussion|| |
Dental caries is an infectious and multifactorial disease caused by interaction between microorganisms, substrate, tooth, and time. The evidence in support of an inherited susceptibility to dental caries is quite limited. From a preventive aspect, the relative influence of genetics and environment should be known as that would help in modifying and recommending the preventive measures. Genes are involved in tooth eruption, tooth morphology, saliva, oral flora, arch shape, dental spacing, and immune response; hence, they are capable of influencing the individual susceptibility to dental caries.
In the clinical examination of this study, DMFT score for non-consanguineous group and consanguineous group was 2.02 ± 1.42 and 1.82 ± 0.90, respectively. The deft score for non-consanguineous group and consanguineous group was 3.02 ± 2.13 and 4.06 ± 2.32, respectively, which was statistically significant (P < 0.001). Major contribution was offered by the decayed component, probable explanation being that dental care is still considered to be neglected in developing countries. Furthermore, poor accessibility, availability of dental health services, and cost also play their role. Reddy et al. reported a deft and DMFT score of 1.49 and 0.57, respectively, whereas Poornima et al. found a deft and DMFT score of 2.77 and 0.26, respectively, in their studies. The DMFT score was lower as compared to deft score in this study, as the majority of respondents in non-consanguineous group were 8-year olds, whereas in consanguineous group, the majority were represented by 7-year-old respondents where only a few permanent teeth had erupted.
Consumption of cream biscuits/cakes once a week, soft drinks every day, sweets/candy several times a week (2–3 times), and tea with sugar are documented risk factors associated with dental caries., These refined and additional sugar provides more carbohydrate source to promote acid production, hence favoring a high DMFT/deft score. Using toothbrush and paste as a cleaning aid and having knowledge about fluoride in the same group with aforementioned quoted favorable eating habits for the causation of dental caries can be attributed to the social desirability to provide correct answers, similar views were expressed in studies by Ahamad et al., Al-Darwish, and Al-Samadani et al. Another probable possible explanation could be the role of genes in saliva, tooth morphology, immune response, and oral flora, rendering the respondents more susceptible to dental caries in this study, again an interesting area of further research.
| Conclusion|| |
After studying the confounding factors and the statistically significant association of deft score with consanguineous group, one can conclude that dental caries that has multifactorial etiology, both environmental and genetic factors, had an influence in the causation of dental caries in this study. Individual, family, and community have to be educated through information education communication programs, and awareness has to be created among them, regarding the consequences of consanguineous marriages. Collaboration between dental professionals and geneticists is needed.
For this study, there is a possibility of information bias, especially regarding memory recall. Being a cross sectional study, it gave no idea about the etiology, period prevalence and incidence rate.
Importance to pediatric dentists
- Dentist should know that dental caries follow an inheritance pattern, and they can play an active role with the geneticist in premarital counseling and patient education.
- This voluntary action will help to create awareness among patients that not only medical conditions but dental conditions too have an association with consanguinity.
I thank all my patients for their immense cooperation.
Financial support and sponsorship
This was a self-financed study.
Conflicts of interest
There are no conflicts of interest.
As per ICJME guidelines, only I was involved in the study design, conception, data collection and acquisition, interpretation and manuscript writing.
Ethical policy and institutional review board
All procedures have been performed a per the ethical guidelines laid down by the Declaration of Helinski (2008). Permission to carry out the study was obtained from the Institutional Ethics and Research Advisory Committee of Faculty of Medicine, Aligarh Muslim University (D.No.41/FM/04/08/15).
Patient declaration of consent
Informed written consent was obtained from all the parents of the respondents for participation in the study and publication of the data for research and educational purposes was sought before the start of the study.
Data availability statement
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[Table 1], [Table 2], [Table 3], [Table 4]