transient ischemic attack

HARM/ ETIOLOGY

A RTICLE A NALYSIS &

Association between periodontal disease, edentulism, and stroke/transient ischemic attack

E VALUATION Original Article

Level of Evidence

Elter JR, Offenbacher S, Toole JF, Beck JD. Relationship of periodontal disease and edentulism to stroke/TIA. J Dent Res 2003;82(12):998-1001.

3b

Purpose

To determine whether there is an association between periodontitis or edentulous and a combined outcome of stroke and/or transient ischemic attack (TIA)

Source of Funding

Government: NIDCR grant R01DE11551 and contracts from NHLBI

Type of Study/Design

Cross-sectional study

Summary SUBJECTS The sample size consisted of 10,906 adults (9415 dentate and 1491 edentulous); 6436 of the dentate group had periodontal examinations. Fifty-four percent were female. Study locations consisted of 3 US communities: Forsyth County, NC (whites and blacks); Minneapolis, MN, (whites); Jackson, MS, (blacks). Patients were recruited between 1996 and 1998. The disease characteristics were the following: mean 26.1% of sites with attachment loss of 3+ mm among the stroke/transient ischemic attack (TIA) patients, and 22.7% among the group with no stroke/TIA; stroke/ TIA was present in 13.5% of the periodontal examinees, 15.6% among the remaining dentate, and 22.5% of the

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edentulous. There were similar proportions of stroke and TIA cases.

EXPOSURE The primary exposure was percent of sites with 3+ mm attachment loss categorized into 4 groups according to the extent of attachment loss (quartiles). MAIN OUTCOME MEASURE The primary outcome measure is a combined measure of stroke and/or TIA. MAIN RESULTS The odds ratio comparing stroke/TIA in the group in the highest quartile of percent of sites with 3+ mm attachment loss against the group in the lowest quartile is 1.3 (95% CI 1.02–1.7), controlling for adjustment for 5-year increments of age, sex, race/center, education, smoking status and intensity, hypertension, diabetes,

and prevalent coronary heart disease. The multivariate association between edentulism and stroke/TIA is 1.4 (95% CI 1.1–1.7).

CONCLUSIONS Edentulous subjects and those with periodontal disease were more likely to have stroke or TIA compared to subjects who are dentate and subjects without periodontal disease, after controlling for confounders.

Commentary and Analysis This is a well conducted, cross-sectional study. The results suggest significant but weak associations between periodontal disease and stroke/TIA and between edentulism and stroke/TIA. The authors are cautious in their interpretation of the results and acknowledge the limitations of the study, including its cross-sectional nature, possible residual confounding, limitations in self-reported measures of stroke/ TIA, inability to distinguish between hemorrhagic and ischemic stroke, and possible selection bias due to exclusion of people needing antibiotic pre-medication among the periodontal examinees. The only additional concern is the combination of stroke and TIA into a single outcome, especially when they mention that there is no independent association with stroke. The authors did not present the relative risks separately for stroke and TIA, hence it is difficult to know whether the results are qualitatively different or only different in the significance. They reason that the lack of association with stroke may be due to exclusion of fatal stroke due to the cross-sectional study design, leading to probable exclusion of people with the most severe periodontal disease. If this were true, it could also impact the association with TIA. Another

Journal of Evidence-Based Dental Practice Volume 4, Number 4

likely explanation is that the inclusion of hemorrhagic stroke, which is less likely to be associated with periodontal infection than ischemic stroke1,2 and could bias the results towards the null. The authors mention that a relation between periodontitis and TIA is less susceptible to bias because it is not likely to be impacted by selective survival. This is true; on the other hand, TIA is likely to be more misclassified than stroke.3 If the detection and misclassification is related to access to health care and hence to behavioral factors, there could be potential detection bias which may result in a stronger association for TIA. The authors caution that no inference about causality should be made from the results of this cross-sectional study. In addition, the small associations detected could possibly be attributed to other explanations such as residual confounding. Additional studies in different populations showing consistent results and a satisfaction of causal criteria are needed before the inference is carried to clinical practice. REFERENCES 1. Wu T, Trevisan M, Genco RJ, Dorn JP, Falkner KL, Sempos CT. Periodontal disease and risk of cerebrovascular disease: the first national health and nutrition examination survey and its follow-up study. Arch Intern Med 2000;160:2749-55. 2. Joshipura KJ, Hung HC, Rimm EB, Willett WC, Ascherio A. Periodontal disease, tooth loss, and incidence of ischemic stroke. Stroke 2003;34:47-52. 3. Johnsen SP, Overvad K, Sorensen HT, Tjonneland A, Husted SE. Predictive value of stroke and transient ischemic attack discharge diagnoses in The Danish National Registry of Patients. J Clin Epidemiol 2002;55:602-7.

Reviewer: Kaumudi Joshipura, BDS, MS, ScD Harvard School of Dental Medicine Boston, Massachusettes

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