Prevalence of chronic periodontitis in an obese population: a preliminary study
Khan et al. BMC Oral Health
Prevalence of chronic periodontitis in an obese population: a preliminary study
Shahrukh Khan 0
Roslan Saub 2
Rathna Devi Vaithilingam 0
Syarida Hasnur Safii 0
Shireene Rathna Vethakkan 1
Nor Adinar Baharuddin 0
0 Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya , Lembah Pantai, 50603 Kuala Lumpur , Malaysia
1 Department of Medicine, Faculty of Medicine, University of Malaya , 50603 Kuala Lumpur , Malaysia
2 Department of Community Oral Health & Clinical Prevention, Faculty of Dentistry, University of Malaya , Lembah Pantai, 50603 Kuala Lumpur , Malaysia
Background: Chronic periodontitis (CP) is a global public health issue. Studies have suggested CP could be linked to obesity due to their similar pathophysiological pathway. The aim of this study is to determine the prevalence of CP and to assess the predictors for CP among the obese Malaysian population. Methods: This is a cross-sectional study on obese participants. Obesity is defined as an individual who has Body Mass Index (BMI) ≥27.5 kg/m2. A convenience sampling method was used. A total of 165 paricipants were recruited. This study involved answering questionnaires, obtaining biometric and clinical measurements of Visible plaque index (VPI), Gingival bleeding index (GBI), Probing pocket depth (PPD) and Clinical attachment loss (CAL). Data analysis was carried out using SPSS statistical software (SPSS Inc., version 20, US). Results: A total of 165 participants; 67 (40.6 %) males and 98 (59.4 %) females participated in the study. Mean age of the participants was 43.9 (±8.9). The prevalence of CP among the obese population was found to be 73.9 %. Out of this, 43 and 55 % were categorised as moderate and severe CP respectively. Around 64 % of participants had sites with CAL ≥4 mm and participants with sites with PPD ≥4 mm were reported to be 25 %. Around 83 % of the participants had sites with GBI ≥30 and 92 % of participants had sites with VPI ≥20 %. GBI and VPI were found to have significantly higher odds for CP. Conclusion: Prevalence of CP was high among obese Malaysians. GBI and VPI were potential predictors for CP in this obese population.
Chronic periodontitis; Obesity; BMI
Chronic periodontitis (CP) is a major oral health
problem and it is considered as one of the reasons for tooth
loss in developing and developed nations. Worldwide,
the prevalence of CP in the general adult population is
reported to be 30–35 %, with approximately 10–15 %
diagnosed with severe CP . In Malaysia, the
prevalence of the CP and severe CP was reported as 48.5 and
18.2 % respectively . Studies have suggested that CP
may have a negative impact on the quality of life (QoL)
of the affected adults and this could include difficulty in
chewing, speaking, or social interactions . Various risk
factors have been identified associated with CP such as
diabetes mellitus, cardiovascular diseases, smoking and
Obesity is a major public health concern in both
developing and developed countries. The prevalence of
obesity among adults was estimated at 24 % worldwide ,
10–30 % in South East Asia  and 27.2 % in Malaysia
. Obesity is a potential risk factor for major complex
diseases such as diabetes, cardiovascular diseases,
metabolic syndromes as well as CP . The relationship
between obesity and CP was first reported in
experimental animals . Subsequent human studies have
confirmed that obesity increases risk for CP [10, 11]. A
5 year longitudinal study conducted in Japanese workers
demonstrated a positive relationship between BMI and
periodontal disease . A systematic review based on
26 cross sectional studies, 6 case control studies and 1
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cohort study concluded that there was a positive
association between obesity and periodontitis .
To date, there is no published study on the
prevalence of CP among the obese Malaysian population
and only limited published information in the South
East Asia region. The aim of this study was to
determine the prevalence of CP and its predictors in the
obese Malaysian population.
Study design and population
This is a cross sectional study on the obese participants.
Obesity is defined as an individual who has body mass
index (BMI) ≥27.5 kg/m2 based on the Asian
classification of BMI . A convenience sampling method was
used for the participant’s recruitment. The inclusion
criteria consisted of the obese participants, aged 30 years
and above and have at least 12 teeth present. Participants
who had received periodontal treatment within the last
4 months and who had been on the antibiotics within the
past 4 months were excluded, also those participants who
required prophylactic antibiotic coverage or those on
systemic or topical steroidal anti-inflammatory drugs for
the past 4 months, pregnant or lactating mothers and
those with learning disability were excluded.
Participants who fulfilled the inclusion and exclusion
criteria were invited to participate. Participants were
recruited for a period of 9 months from February 2013
until October 2013. Participants were recruited through
three different routes i.e. Obesity clinics (University
Malaya Medical Center), Primary Care Unit (Faculty of
Dentistry, University of Malaya) and from the Malaysian
Periodontal Database and Bio bank System . The
nature of the study was explained and a written
informed consent was obtained from participants who
agreed to take part in the study. Ethical approval was
obtained from the Medical Ethical Committee Faculty of
Dentistry (DFOP 1213/0079 (L)) and the University
Malaya Medical Centre (MEC 96223). This research was
carried out in accordance with the World Medical
Association, Declaration of Helsinki guidelines. All participants
(i) answered the questionnaire and (ii) underwent clinical
assessments (biometric and clinical measurements).
The questionnaire covered the socio-demographic of
participants (age, gender, ethnicity and level of
education), habits of smoking and alcohol intake, tooth
brushing frequency and last dental visit. The participants were
divided into three subgroups based on age i.e. (i) 30–39
years, (ii) 40–49 years and (iii) 50 and above. Ethnic
groups consisted of Chinese, Malays and Indians.
Education level was assessed as primary, secondary or tertiary
level of education. Smoking habit was categorized into
two sub-categories: (i) current smokers and (ii) former/
never smokers. Alcohol intake was classified as: (i) yes
(alcohol users) and (ii) no (non-alcohol users). The
participants were classified into 3 categories based on
their last dental visits as those (i) who last visited a
dentist <2 years, (ii) who last visited a dentist ≥2 years
and (iii) who never visited a dentist. Tooth brushing
frequency was classified as participants who brush their
teeth, (i) ≥2times per day and (ii) once daily.
The biometric assessment was carried out using the
body mass index (BMI) as a measure of obesity. The
height (in meter) and body weight (in kg) were measured
and used to calculate the BMI using the formula below:
BMI = Body weight (kg)/Body height2 (m2)
Obesity was subcategorised based on the BMI as
Obese I i.e. those with 27.5–34.9 kg/m2, Obese II i.e.
those with 35–39.9 kg/m2 and Obese III i.e. those with
BMI ≥ 40 kg/m2.
A full mouth periodontal measurement (FMPM)
included Visible Plaque Index (VPI) , Gingival
Bleeding Index (GBI) , Probing Pocket Depth (PPD),
Recession (R) and Clinical attachment loss (CAL)
assessment. A William’s periodontal probe (Nordent, US) with
calibrated markings was used and measurements were
recorded in millimetres (mm). The FMPM were carried
out on all teeth present except third molars. Six sites per
tooth were examined which included mesio-buccal,
mid-buccal and disto-buccal and also the
mesiopalatal/lingual, mid-palatal/lingual and disto-palatal/
lingual surfaces. VPI and GBI were recorded using
CP was defined based on the case definition as shown
in Table 1 . Three examiners carried out the FMPM
(SK, ZA and SB). Standardisation and calibration were
carried out. Inter- and intra-examiner reproducibility
was conducted. Kappa scores were estimated as 0.76
and 0.82 for inter-examiner and intra-examiner
Statistical analysis was carried out using statistical
packages for social sciences software (SPSS Inc., version 20,
US). The characteristics of participants were assessed
using frequency distribution for categorical variables and
mean (standard deviation, ±) for continuous variables.
The frequency distribution was used to estimate
prevalence of CP in relation to socio-demographics, habits,
last dental visit, tooth brushing frequency and BMI
Table 1 Case Definition Proposed for Population-Based
Surveillances of Chronic Periodontitis by Eke et al. 
Table 2 Socio-demographic characteristic s, habits and BMI
distribution among obese and their CP prevalence
≥2 interproximal sites with CAL ≥3 mm and ≥2
interproximal sites with PPD ≥4 mm (not on
same tooth) or one site with PPD ≥5 mm
≥2 interproximal sites with CAL ≥4 mm and ≥2
interproximal sites with PPD ≥5 mm (not on
≥2 interproximal sites with CAL ≥6 mm (not on
same tooth) and ≥1 interproximal site with
PPD ≥5 mm
indicator of obesity. The cross tabulation was carried
out for VPI, GBI, PPD ≥4 mm and CAL ≥4 mm in
relation to CP. Mean (standard deviation “±”) were
calculated for mean PPD and mean CAL. Multivariate binary
logistic regression analysis was used to identify the
predictors for CP in obese population, which includes social
demographic factors (gender, level of education and
ethnicity), smoking and alcohol habits, last dental visit,
tooth brushing frequency, level of BMI and periodontal
parameters (GBI and VPI).
A total of 165 obese participants with mean age 43.9
(±8.9) participated in the study. The participants’ age
ranged from 30 to 66 years. Table 2 summarizes the
socio-demographic characteristics, habits and BMI of
the participants and its CP prevalence. On the basis of the
characteristics of the participants, around 70 % of the
participants were in an age range of 30–49 years. Females
were predominant part of the sample (59.4 %). Around
77 % of the participants were Malays. Almost 93 % of the
participants had at least secondary education. Smoking
and alcohol intake were found uncommon characteristics
of the sample population. About 6 out of 10 participants
last visited a dentist more than 2 years ago. Most of the
participants (84.8 %) brushed their teeth twice daily.
Around 70 % of the participants were in Obese I category.
In this study, the prevalence of CP among the obese
participants was reported to be 73.9 %. Out of this, 43.4
and 55 % were moderate and severe CP respectively. Of
those with CP, almost 40 % was those in the young age
group (30–39 years) and almost two third were females.
Around 23 % obese participants with CP were
nonMalays and around 91 % obese participants with at least
secondary education had CP. Obese smokers and alcohol
users had a CP prevalence of 17.2 and 9 % respectively.
Around 62 % of the obese participants with CP had last
dental visit more than 2 years ago. Almost 83 % of obese
participants with CP brushed their teeth twice daily.
• Secondary and Tertiary
Tooth Brushing frequency
• ≥2 year
Table 3 shows the distribution of periodontal
parameters in relation to CP among obese participants. Around
83 % participants had sites with GBI ≥30 %. Eighty
percent of CP patients had sites with VPI ≥ 20 %. The
distribution of sites with PPD ≥4 mm and CAL ≥4 mm were
Table 3 Periodontal parameters in relation to CP
CP N = 122 Number of participants n (%)
≥30 % sites
≤20 % sites
≥20 % sites
PPD ≥4 mm
CAL ≥4 mm
GBI Gingival Bleeding Index, VPI Visible plaque index, PPD Probing pocket
depth, CAL Clinical attachment loss, SD “±”, CP chronic periodontitis
estimated as 25.4 and 63.9 % respectively. The mean
scores of PPD and CAL were 3.1 (±0.8) and 3.6 (±0.6).
Table 4 shows the logistic regression of the
sociodemographic characteristics, habits and periodontal
parameters in relation to the prevalence of CP in the
obese population. No significant differences were noted
for socio-demographics, habits and level of BMI.
Participants who last visited a dentist ≥2 years were found to
have significantly higher risk for having CP. The sites
with GBI ≥30 % and VPI ≥20 % were found to have
significantly strong risk of having CP.
The present study found that the prevalence of CP
among the obese Malaysian population was almost 74 %.
In Malaysia, there has been a rising trend in the
prevalence of CP over the years among the general
population. The NOHSA 2010 estimated the prevalence of CP
to be 48.5 %, which is almost two folds of that which
was reported by NOHSA 2000 (25.2 %) . Even the
globally reported prevalence of CP is 30–35 % among
the general adult population .
Studies in the Jordanian and the USA populations,
reported that the prevalence of CP among the obese was
51.9 and 35 % respectively [10, 11]. Although their
prevalence of CP was lower than the Malaysian obese
population, nonetheless, they concurred that obese
participants have a higher CP prevalence compared to
their general populations. In this study, out of the 73.9 %
obese participants with CP, 54.9 % participants were
categorised as severe stage of CP. This is alarmingly
high compared to only 18.2 % reported in the general
Malaysian population . The worldwide prevalence of
severe CP in the general adult population was
approximately between 10–15 % .
Table 4 Logistic regression showing socio-demographic characters,
habits and periodontal parameters in relation to CP
• Secondary and Tertiary
• ≥2 year
Tooth Brushing frequency
• ≤30 %
• ≥30 %
• ≤20 %
• ≥20 %
CP OR (95 % CI)
Since the population of the present study are obese, it
could be speculated that obesity could have contributed to
the increased burden of inflammation through increased
expression of pro-inflammatory cytokines . Obesity is
associated with production of pro-inflammatory cytokines
that may play a role in the already existing burden of
inflammation associated with CP .
This study found around 36.8 % of participants who
had CP came from the 30–39 years old age group. This
finding differed from previous study on general
populations whereby higher pevalence of CP was associated
with older age groups . It could be speculated that
the high prevalence of CP among this age group could
be due to the fact that this group belongs to the working
age group. They could be preoccupied with their daily
routine, thus, they do not have time to visit the dental
clinic regularly. The busy lifestyle among the younger
adults also could have indirectly induced stress which
may have contributed to the overall burden of
inflammation . In the present study, the prevalence of CP was
much higher in females as compared to male
participants. Under obese conditions, females and males are
both equal in terms of obesity-induced burden of
inflammation. However, females experience changes in
hormonal levels of estrogen and progesterone during
pre-menstrual and menstrual phases . A study by
Machtei et al. (2004) among Israeli women found that
such an increase in hormonal levels have a negative
impact on the periodontal status . This could be
explained based on the fact that hormones modulate
changes through alterations in the host immune
response and cellular functions in gingival tissues .
In the present study, around 17 % of the obese
participants who smoke had CP. This finding disagrees with
previous study conducted in the Swedish population,
reporting a high prevalence of CP with smoking habit
. Smoking has the potential to affect the host
response at the cellular, vascular and tissue repair level
including alteration in neutrophil function, antibody
production, fibroblast activities, vascular factors and
inflammatory mediator production, thus, supresses the
host healing ability and contributes to disease
accumulation and progression . However, this finding was not
reflected in the obese participants in the current study
probably due to the small sample size of the study
population. This makes it difficult to establish a pattern
between CP with smoking habits among the obese
This study reported percentages of population with
CAL ≥4 mm as 64 %. No data was reported in previous
obese population studies to allow further comparison.
Meanwhile, among various populations, percentages of
CAL ≥4 mm vary between 48 to 84 % [25, 26]. This
finding is expected because CAL is an indicator of past
disease experience and also an estimate of accumulative
periodontal tissue destruction . The extent of
periodontal tissue destruction would therefore depend on
how long the investigated population has been exposed
to the disease.
In this study, almost 25 % of the obese individuals had
PPD ≥4 mm. Studies among different populations have
reported that about 20–28 % of their participants have
PPD ≥4 mm [26, 28, 29]. The finding of the current
study suggests that regardless of the state of obesity,
exposure to periodontal disease may depend upon the
susceptibility of an individual’s genetic makeup .
Variation in periodontal measures can be a result of
genetic factors. The USA twin based survey conducted
among 117 pairs of adult twins showed 50 %
susceptibility of CP is associated with genetics . This suggests
that the heritable nature of CP is biologically possible
and reflects genetically determined variations in host
immune responses .
Unlike CAL, PPD is the periodontal measurement of
active disease and provides information on current
disease status . However, the measurement of PPD is
not as reliable as the CAL. It depends on various factors
such as inflammatory condition of the marginal gingiva.
Almost 83 % participants in this study had sites with
GBI ≥30 %. There are no comparative studies reporting
bleeding scores in other obese populations. Previous
studies conducted in Danish and Thai general adult
populations reported 90–95 % individuals having BOP
[28, 31]. This shows that regardless of obesity, the
participants in the current study had gingival
inflammation which is an indicator of the presence of CP
instability and the existence of inflammation. BOP is a sign of
gingival inflammation. Persistent BOP is a positive
indicator for CP progression by 30 % . On the other
hand, absence of BOP was a negative predictor for CP
by 96 % .
In the present study, 91.8 % participants had sites with
VPI ≥20 %. Dental plaque is the etiological factor for CP
. Since 74 % participants in the current study had
CP, it was expected that participants in the current study
would have high VPI scores. A Brazilian population
based study among CP patients reported almost 86.5 %
of participants with plaque accumulation . This
concurs with the fact that plaque accumulation is a
prerequisite for gingival inflammation and CP .
The current results showed that those who had their
last dental visit more than 2 years ago was found to be
significantly associated with CP (p < 0.001). The current
finding disagrees with the US study on dentate diabetic
adults that showed no significant influence of dental visit
pattern on periodontal disease status of the participants
. The reason for irregular dental visits in the current
study could be due to lack of awareness on the
importance of regular dental visits. Also, dental anxiety and
fear could have contributed to irregular dental visit .
Furthermore, an increase in cost of dental treatment
with no provision of dental care insurance could have
influenced the association further .
The current study also showed no significant
association between tooth brushing frequency and CP. This
finding is in disagreement with previous studies which
reported significantly higher odds ratios for the association
between tooth brushing frequency and CP . Tooth
brushing is an important measure for plaque control .
However, efficient tooth brushing technique has been
shown to be the primary factor in obtaining optimum
plaque control, rather than the frequency of tooth
brushing . In addition, the participants in the current study
suffered from moderate to severe CP. Therefore, tooth
brushing alone may not be sufficient to prevent further
deterioration of periodontal health. Provision of
nonsurgical periodontal treatment would benefit further in
controlling the CP progression .
The current study showed that the increase in obesity
level had no significant association with CP in this obese
sample of Malaysians. This finding was in disagreement
with studies conducted in the Japanese, Jordanian and
the USA populations, where increased BMI was found
associated with periodontal disease. The findings of
AlZahrani et al. (2003), reported an increase in BMI (above
30 kg/m ) was associated with increased prevalence of
CP . Khader et al. (2009) also showed significant
associations between BMI and CP . The biological
plausability for the link between obesity and CP is yet to
be established. However, obesity is a state of chronic
inflammation, and increase in BMI levels has been found
to be associated with increased adipokine levels. These
inflammatory adipokines like TNFα and IL-6 contribute
to the pre-exiting inflammatory state associated with CP
and breakdown of periodontal tissue support .
Participants with GBI ≥30 % (p < 0.001) and VPI
≥20 % (p < 0.001) were found to have a significantly
stronger risk associated with CP. Similar findings was
reported in previous study where having higher GBI and
VPI scores were associated with a stronger risk of CP
. These findings could be explained by the fact that
persistent inflammation and dental plaque accumulation
are measures of gingival inflammation  and
predictors of CP . This is supported by the understanding
that dental plaque is an etiological factor for CP and its
accumulation is associated with inflammation of the
gingival tissues leading to gingivitis, which if left
untreated progresses to CP . The current study did not
collect information on presence of diagnosed diabetes
mellitus and cardiovascular diseases, which are
established risk factors for periodontal diseases. The research
is not intended to establish obesity as a risk factor for
There were certain limitations of this study: (i) cross
sectional study design, limits our ability to assess
association between CP and obesity which can be better done
with longitudinal cohort studies, (ii) the small sample
size limited our ability for evaluating the relationship of
obesity and CP across subgroups (age, gender, ethnicity,
educational level, smoking and alcohol intake), (iii)
absence of non-obese group, (iv) the body fat percentage
was not measured because of financial constraints,
logistical problems and patient mobility. The body fat
percentage could help us identify the overall distribution
of obesity, (v) Furthermore this study had a limited
number of smokers which made it difficult to assess the
risk of smoking on periodontal health.
The advantages of this study are: (i) using a definite
case definition for CP which is universally acceptable,
(ii) using FMPM, as it provides the true prevalence and
(iii) using the Asian cut off BMI for obesity. This study
is reflective of a selected Asian population and could
henceforth pave the way for future researchers to relate
to our findings.
This study reported a high prevalence of CP in the
obese Malaysian population. In this particular
population, the strong predictors for CP found were GBI and
CAL: Clinical attachment loss; CP: Chronic periodontitis; BMI: Body mass
index; BOP: Bleeding on probing; FMPM: Full mouth periodontal
measurement; GBI: Gingival bleeding index; NOHSA: National oral health
survey in adults; PPD: Probing pocket depth; USA: United States of America;
VPI: Visible plaque index; WHO: World health organization.
The authors declare that they have no competing interest.
SK is the principal investigator, carried out periodontal examinations and
collection of epidemiological data. NAB was involved in design of the
project, supervision in the clinics and drafting the manuscript. RS was
involved in project design, supervision and performed the statistical analysis.
RDV was involved in supervision, design of this project and drafting of the
manuscript. SHS was involved in project design and drafting of manuscript.
SRV was involved in the supervision in the obese clinics. All authors read and
approved the final manuscript.
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