Shinshu Med J, 67⑶：167～181, 2019

A Cross-sectional Multivariate Analysis of the Relationship Between
Dental Health and Metabolic Syndrome
Imahito Karasawa, Shin-ichi Yamada＊, Akinari Sakurai and Hiroshi Kurita
Department of Dentistry and Oral Surgery, Shinshu University School of Medicine

Objective : The aim of the present study was to investigate the relationship between periodontal diseases andmetabolic syndrome (MetS) with a combination of specific health and dental check-ups based on a cross-sectional
study.
Methods : Data obtained from 985 subjects aged 30 and older who participated in specific health check-ups andsimultaneous dental check-ups in 2014 were reviewed and investigated.
Results : An assessment of correlation coefficients among risk factors revealed that age and smoking were con­founding factors for the number of MetS components and dental periodontitis. A multivariate analysis revealed
that periodontitis correlated with each component of MetS (obesity (Community Periodontal Index (CPI) code 0
vs code 1, odds ratio (OR) : 1.34, 95 ％ confidence interval (CI) : 0.67-2.57, code 0 vs code 2, OR : 1.20, 95 ％ CI :0.81-1.78, code 0 vs code 3, OR : 1.70, 95 ％ CI : 1.05-2.70, and code 0 vs code 4, OR : 1.01, 95 ％ CI : 0.35-2.56, p＜0.05), hypertension (CPI code 0 vs code 1, OR : 1.02, 95 ％ CI : 0.57-1.81, code 0 vs code 2, OR : 1.60, 95 ％ CI : 1.142.26, code 0 vs code 3, OR : 1.29, 95 ％ CI : 0.83-1.99, and code 0 vs code 4, OR : 1.83, 95 ％ CI : 0.7-4.64, p＜0.05),
and hyperglycemia (CPI code 2 vs 3, OR : 1.52 95 ％ CI : 1.00-2.31, code 2 vs 4, OR : 1.29 95 ％ CI : 0.56-2.87, p＝0.07)) in considering common risk factors.
Conclusions : Periodontitis and MetS might be generated from the same common risk factors, including age andsmoking. However, periodontitis may also have some direct relationship with MetS. MetS and periodontitis
should be evaluated collaboratively. Shinshu Med J 67 : 167―181, 2019
(Received for publication December 25, 2018 ; accepted in revised form January 21, 2019)
Key words : periodontal disease, metabolic syndrome, cross-sectional study, community periodontal index,
common risk factor

Ⅰ Introduction

ances, and a genetic predisposition have also beenshown to play contributing roles1）2）. In the USA, theMetabolic syndrome (MetS) is a complex collection

estimated prevalence of MetS was reported to beof components that are considered to arise from vis­

34.7 ％ in 2011-20123）. Furthermore, the prevalence

ceral fat-type obesity, involving hypertension andof MetS was found to increase with age : 18.3 ％ of

the abnormal metabolism of glucose and lipids. MetS

20-39-year-old adults and 46.7 ％ of those aged 60

is associated with an increased risk of cardiovascular

years or older3）. In middle-aged Japanese individuals,

disease and type 2 diabetes mellitus (DM). Risk

the prevalence of MetS was reported to be 14.9 ％4）.

factors for MetS include obesity, physical inactivity,

MetS is considered to originate from a pro-inflam­and insulin resistance, while aging, hormonal imbal­

matory state as a result of the effects of insulin
resistance5）. Insulin resistance is associated with＊

Corresponding author : Shin-ichi Yamada
Department of Dentistry and Oral Surgery,
Shinshu University School of Medicine,
3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
E-mail : yshinshin@shinshu-u.ac.jp

No. 3, 2019an increased body mass index and waist circum­
ference, both of which reflect increased levels of
adiposity and the deposition of visceral adipose
tissue. Adipocytes and infiltrating macrophages pro­167

Karasawa・Yamada・Sakurai et al.

Metabolic syndrome

Exercise

Obesity
Diet
Hypertension

AlcoholLipid
abnormalities

Smoking

Hyperglycemia
Age

Oral hygiene
Fig. 1

Periodontitis

Tooth loss

Schema of the common risk factor approach

duce cytokines, such as tumor necrosis factor-alpha,sion, and diabetes mellitus, are influenced by common

interleukins, and other signaling molecules associatedrisk factors (Fig. 1, such as diet, smoking, alcohol,with pro-inflammatory activity and insulin resis­

exercise, and stress18）). Therefore, when the relationshiptance6）. The circulating levels of these inflammatory

between periodontal diseases and MetS is being in­molecules are elevated in individuals with obesity

vestigated, it is important to consider the impact of

7）

and insulin resistance . Furthermore, insulin resis­

these common risk factors.

tance may be associated with oxidative stress5）. Sys­

Since 2008, the Ministry of Health, Labour andtemic oxidase stress was shown to be significantly

Welfare of Japan has obliged the insured and their

8）greater in individuals with MetS than in those without .

dependents aged＞40 years to receive specific health

Close interactive relationships have been reported

check-ups focusing on visceral -fat obesity19）. How­between periodontitis and MetS1）2）5）8）-15）. In a system­

ever, dental check-ups are not included in specificatic review, being overweight, obesity, weight gain,

health check-ups. In the present study, we performed

and an increased waist circumference were proposed

dental check-ups on individuals who participated in16）

as risk factors for periodontitis . The prevalence ofspecific health check-ups. We examined the cross-

MetS was higher in individuals with severe peri­

sectional relationship between dental health andodontitis (37 ％) than in those with no/mild periodon­

MetS in the light of common risk factors.

titis (18 ％)9）. In a comprehensive health examinationof 6,421 Japanese individuals (aged between 34 and 77
years), those with a deep periodontal probing depth(PD) and clinical attachment level (CAL) or withmoderate PD and CAL had a significantly higher odds
4）

Ⅱ

Materials and Methods

This study protocol was approved by the Committee
on Medical Research of Shinshu University (#2775).
In 2010, 2,716 individuals with national health in­ratio for MetS . Furthermore, the prevalence of asurance aged 30 and older (including self-employedhigh Community Periodontal Index (CPI) code was signi­

workers, farmers, and the elderly) underwent specificficantly higher in individuals with three components

health check-ups in Shiojiri city, Nagano Prefecture,of MetS and those with four or five components thanJapan. Of these, 985 individuals (461 men and 524

11）
17）

. Manywomen) who agreed to dental check-ups were includ­

chronic diseases, including periodontitis, hyperten­

ed as subjects in the present study. Written informedin those without positive components

168

Shinshu Med J

l. 67

Relationship between periodontal diseases and metabolic syndrome

consent was obtained from all subjects.

included the inspection of dental and periodontalＡtissues as well as oral hygiene. The presence ofMedical check-ups
Specific health check-ups were conducted following

periodontal diseases was evaluated according to thethe standard program supplied by the Ministry ofWorld Health Organization (WHO) CPI criteria26）.

Health, Labour and Welfare of Japan (2013)20）. TheyCPI was originally developed by WHO to measureincluded an interview on lifestyle habits and systemic

community oral health and commonly used for peri­disease treatment status, measurements of height,

odontal screening. CPI criteria were defined fromweight, waist circumference, and blood pressure, andCode 0 to Code 4 (Code 0 : healthy periodontal conditions ;blood tests. Subjects were asked about their recent

Code 1 : gingival bleeding on probing ; Code 2 : calculus(within one year) smoking habit (yes or no). The fre­and bleeding ; Code 3 : periodontal pocket 4-5 mm ;quency of alcohol intake and the amount were evalu­

and Code 4 : periodontal pocket ≥ 6 mm26）27）. PD wasated and classified into four categories (non-drinker,

measured using standard WHO probes and recorded

occasional drinker, daily light-moderate drinker ofaccording to the periodontal disease examination

less than 43 g of alcohol, and daily heavy drinker).

manual proposed by the Ministry of Health, Labour

Individuals were also asked whether they ate mid­and Welfare of Japan (2015)28）.

night snacks (yes or no) and performed regular exer­

Oral hygiene was assessed by dentists and classi­

cise (yes or no). Blood tests included measurements

fied into three categories (good : clean and no foodof triglycerides, low/high-density lipoprotein choles­

particles or tartar in mouth or dentures ; fair : foodterol, blood sugar, hemoglobin A1c (HbA1c), and cre­particles/tartar/plaque in 1-2 areas of the mouth oratinine level. Regular exercise was defined light-

small area of denture or halitosis ; or poor : foodsweat exercise of more than 30 minutes for moreparticles/tartar/plaque in most areas of the mouth

20）

than 2 days a week, for 1 year or more .

The Japanese criteria (modification of the Interna­
tional Diabetes Federation (IDF) criteria21）) for MetS

or on most of dentures or severe halitosis), according
to the Oral Health Assessment29）.
Ｃ

Statistical analyses

were utilized in the present study : (a) dyslipidemia

A univariate analysis was performed with the Wil­

(triglycerides ≥ 150 mg per dL and/or high-density

coxon rank-sum test, Kruskal Wallis test, chi-squarelipoprotein cholesterol (HDL-C)＜40 mg per dL or

goodness of fit test, and the chi-squared test. A

specific treatments for these lipid abnormalities) ; (b)multivariate analysis was performed with a multi­

hypertension (systolic blood pressure ≥ 130 mmHg

variate logistic regression. Statistical analyses were

and/or diastolic blood pressure ≥ 85 mmHg or the

performed using JMP ver.12 (SAS Institute Inc.,

treatment of previously diagnosed hypertension) ;North Carolina, USA). P values＜0.05 were consid­

and (c) hyperglycemia (fasting plasma glucose ≥ 110

ered to be significant.

mg/dL, HbA1c (NGSP) ≥ 5.6 ％, or a specific treatment

Ⅲfor diabetes mellitus (DM))22）-25）. Waist circumference
was measured at the navel in a standing position, andＡ

Results

Subject characteristics

visceral fat accumulation was assessed as being posi­

Among 1,027 individuals who underwent spe­tive at a waist circumference ≥ 85 cm for men and ≥ 90

cific health check-ups in 2014, 985 (461 men and 524

cm for women.

women) who agreed to dental check-ups were in­Ｂ

cluded as subjects in the present study. The mean

Dental check-ups
Each individual underwent dental check-ups thatage±standard deviation (SD) of subjects was 59.4±

evaluated dental and periodontal conditions by train­

12.1 year-old. Sixty subjects (6.1 ％ ) had a recent

ed dentists. Seven trained dentists participated in thissmoking habit within 1 year. Four hundred andstudy and unification of the dental examination method

eighty individuals (48.7 ％) did not drink alcohol. The

had been carried out prior to the study. Dental check-ups

mean number of present teeth was 25.5±5.3 and theNo. 3, 2019169

circumference, hypertension, lipid abnormalities, andhyperglycemia) was analyzed. A positive number
correlated with sex (p＜0.01), age (p＜0.01), a recent
smoking habit (p＜0.01), regular exercise (p＜0.01),
oral hygiene (p＜0.01), CPI (p＜0.01), PD (p＜0.01),
and the number of present (p＜0. 01) and unreplaced
missing teeth (p＜0.01) in the univariate analysis.
The multivariate analysis revealed that the number－0.3496＊-0.1045＊－0.122＊-0.1111＊－0.0378
0.7319＊-0.02510.1522＊－0.1128＊0.3046＊
0.343＊-

0.0182－0.0774＊＊0.00180.39870.0052－0.0216－0.0198
0.0321－0.0034

0.01230.03070.0732－0.0106－0.0751-－0.0642＊＊0.1024＊0.033

0.0888＊0.1549＊0.1502＊0.15890.1679－0.03110.1048＊0.1307＊0.2636＊

CPI codeOralhygiene＊＊0.0596＊＊-the number of positive components of MetS (waist

0.0569The relationship between dental conditions and0.1182＊

number of positive components of MetS (Table 2)-

Ｂ Relationship between dental conditions and the－0.0383－0.1252＊

collinearity.

0.3325＊－0.0232

ate analysis was carried out considering the multi­

0.1950＊－0.0274

or unreplaced missing teeth). Thereafter, multivari­

0.0278-

tions (CPI/PD, oral hygiene, and number of present

Regularexercisesex, age, or recent smoking habit and dental condi­

Midnight
snacking＜0.3) but significant correlation was found between

Alcoholintaketeeth and that of unreplaced missing teeth. Weak (rRecentsmokinghabit

CPI and PD, and between the number of present

Agebetween oral hygiene and CPI code or PD, between

Table 1behavior, between age and number of present teeth,

Correlation matrix (Spearman’s rank correlation coefficient) of risk factors0.3) were observed between sex and alcohol drinking-

Significant and moderate to strong correlations (r＞

0.0177

Pocketdepthtion coefficient) of risk factors is shown in Table 1.

＊＊

The correlation matrix (Spearman’s rank correla­－0.0676＊＊mm in 163 (16.5 ％), and ≥ 6 mm in 29 (2.9 ％).

0.1359＊(2.9 ％). PD was 1-3 mm in 778 subjects (79.0 ％), 4-5－0.4647＊

No. ofpresentteeth％), 2 in 368 (37.4 ％), 3 in 163 (16.5 ％), and 4 in 29

0.1786

CPI code was 0 in 321 subjects (32.6 ％), 1 in 69 (7.0

0.0898＊％), fair in 344 (34.9 ％), and poor in 51 (5.2 ％). The＊±4.67. Oral hygiene was good in 598 subjects (60.7

0.0895＊

No. ofunreplaced
missing teeth

mean number of unreplaced missing teeth was 2.26

0.1762＊

Karasawa・Yamada・Sakurai et al.

of positive components correlated with sex (p＜0.01),

170

Shinshu Med J: p＜0.05＊＊: p＜0.01＊

Number of present teeth
No. of unreplaced missing teeth

Pocket depth

ber of positive MetS components.

Sex
Age

placed missing teeth was associated with the num­

CPI codethe multivariate logistic model, the number of unre­

Oral hygiene

collinearity. Therefore, when age was removed from

Midnight snacking
Regular exercise

of positive components of MetS. The age had multi­

Alcohol intake

uals without recent smoking habit had less number

Recent smoking habit

the number of positive components of MetS. Individ­

Sex

Female and advanced age affected the increase of-age (p＜0.01), and a recent smoking habit (p＜0.01).

l. 67

No. 3, 2019

Pocket depth

3

0.2 (0.9)

0.4 (1.2)

3
25.6 (5.1)

225

3
26.5 (4.6)

3

24
120
44
13

44
13

283

23
135
38
1

81

110
13

86
162

31
199

50
8
254

139
88

15

153
132
61.7 (10.1)
270

1 (285)38
1

1 : Presence of MetS＞absence of or potential for Mets
NS : Not significant.

＊Mean (SD)1 (69)
2 (388)3 (163)4 (29)
missing data (15)
1-3 mm (778)CPI

No. of present teeth

93
12

Fair (344)
Poor (51)
missing data (1)0 (321)

Oral hyigiene

No. of un-replaced missing teeth96
220

Yes (319)
Good (589)

Regular exercise

4-5 mm (163)6＝＜mm (29)
missing data (15)Mean (SD)39
229

Yes (111)
No (666)

Midnight snacking

125

53
11
286

Daily, right-moderate (171)
Daily, heavy (37)No (874)

2

205
120
52.4 (13.3)
323
151
110

Yes (60)

Female (524)Male (461)
Mean (SD)No (925)

0 (325)41

0.8 (2.9)4
24.4 ( 6.0)

47
8

148

12
71
47
8

65

75
13

81
118

25
126

34
6
182

113
54

24

104
103
63.7 (9.6)
183

2 (207)4

0.7 (2.0)

4
24.2 (6.3)

25
4

91

7
45
25
4

39

45
7

50
72

12
74

23
10
112

58
33

16

52
72
63.5 (10.0)
108

3 (124)

No. of MetS components

1

0.6 (1.4)

125.9 (4.4)

9
3

31

3
17
9
3

11

21
6

6
17

4
38

11
2
40

19
12

3

10
34
64.4 (6.9)
41

4 (44)

＜0.01

＜0.01

＜0.01

＜0.01

＜0.01

＜0.01

NS

NS

＜0.01
＜0.01

＜0.01

Wilcoxon test

Wilcoxon test

Goodness test of fit for chi-square

Goodness test of fit for chi-square

Goodness test of fit for chi-square

Goodness test of fit for chi-square

Goodness test of fit for chi-square

NS

NS

NS

NS

NS

NS

NS

NS

＜0.01

Goodness test of fit for chi-square＜0.01

Goodness test of fit for chi-square＜0.01

Result of orderedlogistic regression
analysis (p value)

Wilcoxon test

Chi-squared test

Result of univariate analysis (p value)

Association between number of metabolic syndrome (MetS) components and independent variables

No (480)
Chance (297)

Alcohol drinking behavior

Age
Recent smoking

Sex

Table 2

Relationship between periodontal diseases and metabolic syndrome

171Karasawa・Yamada・Sakurai et al.

Ｃ Relationship between dental conditions and obe-

Lipid abnormalities were also associated with regularsity (waist circumference) (Table 3)

exercise (p＝0.07). The multivariate analysis revealed

In the univariate analysis, obesity correlated withthat lipid abnormalities correlated with age (OR :sex (p＜0.01), a recent smoking habit (p＜0.01), alcohol

1.03, 95 ％ CI : 1.02-1.05, p＜0.01) and a recent smoking

intake (p＜0.05), oral hygiene (p＜0.01), CPI (p＜0.05),

habit (no vs yes, OR : 2.90, 95 ％ CI : 1.68-5.05, p＜0.001).

PD (p＜0.05), and the number of unreplaced missing

Furthermore, alcohol intake was associated withteeth (p＜0.05). Regular exercise tended to be associ­lipid abnormalities (non-drinker vs occasional drinker,

ated with obesity (p＝0.079). The multivariate analysis

OR : 0.69, 95 ％ CI : 0.50-0.69, non-drinker vs light-

revealed that obesity correlated with sex (female vsmoderate drinker, OR : 0.80, 95 ％ CI : 0.5-1.17, non-male odds ratio (OR) : 4.06, 95 ％ confidential interval

drinker vs heavy drinker, OR : 1.16, 95 ％ CI : 0.57-(CI) : 2.90-5.74, p＜0.01), regular exercise (no vs yes,

2.35, p＝0.051). These results revealed that individuals

OR : 1.51, 95 ％ CI : 1.06-2.16, p＜0.05), and CPI (codeof advanced age and with a recent smoking habit

0 vs code 1, OR : 1.34, 95 ％ CI : 0.67-2.57, code 0 vs

were associated with lipid abnormalities.

code 2, OR : 1.20, 95 ％ CI : 0.81-1.78, code 0 vs code 3,

Ｆ Relationship between dental conditions and hy-

OR : 1.70, 95 ％ CI : 1.05-2.70, and code 0 vs code 4,

perglycemia (Table 6)

OR : 1.01, 95 ％ CI : 0.35-2.56, p＜0.05). These results

In the univariate analysis, hyperglycemia correlatedsuggested that male gender, no regular exercise, andwith age (p＜0.01), a recent smoking habit (p＜0.01),

periodontitis was associated with obesity.

CPI (p＜0.01), PD (p＜0.01), and the number of pres­Ｄ Relationship between dental conditions and hy-

ent teeth (p＜0.01) and unreplaced missing teeth (ppertension (Table 4)＜0.01). Midnight snacking was associated with MetSIn the univariate analysis, hypertension correlated(p＝0.069). The multivariate analysis revealed thatwith sex (p＜0.05), age (p＜0.01), a recent smoking

hyperglycemia correlated with age (OR : 1.06, 95 ％habit (p＜0.01), oral hygiene (p＜0.01), CPI (p＜0.01),

CI : 1.04-1.08, p＜0.001) and a recent smoking habit

PD (p＜0.01), and the number of unreplaced missing(no vs yes, OR : 2.84, 95 ％ CI : 1.60-5.01, p＜0.001).

teeth (p＜0.01). The multivariate analysis revealed

CPI tended to be associated with hyperglycemia (codethat hypertension correlated with age (OR : 1.08, 95

2 vs 3, OR : 1.52 95 ％ CI : 1.00-2.31, code 2 vs 4, OR :％ CI : 1.07-1.10, p＜0.01), a recent smoking habit (no1.29 95 ％ CI : 0.56-2.87, p＝0.07). These results re­vs yes, OR : 2.23, 95 ％ CI : 1.16-4.16, p＜0.05), CPI

vealed that individuals with advanced age and a(code 0 vs code 1, OR : 1.02, 95 ％ CI : 0.57-1.81, code

recent smoking habit were associated with hyper­

0 vs code 2, OR : 1.60, 95 ％ CI : 1.14-2.26, code 0 vsglycemia. It was also suggested that the presence ofcode 3, OR : 1.29, 95 ％ CI : 0.83-1.99, and code 0 vsperiodontal pockets tended to be associated with hy­code 4, OR : 1.83, 95 ％ CI : 0.7-4.64, p＜0.05), and theperglycemia.

number of unreplaced missing teeth (OR : 1.12, 95 ％Ｇ Relationship between dental conditions and renal

CI : 1.003-1.26, p ＜0.05). These results revealed thatfunction (Table 7)

individuals with advanced age, recent smoking habit,

In the present study, renal function was assessed

periodontitis, and large number of unreplaced miss­in specific medical check-ups, and its relationshiping teeth were associated with hypertension.

with dental conditions was also evaluated. Renal dys­Ｅ Relationship between dental conditions and lipidfunction correlated with sex (p＜0.01), age (p＜0.01),

abnormalities (Table 5)

regular exercise (p＜0.05), and oral hygiene (p＜0.01).

Lipid abnormalities correlated with sex (p＜0.01),

In the multivariate analysis, renal dysfunction cor­age (p＜0.01), a recent smoking habit (p＜0.01), alcohol

related with sex (female vs male, OR : 1.66, 95 ％ CI :intake (p＜0.05), CPI (p＜0.05), PD (p＜0.05), and the1.07-2.59, p＜0.05) and age (OR : 1.02, 95 ％ CI : 1.002-

number of residual teeth (p＜0.01) and unreplaced

1.04, p＜0.05), and tended to be associated with oral

missing teeth (p＜0.01) in the univariate analysis.

hygiene (p＝0.050). These results revealed that male172

Shinshu Med J

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No. 3, 2019

NS : Not significant

No. of present teeth
No. of unreplaced missing teeth

Pocket depth

CPI

Oral hygiene

Regular exercise

Midnight snacking

Alcohol intake

Age
Recent smoking habit

Sex

466
304
59.2 (12.3)
733
37
388
231
128
23
687
83
510
260
486
246
37
1
266
54
301
114
23
12
621
114
23
12
25.4 (5.4)
0.5 (1.9)

Non-obese

55
15
87
49
6
3
157
49
6
3
25.7 (5.0)
0.5 (1.2)

58
157
60.0 (11.4)
192
23
92
66
43
14
187
28
156
59
103
98
14

Obese

NS
＜0.05

＜0.05

＜0.05

＜0.01

0.079

NS

＜0.05

NS
＜0.01

＜0.01

p value

Wilcoxon rank-sum test
Wilcoxon rank-sum test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Wilcoxon rank-sum test
Chi-squared test

Chi-squared test

test nameResults of the univariate analysis

Association between obesity and independent variables

Female (524)Male (461)
Mean (SD)No (925)
Yes (60)
No (480)
Occasional (297)
Daily, light-moderate (171)
Daily, heavy (37)No (874)
Yes (111)
No (666)
Yes (319)
Good (589)
Fair (344)
Poor (51)
missing data (1)0 (321)
1 (69)
2 (388)3 (163)4 (29)
missing data (15)
1-3 mm (778)
4-5 mm (163)≥ 6 mm (29)
missing data (15)Mean (SD)
Mean (SD)

Table 3

NS
NS

NS

＜0.05

NS

＜0.05

NS

NS

NS
NS

＜0.01

p value

1.00
1.34 (0.67-2.57)
1.20 (0.81-1.78)
1.70 (1.05-2.70)
1.01 (0.35-2.56)

1.51 (1.06-2.16)
1.00

1.00
4.06 (2.90-5.74)

odds ratio (95 ％CI)

Results of a logistic regression
analysis (p value)

Relationship between periodontal diseases and metabolic syndrome

173

174

Shinshu Med J

NS : Not significant

No. of unreplaced missing teeth

No. of present teeth

Pocket depth

CPI

Oral hygiene

Regular exercise

Midnight snacking

Alcohol intake

Age
Recent smoking habit

Sex

Mean (SD)

Female (524)Male (461)
Mean (SD)No (925)
Yes (60)
No (480)
Occasional (297)
Daily, light-moderate (171)
Daily, heavy (37)No (874)
Yes (111)
No (666)
Yes (319)
Good (589)
Fair (344)
Poor (51)
missing data (1)0 (321)
1 (69)
2 (388)3 (163)4 (29)
missing data (15)
1-3 mm (778)
4-5 mm (163)≥ 6 mm (29)
missing data (15)Mean (SD)

Table 40.3 (0.9)

206
41
214
80
9
5
461
80
9
5
25.5 (5.4)

312
243
55.3 (13.0)
533
22
266
183
88
18
491
64
381
174
351
185
19

Nonhypertensive

0.7 (2.4)

212
218
64.5 (8.3)
392
38
214
114
83
19
383
47
285
145
238
159
32
1
115
28
174
83
20
10
317
83
20
10
25.8 (4.7)

Hypertensive

Wilcoxon rank-sum test
Wilcoxon rank-sum test

NS
＜0.01

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Welch’s t-test
Chi-squared test

Chi-squared test

test namep ＜0.01

＜0.01

＜0.01

NS

NS

NS

＜0.01
＜0.01

＜0.05

p value

Results of the univariate analysis

Association between hypertension and independent variables

＜0.05

NS

NS

＜0.05

NS

NS

NS

NS

＜0.01
＜0.05

NS

p value

1.12 (1.003-1.26)

1.00
1.02 (0.57-1.81)
1.60 (1.14-2.26)
1.29 (0.83-1.99)
1.83 (0.77-4.64)

1.08 (1.07-1.10)
2.27 (1.16-4.16)

odds ratio

analysis (p value)

Results of a logistic regression

Karasawa・Yamada・Sakurai et al.

l. 67

No. 3, 2019

NS : Not significant

No. of unreplaced missing teeth

No. of present teeth

Pocket depth

CPI

Oral hygiene

Regular exercise

Midnight snacking

Alcohol intake

Age
Recent smoking habit

Sex

Mean (SD)

0.4 (1.4)

210
51
270
106
13
7
531
106
13
7
25.8 (5.3)

372
285
57.7 (12.7)
631
26
306
216
114
21
581
76
457
200
406
221
30

abnormality

No lipid

0.7 (2.3)

152
176
62.6 (10.1)
294
34
174
81
57
16
293
35
209
119
183
123
21
1
111
18
118
57
16
8
247
57
16
8
25.0 (5.3)

With lipid
abnormalities

＜0.01

＜0.01

＜0.05

＜0.05

NS

0.07

NS

＜0.05

＜0.01
＜0.01

＜0.01

p value

Wilcoxon rank-sum test

Wilcoxon rank-sum test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Welch’s t-test
Chi-squared test

Chi-squared test

test nameResults of the univariate analysis

Association between lipid abnormalities and independent variables

Female (524)Male (461)
Mean (SD)No (925)
Yes (60)
No (480)
Occasional (297)
Daily, light-moderate (171)
Daily, heavy (37)No (874)
Yes (111)
No (666)
Yes (319)
Good (589)
Fair (344)
Poor (51)
missing data (1)0 (321)
1 (69)
2 (388)3 (163)4 (29)
missing data (15)
1-3 mm (778)
4-5 mm (163)≥ 6 mm (29)
missing data (15)Mean (SD)

Table 5

NS

NS

NS

NS

NS

NS

NS

0.051

＜0.001＜0.001NS

p value

1.00
0.69 (0.50-0.96)
0.80 (0.54-1.17)
1.16 (0.57-2.35)

1.04 (1.02-1.05)
2.90 (1.68-5.05)

odds ratio

analysis (p value)

Results of a logistic regression

Relationship between periodontal diseases and metabolic syndrome

175

176

Shinshu Med J

NS : Not significant

No. of unreplaced missing teeth

No. of present teeth

Pocket depth

CPI

Oral hygiene

Regular exercise

Midnight snacking

Alcohol intake

Age
Recent smoking habit

Sex

Mean (SD)

0.4 (1.7)

389
322
57.4 (12.8)
679
32
345
215
123
28
623
88
491
220
431
245
34
1
230
49
302
103
18
9
581
103
18
9
25.9 (5.0)

Nonhyperglycemic

0.7 (2.0)

91
20
86
60
11
6
197
60
11
6
24.4 (6.1)

135
139
64.5 (8.1)
246
28
135
82
48
9
251
23
175
99
158
99
17

Hyperglycemic

Wilcoxon rank-sum test
Wilcoxon rank-sum test

＜0.01
＜0.01

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Welch’s t-test
Chi-squared test

Chi-squared test

test name

＜0.01

＜0.01

NS

NS

0.069

NS

＜0.01
＜0.01

NS

p value

Results of the univariate analysis

Association between hyperglycemia and independent variables

Female (524)Male (461)
Mean (SD)No (925)
Yes (60)
No (480)
Occasional (297)
Daily, light-moderate (171)
Daily, heavy (37)No (874)
Yes (111)
No (666)
Yes (319)
Good (589)
Fair (344)
Poor (51)
missing data (1)0 (321)
1 (69)
2 (388)3 (163)4 (29)
missing data (15)
1-3 mm (778)
4-5 mm (163)≥ 6 mm (29)
missing data (15)Mean (SD)

Table 6

NS

NS

NS

0.07

NS

NS

NS

NS

＜0.001＜0.001NS

p value

1.00
1.52 (1.00-2.31)
1.29 (0.56-2.87)

1.06 (1.04-1.08)
2.84 (1.60-5.01)

odds ratio

analysis (p value)

Results of a logistic regression

Karasawa・Yamada・Sakurai et al.

l. 67

No. 3, 2019

NS : Not significant

No. of unreplaced missing teeth

No. of present teeth

Pocket depth

CPI

Oral hygiene

Regular exercise

Midnight snacking

Alcohol intake

Age
Recent smoking habit

Sex

Mean (SD)

Female (524)Male (461)
Mean (SD)No (925)
Yes (60)
No (480)
Occasional (297)
Daily, light-moderate (171)
Daily, heavy (37)No (874)
Yes (111)
No (666)
Yes (319)
Good (589)
Fair (344)
Poor (51)
missing data (1)0 (321)
1 (69)
2 (388)3 (163)4 (29)
missing data (15)
1-3 mm (778)
4-5 mm (163)≥ 6 mm (29)
missing data (15)Mean (SD)

Table 70.5 (1.8)486
40159.0 (12.2)
831
56
443
260
151
33
782
105
609
278
546
295
45
1
295
62
348
145
24
13
705
145
24
13
25.5 (5.3)

Normal0.5 (1.3)

26
7
40
18
5
2
73
18
5
2
25.7 (5.8)

3860
62.6 (10.2)
94
4
37
37
20
4
92
6
57
41
43
49
6

renal function

Decreased

NS

NS

NS

NS

＜0.01

＜0.05

NS

NS

＜0.01
NS

＜0.01

Wilcoxon rank-sum test

Wilcoxon rank-sum test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Chi-squared test

Welch’s t-test
Chi-squared test

Chi-squared test

NS

NS

NS

NS

0.050

NS

NS

NS

＜0.05
NS

＜0.05

1.00
1.75 (1.12-2.74)
1.36 (0.54-3.46)

1.02 (1.002-1.04)

1.66 (1.07-2.59)

odds ratio

p valuep valuetest nameResults of a logistic regression
analysis (p value)

Results of the univariate analysis

Association between renal function and independent variables

Relationship between periodontal diseases and metabolic syndrome

177

Karasawa・Yamada・Sakurai et al.

gender and individuals of advanced age were associ­female employees ranging in age between 20 and 59

ated with renal dysfunction. Poor oral hygiene had ayears revealed that individual components of MetS,

tendency toward renal dysfunction.

including obesity, hypertension, lipid abnormalities,Ⅳand hyperglycemia, were associated with periodontal

Discussion

diseases10）. Additionally, in a cohort study during a

Periodontal conditions were previously reported to

4-year observation period, the presence of periodon­

be closely associated with MetS. The number of pos­

tal pockets was associated with the positive conver­

itive MetS components correlated with gingivitis,

sion of one or more MetS components12）. Among MetS

even in participants aged between 12 and 18 years15）.

components, the positive conversion of blood pressure

A meta-analysis revealed that individuals with MetS

and the blood-lipid index correlated with the pres­were nearly 2-fold more likely to have periodon­ence of periodontal pockets12）. Furthermore, individuals

titis than those without13）. Japanese individuals with

with untreated MetS presented with markedly worse

deep PD ( ≥ 6 mm) and severe CAL ( ≥ 6 mm) as wellperiodontal conditions than healthy participants.

as those with moderate PD (4-5 mm) and moderate

However, the prevention of periodontitis has been

CAL (4-5 mm) were shown to be at a significantly

suggested to reduce the risk of MetS. According to4）

increased risk of MetS . Similarly, a higher CPI codea double-blinded randomized clinical study, periodontal

was associated with the presence of a greater num­

therapy, including root planing＋systemic antibiotics

11）

ber of MetS components . The prevalence of MetS

or plaque control＋subgingival scaling, successfully

was 18 ％ in individuals with no/mild periodon­

decreased C-reactive protein levels in MetS patients30）.

titis, whereas it was 37 ％ in those with severe perio­

The reduction of periodontal inflammation was

dontitis (classified by the clinical criteria of Page &reported to be the key in reducing systemic inflam­

9）Eke) . However, in the present study, the multivari­mation in patients with MetS30）. Even supragingival

ate analysis revealed no correlations between theplaque control was sufficiently effective to siginificantly

positive number of MetS components and periodon­

improve periodontal inflammation and to reduce its

tal conditions. Oral health is influenced by diet,

impact on systemic inflammation as measured by

18）

hygiene, smoking, alcohol intake, stress, and trauma .

CRP30）. Since more frequent toothbrushing was related

MetS is also influenced by these risk factors. Many

to a lower prevalence and incidence of MetS, morechronic diseases, including periodontitis, hypertension,

frequent toothbrushing may contribute to the pre­18）

and DM, are influenced by common risk factors . In

vention of MetS due to the inflammation/triglyceride

the present study, the assessment of correlation coeffi­

pathway31）. Therefore, collaborations between den­cients among independent valuables revealed that age

tists and physicians are important. In addition, theand a recent smoking habit influenced MetS and dental

specific health check-ups, including dental check-conditions (CPI/PD, oral hygiene, and number of present

ups, were demonstrated to be effective for the earlyor unreplaced missing teeth). These results suggest

detection of periodontitis, a precursor of pre-MetS

that age and smoking are confounding factors for

and MetS. Since the key concept underlying the in­periodontitis and MetS. MetS and periodontitis may

tegrated common risk approach is that the promo­

be generated from common risk factors (such as age,tion of general health by controlling a small number

smoking, and alcohol intake).

of risk factors may have a major impact on a large

However, in the present study, periodontitis (highnumber of diseases at a lower cost and greater efficacy

CPI code) correlated with some components of Mets,

and effectiveness than disease-specific approaches32）,

including obesity, hypertension, and hyperglycemia.

the addition of dental check-ups to specific health

These results suggest a possible relationship bet­

check-ups may be effective for the early detection

ween periodontitis and any component of MetS. A

of individuals with pre-MetS and MetS.

cross-sectional study on adult Japanese male and178

With the inclusion of dental check-ups in specific
Shinshu Med J

l. 67

Relationship between periodontal diseases and metabolic syndrome

health check-ups, dental interventions may reduce

CPI in a large population-based survey were reported

the risk of MetS. However, since the questionnaires

to be underestimated without correcting for mea­of this study did not include the question whether

surement errors36）. Therefore, further studies areindividuals had received periodontal treatment/

needed to investigate the efficacy of dental check-

maintenance or not, the result of this question mightups on the prevention of the progression of MetS

have affected the outcomes of the study. The limita­

based on a cohort study.

tion of the present study was that since this was aⅤcross-sectional study, the intervention effects ofConclusion

dental check-ups to reduce the risk of MetS were

The aim of the present study was to investigate

unclear. Furthermore, since most individuals who

the relationship between periodontal disease andunderwent specific health check-ups were aware of

MetS with a combination of the specific health andtheir health conditions, the frequency of medical

dental check-ups based on a cross-sectional study.

care use in these individuals may affect investiga­

The results obtained suggest that periodontitis andtions of medical expenditure. The dentist’s calibra­

Mets are generated from the same common risk

tions of periodontal measurements might also affectfactors including age, smoking, and alcohol intake.

the outcomes of the study. In this study, although

However, periodontitis was directly related to someperiodontal measurements were determined by

MetS components (obesity, hypertension, and hyper­

index teeth, the accuracy of measuring CPI was

glycemia). Since the key concept underlying the in­reported to vary with the dentist during the training

tegrated common risk approach is the promotion ofprocess33）
34）. Additionally, CPI was reported to vary

general health by controlling a small number of risk

between studies and such variation would affect thefactors, the addition of dental check-ups to specificeffect of each predictor on risk for periodontal dis­health check-ups is warranted.

35）

eases . Therefore, since the dental model was reportedⅥ

to be effective for periodontal pocket probing training
and for the evaluation and standardization of the ex­
35）

aminer’s probing skill , all the dentists who partici­

Conflict of interest

The authors declare that they have no conflict ofinterest.

pated in this study were trained with dental models

Ⅶ Acknowledgementfor dentist’s calibration. According to WHO, although
CPI is recommended for use as an indicator of earlyThis study was supported by the 8020 Promotion

periodontitis in individuals of 35 and older as part ofFoundation. Funding from the 8020 Promotion Foun­large community-based screening programs, thedation is gratefully acknowledged.

effects of risk factors on periodontitis measured with
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