Informative cluster sizes for subcluster-level covariates and weighted generalized estimating equations

Summary Williamson, Datta, and Satten's (2003, Biometrics 59 , 36–42) cluster‐weighted generalized estimating equations (CWGEEs) are effective in adjusting for bias due to informative cluster sizes for cluster‐level covariates. We show that CWGEE may not perform well, however, for covariates that can take different values within a cluster if the numbers of observations at each covariate level are informative. On the other hand, inverse probability of treatment weighting accounts for informative treatment propensity but not for informative cluster size. Motivated by evaluating the effect of a binary exposure in presence of such types of informativeness, we propose several weighted GEE estimators, with weights related to the size of a cluster as well as the distribution of the binary exposure within the cluster. Choice of the weights depends on the population of interest and the nature of the exposure. Through simulation studies, we demonstrate the superior performance of the new estimators compared to existing estimators such as from GEE, CWGEE, and inverse probability of treatment‐weighted GEE. We demonstrate the use of our method using an example examining covariate effects on the risk of dental caries among small children.     

Relative efficiency of unequal versus equal cluster sizes in cluster randomized trials using generalized estimating equation models

There is growing interest in conducting cluster randomized trials (CRTs). For simplicity in sample size calculation, the cluster sizes are assumed to be identical across all clusters. However, equal cluster sizes are not guaranteed in practice. Therefore, the relative efficiency (RE) of unequal versus equal cluster sizes has been investigated when testing the treatment effect. One of the most important approaches to analyze a set of correlated data is the generalized estimating equation (GEE) proposed by Liang and Zeger, in which the “working correlation structure” is introduced and the association pattern depends on a vector of association parameters denoted by ρ. In this paper, we utilize GEE models to test the treatment effect in a two‐group comparison for continuous, binary, or count data in CRTs. The variances of the estimator of the treatment effect are derived for the different types of outcome. RE is defined as the ratio of variance of the estimator of the treatment effect for equal to unequal cluster sizes. We discuss a commonly used structure in CRTs—exchangeable, and derive the simpler formula of RE with continuous, binary, and count outcomes. Finally, REs are investigated for several scenarios of cluster size distributions through simulation studies. We propose an adjusted sample size due to efficiency loss. Additionally, we also propose an optimal sample size estimation based on the GEE models under a fixed budget for known and unknown association parameter (ρ) in the working correlation structure within the cluster.     

Relative contribution of caries and periodontal disease in adult tooth loss among patients reporting to the Institute of Dental Sciences,Belgaum, India

Objectives: To examine the reasons for tooth loss in an adult population. Methods: Patients who reported to the department of prosthodontics in Institute of Dental Sciences, Belgaum, located in the north‐western part of the state of Karnataka, in the southern region of India over a period of 2 months, with at least one missing tooth (excluding third molars) constituted the sample size. There were a total of 365 patients (185 females and 180 males) within the age group of 16–84 years (mean age 51.06 ± 16.47 years) who fulfilled this criterion. Socio‐demographic profile was recorded along with a clinical examination for assessing the number and pattern of tooth loss. The reasons for tooth loss were recorded according to the history reported by the patient. Results: In the present study of 365 patients, 58.9% of the patients were completely edentulous, 41% were partially dentate, of which 20.8% had lost their teeth from caries, 11% from periodontal disease and 9.3% from a combination of reasons. More females had lost their teeth because of dental caries whereas more males had lost their teeth because of periodontal disease, this being statistically significant. (χ² = 16.53, p = 0.001). Highly significant results were obtained for age and reasons for tooth loss. (χ² = 150.39, p < 0.001). Irrespective of the socio‐economic status, dental caries was the most common cause for tooth loss in partially dentate patients though it was not statistically significant (χ² = 13.62, p = 0.325). Mandibular first molars were the teeth most frequently lost due to dental caries. The maxillary left central incisor was most frequently lost due to periodontal disease, followed by the maxillary right central incisor. Conclusions: Since both dental caries and periodontal disease contributed to tooth loss at different ages, risk indicators need to be identified.     

The relationship between seven health practices and oral health status in community‐dwelling elderly Thai

Gerodontology 2012; doi: 10.1111/j.1741‐2358.2012.00672.x The relationship between seven health practices and oral health status in community‐dwelling elderly Thai Objective: This study aims to analyse the relationship between seven health practices, oral health behaviors, and oral health status in community dwelling elderly Thai. Materials and methods: The subjects were 612 elderly people (mean age = 68.8 ± 5.9 years). Questionnaires survey about sociodemographics, self‐reported seven health practices and oral health behaviors were conducted by trained interviewers. Oral examinations investigated the number of teeth present, decayed teeth, periodontal status and functional tooth units (FTUs). Oral malodor was assessed by Organoleptic Test, and unstimulated saliva was collected for 5 min. Results: Five health practices (smoking, drinking, physical activity, breakfast and weight maintenance) were significantly related with oral health behaviors. ancova analysis demonstrated the following significant associations: (i) smoking behavior with number of teeth present, number of FTUs, decayed teeth, periodontal disease, oral malodor and salivary flow rate, (ii) drinking alcohol behavior with number of teeth present, number of FTUs, periodontal disease, oral malodor and salivary flow rate, (iii) eating breakfast behavior with periodontal disease, oral malodor and salivary flow rate, (iv) eating between‐meal snack with number of teeth present, number of FTUs, decayed teeth and periodontal disease, (v) maintaining weight with number of teeth present, number of FTUs, periodontal disease and oral malodor, (vi) sleeping with number of teeth present, number of FTUs, periodontal disease, oral malodor and salivary flow rate, (vii) physical activity with periodontal disease and salivary flow rate. Conclusion: Good health practices were related with good oral health behaviors. Moreover, general health practices were associated with the clinical oral health status such as number of teeth present, decayed teeth, FTUs, periodontal disease, oral malodor and salivary flow rate. The elderly with good general health practices were considered to have good oral health status. Improving general health habits are suggested to lead to better oral health for the elderly, and vice versa.     

Epidemiological study on improving the QOL and oral conditions of the aged--Part 2: Relationship between tooth loss and lifestyle factors for adults men

Oral health in early- and mid-adulthood is essential for the improvement of one's QOL, this study was investigated to include an epidemiological analysis of the relationship between tooth loss and life style, such as smoking, regular exercise, and the food habits of approximately 2,000 employees. Compared with the group with mild or no periodontal disease (CPI of 0, 1, or 2), the frequency of tooth loss in the group with advanced periodontal disease (CPI of 4) was 2.00 times (odds ratio, 2.00; 95% confidence limit, 1.37 to 2.93). The probability of tooth loss showed statistical significance in relation to smoking, alcohol drinking, and frequency of meals. Compared with non-smokers, the probability that current smokers will lose teeth is 1.53 times greater (odds ratio, 1.53; 95% confidence limit, 1.20 to 1.96). It was concluded that periodontal disease and smoking must be averted for preventing tooth loss.     

Tooth loss and associated factors in long-term institutionalised elderly patients

Objective: To compare partial and total tooth loss in dependent institutionalised elderly patients and identify any associated factors. Background: A poor oral health status, together with a reduction of autonomy can seriously affect the general health and increase the risk of death in elderly people. Those with total tooth loss and in need of assistance are the most at risk. Materials and methods: In 2004, a cross‐sectional study of 321 elderly patients was conducted in long‐term hospital services provided in Montpellier, France. Socio‐demographic, behavioural, medical and oral health information was recorded for each patient. Multivariate logistic regression models were performed to test the relationship between those covariates and partial or total tooth loss. Pearson chi‐squared tests were used for bivariate analyses. Results: The proportion of edentulousness was 26.9%; among these12.6% had no dentures. The factors significantly associated with edentulism were: an age ‘older than 87 years’ [odds ratio (OR) = 9.4], the presence of a nephropathy (OR = 6.8), and inadequate oral hygiene (OR = 0.1). The factors most significantly associated with partial tooth loss (at least 21 missing teeth) were ‘cancerous disease’ (OR = 9.9), the presence of a nephropathy (OR = 5.6) and the presence of a neurological disease (OR = 4.1). The factors significantly related to dentate status (20 or more natural teeth retained) were ‘hypertension treatment’ (OR = 2.4), and ‘cortisone treatment’ (OR = 0.2). Conclusion: General health problems as well as a poor oral condition were significant risk indicators for tooth loss among the long‐term institutionalised elderly. This suggests that the number of remaining teeth has a strong effect on oral health‐related quality of life.     

Marginal analyses of clustered data when cluster size is informative

We propose a new approach to fitting marginal models to clustered data when cluster size is informative. This approach uses a generalized estimating equation (GEE) that is weighted inversely with the cluster size. We show that our approach is asymptotically equivalent to within-cluster resampling (Hoffman, Sen, and Weinberg, 2001, Biometrika 73, 13-22), a computationally intensive approach in which replicate data sets containing a randomly selected observation from each cluster are analyzed, and the resulting estimates averaged. Using simulated data and an example involving dental health, we show the superior performance of our approach compared to unweighted GEE, the equivalence of our approach with WCR for large sample sizes, and the superior performance of our approach compared with WCR when sample sizes are small.     

Why do some people lose teeth across their lifespan whereas others retain a functional dentition into very old age?

doi:10.1111/j.1741‐2358.2009.00297.x
Why do some people lose teeth across their lifespan whereas others retain a functional dentition into very old age? Objectives: To analyse the importance of caries, periodontitis, and medical and psychosocial factors for risk of becoming edentulous across their lifespan and to examine factors critical for retaining functional dentition into very old age. Methods: From the longitudinal population‐based Octogenarian Twin study which analysed psychosocial and health variables, 357 individuals aged 82 + in 1995–1998 were collected. Information about number of teeth, decayed and filled surfaces percentage and periodontal disease experience were drawn from dental records. Reasons for and time of edentulousness were recorded. Results: Outcome varied – depending on perspective and factors for losing or retaining teeth. Significant factors for losing teeth varied over the lifespan. Losing teeth early in life was related to lower social class; in middle age, to lower education; and in old age, to poor lifestyle factors and low social class. Caries constituted the main reason for tooth loss (about 55%). This increased substantially in the >80 year age‐group (75%). Maintaining a functional dentition into old age was significantly associated with non‐smoking, more education, being married and good periodontal health. Conclusion: It is important to apply life‐span and cohort perspectives to oral health and disease. In our sample of persons born before World War I, caries was the main reason for losing all teeth, with substantially increased prevalence by age. Lifestyle factors were significant for losing and for retaining teeth. Periodontal condition had a significant influence on the likelihood of retaining functional dentition, and also when taking psychosocial variables into account.     

The reasons for tooth loss in geriatric patients attending two surgical clinics in Jerusalem,Israel.

Abstract Objectives Numerous studies around the world have been conducted in order to understand the reasons for tooth extractions in various age groups. Most studies have dealt with the general adult population but little attention has been paid to the elderly population. In Israel, as in most of the western countries, the elderly population is growing rapidly and thus demands for its dental needs are also increasing. In order to meet the dental requirements of the geriatric population, data on the main reasons of tooth mortality have been collected. Design Retrospective analysis of reasons for extraction divided into three categories: caries, periodontal disease and “other’’. Subjects The files of 302 consecutive elderly patients aged 65-95 years attending for extraction. The cause for tooth extraction was gathered from the written diagnosis described by the operator as well as from radiographs. Setting Two surgical clinics in Jerusalem serving low income residents. Results Results indicated that 30% of the extractions were due to caries, 65% were due to periodontal disease and only 6.4% related to “other’’ reasons. In both, males and females, periodontal disease was the major cause for tooth loss yet, females exhibited more extractions due to caries than males (35%vs 23% respectively). A relatively high incidence of tooth loss was documented for the 85+ age group. Of the teeth that were extracted, incisors and molars were equally the most frequent (29%) followed by premolars (26%) and canines (17%). Premolars were the teeth most frequently extracted out of the teeth removed due to caries (32%) whereas incisors were the most frequently removed within the group of teeth extracted due to periodontal disease (31%). Conclusions The results of this study point to the importance of prevention and treatment of dental diseases, particularly periodontal disease, in adults aged 0 years and above in order to prevent tooth loss in their later years.     

Pattern of tooth loss in an elderly population from Ibadan, Nigeria

Objectives: To determine tooth loss, edentulousness, causes of tooth loss and pattern of tooth loss in the elderly in South East Local Government area (SELGA) in Ibadan. Background data: SELGA is one of the largest in Oyo State, Nigeria and has a population of 225 800. Design: A cross‐sectional survey. Methodology: A total of 690 elderly individuals who were 65 years and above living in various wards in SELGA were interviewed by two interviewers and examined by two trained and calibrated examiners whilst two record clerks recorded all the findings of the examination. Result: Forty‐eight per cent of the subjects in the study had not lost any teeth. The mean tooth loss was 4.5 ± 7.6. Percentage edentulousness was 1.3% and this was higher in males than in females. This difference was not statistically significant (χ² = 0.07 p = 0.7). The total number of teeth lost was 3102, 14% of the total number of teeth examined. The study showed that caries was not a major cause of tooth loss. Only 22 (0.7%) teeth were lost as a result of caries, 19 (0.6%) were lost because of trauma and periodontal disease contributed to loss of 3061 (98.7%) teeth. Mandibular teeth exhibited a higher rate of retention than maxillary teeth. The percentage of elderly individuals with tooth loss increased with age. Conclusion: The study highlights the high life expectancy of a tooth among the elderly in SELGA. Despite the different cause of tooth loss in this area, in comparison with developed countries, the pattern of tooth retention appeared similar.     

Oral status in home-dwelling elderly dependent on moderate or substantial supportive care for daily living: prevalence of edentulous subjects, caries and periodontal disease

doi: 10.1111/j.1741‐2358.2011.00507.x Oral status in home‐dwelling elderly dependent on moderate or substantial supportive care for daily living: prevalence of edentulous subjects, caries and periodontal disease Objectives: The aim of this study was to compare the prevalence of edentulous subjects, caries and periodontal disease among the home‐dwelling elderly with moderate and substantial needs of support for daily living. Materials and method: A sample of 302 randomly selected elderly with moderate or substantial needs of supportive care were examined in Sweden. Several oral clinical variables were registered: number of teeth, dentures, caries, probing pocket depth, gingival bleeding and Eichner’s index. Results: Both in general and in oral health, the differences were small when comparing elderly with moderate and substantial care needs for daily living. Those with substantial needs had more caries lesions (p < 0.01) and more gingival bleeding (p < 0.05), while the number of teeth and prevalence of edentulous subjects did not differ in relation to the need of daily support. The elderly had, on average, 9.8–11.7 teeth, one‐third of whom had no natural teeth. According to Eichner’s index, half of the elderly in both groups had no opposing tooth contacts. Fifty‐five per cent used dentures. Conclusions: Elderly people with needs of supportive care have lost many teeth before they become dependent. Health promotion should be a priority in early ageing populations to prevent oral diseases and tooth loss.     

Optimal design of longitudinal data analysis using generalized estimating equation models

Longitudinal studies are often applied in biomedical research and clinical trials to evaluate the treatment effect. The association pattern within the subject must be considered in both sample size calculation and the analysis. One of the most important approaches to analyze such a study is the generalized estimating equation (GEE) proposed by Liang and Zeger, in which “working correlation structure” is introduced and the association pattern within the subject depends on a vector of association parameters denoted by ρ. The explicit sample size formulas for two‐group comparison in linear and logistic regression models are obtained based on the GEE method by Liu and Liang. For cluster randomized trials (CRTs), researchers proposed the optimal sample sizes at both the cluster and individual level as a function of sampling costs and the intracluster correlation coefficient (ICC). In these approaches, the optimal sample sizes depend strongly on the ICC. However, the ICC is usually unknown for CRTs and multicenter trials. To overcome this shortcoming, Van Breukelen et al. consider a range of possible ICC values identified from literature reviews and present Maximin designs (MMDs) based on relative efficiency (RE) and efficiency under budget and cost constraints. In this paper, the optimal sample size and number of repeated measurements using GEE models with an exchangeable working correlation matrix is proposed under the considerations of fixed budget, where “optimal” refers to maximum power for a given sampling budget. The equations of sample size and number of repeated measurements for a known parameter value ρ are derived and a straightforward algorithm for unknown ρ is developed. Applications in practice are discussed. We also discuss the existence of the optimal design when an AR(1) working correlation matrix is assumed. Our proposed method can be extended under the scenarios when the true and working correlation matrix are different.     

Relationship between salivary haemoglobin and number of remaining teeth in older Koreans

Objective

We investigated the relationship between saliva and dental biofilm characteristics, oral hygiene behaviours and the number of remaining teeth in a sample of older Koreans.

Materials and methods

This cross‐sectional study included 133 participants, aged 65 years and older, recruited from senior welfare facilities in Incheon, South Korea. The outcome variable was the number of remaining teeth, and its associations with the independent variables of participants’ general characteristics, salivary haemoglobin level, dental biofilm acidogenicity, salivary flow rate and oral hygiene behaviours were assessed. For statistical analyses, chi‐squared test and step‐wise multiple linear regression were used.

Results

The multiple linear regression model, which included all related factors identified in the bivariate analyses, showed that older adults who had high salivary haemoglobin levels (P < .05), brushed their teeth using the horizontal scrub method (P< .001), and did not use an interproximal cleaning device (P < .01) were more likely to have fewer remaining teeth. However, dental biofilm acidogenicity was not associated with the number of remaining teeth.

Conclusion

The number of remaining teeth was associated with salivary haemoglobin level, appropriate toothbrushing technique and interdental cleaning. These findings suggest that the monitoring of salivary haemoglobin may contribute to the prevention of tooth loss caused by periodontal disease.     

Oral health status in elders from South Brazil: a population-based study

doi: 10.1111/j.1741‐2358.2011.00617.x Oral health status in elders from South Brazil: a population‐based study Objective: To assess the oral health status of community‐dwelling adults aged 60 years and older from southern Brazil and to determine demographics, socioeconomic, behavioural and dental risk indicators. Materials and methods: This cross‐sectional study used a multistage, probability sampling method to draw a representative sample of the metropolitan area of Porto Alegre, Brazil. A subsample of 217 subjects was included in this analysis. Oral mucosal lesions, dental caries, tooth loss and periodontal status (full‐mouth, six sites per tooth exam) were assessed by calibrated examiners. Results: Prevalence of edentulism was 39.5%, and mean tooth loss was 20.2 (SE = 0.6). Older individuals [Odds Ratio (OR) = 2.2], women (OR = 2.3), white people (OR = 5.9), individuals of lower socioeconomic status (OR = 5.6) and smokers (OR = 3.5) had higher likelihood of being edentulous. Approximately 36% of dentate individuals had caries and/or restoration affecting, in average, 5.0 teeth. Periodontitis affected 79% of subjects, and it was associated with older age (OR = 4.0), men (OR = 3.4) and large amounts of supragingival plaque (OR = 3.0). Conclusion: Poor oral health was observed in this elderly population from South Brazil. Sociodemographic disparities accounted for most of the burden of disease and treatment needs.     

A semiparametric joint model for cluster size and subunit-specific interval-censored outcomes

Clustered data frequently arise in biomedical studies, where observations, or subunits, measured within a cluster are associated. The cluster size is said to be informative, if the outcome variable is associated with the number of subunits in a cluster. In most existing work, the informative cluster size issue is handled by marginal approaches based on within-cluster resampling, or cluster-weighted generalized estimating equations. Although these approaches yield consistent estimation of the marginal models, they do not allow estimation of within-cluster associations and are generally inefficient. In this paper, we propose a semiparametric joint model for clustered interval-censored event time data with informative cluster size. We use a random effect to account for the association among event times of the same cluster as well as the association between event times and the cluster size. For estimation, we propose a sieve maximum likelihood approach and devise a computationally-efficient expectation-maximization algorithm for implementation. The estimators are shown to be strongly consistent, with the Euclidean components being asymptotically normal and achieving semiparametric efficiency. Extensive simulation studies are conducted to evaluate the finite-sample performance, efficiency and robustness of the proposed method. We also illustrate our method via application to a motivating periodontal disease dataset.     

Epidemiological study on improving the QOL and oral conditions of the aged--Part 1: The relationship between the status of tooth preservation and QOL

In part 1 of this epidemiological study, a survey was conducted for all senior citizens aged 70 and over who resided in a mountainous village in the mid-section of Hyogo Prefecture. It focused on the relationship among the number of existing teeth, life environment, health status, and activities of daily living; and the correlation between oral status and QOL was analyzed. The daily activities of individuals were compared between those having one or more teeth and others who were totally edentulous. Subsequently, it was found that for both males and females, the odds ratio was significantly high for the dentulous individuals, in comparison with edentulous individuals, to exhibit a behavior indicative of a better QOL (such as "opportunity for conversation with family members or others)", "regular physical activities", and "attend meetings or group outings"). The result of this survey indicates that the presence of teeth is very closely related to one's daily activities. It was concluded that preventing tooth loss is vital for maintaining the masticatory function; so to prevent tooth loss, periodontal disease must be averted.     

Estimating marginal proportions and intraclass correlations with clustered binary data

A logistic regression with random effects model is commonly applied to analyze clustered binary data, and every cluster is assumed to have a different proportion of success. However, it could be of interest to obtain the proportion of success over clusters (i.e. the marginal proportion of success). Furthermore, the degree of correlation among data of the same cluster (intraclass correlation) is also a relevant concept to assess, but when using logistic regression with random effects it is not possible to get an analytical expression of the estimators for marginal proportion and intraclass correlation. In our paper, we assess and compare approaches using different kinds of approximations: based on the logistic‐normal mixed effects model (LN), linear mixed model (LMM), and generalized estimating equations (GEE). The comparisons are completed by using two real data examples and a simulation study. The results show the performance of the approaches strongly depends on the magnitude of the marginal proportion, the intraclass correlation, and the sample size. In general, the reliability of the approaches get worsen with low marginal proportion and large intraclass correlation. LMM and GEE approaches arises as reliable approaches when the sample size is large.     

The number of missing teeth in people of the Edo period in Japan in the 17th to 19th centuries

doi: 10.1111/j.1741‐2358.2011.00511.x The number of missing teeth in people of the Edo period in Japan in the 17th to 19th centuries Objective: The aims of this study were to examine the number of missing teeth in the people of the Edo period (or number of remaining teeth) and to contribute to the 8020 movement proposed in Japan to help people retain 20 or more of their own teeth until the age of 80. Background: The study of dentition in ancient skeletal remains of our ancestors from multiple perspectives can yield information that can contribute to the study of physical anthropology and the leading edge of modern dental research. Materials and methods: The materials were 82 excavated individuals (52 males and 30 females) from 1603 to 1868 whose maxillas and mandibles were both examinable. The age and sex were estimated by anthropological methods, and the individuals were divided into five groups. The status of missing teeth was compared between groups, and a chi‐square test was used to test significant differences between groups. The rates of tooth loss were examined in the maxillas and mandibles. Results: In the people of the Edo period, many teeth remained in good condition until early to late middle age. There were more remaining teeth in these individuals than in modern‐day individuals. However, the Edo people clearly showed increased tooth loss with age. There were no differences in tooth loss by sex. The tooth type with a high rate of tooth loss was posterior teeth, but incisor loss also occurred with ageing. Mandibular canines were most likely to be remaining. Conclusion: The Edo people had more remaining teeth than modern‐day society. This finding was unexpected. The notion that “people of long past ages lost more teeth more quickly” does not seem to apply to people in the Edo period in Japan.     

Age,sex, and antemortem loss of teeth in prehistoric Eskimo samples from point hope and Kodiak Island,Alaska

The incidence of teeth lost antemortem was investigated in 244 archeologically derived dried skeletal specimens from the Ipiutak and Tigara burials at Point Hope, Alaska, and 83 Koniag Eskimo specimens excavated at Jones Point, Uyak Bay, Kodiak Island, Alaska. Ipiutak skeletal remains date from approximately 1500 years B.P. and the Tigara remains from 300–400 years B.P. The Kodiak Island sample is undated. Specimens were sexed and aged in five-year groupings using standard techniques. Teeth lost antermortem were identified as having occupied tooth sockets which showed healing of alveolar bone following exfoliation. Numbers of lost teeth were calculated as percentages of total number of tooth sites of each tooth classification for each age, sex, and site subgrouping. Tooth loss was very low in the Kodiak Island sample, with little difference between sexes and no identifiable age trends. The Tigara ramains displayed moderate tooth loss, with strong correlations to increasing age and little differentiation between the sexes. The Ipiutak specimens lost the most teeth antemortem, with notable between-sex differences and strong correlations with increasing age. In all groups loss of anterior teeth was probably due to accident or heavy wear, while loss of posterior teeth was due to heavy wear, periodontal disease, or agenesis.     

Periodontal health status in the elderly with different levels of education: a 5-year follow-up study

doi: 10.1111/j.1741‐2358.2010.00437.x Periodontal health status in the elderly with different levels of education: a 5‐year follow‐up study Objective: To assess the association between the periodontal health status and level of education over a 5‐year period among the elderly aged 75 years and older. Background: Oral health among the higher educated is known to be better than among the less‐well educated. On the other hand, the prevalence and severity of periodontal disease has been found to grow with increasing age. Methods: The participants were derived from a population‐based Helsinki Aging Study, a random sample of 76‐, 81‐ and 86‐year‐old elderly. The 170 dentate elderly who underwent clinical oral examinations at baseline and 71 who participated in the follow‐up were included in this study. The data was collected from intraoral and radiological examinations and from a structured questionnaire. Results: Subjects with a higher level of education had more retained teeth than subjects with a lower level of education. According to CPITN index, better‐educated participants had more healthy sextants, but they also had more sextants with periodontal pockets. Radiographic examination showed similar results. Conclusion: Level of education has a clear effect on the periodontal health status in the elderly. More treatment need seems to polarise into those elderly who are better educated as they retain more teeth into old age.