Prevalence and determinants of periodontitis among a population with knee osteoarthritis, a cross-sectional study at the Douala General Hospital (Littoral, Cameroon)

Abstract

Osteoarthritis (OA) is a slowly evolving, multifactorial disorder that affects joints, particularly the knee. Periodontitis is an infection of the tissues supporting the teeth, leading to significant tooth loss. Recent studies suggest an association between Knee OA (KOA) and periodontitis, with the prevalence of periodontitis increasing with the severity of KOA. We aimed to determine the prevalence and distribution of periodontitis and the association between the severity of KOA and periodontitis in subjects living with KOA. A cross-sectional study was conducted in an outpatient clinic at the Rheumatology unit of the Douala General Hospital between October 2022 and June 2023. Data were collected using a questionnaire, an endo-buccal examination grid, radiological images and medical records. A multivariate analysis using logistic regression was performed, including the relevant variables in the bivariate analysis. We included 253 participants (201 women) with a median age of 63 years [54–70]. The mean visual analog scale was 52.7 ± 27.9 mm. The mean Lequesne index was 12.25 ± 5.03. Kellgren and Lawrence (K&L) grade 2 was predominant (61.7%), as was tricompartimental KOA (85.4%). The brushing method was appropriate for 40.3% of the participants, while more than a quarter (26.7%) were brushing their teeth for more than 3 min. The oral hygiene was good for only the third (33.6%) of the population. The prevalence of periodontitis was 62.5% [56.1–68]. Periodontitis was significantly associated with radiological K&L grade 4 (OR 5.39 [1.27–28.98]; p = 0.03), poor oral hygiene (OR 34 [7.46–277.71]; p < 0.001), visits to the dentist [in case of problems] (OR 8.54 [3.09–28.58]; p < 0.001) and brushing time (OR 21.93 [5.66–123.24]; p < 0.001). Many participants in this study had poor brushing habits, and only a few had good oral hygiene. Periodontitis is common in patients with KOA, affecting almost 2 patients out of three at the Douala General Hospital in Cameroon and is associated with the severity of KOA, poor oral hygiene and poor oral hygiene habits.

Introduction

Knee osteoarthritis (KOA) is the most common type of osteoarthritis (OA) of the limbs and one of the leading causes of disability^1,2. Previously, OA was considered a “degenerative” disease, the inevitable accompaniment of aging, with ‘‘wear-and-tear” as the main pathogenic mechanism¹. Now, the pathogenesis of OA continues to evolve, moving from a cartilage-limited to a multifactorial disease that affects the whole joint². Indeed, OA is increasingly seen as a metabolically active and dynamic process arising from an imbalance between the repair and destruction of joint tissues, which may be triggered by a variety of mechanical and biochemical insults^1,2. Accumulating evidence indicates that chronic and low-grade joint inflammation, mediated primarily by the innate immune system and to a lesser degree the adaptive immune system, has a critical role in the pathogenesis of OA³. In addition to co-morbidities such as obesity, excessive joint stress triggers inflammation of the cartilage with subsequent degradation, mediated by the release of inflammatory and extracellular cartilage matrix-degrading factors such as cytokines, nitric oxide, toll-like receptors, and matrix metalloproteinases^3,4. In addition, complement activation is thought to play an essential role by affecting the expression of inflammatory and degradative molecules in joints^3,4.

Periodontitis is another disease whose pathogenesis is mediated by the inflammatory complement cascade⁵. Periodontitis is a chronic, multifactorial inflammatory disease associated with dysbiotic plaque biofilms and characterized by progressive destruction of the periodontium and alveolar bone caused by biofilm-forming microorganisms⁶. Its primary features include the loss of periodontal tissue support, manifested through clinical attachment loss (CAL) and radiographically assessed alveolar bone loss, the presence of periodontal pocketing (PP) and gingival bleeding⁶. Periodontitis has been found to be associated with many diseases, including vascular, inflammatory and metabolic diseases^{7, 8, 9–10}. The pathogenesis includes mainly systemic chronic inflammation, but also microbial dysbiosis and autoimmune mimicry^11,12.

The relationship between periodontitis and chronic inflammatory rheumatic diseases like rheumatoid arthritis (RA) and osteoporosis is well documented¹³. There is scarce information about the link between periodontitis and OA. Periodontal pathogens, in PD, may indirectly trigger OA through several mechanisms, including autoantibodies production or humoral immunity related to bacterial infection. Data suggests a time-dependent bidirectional pattern between KOA and periodontitis^{14, 15, 16, 17–18}, and the more severe the KOA, the stronger the association^{15, 16–17}. To our knowledge, there are no African studies on periodontitis in OA. Given the importance of infectious diseases in sub-Saharan Africa and the difficulties in maintaining adequate dental hygiene, we assume that the prevalence of periodontitis will be higher in the population of people living with KOA and associated with the severity of the disease. This prompted us to investigate the prevalence, the distribution and determinants of periodontitis in patients with symptomatic KOA at the Douala General Hospital (a reference hospital in Douala, Cameroon), as well as the association between the severity of KOA and periodontitis.

Patients and methods

Study design

We performed a hospital-based cross-sectional study and a nested case–control study with prospective recruitment over 09 months (from October 2022 to June 2023) at the outpatient Rheumatology unit of the Douala General Hospital, Cameroon.

Participants and sampling

Our source population consisted of patients aged 30 and over, followed up or newly diagnosed for KOA, defined according to the ACR¹⁹, EULAR²⁰ criteria, or NICE guidance²¹, and with a radiographic grade of Kellgren and Lawrence ≥ 2²².

Using a prevalence of 9.9%²³, our minimum sample size was calculated as 138 individuals for the descriptive component and 178 individuals (1:1), i.e. 89 cases and 89 controls, for the analytical component. For the descriptive part of our study, we included all patients with KOA who met the following criteria: (i) had at least 50% of their teeth present in the mouth, (ii) had given their consent to participate in the study. Patients who had undergone periodontal therapy in the previous 6 months, or with a knee infection or trauma or pregnant women were not included. Concerning the analytical part, matched by age and sex, cases were defined as patients with KOA with at least 50% of teeth present in the mouth, who have not received periodontal therapy in the last six months, and with findings consistent with periodontitis⁶. Controls were patients with KOA with at least 50% of teeth present in the mouth, who had not received periodontal therapy in the last six months, and without periodontitis.

Data collection and procedures

All methods related to the study were performed in accordance with the Declaration of Helsinki. The research protocol of the study was approved by the regional ethics committee (n° 2023/6/CE/CRERSH-LITTORAL) and research authorization from the institutional board of the Douala General Hospital (n°033/AR/MINSANTE/HGD/DM/02/23). Consecutive sampling methods were used to recruit outpatients with KOA. All participants were informed of the objectives and procedures of the study, and only those who consented to participate were included, interviewed and examined. Informed consent was validated by a signature on a consent form.

We recorded in a pre-tested questionnaire socio-demographic data, clinical data, particularly KOA-related data (including a visual analog scale for pain, Lequesne’s algofunctional index²⁴, and Kellgren and Lawrence classification²²), and oral and dental hygiene habits. Oral hygiene habits included information on tooth brushing (whether or not the teeth were brushed, the purpose of brushing, daily frequency, type, means used and technique), knowledge of the most frequent oral pathologies and information on dental consultations (annual frequency, indication and previous dental treatments).

The endo-buccal examination was carried out on all participants using a sterile consultation kit (consultation tray, oral plane mirror, dental exploration probe, graduated periodontal probe, treatment gloves). The teeth were dried with an air spray prior to the examination. No staining of the plaque was necessary beforehand. Each tooth was divided into four surfaces: vestibular, lingual (palatal), mesial and distal. It enabled us to search for dental hygiene (through the Silness and Loe Plaque Index²⁵) and the periodontal parameters. A periodontal examination was carried out in the mouth using a graduated Williams’ periodontal probe on all the teeth. The periodontal probing was performed at the proximal mesiovestibular, disto-vestibular, mesio-lingual (mesio-palatal), disto-lingual (disto-palatal), vestibular (midvestibular) and lingual (palatal) (midlingual/palatal) sites of all teeth, i.e. 06 sites per tooth. Third molars, teeth with cervical fillings, vertical root fractures or traumatic gingival recession were not considered. The probing values were recorded on the survey form. Periodontal pocket depth (PP) was measured as the distance from the gingival margin to the bottom of the sulcus (PP). Clinical attachment loss (CAL) was measured as the distance from the enamel-cement junction (ECJ) to the bottom of the sulcus.

The periodontal examination was performed by 2 dental surgeons (HSCT, CDB) to ensure the reliability of our data and to determine the Kappa index. For those participants whose difference was greater than one grade, the opinion of a third dental surgeon (LEEB) was taken. A preliminary scaling was carried out in patients with excess tartar to better assess the PP and CAL. The prevalence of periodontitis and its severity were estimated based on the CAL: stage I or early periodontitis for the site with the largest CAL < 3 mm; stage II or moderate periodontitis for a CAL [3–5]mm; and stage III or severe periodontitis for a CAL ≥ 5 mm⁶.

Variables

The study variables were:

• Sociodemographic: age, gender, occupation, monthly income, residence, marital status, level of education²⁶.

• Variables related to oral health education needs: Time of brushing, means used for brushing, frequency of brushing, duration of brushing, frequency of annual visits to the dentist.

• Co-morbidities: Hypertension, diabetes mellitus, hyperuricemia, epilepsy, peptic ulcer disease (PUD), cancer, gastro-oesophageal reflux disease (GERD), HIV, Hepatitis B virus infection, Hepatitis C virus infection, smoking and alcohol consumption.

• Endo-buccal examination variables: oral hygiene (plaque index), periodontal status (EFP/AAP).

• Radiographic variables of KOA: Kellgren and Lawrence index, location and lesions of KOA.

• Clinical and anthropometric variables: weight, height, BMI (Body Mass Index), pain (VAS, schedule, site), blood pressure and menopause.

• Variables related to risk factors for KOA: history of trauma, age, sex, menopause, obesity, knee arthritis, family history of KOA.

• Variables related to the severity of KOA: Lequesne’s algofunctional index.

• Variables related to other rheumatological conditions: digital osteoarthritis, lumbar osteoarthritis, scapulohumeral osteoarthritis, and coxarthrosis.

Statistical analysis

All statistical analyses were performed using SPSS Statistics version 23.0 (IBM Statistics, Armonk, NY, USA) with significance levels set at α < 0.05. Quantitative variables were described by means (± standard deviation) or by medians (interquartile ranges). Qualitative variables were described as numbers (percentages). The Chi-square test and Fisher’s exact test were used to compare categorical variables in the bivariate analysis.

To eliminate confounding factors such as age, weight and BMI, a multivariate analysis using logistic regression was performed, enabling us to determine the factors associated with periodontitis in our sample. The adjusted odds ratio (ORa) enabled us to identify the risk factors for periodontitis in patients with KOA with a 95% confidence interval. We included in the regression model the relevant variables in association with periodontitis in bivariate analysis.

Results

Baseline characteristics of participants with KOA

Of the 296 patients with KOA received during the study period, 253 (52 men) were included. The flow chart shows the progression of participants throughout the study (Fig. 1). The median age was 63 years [IQ 54–70]. BMI was 32.67 ± 7.73 kg/m². The mean pain VAS was 52.7 ± 27.9 mm, with 62.5% of patients having a pain VAS > 40 mm. The mean Lequesne’s index was 12.25 ± 5.03. An extremely severe disability was found in 40.7% of participants. Two-thirds of our participants had K&L grade 2 (61.6%). Table 1 shows the baseline characteristics of the study population.

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Fig. 1

Participant's flow chart.

Table 1. Baseline characteristics of subjects with knee osteoarthritis.

Variables	Terms	Periodontitis		p value
		Yes	No
Sex	Male	19 (23.2)	19 (23.2)	1
	Female	63 (76.8)	63 (76.8)	1
Level of study	Illiterate	3 (3.7)	6 (7.3)	0.495
	Primary	39 (47.6)		< 0.001
	Secondary	20 (24.4)	38 (46.3)	0.003
	Superior	20 (24.4)	29 (35.4)	0.125
Type of comorbidities	Diabetes	4 (6.6)	8 (14.3)	0.169
	Cancer	0 (0)	5 (8.9)	0.023
	HIV	8 (13.1)	2 (3.6)	0.097
	Hypertension	52 (85.2)	38 (67.9)	0.028
	Gastroesophageal reflux	4 (6.6)	9 (16.1)	0.102
	Hyperuricemia	0 (0)	14 (25)	< 0.001
	Smoking	0 (0)	9 (11)	0.003
	Alcoholism	15 (18.3)	17 (20.7)	0.694
	Others	3 (4.9)	19 (33.9)	0.479
History of familial knee osteoarthritis	Yes	46 (56.1)	48 (58.5)	0.752
Menopause	Yes	44 (69.8)	53 (84.1)	0.057
BMI (Kg/m2)	Normal	14 (17.1)	9 (11)	0.261
	Overweight	18 (22)	35 (42.7)	0.005
	Obese	50 (61)	38 (46.3)	0.060
Location of pain	Median	45 (54.9)	31 (37.8)	0.028
Pain schedule	Mechanical	67 (81.7)	64 (78)	0.559
VAS	[0–4]	42 (51.2)	31 (37.8)	0.084
	[5–7]	35 (42.7)	24 (29.3)	0.073
	[8–10]	5 (6.1)	27 (32.9)	< 0.001
Lequesne Algofunctional Index	14 and over (Extremely significant disability)	33 (40.2)	25 (30.5)	0.191
Lumbar Osteoarthritis	Yes	1 (1.2)	0 (0)	1
Grade of KOA	Grade 2	55 (67.1)	57 (69.1)	0.737
	Grade 3	13 (15.9)	22 (26.8)	0.086
	Grade 4	14 (17.1)	3 (3.7)	0.005
Patellofemoral KOA	Bilateral	29 (100)	28 (100)	1
KOA	Unicompartimental	82 (100)	81 (98.8)	1
	Bicompartimental	0	1 (1.2)
	Tricompartimental	0	0

BMI: Body Mass Index, HIV: Human Immunodeficiency Virus; KOA: Knee Osteoarthritis, VAS: Visual analog Scale.

The quality of oral hygiene in our series was average in 127 (50.2%) participants (Fig. 2). Brushing methods were bad in 151 (59.7%) participants. Table 2 describes the participant’ knowledge of dental disease and their oral hygiene. The mean kappa score for periodontal examination was 1.

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Fig. 2

Distribution of participants according to the quality of their oral hygiene (according the Silness and Loe Plaque index).

Table 2. Dental disease Knowledge and Oral practices among our study population.

Variables	Terms	Periodontitis		p value
		Yes n(%)	No n(%)
Have you ever heard of periodontitis?	Yes	1 (1.2)	4 (4.9)	0.367
	No	81 (98.8)	78 (95.1)
Definition of periodontitis (n = 5)	Good	1 (100)	0	0.200
	Poor	0	4 (100)
Definition of dental caries	Good	77 (93.9)	82 (100)	0.059
	Poor	5 (6.1)	0 (0.0)
Annual frequency of visits to the dentist	Once	2 (2.4)	6 (7.3)	0.277
	In the event of a problem	68 (82.9)	41 (50)	< 0.001
	Never	12 (14.6)	35 (42.7)	< 0.001
Daily frequency of brushing	Once	29 (35.4)	25 (30.5)	0.506
	Twice and Thrice	53 (64.6)	57 (69.5)
Timing of tooth brushing	Morning before meal	30 (36.6)	26 (31.7)	0.510
	Evening at bedtime	1 (1.2)	1 (1.2)	1
	Morning before meal and evening at bedtime	50 (61)	41 (50)	0.157
	Morning after meal and evening at bedtime	1 (1.2)	0 (0.0)	1
	Morning before and after meal and evening at edtime	0 (0.0)	14 (17.1)	< 0.001
Dental brushing materials	Toothbrush only	0 (0.0)	8 (9.8)	0.007
	Toothbrush and toothpaste	80 (97.6)	72 (87.8)	0.0016
	Salt	2 (2.4)	2 (2.4)	1
	Bicarbonate	4 (4.9)	2 (2.4)	0.682
	Ashes	5 (6.1)	2 (2.4)	0.443
	Coal	5 (6.1)	1 (1.2)	0.210
Brushing method	Good	18 (22)	43 (52.4)	< 0.001
	Poor	64 (78)	39 (47.6)
Duration of dental brushing (in minutes)	˂ 3	28 (34.1)	3 (3.7)	< 0.001
	≥ 3	54 (65.9)	79 (96.3)
Dental brushing motivation	To keep it clean	70 (85.4)	74 (90.2)	0.34
	To avoid dental cavities	56 (68.3)	62 (75.6)	0.297
	For a beautiful smile	8 (9.8)	11 (13.4)	0.464

Prevalence and determinants of periodontitis

The diagnosis of periodontitis was made in 158 patients (62.5%) (Fig. 3). The distribution of the severity of periodontitis is shown in Fig. 4. Moderate periodontitis accounted for 57.6% of the patients.

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Fig. 3

Prevalence of periodontitis in subjects with knee osteoarthritis in our study population.

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Fig. 4

Distribution of the severity of periodontitis.

Table 3 shows the factors associated with the presence of periodontitis, after bivariate and multivariate analysis. In bivariate analysis, the factors significantly associated with periodontitis included: level of education, overweight, housewife, K&L grade 4, severe pain, moderate disability, hypertension, annual visit to the dentist in the event of a problem, and poor brushing duration, and poor oral hygiene (Tables 1 and 2). However, in multivariate analysis, factors that independently influenced the presence of periodontitis included: K&L grade 4 (ORa 5.39 [1.27–28.98]; p = 0.03), annual visit to the dentist in the case of a problem (ORa 8.54 [3.09–28.58]; p < 0.001), poor brushing duration (ORa 21.93 [5.66–123.24]; p < 0.001), poor oral hygiene (ORa 34.92 [7.46–277.71]; p < 0.001).

Table 3. Multivariate analysis of factors associated with the presence of periodontitis in subjects living with KOA.

Variables	p value	cOR (95% CI)	Adjusted p value	aOR (95% CI)
Grade 4 KOA (yes/no)	0.005	5.42 (1.49–9.97)	0.03	5.39 (1.27–28.98)
Annual frequency of visits to the dentist (in case of problem)	< 0.001	4.857 (2.364–9.975)	< 0.001	8.54 (3.09–28.58)
Brushing method (bad/good)	< 0.001	3.920 (1.988–7.732)	0.07	2.29 (0.94–5.73)
Brushing duration (Bad/good)	< 0.001	13.654 (3.52–47.181)	< 0.001	21.93 (5.66–123.24)
Poor oral hygiene (yes/no)	< 0.001	1.667 (3.320–64.800)	< 0.001	34 (7.46–277.71)
Hypertension (yes/no)	0.028	2.007 (1.075–3.749)	0.11	2.00 (0.86–4.79)

KOA: Knee Osteoarthritis, CI: confidence Interval, cOR: crude Odd Ratio, aOR: Adjusted Odd ratio.

Discussion

To the best of our knowledge, this is the first study to demonstrate that periodontitis is associated with KOA in an African setting. We found periodontitis in two-thirds of our patients with KOA. This prevalence is higher than those previously described, varying between 26 and 54.6%^{16, 17–18}. This elevated prevalence could be explained mainly by the greatest prevalence and impact of periodontitis in Africa^27,28, probably as a result of the burden of infections^29,30, the design of each study, the older age of participants, the different methods used to determine periodontitis in the studies and by the large number of co-morbidities presented by the participants. Specifically, and as in a previous study¹⁶, we showed that periodontitis was significantly associated with poor oral health-related behaviors and limited access to dental care.

This study found that the severity of periodontitis increased as the radiographic grade of the KOA increased. These results are consistent with those found in Iraq (2020) in a population of Iraqi patients, where those with KOA were 2.3 times more likely to have periodontitis¹⁸. Furthermore, the presence of periodontitis was not affected by age or sex¹⁸. Participants with radiographic grade 4 in this study were five times more likely to develop periodontitis. This result is similar to those found in several previous studies. In Korea, periodontitis is associated with the presence and severity of KOA. The risk of periodontitis increased significantly with increasing severity of osteoarthritis (according to K&L) from aOR 1.30 for grate 1–1.39 for grade 4¹⁶.

Although the prevalence of periodontitis is lower in KOA than in RA^{31, 32–33}, KOA joins inflammatory rheumatic diseases and bone diseases in their association with periodontitis. While, like us, some studies have observed periodontitis in patients with KOA, other studies have shown that periodontitis can precede the onset of KOA. When asked "Who is the chicken and who is the egg", a recent study suggested that an increased risk of periodontitis and KOA were observed for patients with either disease¹⁴. This association would be associated with the severity of KOA and/or periodontitis^{14, 15–16}. In our study, this link with the severity of OA was only found for severe structural damage and not for pain and disability. This discrepancy is also found in certain studies^{16, 17–18}. We are unable to say whether the radio-clinical dissociation in OA could explain this discrepancy. Nevertheless, previous studies globally suggested that periodontitis is associated with the presence of KOA^{14, 15, 16, 17–18}, structural severity of KOA leading to prosthetic surgery^{15, 16–17} and type 2 diabetes might be a booster of this relationship¹⁵. However, a two-sample bidirectional Mendelian randomization analysis using publicly released genome-wide association studies (GWAS) statistics did not demonstrate a causal effect of genetically predicted periodontitis and OA, neither did genetically predicted OA on periodontitis³⁴. Nevertheless, apart from the complement pathway, some other pathways could explain the link between periodontitis and KOA. In a mouse model of OA, greater alveolar bone loss was found in cases of periodontitis³⁵. Also, the same bacterial DNA has been found in the periodontal tissue and synovial fluid of patients with OA³⁶. These suggest that bacterial pathogens causing periodontitis might spread to joints through the bloodstream³⁷ and/or bacterial lipopolysaccharides may increase the risk of individuals developing OA³⁶. These findings support the hypothesis that periodontal pathogens could modify the homeostasis of the joint via a direct effect or a cross-reaction with immunologic tolerance of the bacterial biofilm acting on the cartilage and surrounding tissues. In addition, an Omics-based study has identified gene signatures as common significant biomarkers/targets associated with the molecular mechanism of periodontitis, RA and OA³⁸. Otherwise, promising results already suggest the efficacy of certain symptomatic slow-acting drugs for OA in periodontitis^17,39. Conversely, introducing a conditioned medium from periodontal ligament-derived stem cells to osteoarthritic joints could be a potential treatment to prevent OA progression by inhibiting inflammation³¹. Further studies are needed to appreciate if specific treatment of periodontitis or KOA might be effective for patients with either disease. Also, it will be interesting to know whether improving oral health-related behaviors and access to oral health care could be a solution to reduce the prevalence and severity of both periodontitis and KOA. In the meantime, clinicians treating OA should consider the need for dental care for their patients¹⁷.

This study has many limitations. Using a cross-sectional study design does not allow us to demonstrate a cause-and-effect relationship between periodontitis and OA and evidence for the bidirectional nature of the association, as would have been possible with a prospective cohort study. Data on oral health practices relies on participant declarations. It is therefore impossible to confirm it. Also, performing bacteriological samples from the knee and oral cavity would have provided further evidence in favor of this link. However, for ethical reasons, samples from the knee can be taken globally during surgery, which was not the case for the patients in our study. The non-randomized sampling technique related to the hospital-based design is a major selection bias. Furthermore, the data collected here are hospital data, only from outpatients. We did not include any inpatients. Then, the findings of this study cannot be generalized without caution. A community evaluation could probably provide more reliable and extrapolable results.

In conclusion, in this study, aiming to determine the prevalence and distribution of periodontitis and the association between the severity of KOA and periodontitis in subjects living with KOA, we found that periodontitis prevalence is very high with most of participants having a poor oral hygiene and practices. Periodontitis was associated with severe KOA, poor oral health practices and poor oral hygiene. There is a need for studies to indisputably demonstrate the link between KOA and periodontitis, specifically in the community with a random sampling. Until then, there is a need to improve oral health-related behaviors and access to oral health care for patients with KOA.

Acknowledgements

An earlier version of this manuscript was presented as an abstract entitled Prévalence et déterminants des parodontites chez les sujets suivis pour gonarthrose au Cameroun at The French Congress of Rheumatology (December 2023, Paris, France). according to the following link: https://www.sciencedirect.com/science/article/abs/pii/S1169833023007676; https://doi.org/10.1016/j.rhum.2023.10.394. We thank the participants and all the Rheumatology and Stomatology Units of the Douala General Hospital staff and its Director Pr Henri Nname Luma.

Author contributions

Design and design: HSCT, FKL, SRSN, CMT, JA. Data collection: HSCT, FKL, SRSN, CDN, LEEB. Data analysis and interpretation: CDN, HSCT, FKL, SRSN. Manuscript writing: HSCT, FKL, SRSN, CMT, CDN, FAT, SPC. Manuscript revision: HSCT, FBS, FKL, SRSN, CMT, LEEB, SPC. All authors read and approve the final version for publication.

Funding

No funding was received for this study.

Data availability

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request. Data are located in controlled access data storage at the Faculty of Medicine and Pharmaceutical Sciences of the University of Dschang.

Declarations

Competing interests

The authors state they have no competing interests.

Ethics approval and consent to participate

We have obtained an ethical clearance from the Ethical Regional Committee for the Littoral Region (n° 2023/6/CE/CRERSHLITTORAL) and research authorization from the institutional board of the Douala General Hospital (n°033/AR/MINSANTE/HGD/DM/02/23). We conducted this study in strict compliance with the fundamental principles of scientific research in medicine. Patients were free to participate in the study without external constraints. We obtained an informed, written and signed consent form from each participant. Data were only available only for the collection data team through an Excel file.

Abbreviations

AAP

American Association of Periodontology

ACR

American Collège of Rheumatology

ADA

American Diabetes Association

BMI

Body mass index

CAL

Clinical attachment loss

DPSI

Dutch periodontal screening index

EFP

European Federation of Periodontology

EULAR

European Alliance of Association for Rheumatology

HBP

High blood pressure

K&L

Kellgren and Lawrence

KOA

Knee osteoarthritis

MOH

Motivation for oral hygiene

NICE

National Institute for Health and Care Excellence

PLHIV

Patient living with HIV

PP

Periodontal pocket

SPSS

Statistical Package for Social Sciences

VAS

Visual analog scale

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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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