The global burden of periodontal disease: towards integration with chronic disease prevention and control

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1 Periodontology 2000, Vol. 60, 2012, Printed in Singapore. All rights reserved Ó 2012 John Wiley & Sons A/S PERIODONTOLOGY 2000 The global burden of periodontal disease: towards integration with chronic disease prevention and control P OUL E. PETERSEN &HIROSHI O GAWA Chronic diseases are the leading causes of death and disability worldwide. Disease rates from these conditions are accelerating globally, advancing across every region and pervading all socioeconomic classes. According to the World Health Organization (WHO) (85, 90, 91, 93), the major chronic diseases currently account for about 40% of the global burden of disease and by year 2020, their contribution is expected to rise to 60% of the global burden of disease. The most rapid increase in the burden of chronic diseases is occurring in developing countries (33). Four of the most prominent chronic diseases cardiovascular diseases, cancer, chronic obstructive pulmonary disease and type 2 diabetes are linked by common and preventable biological risk factors, notably high blood pressure, high blood cholesterol and being overweight, and by related major behavioral risk factors. An unhealthy diet and poor nutrition over a prolonged period of time, physical inactivity, tobacco use, excessive use of alcohol and psychosocial stress are the important lifestyle components (18). Diabetes mellitus is a heterogeneous group of disorders with different causes, but all are characterized by hyperglycemia. Type 1 (insulin-dependent diabetes mellitus) is caused by destruction of the insulinproducing cells. Type 2 (noninsulin-dependent diabetes mellitus) is the result of insulin resistance coupled with relative beta-cell failure (32). It has recently been reported that Type 2 diabetes accounts for ca. 90% of all cases of diabetes mellitus in the populations of several countries (32, 85). Approximately 285 million people worldwide suffer from diabetes mellitus and this number is predicted to increase by about 50% by year 2030 (32). Figure 1 indicates that the incidence of diabetes will rise considerably in the near future, and this may increase the burden of periodontal disease and tooth loss. Much of this increase will occur in developing countries and will be caused by population growth, ageing, unhealthy diets, obesity and sedentary lifestyles. The years age-group currently has the greatest number of people with diabetes (132 million in 2010), more than 75% of whom live in developing countries (32). Available data suggest that the prevalence of diagnosed and undiagnosed diabetes mellitus in older subjects approaches 20% (49). In the child populations of many countries, diabetes also adds to the burden of disease, and Type 2 diabetes mellitus has been described as a new epidemic (85). In 1992, the incidence of Type 2 diabetes was rare in most child populations, whereas during recent years it was found to range from 8% to 45%, depending on geographic location (32, 37). Tobacco use is a most important risk factor for chronic disease. In the WHO European and Western Pacific Regions, the prevalence rates of tobacco use are high among adults, particularly men (Fig. 2A,B) (95). During recent years, the global pattern of tobacco consumption has changed dramatically. Previously, the consumption of tobacco was prevalent in high-income countries; however, a decline of tobacco use in these countries is now taking place. In contrast, the consumption of tobacco in middleand low-income countries shows a dramatic 15

2 Petersen & Ogawa Fig. 1. Global projection for the number of people with diabetes. From International Diabetes Foundation, Diabetes Atlas (32). increase, which may have a significant bearing on the burden of chronic disease, including periodontal disease. The entire population is at risk because of the presence of many elevated risk factors in which individual susceptibility is affected by culture, socioeconomic factors and the environment. Action to prevent the major chronic diseases should focus on these upstream social determinants and on controlling the behavioral risk factors in a well-integrated manner. The population risks are amenable to change through community-wide strategies. Community interventions use education or environmental change to promote and facilitate lifestyle and behavior changes needed to address a particular problem. Periodontal disease Periodontal disease is one of the two most important oral diseases contributing to the global burden of chronic disease (12); the disease is highly prevalent worldwide and therefore represents a major public health problem to countries. There are different clinical manifestations of periodontal disease, and it may be acute or chronic (45). Gingivitis refers to the inflammation of gingiva caused by bacteria accumulating along the gingival margin. Periodontitis is a more advanced inflammatory form of periodontal disease, in which breakdown of the supporting tissues of the teeth occurs. Clinical signs of the disease include deepening of periodontal pockets and loss of attachment, progressively leading to loosening of teeth and ultimately to tooth loss. Periodontal destruction may be caused by local factors, such as dental biofilm, or it may reflect an inadequate immune response. Gingivitis and periodontitis can also be manifestations of certain systemic diseases, for example, in people with general infection or among people infected with HIV (45). In addition to the chronic form of periodontal disease (i.e. gingivitis and periodontitis), periodontal disease may manifest in acute forms, such as necrotizing ulcerative gingivitis with painful infection, which may destroy the gingival tissue, or as necrotizing ulcerative periodontitis in which the bone beneath the gingival tissue becomes infected or exposed. Aggressive forms of periodontitis may be found in young individuals, but the prevalence of this condition is low. The aim of the present report was to highlight the global burden of periodontal disease. The ultimate burden of periodontal disease tooth loss and the periodontal health status are described from WHO epidemiological data. In addition, the importance of key risk factors and oral health systems are emphasized, and essential national approaches for the effective control and prevention of periodontal disease are considered from a public health perspective. 16

3 Global periodontal health A B Fig. 2. Percentage of male (A) and female (B) tobacco users worldwide. From World Health Organization (95). The global burden of tooth loss Periodontal disease, along with severe dental caries, is a major cause of tooth loss, which directly affects the quality of life of people in terms of reduced functional capacity (e.g. chewing or biting), self-esteem and social relationships. Experience of severe periodontal disease over the course of life ultimately may manifest in the complete loss of natural teeth, particularly at old age. The burden of complete tooth loss was highlighted in the recent World Health Survey (WHS) (60, 88). The WHS is a global survey covering the adult population and it was designed to collect national representative data on the state of health and on the performance of health systems. In all, 72 countries took part in the survey and data were 17

4 Petersen & Ogawa collected by standardized personal interviews. The participating countries were finally categorized into low-, middle- and high-income countries based on their gross national income according to the World Bank criteria (81). Figure 3 provides an overview of the global burden of tooth loss among older people (65 74 years of age) according to national income level. A high prevalence rate (35%) of edentulism is found in upper middle-income countries, whereas the prevalence rate at the time of writing was low (10%) for low-income countries. In high-income countries somewhat lower figures for edentulism are found when compared with upper middle-income countries. In several high-income countries older people often have had their teeth extracted early in life because of pain or discomfort, leading to reduced quality of life. Remarkably, in many of these countries there has been a positive trend of a significant reduction in tooth loss among older adults during recent years owing to changing lifestyles and the effective use of preventive oral health services (14, 60). Self-reported oral health problems and care The WHS (88) also incorporated information on perceived mouth problems and the capacity of including the responsiveness of national health systems. At the global level, the evidence of social inequality was documented regarding the experience of problems with mouth teeth among the elderly (Fig. 3). In low-income countries, about 40% of 65- to 74-year-old subjects reported health problems, whereas the corresponding value for high-income countries was about 30%. Around the world, social inequality in oral illness was also manifest within countries, particularly when education was used as an indicator of social position. To ascertain whether national health systems actually met the dental care needs of older people, participants in the WHS were asked whether they received care for their dental health problems. Some 48% of all age groups received medication for control of infection; this was the case for 80% of people living in low-income countries vs. 25% of people living in high-income countries. In all, 40% of people had instruction in oral hygiene and counseling on dental care. As illustrated in Fig. 4, the global social inequality in health care was profound because fewer people living in poor countries received care for their teeth or mouth problems. In addition to the inequalities across the world, the WHS data revealed huge disparities within countries; in particular, the poor and less educated older people were noticeably underserved and without any natural teeth. Moreover, for low- and middle-income countries the survey demonstrated that people living in rural areas were less likely to have oral health care. This is in contrast to high-income countries where equal proportions of older people living in urban and rural areas reported having such care. Value (percentage) Edentulous Problems with mouth/teeth during the past year Value (percentage) Urban Rural 0 Low Lower Upper High Total middle middle Income category of country Fig. 3. Percentage of 65- to 74-year old subjects in low-, middle- and high-income countries with no natural teeth (edentulous) and percentage of people having experienced problems with mouth teeth during the past year (60, 88). 0 Low Lower Upper High Total middle middle Income category of country Fig. 4. Percentage of 65- to 74-year-old subjects in low-, middle- and high-income countries who received health care related to problems with mouth and teeth, stratified by urbanization (60, 88). 18

5 Global periodontal health The global burden of periodontal disease The prevalence and severity of chronic periodontal disease have been measured in population surveys undertaken in countries with a wide range of objectives, designs and measurement criteria (39). The Community Periodontal Index (CPI) (64, 84) was introduced by the WHO as a tool with which countries may produce profiles of their periodontal health status and plan intervention programs for effective control of periodontal disease. In addition, the CPI population data may be helpful in oral health surveillance at country and intercountry levels. While this index has certain shortcomings as a stand-alone means of assessing the extent and severity of periodontal disease (53), it has been widely used for descriptive periodontal epidemiological studies and for needs assessment in both developed and developing countries. The major advantages of the CPI are simplicity, speed, reproducibility and international uniformity. In 1997, the WHO suggested including information on loss of periodontal attachment in oral health surveys (84). However, data on loss of attachment are scarce as, to date, only a few countries have carried out such systematic surveys. According to the WHO experience, the recording of loss of attachment is often considered difficult to carry out in the field and time-consuming. Certain indicator age groups have been chosen by the WHO for intercountry comparisons of oral health status and oral health surveillance. The essential age-groups relevant to periodontal health are 15 19, and years. Over the past decades several countries have provided CPI data for warehousing in the WHO Global Oral Health Data Bank (89). These are displayed through a component of the socalled WHO Country Area Profile Programme ( html). The standard parameters for presentation of CPI data (84) are percentage of persons by their maximal CPI score (prevalence rate) and the mean number of sextants (severity) with certain CPI scores: Score 0 = healthy periodontal conditions; Score 1 = gingival bleeding; Score 2 = gingival bleeding and calculus; Score 3 = shallow periodontal pockets (4 5 mm); Score 4 = deep periodontal pockets ( 6 mm); Score 9 = excluded; and Score X = not recorded or not visible. The extent of loss of attachment (LA) is recorded for sextants using the following codes: Score 0 = LA 0 3 mm; Score 1 = LA 4 5 mm; Score 2 = LA 6 8 mm; Score 3 = LA 9 11 mm; Score 4 = LA 12 mm; Score X = excluded; and Score 9 = not recorded. The CPI databank is updated continuously and the population data available in the WHO Global Oral Health Data Bank are summarized in Figs 5 9, according to WHO region, as follows: the African Region (AFRO), the Americas Region (AMRO), the Eastern Mediterranean Region (EMRO), the Euro- Percentage AFRO AMRO EMRO EURO SEARO WPRO WHO region Score 4 Score 3 Score 2 Score 1 Score 0 Fig. 5. Maximal Community Periodontal Index (CPI) scores of 15- to 19-year-old subjects, expressed as a percentage and stratified according to World Heath Organization (WHO) region (89). AFRO, the African Region; AMRO, the Americas Region; EMRO, the Eastern Mediterranean Region; EURO, the European Region; SEARO, the South-East Asia Region; WPRO, the Western Pacific Region. Percentage AFRO AMRO EMRO EURO SEARO WPRO WHO region Score 4 Score 3 Score 2 Score 1 Score 0 Fig. 6. Maximal Community Periodontal Index (CPI) scores of 35- to 44-year-old subjects, expressed as a percentage and stratified according to World Heath Organization (WHO) region (89). AFRO, the African Region; AMRO, the Americas Region; EMRO, the Eastern Mediterranean Region; EURO, the European Region; SEARO, the South-East Asia Region; WPRO, the Western Pacific Region. 19

6 Petersen & Ogawa Mean number of sextants AFRO AMRO EMRO EURO SEARO WPRO WHO region X Score 4 Score 3 Score 2 Score 1 Score 0 Fig. 7. Distribution of certain Community Periodontal Index (CPI) scores, shown as mean numbers of sextants, in 35- to 44-year-old subjects according to World Health Organization (WHO) region (89). AFRO, the African Region; AMRO, the Americas Region; EMRO, the Eastern Mediterranean Region; EURO, the European Region; SE- ARO, the South-East Asia Region; WPRO, the Western Pacific Region. pean Region (EURO), the South-East Asia Region (SEARO) and the Western Pacific Region (WPRO). The CPI data are expressed as the mean percentage of subjects with certain CPI scores. In addition, countryspecific data are given in Table 1. The most severe score or sign of periodontal disease (CPI Score = 4) varies worldwide, from 10% to 15% in adult populations; however, the most prevalent score in all WHO Regions is a CPI Score of 2 (gingival bleeding and calculus), which primarily reflects poor oral hygiene. For a few countries, sufficient data over time are available for surveillance and this may allow assessment of the impact of oral health programs. The mean number of sextants with CPI scores is presented for the three age-groups of adults and by WHO region. Poor periodontal health is particularly reported at old age. For older people of both developing and developed countries the severe CPI scores are profound; this pattern is also observed for coun- Value (percentage) Mean number of sextants Australia Cambodia Cambodia Chile China China-Hong kong Denmark Gambia India Japan Lao Madagascar Myanmar New Zealand Republic of Korea Saudi Arabia CPI 0 CPI 1 CPI 2 CPI 3 CPI 4 CPI X CPI 9 China China-Hong kong Denmark Japan Lebanon Madagascar New Zealand Republic of Korea Saudi Arabia UR Tanzania USA CPI 0 CPI 1 CPI 2 CPI 3 CPI 4 CPI X CPI 9 UR Tanzania USA Fig. 8. Maximal Community Periodontal Index (CPI) scores, expressed as a percentage, of 65- to 74-year-old subjects in selected countries (89). Fig. 9. Distribution of Community Periodontal Index (CPI) scores, shown as mean numbers of sextants, among 65- to 74-year-old subjects in selected countries (89). 20

7 Global periodontal health Table 1. Community Periodontal Index (CPI) data, stratified by specific age-group(s) within countries, as reported to the World Health Organization (WHO) (89) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Deep periodontal pockets: 6 mm (Score 4) Others (Score X or 9) AFRO Algeria Benin Burkina Faso Cape Verde Central African Republic Comoros Djibouti Ethiopia Gambia Ghana Kenya Lesotho Madagascar

8 Petersen & Ogawa Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Deep periodontal pockets: 6 mm (Score 4) Malawi Mauritius Namibia Niger Nigeria Seychelles Sierra Leone South Africa Tanzania Togo Zaire Zimbabwe Others (Score X or 9) 22

9 Global periodontal health Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Deep periodontal pockets: 6 mm (Score 4) AMRO Argentina Brazil Canada Chile El Salvador Jamaica Mexico Saint Vincent, the Grenadines Uruguay USA West Indies EMRO Bahrain Cyprus Egypt Others (Score X or 9) 23

10 Petersen & Ogawa Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Iran Deep periodontal pockets: 6 mm (Score 4) Others (Score X or 9) Iraq Jordan Lebanon Libyan Arab J Morocco Oman Pakistan Saudi Arabia Slovenia Somalia Sudan Syrian Arab Republic Yemen

11 Global periodontal health Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Deep periodontal pockets: 6 mm (Score 4) EURO Armenia Belarus Belgium Bulgaria Croatia Denmark Estonia Finland France Germany Greece Others (Score X or 9) 25

12 Petersen & Ogawa Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Hungary Deep periodontal pockets: 6 mm (Score 4) Others (Score X or 9) Ireland Israel Italy Kyrgyzstan Lithuania Malta the Netherlands Norway Poland Portugal Russian Fed San Marino

13 Global periodontal health Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Slovakia Deep periodontal pockets: 6 mm (Score 4) Slovenia Spain Tajikistan Turkey Turkmenistan UK The former Yugoslavia SEARO Bangladesh Bhutan Others (Score X or 9) 27

14 Petersen & Ogawa Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) India Deep periodontal pockets: 6 mm (Score 4) Others (Score X or 9) Indonesia Maldives Myanmar Nepal Sri Lanka Thailand WPRO Australia Cambodia China Cook Islands

15 Global periodontal health Table 1. (Continued ) Country Age-group (years) No symptoms (Score 0) Gingival bleeding (Score 1) Gingival bleeding + calculus (Score 2) Shallow periodontal pockets: 4 5 mm (Score 3) Fiji Deep periodontal pockets: 6 mm (Score 4) French Polynesia Hong Kong Japan Korean Republic Lao P.D. Republic Malaysia New Zealand Niue Papua New Guinea Others (Score X or 9) 29

16 Petersen & Ogawa Table 1. (Continued ) Others (Score X or 9) Deep periodontal pockets: 6 mm (Score 4) Shallow periodontal pockets: 4 5 mm (Score 3) Gingival bleeding + calculus (Score 2) Gingival bleeding (Score 1) No symptoms (Score 0) Country Age-group (years) The Philippines Singapore Tonga Vanuatu Vietnam Data are given as percentage of maximal CPI score. AFRO, the African Region; AMRO, the Americas Region; EMRO, the Eastern Mediterranean Region; EURO, the European Region; SEARO, the South-East Asia Region; WPRO, the Western Pacific Region. tries with advanced oral health systems, reflecting the fact that systems may have only a modest impact on periodontal disease control at the population level. Public health: recording of periodontal disease The CPI measure was included in the 1987 WHO manual on oral health surveys (83) and since then it has been widely used in oral health surveys undertaken for planning programs and determining the need for specific intervention. The system has been a valuable tool, although it has shown certain limitations. The scoring system is based on the assumption of conditions following an ordinal scale; this may be questioned from the current understanding of mechanisms involved with gingivitis, development of periodontal pocketing and loss of attachment. Another difficulty relates to the recording of CPI in tooth loss, particularly regarding the specification of teeth for replacement if indicator teeth are not present. While the original CPI may have relevance for planning health programs, the system has been shown to be weak in the evaluation of periodontal disease action programs. For the 5th edition of the WHO manual for oral health surveys (94), the WHO designed a new, modified CPI system, taking weaknesses of the original CPI into consideration while ensuring simplicity and reproducibility. The new system reflects an effort of giving higher public health priority to periodontal disease as a significant component of the burden of oral disease. As is the case for dental caries, the periodontal status of all teeth present is recorded. Scores relevant to specific disease conditions are applied to the individual tooth, namely the presence absence of gingival bleeding and the presence absence of periodontal pockets of 4 5 or 6 mm. Calculus is not recorded because this is not a disease condition. Recording of all teeth present will allow identification of indicator teeth as used in the previous CPI system. The new modified system has been field tested in several oral health surveys carried out in countries of different size and of different economies, ranging from Bahrain to China. Socio-environmental conditions Reviews of the oral health literature (14, 43) indicate significant intercountry and intracountry variability in the prevalence of periodontal disease, and great variations are shown in socio-environmental conditions, oral health systems, behavioral risk factors and in the general health status of people. 30

17 Global periodontal health Several epidemiological studies have established a significant relationship between socioeconomic status and periodontal disease in various age groups, in other words poor periodontal disease status is linked to low income or to low education (2, 11, 14, 19, 53). For instance, in a study carried out by Drury et al. (19), there was a 10 20% difference in periodontal disease prevalence and severity between people of higher and of lower socioeconomic status in the United States (US) population. The WHO International Comparative Surveys (ICSII, 1997) (14) documented that this pattern was also found in Germany, Japan, Latvia, New Zealand, Poland and the USA. In France, however, studies of adult people showed only minor differences in periodontal status when stratified by income and education (30). In Denmark, the new modified CPI system was used recently in a nationwide survey of subjects in and years agegroups, and significant social inequalities in indicators of periodontal disease were found for both age-groups (i.e. teeth affected by gingival bleeding, pockets 4 5 mm and pockets of 6 mm) (41). The vast majority of epidemiological studies on periodontal health have been conducted in high-income countries (14, 64). However, in some low- and middle-income countries, surveys on social factors in periodontal health have been carried out during recent years, encompassing children, adolescents and adult population groups. These studies demonstrated that poor periodontal status was most prevalent among people living in poverty. For example, in Africa, comparative studies based on use of the CPI index have been undertaken in Madagascar (62), Tanzania (61) and Burkina Faso (79), and in Asia comprehensive information is available from China (31). In Lao PDR, the new modified WHO CPI recording system was used in a recent survey of gingival health in children (35) and it was found that the percentage of teeth with gingival bleeding was relatively high among children living under poor socioeconomic conditions. Socio-environmental factors are highly responsible for distinct profiles of periodontal disease observed in populations living in certain geographical regions or locations; for example, there are considerable differences in the occurrence of periodontal disease in urban vs. rural populations (14). In addition to intercountry variation, the distribution of periodontal disease within countries also differs according to race or ethnic group, regarding both prevalence and severity (10, 11, 54). Beck et al. (7) showed that groups of Black people in the USA had a risk of periodontal destruction three times higher than that of White people of the same age cohort, and studies by Borrell et al. (10) found that African-Americans were twice as likely to have periodontal disease as were Caucasian-Americans. The effect of ethnic group on periodontal health status was also documented in adults of certain developing countries in Africa and Asia (31, 40, 59, 62, 79). Behavioral factors in periodontal disease In addition to poor oral hygiene, the important risk factors for severe periodontal disease relate to the use of tobacco, to malnutrition, excessive alcohol consumption, stress, diabetes mellitus and certain other systemic disease conditions (27, 52, 65, 67, 74). Tobacco Smokers have a high risk of periodontal disease and lesions of the oral mucosa (26, 66). In addition, there is strong evidence that smokeless tobacco, or tobacco chewing, has a significantly adverse effect on periodontal health (1, 46). A dose-response effect of tobacco consumption on periodontal disease has been documented (13, 38, 75), in which the prevalence rates and severity of periodontal disease increased in relation to the number of cigarettes consumed and years of smoking. Stopping smoking means a lower risk of periodontal disease. Tobacco consumption may also diminish the immune response, aggravate periodontal disease and thereby lead to the loss of natural teeth (38). Studies have shown that smoking may account for more than half of the cases of periodontitis among American adults (75). Traditionally, the use of tobacco was frequent in many high-income countries and this may help to explain the current levels of poor periodontal health status in middle-aged and older people. Diet Most chronic diseases, such as cardiovascular disease, diabetes, cancers, obesity and dental disease, are strongly related to diet (50, 52, 86), and a series of studies has concluded that this is caused particularly by diets rich in saturated fatty acids and nonmilk extrinsic sugars, and by diets low in polyunsaturated fats, fibre and vitamins A, C and E. Severe vitamin C deficiency and malnutrition may result in aggravated periodontal disease (52); however, relatively few re- 31

18 Petersen & Ogawa ports are available on the role of diet and nutrition in the etiology of periodontal disease (86). Hence, it is necessary to investigate further the evidence of an association between dietary factors and periodontal disease. As a result of reduced oral functioning, tooth loss often has a negative impact on dietary habits and therefore also has an adverse effect on nutrition status. This has been reported particularly in older people (36, 63). Alcohol High alcohol consumption aggravates the risk of a wide variety of conditions, such as increased blood pressure, liver cirrhosis, cardiovascular disease, diabetes and cancers of the mouth (86). Recent research also indicates that excessive alcohol consumption is associated with increased severity of periodontal disease (65, 74). People who use tobacco are more likely to drink alcohol and eat a diet high in fats and sugars but low in fibre and polyunsaturated fatty acids, and those with a heavy consumption of tobacco and alcohol are thus more likely to be at higher risk of severe periodontal disease. Stress It is well known that cardiovascular disease, diabetes and other chronic diseases are related to psychosocial factors (42, 47), but there is also evidence that stress is linked to periodontal disease (27). Moreover, significant life events are associated with periodontal disease, possibly through physiological responses, which increase susceptibility (17). Oral hygiene Oral hygiene habits fluctuate by culture across the world. In general, people of high-income countries have adopted healthy lifestyles, including regular tooth brushing and use of fluoridated toothpaste (3, 76). Oral hygiene aids, in terms of dental floss and toothpicks, are widely used. However, oral hygiene habits show substantial variation within countries in relation to personal income, level of education and place of residence (14). In particular, education is a strong determinant of oral hygiene practices as reported by the WHO International Collaborative Studies II (14) and other studies carried out in different countries (55). Meanwhile, regular oral hygiene practices are less frequent in middle- and low-income countries but are linked to social status indicators (5, 44). In certain cultures, the tradition of oral hygiene is weak or mouth cleaning is ritual, for example, the use of Miswaki, and oral cleaning by the use of fingers and charcoal or salt is common in some settings (4, 34). It is worth noting that modern oral hygiene measures, such as the use of manufactured toothbrushes, are now being adopted in middle- and low-income countries; however, the use of affordable fluoridated toothpaste is still an important challenge. Knowledge and attitudes in relation to periodontal disease have been studied in populations of several countries (55). Most people are aware of the importance of bacteria and the importance of preventing periodontal disease by oral hygiene. However, the relevance of tobacco and diet is seldom emphasized. In certain settings people may have a rather diffuse understanding of the prevention of periodontal disease; for example, the importance of using fluoride is reported along with relevant answers. In general, knowledge about the causal factors and the prevention of periodontal disease is lower than for dental caries (55). Periodontal health and diabetes mellitus Of the associations observed between oral health status and chronic systemic diseases, the link between severe periodontal disease and diabetes mellitus is the most consistent (28, 48, 69, 70). It is widely documented that people with diabetes have a higher risk of periodontal disease, and periodontal disease has been considered as the sixth complication of diabetes (29, 70, 72). Extensive studies have reported significant associations between diabetes and the severity of periodontal disease (28, 69, 71). Taylor (71, 73) concluded, from his literature review of severe periodontal disease and diabetes mellitus, that not only was there a greater prevalence of periodontal symptoms in patients with diabetes mellitus but the progression of periodontal disease was also more aggressive or rapid. One epidemiological study has been conducted among the Pima Indians (51). Significantly poorer periodontal health was reported in patients with Type 2 diabetes, and the relative risk of periodontal disease in subjects with diabetes was 2.6 after controlling for confounding factors such as age and sex. In studies of subjects with Type 2 diabetes, the odds of destructive loss of attachment were about three times higher than among nondiabetic subjects (8, 20). 32

19 Global periodontal health HIV AIDS and periodontal health The HIV AIDS pandemic has become a human, social and economic disaster, with far-reaching implications for individuals, communities and countries (Fig. 10). No other disease has so dramatically highlighted the current disparities and inequities in healthcare access, economic opportunity and the protection of basic human rights. Sub-Saharan Africa has been most severely affected, with an estimated 22.5 million people living with HIV (78). In South- East Asia there are more than 4 million people infected, and further spread could lead to millions more becoming infected in the coming decade. The epidemic in Latin America is well established with nearly 2 million people infected, and rapid growth has been observed in recent years in Eastern Europe and central Asia. Globally, the major mode of HIV transmission is through sexual intercourse, injecting drug use, mother-to-child transmission and through contaminated blood in healthcare settings. The relative importance of the different modes of transmission varies between and within regions of the world. A number of studies have demonstrated the negative impact on oral health of HIV infection (16). Because of the compromised immune system and a poor oral hygiene status, infected people are vulnerable to periodontal disease. In addition to severe chronic gingivitis, poor periodontal health may manifest as acute necrotizing gingivitis, which is often seen in children and adolescents, and as necrotizing periodontitis, which is mostly seen among adults (16). In particular, such disease conditions are observed in Sub-Saharan Africa and in remote areas of South-East Asia where people have little access to oral health care, including periodontal care. Noma (debilitating oro-facial gangrene) is an important disease burden in certain developing countries, particularly among young children in Africa and Asia (21 25). Severe acute periodontal disease manifests at the onset of noma. Noma primarily starts as a localized gingival ulceration and spreads rapidly through the oro-facial tissues, establishing itself with a blackened necrotic centre. About 70 90% of cases are fatal in the absence of care. Fresh noma is seen predominantly in the 1 4 years age-group, although late stages of the disease occur in adolescents and adults. Poverty is the key risk condition for development of noma; the environment inducing noma is characterized by severe malnutition and growth retardation, unsafe drinking water, deplorable sanitary practices, residential proximity to unkempt animals and a high prevalence of infectious diseases, such as measles, malaria, diarrhea, pneumonia, tuberculosis and HIV AIDS. Periodontal problems among people with disabilities The oral health of people who are physically or mentally disabled is often impaired (6, 68). They may have limited capacity to detect and recognize early symptoms of disease. They may have limited ability to cope with everyday tasks related to personal hygiene, including oral hygiene, which are critical to the maintenance of an independent existence. Oral Western & Central Europe [ ] Eastern Europe & Central Asia 1.4 million [1.3 million 1.6 million] North America 1.5 million [1.2 million 2.0 million] East Asia [ million] Caribbean [ ] Central & South America 1.4 million [1.2 million 1.6 million] Middle East & North Africa [ ] Sub-Saharan Africa 22.5 million [20.9 million 24.2 million] South & South-East Asia 4.1 million [3.7 million 4.6 million] Oceania [ ] Total: 33.3 million [31.4 million 35.3 million] Fig. 10. Global estimates of adults and children living with HIV/AIDS, 2009 (78), UNAIDS,

20 Petersen & Ogawa disease including periodontal problems is often given low priority, especially among disadvantaged people and people with disabilities in developing countries. Several studies reported that such population groups have higher levels of periodontal problems and that they are more likely to experience oral pain and discomfort (9, 15, 40, 77). Oral health systems The availability of oral health manpower varies greatly across countries, which has a bearing on the delivery of oral health care. For example, in several developing countries of Africa, the dentist to population ratio is 1:150,000 or more, in contrast to 1:2,000 in industrialized countries. In low- and middle-income countries, the shortage of dentists is critical and service is primarily confined to tackling pain or discomfort through radical care, such as tooth extraction. Periodontal care is highly neglected in these countries. Meanwhile, most high-income countries have private systems for oral health care; third-party payment systems involving private health insurance or public reimbursement schemes are often implicated, whereas in some countries oral health services are based on high public or government participation. The Second WHO International Collaborative Study (14) was undertaken to measure the health outcome of oral health systems. In order to include different oral health systems, the study comprised selected countries: France, Germany, Japan, Latvia, New Zealand, Poland and the USA. Periodontal health data were collected in standard population groups by use of the original CPI index. The international comparative data demonstrated in general that the periodontal health status of people was not related to the use of oral health systems available. Meanwhile, it is worth noting that the lack of such an association could be related to limitations of the recording system used. The need for public health intervention: global perspectives Periodontal disease and its ultimate consequence tooth loss are important public health problems in countries around the globe. The intention of the present report was to outline the global pattern of periodontal disease based on WHO epidemiological data and to highlight key risk factors. The health impact of periodontal disease on individuals and communities is considerable as a result of pain and suffering, impairment of function and reduced quality of life. The greatest burden of periodontal disease is on the disadvantaged and poor populations, and the social inequality exists not only within countries but between countries around the world. The current pattern of periodontal disease reflects distinct risk profiles related to living conditions, environmental and behavioral factors and oral health systems, and the implementation of preventive oral-health schemes. Social determinants Causal factors involved in chronic diseases are specified in Fig. 11 (85); the underlying socioeconomic, cultural, political and environmental determinants are important. To reduce the burden of periodontal disease and the pronounced inequities in periodontal health, action is needed to address the underlying social determinants of health. It is vital to tackle root causes rather than symptoms, focusing on structural upstream factors that cause poor health and create inequalities. Thus, policies and legislation for periodontal health must focus on social circumstances such as income, educational attainment, employment and housing. Conversely, measures that focus on downstream factors only, such as lifestyle and behavioral influences, have limited success in reducing the health gap between rich and poor populations (43, 80). Causes of chronic diseases Underlying Socioeconomic, Cultural, Political and Environmental Determinants Globalization Urbanization Population ageing Common Modifiable Risk Factors Unhealthy diet Physical inactivity Tobacco use Nonmodifiable Risk Factors Age Heredity Intermediate Risk Factors Raised blood pressure Raised blood glucose Abnormal blood lipids Overweight/obesity Main Chronic Diseases Heart disease Stroke Cancer Chronic respiratory diseases Diabetes Fig. 11. The chain of causal factors and mechanisms in chronic disease (85). 34

21 Global periodontal health Tobacco Alcohol Cancer, including oropharyngeal Respiratory diseases disease is a particular challenge in high-income countries; control of excessive consumption of alcohol may have a positive contribution to periodontal health. Diet Stress Hygiene Lifestyles Cardiovascular disease Obesity Diabetes Oral disease Fig. 12. Common risk factors for chronic disease, including oral disease (54, 85). Several chronic and oral diseases and conditions have common risk factors related to tobacco use, excessive consumption of alcohol, unhealthy diet and personal hygiene (Fig. 12) (54). The fact that these factors are modifiable provides several unique opportunities in population-oriented periodontal disease prevention. National public health programs focusing on risk factor modification must incorporate concerns for oral health, including periodontal health. Periodontal disease is highly prevalent in most countries of the world. The trend of reduction in tobacco use in several high-income countries may help to prevent periodontal disease and tooth loss. In contrast, unless effective tobacco-prevention programs are established in middle- and low-income countries, severe periodontal disease and tooth loss may increase dramatically and this development may subsequently lead to loss of quality of life. Thus, the implementation of the WHO Framework Convention for Tobacco Control (87) may contribute greatly to the achievement of periodontal health. An important strategy for preventing periodontal disease is the establishment of tobacco-intervention programs, which incorporates concerns for oral health. Wherever oral health professionals are available, it is the responsibility of the profession to initiate or maintain efficient tobacco-prevention programs. In addition, periodontal health concerns are essential to integrate when diet and alcohol interventions are organized. Consumption of a balanced diet is essential to ensure a good nutritional status and development and maintenance of an optimal immune system; at present the challenges in diet are particularly high in community settings of low-income countries. On the other hand, reducing the consumption of alcohol as a risk factor of chronic General health periodontal health The rapidly growing incidence of people who are overweight, obese and with diabetes in several countries may have a harmful impact on the periodontal health of the population. This is particularly the case in the regions of Africa and Asia where growth rates of diabetes are very high. National public health programs for the prevention of diabetes must incorporate concerns to periodontal health; in particular, the need is high for such an intervention in low- and middle-income countries where people have limited access to oral health services. People with HIV AIDS suffer from specific oral lesions; neglect of proper oral hygiene coupled with HIV infection has a negative effect on periodontal health. In addition, pain and restriction in oral functioning may lead to poor dietary habits and poor nutritional status. Prevention of periodontal disease is essential in the prevention of HIV AIDS. Activities may also include screening, early detection of oral lesions and referral for special care. This may require the systematic training of oral health personnel or primary health workers if oral health staff are not available. The key risk factors in noma are severe poverty, malnutrition, unsafe drinking water, deplorable sanitary practices and infectious diseases (e.g. measles, malaria and HIV AIDS). Fighting poverty, improving education and economic growth, and working towards providing a healthy environment are important elements for preventing noma; not only the prevention of periodontal manifestations but also other symptoms of noma will benefit from community development in the countries affected, particularly in Africa and Asia. Self-care: oral hygiene National public health authorities have a significant role to play in improving the personal hygiene of people, including oral hygiene. The authorities must ensure that people are aware of the importance of good oral health and that oral health-related knowledge and attitudes are supportive of health behavior. Communication on the benefits of oral health and on proper oral hygiene techniques may need to be delivered by several types of media and channels in 35

22 Petersen & Ogawa order to reach the whole population because the effectiveness of different types of communication media vary depending on the socio-cultural conditions within countries. In high-income countries, written communication or e-learning will be useful, whereas television and radio are considered powerful in middle- and low-income countries. In many lowincome countries, significant proportions of people are illiterate and this may complicate their understanding of the messages delivered. Therefore, health messages for oral hygiene will also show countryspecific variation. Manufactured toothbrushes for oral cleaning are readily available in high-income countries; in some middle-income countries manufactured toothbrushes might be produced locally but they are often of low quality; whereas in low-income countries toothbrushes are less available or accessible to people living in poverty. In low- and middleincome countries proper sanitary facilities and clean water are also important issues, and the public health authorities play a vital role in ensuring the appropriate infrastructure for oral hygiene. Oral health systems In high-income countries, the burden of oral disease has been tackled through the establishment of advanced oral health systems, which primarily offer curative services to patients. Most systems are based on care provided by private dental practitioners, while organized public oral health systems are in place in a few high-income countries. Some countries have third-party payment systems, which share patient costs in dental care. In general, such reimbursement schemes focus on restorative dental care and in some cases on removable dentures, while periodontal care has low priority. Traditional clinical treatment of periodontal disease by private dental practitioners is extremely costly to patients and there is an urgent need for adjustment of reimbursement schemes in favor of periodontal care. The cost burden is particularly high among underprivileged patients and older people. It is worth noting that private systems do not encompass the whole population because accessibility to services is relatively low among disadvantaged groups. In the case of periodontal care, poor people are mostly underserved; thus, it is emphasized that financially fair healthcare intervention must be introduced in order to tackle the profound social inequality in periodontal care. In contrast to high-income countries, low- and middle-income countries have a critical shortage of dentists and other oral health personnel. Investment in oral health including periodontal health is low, or even neglected by public health authorities. The situation often reflects a lack of national policy for oral health, and the limited resources available are primarily allocated to emergency oral care and pain relief. Thus, in low-resource communities, advanced clinical periodontal care is not realistic in the context of public health and therefore low-cost intervention and integrated disease prevention must be strengthened. Capacity building of oral health systems, including the formulation of oral health policies, legislation, relevant action plans, organization of financially fair primary oral health services and provision of oral health personnel or primary health workers appropriately trained in periodontal care and health promotion, are important challenges for lowand middle-income countries. The Ottawa Health Promotion Charter (1986) (82) emphasized the high need for orientation of health services towards health promotion and disease prevention, and it is still recommended for public health authorities to implement such an appropriate orientation of oral health services. The WHO World Health Report 2008 (92) has underlined the significance of outreach primary health care. Across the world, building capacity for primary oral health care must include mechanisms for outreach care to the poor and disadvantaged population groups and facilitate the delivery of preventive periodontal care and community-oriented health promotion. In all countries, systematic training in periodontal care is important and should be a priority element in undergraduate and continuing education programs for oral health personnel. In areas Ôwhere there is no dentistõ, specially trained primary health workers can play a vital role to cover the underserved population groups. Surveillance, evaluation and research Surveillance underpins public health action by linking data with health policies and programs (58). Surveillance provides ongoing (continuous or periodic) collection, analysis and interpretation of population health data, and the timely dissemination of such data to users. Properly conducted surveillance ensures that countries have the information they need to control disease now or to plan strategies to prevent disease and adverse health events in the future. The goal is to assist governments, health authorities and health professionals to formulate policies and programs to prevent disease and to measure the progress, impact and efficacy of efforts to control diseases that are already affecting their populations. 36