Exploring the Link: A Cross-Sectional Study on the Correlation Between Periodontal Health and ABO & Rh Blood Group Phenotype in Intellectually Disabled Individuals of Dakshina Kannada District

Introduction

Intellectual disability (ID), as defined by American Association of Intellectual and Developmental Disabilities (AAIDD), refers to a condition marked by notable limitations in both cognitive abilities and adaptive skills essential for daily functioning. This encompasses a range of social and practical skills. ID is categorized as either Syndromic intellectual disability (S-ID) or Non-syndromic intellectual impairment (NSID), depending on its co-occurrence with other conditions such as Autism, Down syndrome (DS), and Cerebral palsy (CP).¹ Down syndrome, for instance, results from an additional copy of chromosome 21.² Research has consistently shown a link between inadequate oral hygiene practice and poor oral health, particularly in individuals with Down syndrome.³ Despite similar plaque indices observed among individuals with Down syndrome and their healthy counterparts, altered immune responses among individuals with Down syndrome may have contributed to a higher prevalence of periodontal diseases among them.^4,5 Exploring the origin of periodontal disease is a promising avenue, especially in search for factors that indicate susceptibility to condition. One potential factor under consideration is the correlation between blood groups and periodontal health.⁶ If a definitive link between blood types and periodontal disease were conclusively proven, it could lead to the inference that a particular blood type's antigen enhances susceptibility to the condition. Karl Landsteiner described the blood groups within the "ABO" blood type system.⁷ Faser Roberts explored a connection between blood grouping and vulnerability to chronic diseases, providing an example of genetic susceptibility within families.⁸ While there have been numerous health studies on children with intellectual disabilities, more research is needed, especially in developing countries like India. In light of these considerations, this study was thus undertaken in Dakshina Kannada district of Karnataka state to investigate a possible relationship between periodontal health and blood grouping among intellectually disabled individuals.

Materials and Methods

A total of 548 intellectually disabled individuals attending a special needs school in the Dakshina Kannada district participated in cross-sectional research. Participants with intellectual disability aged between 6 to 25 years, residing in the Dakshina Kannada district, and possessing a minimum of 20 teeth (excluding third molars) were included in study. Consent was obtained from their respective legal guardians. Individuals with history of antibiotic therapy and those who had received periodontal treatment within the past year were excluded. Additionally, individuals with systemic diseases like diabetes mellitus that could possibly affect periodontal health and participants with habits such as smoking, chewing tobacco, or alcohol consumption were excluded.

Written informed consent was obtained from both educational authorities and guardians. Additionally, approval was granted by Institutional Ethical Committee of KVG Dental College, Sullia, under reference number IECKVGDCH/SS41/2022-23. Participants were categorized based on their medical diagnosis (with or without Down syndrome). Socio-demographic details including age, gender, past dental and medical history, and blood group information was documented from existing records. A single examiner conducted clinical examinations using a plane mouth mirror and UNC-15 probe to assess oral health and gingival status. Periodontal health was assessed using the Periodontal Screening and Recording (PSR) index with a WHO probe.

Statistical analysis

Data were analyzed utilizing SPSS version 27, with statistical analyses among the groups performed using a non-parametric test and Chi-square test. P value of less than 0.05 was deemed statistically significant.

Results

Table 1 presents a demographic overview of the study participants. Among 548 individuals, no statistical significance was observed in age distribution; however, males constituted a significantly higher proportion of the sample (61.3%). Participants diagnosed with Down syndrome represented 21%, whereas individuals with cerebral palsy, autism, and learning difficulties comprised 79%. Poor oral hygiene was prevalent among 41% of participants, while mild gingival scores were noted in 71% and a PSR code of 1, indicative of further investigation and treatment was observed in 69.7% of cases. According to Table 1, the distribution of blood groups among participants was as follows: A+ (20.8%), A- (11.3%), B+ (18.7%), B- (7.8%), O+ (16.7%), O- (7.1%), AB+ (7.8%), and AB- (9.8%).

Mean clinical index scores are presented in Table 2, revealing statistically significant differences in terms of oral hygiene, gingival scores, and PSR code among participants.

Table 3 compares mean OHI-S scores, GI scores, and PSR codes with various blood groups, demonstrating a consistent statistically significant difference among all three clinical indices and blood types. Distribution of oral hygiene scores revealed 48% with fair, 44% with good, and 7% with poor oral hygiene. Similarly, significant variations were observed in gingival index values and PSR scores among different blood types, with 71.8% experiencing moderate gingivitis and 69.7% having a PSR code of 1, along with smaller percentages across other PSR codes with 13.32% registering as Score 0, 10.40% as Score 2, 3.46% as Score 3, 3.10% as PSR Score 4. However, no significant differences were observed in clinical parameters when comparing blood groups of participants with Down syndrome, as illustrated in Table 4.

Discussion

Advancements in research have revealed that alongside established etiological agents and environmental factors, several previously unknown variables also play a significant role in causing periodontal disease. Consequently, genetics has emerged as a focal point in evaluating susceptibility to illness. However, there is limited research exploring the correlation between periodontitis and blood grouping system.³ Globally, distribution of ABO system and Rh system blood groups exhibits significant variations. For instance, it is noted that blood type O predominates among Americans and Canadians, blood type B among Chinese and Indians, and blood type A among Eskimos.⁹

Certain forms of disabilities predispose individuals to a higher risk of developing periodontal disease. This heightened susceptibility is attributed to inadequate hygiene stemming from both motor and psychological deficits, alongside systemic alterations that hinder the body's ability to fend off periodontopathogenic bacteria.¹⁰ Down syndrome, or trisomy of the 21st chromosome, is most prevalent chromosomal defect affecting children worldwide. Numerous studies have highlighted development of poor oral health resulting from inadequate oral hygiene practices.³ Only a limited number of studies have endeavoured to explore a correlation between blood group, Rh factor, and periodontal disease among intellectually disabled individuals within the Indian population.

Objective of this study was to examine the potential correlation between ABO blood type and the periodontal condition of individuals with intellectual disabilities. It is recognized that individuals with Down syndrome typically exhibit higher susceptibility to advanced periodontal disease compared to their normal counterparts. This heightened susceptibility is often attributed to the unique composition of subgingival plaque and increased presence of periodontal bacteria in this group. Orner G (1972) conducted a study revealing a notable prevalence of periodontitis among subjects with Down syndrome, assessing their periodontal status using the Russell periodontal index.11 The suitability of the Russell index for community studies over time may be questionable. Therefore, in our current investigation, we utilized OHI-S, GI, and PSR indices to provide a more comprehensive and refined assessment of periodontal health.

In our cross-sectional study, it was additionally discovered that 64.3% of participants with Down syndrome and 56.2% of those with other disabilities exhibited PSR code 1, indicative of plaque-associated gingivitis, necessitating regular oral hygiene interventions. Furthermore, our investigation revealed significantly elevated oral health scores among individuals with Down syndrome compared to subjects with other disabilities. Dinesh et al. observed that children with disabilities encounter significant obstacles in maintaining proper oral hygiene and accessing healthcare, often attributable to a lack of fundamental manual skills or cognitive abilities necessary for establishing appropriate habits.¹² In a cross-sectional analysis conducted by Amira et al. in 2019, involving 174 participants with Down syndrome aged over 14 years, it was reported that only 8.6% of study cohort exhibited severe gingivitis, while 47.2%, 40.8%, and 3.4% experienced mild, moderate, and non-clinical gingivitis, respectively.¹³ Our study reported similar findings, with 51.3% of participants presenting mild gingivitis, 47.8% moderate gingivitis, and 0.8% severe gingivitis.

Roman et al. (2021) found in their study that individuals within the Down syndrome group exhibited clinical periodontal parameters indicative of periodontal health and did not demonstrate clinical differences compared to healthy individuals.¹⁴ Similarly, our study reported comparable results between two groups. However, our study revealed a higher susceptibility to periodontal disease among individuals with Down syndrome belonging to blood group 'O', with individuals of 'AB' group showing the least propensity. This observation echoes findings from studies conducted by Gawrzewska (1975) and Al-askar (2017) on periodontitis in non-Down syndrome patients.^15,6 Moreover, in our study, blood group 'A' was predominant, aligning with findings reported by GP Pai et al. (2012).¹⁶ It is noteworthy that prevalence of ABO blood groups varied across different geographic locations, as noted by Pradhan et al. (1971).¹⁷ However, there is limited evidence regarding an association between ABO blood groups and incidence of dental and oral ailments.

In our study, as depicted in Table 3, a statistically significant relation was observed in percentage distribution of A, B, AB, and O blood groups and oral hygiene, gingival, and periodontal status among groups I and II. These findings are in accordance with the studies conducted by Barros and Witkop (1963) and Al-askar M.^6,18

Furthermore, a noteworthy association was observed between periodontitis and the Rh factor, with a higher prevalence of Rh-positive individuals among those with intellectual disability compared to Rh-negative individuals. This contrasts to the reported findings of Demir et al. (2007) on normal periodontitis patients.¹⁹

It is worth noting that parental blood variables represent significant medical-biological factors contributing to intellectual and physical-movement disabilities. Mehrmohammadi (2015) conducted a study on the relationship between ABO and Rh blood types among parents with multiple disabled children, revealing a significant association between mother's Rh blood type and having a disabled child.²⁰

In terms of limitations of our study, we have not conducted bacterial analysis or immune profiling. However, further research could possibly explore these aspects with a larger sample size, along with microbiological investigations such as culture, PCR, and DNA-DNA panel hybridization, to identify the specific periodontopathic bacteria like P. gingivalis and T. forsythia in the same population. Additionally, we have not considered blood groups of parents. Another significant constraint of our study could be lack of a reference group consisting of orally healthy individuals, which makes interpretation of the data more clear.

Conclusion

To summarize, our study suggests that oral hygiene status of participants with Down syndrome (DS) is reasonably satisfactory, exhibiting less compromise compared to findings from previous research. Findings from our investigation indicate that blood groups and Rh factor can serve as determinants of periodontitis in intellectually disabled individuals. Genetic factors such as blood group antigens may influence the onset and severity of periodontal disease. Thus, incorporating ABO blood group information of patients into periodontal clinics may aid in devising early treatment strategies, particularly for highly susceptible individuals. To further validate our findings and elucidate the biological plausibility, future studies should encompass larger randomly selected samples, point-of-care blood group testing, diverse populations, and longitudinal analyses. This comprehensive approach could enhance external validity of the study and provide a deeper understanding of effects of ABO blood groups on periodontal health.

Conflict of interest

None

Financial support

Nil

Acknowledgment We are thankful to the Principal, participants & guardians of St. Agnes special school, Mangalore, Sandeep special school Sullia, Seon Ashram Trust, Belthangady, Chethana child development centre, Mangalore & Christaraj Navachethan special school, Venoor for their assistance in Data acquisition and help during conduction of the study.