ORIGINAL Kanupuru ARTICLE et al

Relationship Between Oral Health Literacy and Oral Health Status Among College Students Karthik Kumar Kanupurua/Nusrath Fareedb/Kudlur Maheswarappa Sudhirc Purpose: To examine the relationship between oral health literacy and oral health by adapting a valid oral health literacy instrument. Materials and Methods: A random sample of 715 students from 9 institutes was included in the study. Oral health literacy (OHL) was assessed by making the students pronounce a list of 40 words from REALD-99. Oral health status (OHL) was assessed using a modified WHO (1997) proforma. A stepwise logistic regression analysis was performed to assess the impact of independent factors on oral health literacy. Results: The response rate was 97.9%; 15 students refused to participate, leaving 700 participants in the final sample. The mean age of the participants was 20.35 ± 1.66 years. A statistically significant difference was observed in OHL according to the clinical parameters. Caries prevalence was higher among subjects with low OHL with a mean DMFT score of 2.69 ± 1.53, compared with high-OHL students having a mean DMFT of 0.22 ± 0.4. Similarly, oral hygiene status was poor among subjects with low OHL (1.53 ± 0.6). Community periodontal index (CPI) scores were lower (1.06 ± 0.8) in subjects with high OHL than in those with low literacy (CPI: 1.6 ± 0.6). Conclusion: The present study revealed a negative correlation between oral health literacy and clinical parameters measured, that is, higher oral health literacy was associated with better oral health. Key words: college students, health literacy, oral health literacy, oral health status Oral Health Prev Dent 2015;13:323-330 doi: 10.3290/j.ohpd.a33444

O

ver the past several decades, knowledge of the causes and treatments of oral diseases have grown exponentially. Yet the incidence of preventable oral diseases remains high (National Institute of Dental and Craniofacial Research, 2005). There are many reasons why preventable diseases remain so common and why people often do not adopt practices that have been scientifically shown a

Assistant Professor, Department of Public Health Dentistry, Narayana Dental College and Hospital, Nellore, Andhra Pradesh, India. Study concept, realisation, and documentation, analysis of samples, statistical analysis and interpretation of data, wrote manuscript.

b

Professor and Head, Department of Public Health Dentistry, Narayana Dental College and Hospital, Nellore, Andhra Pradesh, India. Supervised development of work, helped in formulation of hypothesis, data interpretation and manuscript evaluation.

c

Reader, Department of Public Health Dentistry, Narayana Dental College and Hospital, Nellore, Andhra Pradesh, India. Evaluated results, edited manuscript, contributed substantially to discussion.

Correspondence: Dr. Karthik Kumar Kanupuru, Assistant Professor, Department of Public Health Dentistry, Narayana Dental College and Hospital, Nellore-524002, Andhra Pradesh, India. Tel: +91-949-010-2107. Email: [email protected]

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Submitted for publication: 03.04.13; accepted for publication: 21.08.13

to be effective in maintaining health. Low health literacy is one of these factors (Aruna et al, 2011). Researchers often use education as a proxy measure for literacy in health research. However, literacy and years of formal education are only moderately correlated, and the association between education and health may disappear after adjusting for literacy. Years of education reflect the educational level attempted, but literacy is an indicator of the educational level attained. Literacy is thus a better indicator of the ability to acquire new knowledge and cope with societal demands. Reading comprehension tests are considered the best measure of health literacy, although the results do not correspond well with years of education (Hahn et al, 2010). Health literacy is a shared function of social and individual factors which emerge from the interaction of the skills of individuals and the demands of social systems (Nielsen et al, 2004). Individuals with low health literacy skills often have poorer health knowledge and health status, unhealthy behaviours, less utilisation of preventive services,

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Table 1 REALD-99 Instrument (Hahn et al, 2010) Column 1

Column 2

Column 3

Column 4

1. Bite

26. Approval

51. Veneer

76. Malignant*

2. Sugar*

27. Pulp*

52. Panoramic

77. Esthetic

3. Smoking*

28. Mouth rinse*

53. Orthodontics

78. Diagnosis*

4. Tooth*

29. Splint

54. Instrument*

79. Abscess

5. Floss

30. Toothpaste*

55. Nutrition*

80. Incipient

6. Habits*

31. Mouth guard

56. Inflammation*

81. Halitosis

7. Brush*

32. Denture

57. Restoration

82. Calculus*

8. Diet*

33. Fracture*

58. Fluoride*

83. Avulsion

9. Dentist*

34. Enamel*

59. Bacteria*

84. Malocclusion

10. Canine

35. Erupt

60. Evaluation

85. Incisor

11. Socket

36. Tongue*

61. Plaque*

86. Transmissibility*

12. Molar

37. Sealant

62. Biopsy

87. Microorganisms*

13. Oral

38. Genetics*

63. Sterilization*

88. Gingiva*

14. Filling

39. Varnish

64. Prescription

89. Ankylosis

15. Bleeding*

40. Referral

65. Suture

90. Dentition*

16. Snacking

41. Copayment

66. Radiograph

91. Bruxism

17. Bridge

42. Coverage

67. Trauma

92. Hyperemia

18. Cavity

43. Surgery*

68. Extraction*

93. Analgesia*

19. Recall

44. Sedation

69. Operative*

94. Amalgam*

20. Implant

45. Deductible

70. Porcelain

95. Hypoplasia

21. Cancer*

46. Diabetes*

71. Benign

96. Apicoectomy

22. Braces

47. Discolored

72. Periodontal

97. Temporomandibular

23. Speech*

48. Caries

73. Fistula

98. Neuralgia*

24. Teething

49. Infection*

74. Fluorosis*

99. Malalignment

25. Bleach

50. Cyst

75. Cellulitis

* Denotes words contained in the REALD-40. REALD, Rapid Estimate of Adult Literacy in Dentistry.

higher rates of hospitalisation, increased health care costs and ultimately poorer health outcomes than do those with higher literacy levels. Health literacy has been shown to function as a mediator between traditional socioeconomic factors, such as race and education, and health behaviours and health outcomes (Lee et al, 2012). The World Health Organisation describes health literacy as cognitive and social skills which determine the motivation and ability of individuals to gain access to, understand and use the information in ways which promote and maintain good health (WHO, 1998). Thus, the purpose of this

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study was to assess the impact of oral health literacy (OHL) on oral health status (OHS) by adapting a valid oral health literacy instrument (REALD-99).

MATERIALS AND METHODS Study design A cross-sectional descriptive epidemiological study was designed to assess OHL and to correlate it to OHL among college students in Nellore district of Andhra Pradesh, India.

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Ethical clearance was obtained from the ethics committee of the Narayana Dental College and Hospital. Permission to conduct the study was obtained from the principals of the respective colleges selected for the study. The purpose of the study was explained to the participants and informed consent was obtained prior to the start of the study. The data were collected using a custom designed proforma having three parts: part 1, for recording sociodemographic details of the participants using Kuppuswamy’s Socioeconomic Status Scale (Sharma, 2012); part 2, clinical examination for recording the OHL and oral hygiene status of the participants using a modified WHO (1997) proforma with the addition of oral hygiene index (Green and Vermillion, 1960); part 3, a set of 40 words adapted from the literacy instrument Rapid Estimation of Adult Literacy in Dentistry (REALD-99) (Richman et al, 2007). The original instrument (REALD-99) had a list of 99 words arranged in four columns at four levels of comprehensions (easy to difficult). In the present study, the original list was distributed to 100 randomly selected participants who were instructed to identify 10 words from each level of comprehension and rank them in order of relevance in daily usage. The words which were identified by the participants were finally included in the newly adapted instrument used in this study. Literacy levels were assessed using the adapted instrument to determine low and high oral health literacy based on recommendations given by the authors of the REALD-30 (Lee et al, 2007). For the categorical analysis, we dichotomised the OHL scores (range: 0–40) into ‘low OHL’, i.e. the lower two-thirds of the scores (≤ 25), and ‘high OHL’, i.e. the upper one-third (≥ 26). The examiner was calibrated for recording the literacy instrument by training in standard pronunciations which were taken from the Oxford English Dictionary and the Dorland’s Illustrated Medical Dictionary. Calibration for recording OHL was done in the Department of Public Health Dentistry by reexamining the OHL among 10% of the subjects. The examiner’s kappa value during the study period was found to be adequate, 0.82.

L2 , where Z is α error, P is prevalence, Q is P-1, and L is P x 0.05/100), the estimated sample size was 650, with an additional 10% of the sample size added to compensate for sampling loss. Thus, the total sample was 715. A list of all professional colleges not affiliated with the health university was obtained from the Andhra Pradesh State Council of Higher Education (APSCHE, 2011). A total of 9 institutes was weighted proportionately from each of the three administrative zones and were randomly included in the sampling frame. All subjects from the randomly selected classes at the selected institutes who were present on the day of the examination were included in the final sample.

Study procedure Data were collected by the principle investigator (KK) over a period of 1.5 months. A type III examination was done for recording the WHO (1997) proforma and oral hygiene index (1960). Oral health literacy (OHL) was measured by providing each participant with a clearly typed list of 40 words adapted from REALD-99. The words were typed on an A4-size sheet of paper with a bold Times-Roman font size of 12. Participants were asked to pronounce clearly and loudly the words in the instrument. One point was assigned to each word pronounced correctly without any hesitations. The scores were then summed to obtain the literacy score for the individual.

Data analysis The data for each item were entered into the STATA 9.2 statistical software programme (Stata; College Station, TX, USA). Oral health literacy scores were correlated with oral hygiene index, community periodontal index (CPI) and DMFT scores using Pearson’s correlation. A stepwise logistic regression analysis was performed to assess the impact of independent factors on oral health literacy. Statistical significance was set at the 5% level.

RESULTS Sampling procedure The sample size was estimated based on caries prevalence of the pilot study (70%) (n = Zα2 x P x Q/

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A total of 715 participants were approached, and 15 of them refused to participate in the study, yielding a response rate of 97.9%. Analysis of the

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Table 2 Sociodemographic characters of the participants with their mean OHL scores Gender

n (%)

OHL scores

Male

367 (52)

26.29 ± 6.3

Female

333 (48)

30.29 ± 6.5

18–20

409 (58)

28.14 ± 6.6

21–23

264 (38)

28.26 ± 6.9

24–26

27 (4)

28.52 ± 6.5

Urban

361 (52)

29.61 ± 6.2

Rural

339 (48)

26.69 ± 6.9

Upper

29 (4)

31.07 ± 6.7

Upper middle

193 (28)

29.31 ± 6.2

Lower middle

307 (44)

27.84 ± 6.9

Upper lower

171 (24)

27.09 ± 6.6

English

483 (69)

29.39 ± 6.4

Telugu

217 (31)

25.53 ± 6.5

Age group in years

Location

Socioeconomic status

Language of education

sociodemographic data showed the mean age of the participants to be 20.35 ± 1.66 years, with a male:female ratio of 1.08:1. There was a slightly higher representation from urban areas (52%) and from among lower middle class (44%). Participants with elementary education in the English language made up 69% of the sample. Analysis of OHL scores revealed a mean score of (28.20 ± 6.7) for the total sample, with a higher OHL among females (30.29 ± 6.5) and those from urban areas (29.61 ± 6.2). It was also found that the OHL scores increased as the socioeconomic status increased (Table 2). Of the total sample, 253 (36%) had low OHL and 448 (64%) had high OHL. Regression of OHL over demographic variables revealed a statistically significant relationship to age groups, with the age groups 21–23 and 24–26 having a lower OHL (OR = 0.2 and 0.26, respectively) than the 18- to 20-year age group (Table 3). Statistically significant differences were observed between OHL and the clinical parameters studied. Caries prevalence was high among subjects with low OHL – their mean DMFT score was 2.69 ± 1.53 (p = 0.001), whereas those with high OHL had a mean DMFT of 0.22 ± 0.4. Similarly,

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oral hygiene status was poor (1.53 ± 0.6, p = 0.001) among subjects with low OHL, but better (1.05 ± 0.7) in subjects with high OHL. CPI scores were lower (1.06 ± 0.8, p = 0.001) for subjects with high OHL than for those having low OHL literacy (CPI: 1.6 ± 0.6, p = 0.001) (Table 4). Correlation of OHL with clinical parameters using Pearson’s correlation revealed a negative correlation (Figs 1 to 3) with all the clinical variables measured. Pearson’s Rho (ρ) for oral hygiene index, DMFT and CPI scores was ˗0.34, ˗0.86 and -0.45, respectively (Table 5).

DISCUSSION The ability to read and comprehend prescription bottles, appointment slips and other essential health-related material represents the cognitive and social skills which determine the motivation and ability of individuals and communities to gain access to, understand and use information in ways which promote and maintain good health (American Medical Association, 1999). Traditionally, researchers and clinicians have used the patients’ level of

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Table 3 Logistic regression analysis of OHL scores with sociodemographic characteristics Factor

Wald**

OR (95% CI)

p-value

Age group in years 18–20 (ref)

–

–

–

21–23

19.0670

0.20 (0.09–0.41)

0.00001*

24–26

12.0880

0.26 (0.12–0.56)

0.0010*

Female (ref)

–

–

–

Male

2.7300

0.65 (0.39–1.08)

0.0980

Rural (Ref)

–

–

–

Urban

0.3130

1.17 (0.67–2.04)

0.5760

Telugu (Ref)

–

–

–

English

1.0890

1.37 (0.75–2.5)

0.2970

Upper (ref)

–

–

–

Upper middle

0.0210

0.88 (0.18–4.32)

0.8840

Lower middle

2.4690

1.77 (0.86–3.63)

0.1160

Upper lower

0.0250

0.95 (0.52–1.74)

0.8750

Gender

Location

Language

Socioeconomic status

*Significant at p < 0.05; OR = odds ratio; CI = confidence interval. **Wald χ2 statistics are used to test the significance of individual coefficients in the model.

Table 4 Comparisons of literacy rates in relation to clinical parameters Variable

Literacy rate

Mean

SD

p-value

OHI

Low

1.5330

0.6707

0.00001*

 

High

1.0531

0.7747

CPI

Low

1.6746

0.6032

 

High

1.0692

0.8011

DMFT

Low

2.6905

1.5382

High

0.2254

0.4183

 

0.00001*#

0.00001*

#

*Significant at p < 0.05; Mann-Whitney U-test.

Table 5 Correlation between OHL scores with OHI, CPI and DMFT Correlation between OHL scores with Parameters

Rho-value (ᴘ)

r²

t-value

p-value

OHI

-0.3454

0.1193

-9.7236

0.00001*

CPI

-0.4508

0.2033

-11.7828

0.00001*

DMFT

-0.8686

0.7545

-46.3186

0.00001*

2

*Significant at p < 0.05 using Pearson’s correlation (r ).

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45 40 35

OHL scores

30 25 20 15 10 5 0 0

1

2

3 OHI scores

4

5

6

0

2

4

6 DMFT scores

8

10

12

Fig 1  Correlation between OHL and OHI scores.

45 40 35 30 OHL scores

25 20 15 10 5 0 -5 -10

Fig 2  Correlation between OHL and DMFT scores.

45 40 35

OHL scores

30 25 20 15 10 5 0 0

1

2 CPI scores

328

3

Fig 3  Correlation between OHL and CPI scores.

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education as an indicator of health literacy. Although education is highly correlated with reading levels, educational level alone cannot predict health literacy (Aruna et al, 2011). A simple answer to the question of why health literacy is important is that poor or low health literacy contributes to disease (Horowitz and Kleinman, 2008). Health literacy is now recognised as an important determinant of health. Being able to understand health information and how to obtain services is critical to all aspects of personal health management. Health literacy skills vary across different health topics, including diabetes, cancer, heart disease and oral health. Oral health literacy is a new imperative in dentistry, one that provides us with the opportunity to build on the foundation of our practices and improve our communication with the general public (Horowitz and Kleinman, 2008). The present study was conducted in English, which is not the language most commonly spoken in India. However, since most of the health information provided in Indian healthcare settings is in English (prescriptions, instructions and treatment planning), the instrument was framed in English. This study involved students from across various professional courses affiliated with Jawaharlal Nehru Technical University, S.V. University and S.V. Veterinary University. Courses affiliated with the Health University were excluded, because it may result in sample selection bias, as it is obvious that healthcare professionals will have higher health literacy. The findings of this study should be interpreted with caution, as the literature published on this topic is scarce. Furthermore, the study was conducted in Nellore district in the southern part of Andhra Pradesh, India; this district is a hub of educational institutions in the state of Andhra Pradesh. Typically, as age increases, literacy increases. However, the findings of this study were otherwise. The probable reason could be cognitive function which is strongly related to both age and health literacy. Studies suggest that reading ability may deteriorate with age, although the difference is not seen between younger age groups (e.g. 26-yearolds vs 18-year-olds) but rather for adolescents vs older adults or the elderly (Kirsch et al, 1993; Williams et al, 1995; Gazmararian et al, 1999). Moreover, reading is a complex cognitive process that requires adequate vision, concentration, word recognition, working memory and information processing (David et al, 2000). Deficits in any of these areas may affect reading comprehension, and the

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prevalence of these problems may increase with age. In the state of Andhra Pradesh, males (75.6%) are more literate than females (59.7%), with a male-female literacy gap of 15% (Census of India, 2011). However, this is not reflected in terms of OHL, where males were shown have lower OHL (OR = 0.65) than females. This might be because females in these age groups are more conscious of and concerned about their oral health. Further studies are needed to more fully explain this difference. Although rurality was not an independent risk factor for low health literacy in this study, only the use of a dichotomous variable allowed assessment of a much more complex dynamic relation between rural and urban populations. Statistically, no significant difference was observed between the urban and rural groups, but a slightly higher OHL was seen in the urban subpopulation (OR = 1.17). Rural individuals generally have less health awareness, are more likely to report their health as poor and have less access to health care, including less access to both primary care providers and specialists when they seek health care (Kirsch et al, 1993). The impact of limited health literacy disproportionately affects lower socioeconomic classes (U.S. Department of Health and Human Services, 2010). Interestingly, in the present study among the students of various professional institutes, there was no statistically significant difference between the levels of OHL according to their socioeconomic status. A focus specifically on health literacy has been emphasised in the last five years following preliminary research findings that started to link literacy levels with patient health outcomes (Institute of Medicine, 2011). OHL had a negative correlation with oral hygiene status and caries prevalence. People with low OHL had poor oral hygiene and higher caries prevalence. These findings were in accordance with studies conducted by Lee et al (2011) and Jones et al (2007), in which there was an association of oral health literacy (REALD-30) with oral health status: a higher OHL was associated with better OHS. Patients with low OHL may be reticent in disclosing their reading difficulties in a regular consultation. Use of a rapid screening tool, however, may alert the clinician to the fact that oral healthcare instructions, both verbal and written, may need to be modified into readily accessible lay language. Alternately, patients with high OHL may appreciate

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more detailed scientific information. Using OHL assessment data may potentially improve clinical interactions, compliance with oral health instructions and, ultimately, oral healthcare outcomes (Wong et al, 2012).

7.

8.

9.

CONCLUSION The present study, using the newly adapted instrument, revealed a negative correlation between oral health literacy and clinical parameters measured. That is, higher OHL was associated with better oral health. Improving health literacy is a critical goal in improving health outcomes. Healthcare providers can make a positive impact on improving health outcomes by critically assessing practice and working to improve communication, knowledge, behaviour and access. Improving oral health literacy will require intensive collaborative efforts among healthcare providers.

10.

11.

12.

13.

14.

15.

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