periodontal disease ( pd ) is part of the global burden of disease ( gbd ) .
pd is possibly associated with 200 systemic diseases . published systematic reviews and meta - analyses
indicate that pd is linked to many systemic diseases , such as pulmonary disease , cardiovascular disease , head and neck cancer , survival of dental implants , and diabetes .
hence , seeking the risk factors for preventing pd is an important task . besides the genetic factors [ 812 ]
sex , cigarette smoking , alcohol , diabetes , obesity , metabolic syndrome , osteoporosis , dietary calcium , vitamin d , and stress are well accepted risk factors for pd .
helicobacter pylori ( hp ) is cultured from gastric biopsy specimens of gastric inflammation and peptic ulcer patients and is considered to be responsible for these diseases , especially for gastric cancer worldwide . besides gastric diseases , published systematic reviews and meta - analyses demonstrated that hp is also associated with diabetes , chronic tonsillitis , atopic diseases , pancreatic cancer , recurrent aphthous stomatitis , myocardial infarction , and esophageal cancer . obviously , pd and hp are both associated with some diseases .
hp is largely transmitted through oral - oral or fecal - oral routes and the oral cavity is a reservoir of pathogens , including hp ; hp is widely detected in the oral pathology .
the first relevant study was performed by asikainen et al .   in 1994 and revealed a negative association ; however , subsequent studies showed inconsistent results   and there is little data from chinese populations .
therefore , this study was designed to investigate the association between hp and pd in han chinese .
we conducted a case - control study according to the strengthening the reporting of observational studies in epidemiology ( strobe ) statement .
the patients were from the department of stomatology , taihe hospital , hubei university of medicine .
all participants were enrolled between september 3 , 2012 and september 2 , 2014 and provided signed informed consent .
we excluded those who used prophylactic antibiotics or anti - inflammatory drugs , had a history of pd treatment , were receiving ongoing orthodontic therapy , had fewer than 6 teeth present , or had current pregnancy .
this study was reviewed and approved by the committee for ethical affairs of the taihe hospital , hubei university of medicine at shiyan city , hubei province .
all potential eligible subjects were selected from han chinese population with similar age , sex , level of education , body mass index ( bmi ) , physical exercise , history of alcohol use and diabetes mellitus , and other demographic characteristics .
two investigators were trained before the study and used standardized procedures to increase consistency . as controls we included all subjects with newly - diagnosed pd during the study period who met the same inclusion criteria as cases but
the diagnostic criteria was : pd was defined as presence of more than 4 teeth with 1 site or more having a probing pocket depth ( ppd ) 4 mm and clinical attachment level ( cal ) 3 mm ( 24 ) .
these ppd and cal were evaluated at 4 sites on each tooth ( mesial , distal , buccal , and lingual ) .
cal was measured as the distance from the cemento - enamel junction ( cej ) to the base of the pocket .
subgingival dental plaques were collected from each case and control using a sterile universal curette .
the dental plaques were broken and cultivated on columbia agar plates ( oxoid of thermo fisher scientific inc . ,
the rapid urease test ( rut ) , a commercially available rapid gastric urease test kit , was used to for detecting hp , and the detailed methods of culture and polymerase chain reaction ( pcr ) are described elsewhere .
the sample was identified as positive hp if the test gel color changed from yellow to red within 20 min , up to a maximum of 60 min .
we used means with standard deviation ( sd ) or percentage to summarize the frequency distributions of age , sex , level of education , other demographic characteristics , and clinical characteristics of the study population . to investigate the association between hp and pd , the chi - square test or fisher z
test was used to analyze the association , and the unadjusted odds ratios ( ors ) with corresponding 95% confidence intervals ( cis ) were calculated .
considering the confounding risk factors of pd , we then performed a multiple logistic regression analysis to obtain adjusted ors and their 95%cis .
we conducted a case - control study according to the strengthening the reporting of observational studies in epidemiology ( strobe ) statement .
the patients were from the department of stomatology , taihe hospital , hubei university of medicine .
all participants were enrolled between september 3 , 2012 and september 2 , 2014 and provided signed informed consent .
we excluded those who used prophylactic antibiotics or anti - inflammatory drugs , had a history of pd treatment , were receiving ongoing orthodontic therapy , had fewer than 6 teeth present , or had current pregnancy .
this study was reviewed and approved by the committee for ethical affairs of the taihe hospital , hubei university of medicine at shiyan city , hubei province .
all potential eligible subjects were selected from han chinese population with similar age , sex , level of education , body mass index ( bmi ) , physical exercise , history of alcohol use and diabetes mellitus , and other demographic characteristics .
two investigators were trained before the study and used standardized procedures to increase consistency . as controls we included all subjects with newly - diagnosed pd during the study period who met the same inclusion criteria as cases but
the diagnostic criteria was : pd was defined as presence of more than 4 teeth with 1 site or more having a probing pocket depth ( ppd ) 4 mm and clinical attachment level ( cal ) 3 mm ( 24 ) .
these ppd and cal were evaluated at 4 sites on each tooth ( mesial , distal , buccal , and lingual ) .
cal was measured as the distance from the cemento - enamel junction ( cej ) to the base of the pocket .
subgingival dental plaques were collected from each case and control using a sterile universal curette .
the dental plaques were broken and cultivated on columbia agar plates ( oxoid of thermo fisher scientific inc . ,
waltham , ma , united states ) . the rapid urease test ( rut ) , a commercially available rapid gastric urease test kit ,
was used to for detecting hp , and the detailed methods of culture and polymerase chain reaction ( pcr ) are described elsewhere .
the sample was identified as positive hp if the test gel color changed from yellow to red within 20 min , up to a maximum of 60 min .
we used means with standard deviation ( sd ) or percentage to summarize the frequency distributions of age , sex , level of education , other demographic characteristics , and clinical characteristics of the study population . to investigate the association between hp and pd , the chi - square test or fisher z
test was used to analyze the association , and the unadjusted odds ratios ( ors ) with corresponding 95% confidence intervals ( cis ) were calculated .
considering the confounding risk factors of pd , we then performed a multiple logistic regression analysis to obtain adjusted ors and their 95%cis .
a total of 212 participants with 103 cases and 109 controls were finally included ( age range , 25 to 95 years ) . tables 1 and 2
tables 1 and 2 shows that the basic characteristics of cases and controls were similar ; however , the ppd , cal , and number of hp - positive individuals were significantly different between cases and controls . in the unadjusted analysis ,
hp - positive subjects had significantly increased risk of pd ( 2.63 times higher ) ( 95%ci=1.484.67 ) than hp - negative subjects .
the estimates remained unaltered after adjustment for age , sex , level of education , physical exercise , body mass index , and history of alcohol and diabetes mellitus , and this association remained significant ( or=2.82 , 95% ci=1.555.13 ) ( table 3 ) .
stratified analysis by sex , bmi categories , alcohol use history , physical exercise , level of education , and history diabetes mellitus indicated there were no significant interactions between pd and any of these exposure variables ( table 3 ) .
hp is a gram - negative , urease - producing bacterium that colonizes gastrointestinal mucosa and is considered as a risk factor for many oral diseases . in this case - control study , we found that hp significantly increased risk of pd ( 2.82 times higher ) after adjusting for age , sex , level of education , physical exercise , bmi , and history of alcohol use and diabetes mellitus .
, published in 1994 and revealing a negative association ; however , our results are similar to those of dye et al .
of course , there are many relevant published studies with inconsistent results   and we suggest a meta - analysis   on this topic , also for detecting the consistency of association .
the association between hp and risk of pd can be explained based on several mechanisms . in 2012
.   carried out a systematic review and meta - analysis of randomized controlled trials , indicating that adjunction of periodontal treatment to eradication therapy appears to reduce gastric hp recurrence .
first , there is experimental evidence that hp probably exists in the gingiva and plays a role in the development of pd .
second , this study included all non - smokers and the well - known risk factors of pd , such as alcohol use , diabetes , bmi , and physical exercise , were adjusted .
after adjusting , the association remained significant and the risk was increased from 2.63 times to 2.82 times . for strength of association , the unadjusted or is 2.63 and the adjusted or is 2.82 , which is a mild - to - moderate association .
third , gastrointestinal mucosa is the well - accepted place of hp colonization , and the oral mucosa is also a place for bacterial colonization , especially the gingival sulcus .
hence , we can conclude that the oral cavity is also a reservoir of hp . based on hill s criteria ,
there are some limitations that should be addressed for further investigating the association besides the above items .
first , our study is a case - control study and therefore it can not reveal the temporal sequence of hp and pd . whether pd exists first and then creates an environment for hp or whether hp plays a role in the onset and development of pd remains unknown . to address this question , we suggest a cohort study , especially a prospective cohort design .
second , the present study did not explore whether the severity of pd increases when the counts of hp are higher .
hence , relevant animal studies need to be carried out to determine if there is a dose - response relationship between hp and pd .
third , due to lacking the tissue of cases and controls , we could not to explore whether there is a genetic background .
there are many increased risk polymorphisms of pd , such as interleukin-4 gene 590 c / t polymorphism , cyclooxygenase-21195g / a polymorphism , and interleukin-1 899 ( + 4845 ) c / t polymorphism .
hence , in further research , we suggest the investigators consider including the risk polymorphism in their study .
this is the first case - control study in a han chinese population who live in an upland city .
periodontists should ask patients about history of gastritis , gastric ulcer , and duodenal ulcer , especially for gastro - esophageal reflux disease ( gerd ) patients .
if the patient has symptoms of these gastric diseases , the periodontist should suggest the relevant treatment in order to maintain the effect of periodontal therapy .
hence , they should advise their patients to check and treat pd status during and after treatment for gastric disorders ; this strategy might decrease the risk of gastric hp recurrence .
hp - positive patients had significantly increased risk of having pd compared with hp - negative subjects .
hence , for better understanding the relationship between these 2 diseases , future cohort , especially prospective cohort studies , on immuno - inflammatory , usual risk factors , and genetic polymorphisms between the hp and pd are necessary .
periodontists and gastroenterologists should know about the potential association between hp and pd , and educate pd patients on the risk and the importance of their gastric disorders during dental visits and supragingival scaling .
 backgroundthis study was performed to test the association between helicobacter pylori ( hp ) and periodontal disease ( pd).material / methodsthis was a case - control study in a comprehensive hospital , including all patients with newly diagnosed pd between 2012 and 2014 as cases and all patients without pd as controls , thorough periodontal examinations . those who tested positive for hp were examined by means of polymerase chain reaction . 
 single and multivariate logistic regression was used to analyze the data using spss 19.0 software.resultsthis case - control study included 212 han chinese non - smoking adults . 
 the results indicated that hp - positive status significantly increased the risk of pd ( 2.63 times higher ( odds ratio [ or]=2.63 ; 95% confidence interval [ ci]=1.484.67 ) . 
 after adjustment for age , sex , level of education , physical exercise , body mass index , and history of alcohol and diabetes mellitus , this association remained significantly ( or=2.82 , 95% ci=1.555.13).conclusionspd might be associated with hp infection in adults and hp infection may be a significant and independent risk factor for pd . 
Background
Material and Methods
Study design and participants
Assessment of 
Statistical analysis
Results
Discussion
Conclusions