Keywords
Oral cancer screening, Risk factors, Tobacco, Model comparison approach, Bangladesh
Oral cancer screening, Risk factors, Tobacco, Model comparison approach, Bangladesh
Oral cancer (OC), comprising lip, tongue, and mouth cancers, collectively represents one of the most common cancers worldwide.1 As with other cancers, OC is a leading cause of death and a barrier to increasing life expectancy globally. A global estimate based on Global Statistics 2020 reports that nearly 377,713 new cases of OC were diagnosed in 185 countries, causing about 177,757 deaths and of which Asian countries accounted for almost two-thirds of all the new cases.2 Unfortunately, according to mouth and oral cancer statistics (2020), Bangladesh ranks second in terms of incidences of mouth and OC but first in deaths.3
OC is a multifactorial disease associated with several risk factors including smoking,4–6 alcohol,1,4,6 human papillomavirus,1,6 smokeless tobacco,7,8 family history (first degree family members),9 and periodontal disease,1,10 while the smokeless tobacco practice and consumption of tobacco and alcohol are reasons that predispose the Asian population to OC.11 In fact, the prevalence of current tobacco use is 34.7% in Bangladesh,12 which is particularly worrying because tobacco use is one of the leading causes of OC.
A number of studies suggest that a lack of early diagnosis and screening services, financial constraints, social and cultural factors, and lack of access to cancer services contribute to global disparities in OC outcomes.6,11,13–15 OC screening consists of a systematic clinical examination of the oral cavity, which includes examining the face, neck, lips, labial mucosa, buccal mucosa, gingiva, and the floor of the mouth, tongue, and palate.4 In order to prevent OC, early detection through screening is highly recommended by several studies,10,13,14 despite some controversy regarding the effectiveness of the assessment.6
Detecting potential malignant lesions in the oral cavity can be done either by self-examination or clinical examination, making early detection more accessible and accurate. Subsequently, this can significantly reduce OC diagnostic delays quite often.6,13,16 Dental providers remain alert for signs of potentially malignant lesions or early-stage cancer in patients during routine oral examinations in practice. Cancer screening produces two special benefits which are “down-stage” and reduced mortality or morbidity. OC is particularly known for its premalignant phase, so the screening process is constructed to not only capture OC but also oral potentially malignant disorders, which are responsible for increasing the risk for OC.17
A great deal of research on oral cancer screening has been conducted in many places like Europe,11 the USA,4 Africa,6 and India.13 At the same time, little work is being undertaken in Bangladesh despite the highest mortality and significant numbers of OC incidence. As a result, a remarkable improvement in screening rates for OC has not been achieved in Bangladesh. To our knowledge, there is a lack of literature that makes use of different statistical models to predict the variables influencing oral cancer screening.
To mitigate this concern, we can find ways to facilitate OC screening uptake in Bangladesh by exploring the status of OC screening and its potential associated variables. As a result, this study compares various regression models to find the odds of OC screening; those models were previously used in different studies for better understanding and outcomes.18–20
This cross-sectional study was carried out among patients at National Healthcare Networks, Adabor Centre and Anan Specialised Dental Clinics, Uttara, Dhaka, Bangladesh. The inclusion criteria of the participants were (a) patient visited the center with dental problems, (b) age group > 18 years old, (c) willingly agreed to participate in the study.
In this study, we used convenience sampling method to collect our desired data. We used this method particularly for the lack of sampling frame, to reduce cost and time. By using formula, we obtained the minimum sample size required for the study.
Where is the sample size, z is the standard normal variate, p is the population’s percentage that possesses the attribute, and p + q = 1, and d is the largest error that can be made while predicting the population percentage. Considering the degrees of accuracy, d = 0.05, z = 1.96 and p = 0.34.12 Thus, we got the required sample size 342. However, for better understanding and analysis, we targeted more samples to be included. Thus, we gathered 423 unique samples.
The data collection was done by the research team. All of them are physicians and directly involved in study centers. Upon receiving written consent, data collectors were recorded patients’ sociodemographic data, clinical history and OC screening information upon inclusion criteria. Moreover, the supervisor randomly checked the collected data forms to avoid errors. For data collection, a semi-structured questionnaire was used that was developed based on previous studies.6,15 The questionnaire had three parts: the first part described the demographic characteristics of the respondents—the second part of the questionnaire, clinical information and healthcare utilisation and the last part-cancer screening data. Finally, we collected 423 data through face-to-face interviews (response rate: 98%) from the study hospitals between February to March 2022.
The dependent variable of this study was the presence of OC screening. We categorized the dependent variable into two categories. Which was defined as
The independent variables of the study were gender, age, marital status, education, occupation, living area, number of family members, monthly income, smokeless tobacco use (paansupari/jorda/tamak pata etc.), smoking status, dentist visit, last visit to the lentist, checkup routine, cost management for treatment, knowledge of OC, medium of getting information about OC, If the respondent had no idea about oral cancer (explain for the lack of knowledge), If OC screening test is free of cost, would the respondent examine or not, family history of OC. We used shortened names of the independent variables for analysis purposes and software restrictions (Table 1).
All statistical analysis was performed using R (R Core Team, 2020), RStudio (Rstudio Team, 2020), version 2021.9.1.372 and Statistical Packages for Social Science (SPSS) version 26. For background study or univariate analysis, we used frequency distribution. To measure the association between the response and the explanatory variable, we used the chi-square test.21 The expression is defined as10
Where, Aj observed and Bj expected cell frequencies. Furthermore, the test statistic follows chi-square distribution with (m-1) (n-1) degrees of freedom. Where m is the number of the categories of the covariate and n is the number of responses.
In order to find out the magnitude of the relationship between response and explanatory variable, we conducted three different regression models, namely Poisson regression, Binary logistic regression, Poisson regression with robust variance.
The binary logistic model is generally used for classification problems while utilizing maximum likelihood estimate.21 Let ai(i = 1, 2, …, n) be our outcome variable with categories 1, …, j, …, c and bi = (bi1, bi2, …, bin)’ as the column vector with k covariates. The expression is defined as22
Where represents probability of the event happening and represents probability of it not happening.
Poisson regression20 is frequently used in epidemiology for longitudinal studies in which the outcome variable is the number of episodes of a disease that occur over time. The model formulation is23
Where n is the number of counts for given individual over time t. Xi is the model covariates and βi are the model parameters, also known as log relative risk. Previous studies showed significant improvement over general model using robust variance estimate and we used Poisson regression with robust variance.18,19 Finally, we compared these three models to using standard error and confidence interval of the estimates.
The written informed consent was obtained from each participant and the hospital authorities. Participants were assured that their personal information would remain confidential and be used only for academic purposes. In addition, participants were informed that they could withdraw at any time without negative consequences. The study protocol was approved by the Institutional Review Board of North South University in Bangladesh (Ref-2022/OR-NSU/IRB/1004).
For background study, we did frequency analysis to compare their frequencies and percentages, presented in Table 1. This table demonstrated that out of all respondents, 96.9% didn’t opt for OC screening, and only 2.4% had gone through the screening. Among our patients, 52% were females, and 48% were males. 83% of our patients were married, and we had only 16.1% of unmarried patients. Our responders were generally more educated (48.5%) than less educated (38%). Only 12.1% of the patients were self-employed, whereas 35.7% (151) were employed. Only 21.7% of respondents resided in rural areas, while 78.3% lived in cities. Only 17% of the respondents had ever used smokeless tobacco, while 23.6% were current users. More than half of the patients (53.7%) had a dental appointment the previous year compared to only 13.2% who had one within the last six months. Merely 12.3% of respondents reported seeing the dentist on a regular basis; the majority of respondents 73.8% only did so when they experienced dental problems. Most of the participants (96.2%) had no family history of oral cancer, and 68.3% of the patients were from lower-income groups. With a monthly income of more than BDT 400000, only 1.7% (7 of our respondents) were in the higher income group.
Initially we performed chi-square test to determine whether our variables are associated with the dependent variable or not. In Table 2 we showed the results of the chi-square association test.
We were able to identify five significant variables that were related to our response variable using the chi-square test. We only selected these five variables to study further.
To determine the optimal result in this research, we applied three alternative regression models. In the first step, we used Poisson regression to find out the estimates as shown in the Table 3.
We discovered three statistically significant results in the Poisson regression model. Our model demonstrated that a person will be 98% (Odd Ratio (OR): 0.012, P < 0.000) less likely to opt for OC screening if all other variables remain constant. We also found that tobacco use significantly increased the odds of OC screening. According to the Poisson model, previous tobacco users were 5 (OR: 5.403, P < 0.05) times more likely than non-user to go for OC screening. Finally, having a family history of OC (FHO) increased the odds of OC screening by 9 (OR: 9.544, P < 0.002) times compared to people without a family history of OC.
We employed binary logistic regression to analyze the results in order to conduct further research. As indicated in Table 4 four statistically significant variables were discovered in our research based on the binary logistic regression. If all other variables remain constant, a person had almost no odds (OR: 0.009, P < 0.000) of OC screening. Additionally, binary logistic regression revealed that compared to non-users, previous tobacco use raised the odds of OC screening by a factor of up to 8 (OR: 7.729, P = 0.033). Also, family history of OC raised the odds of OC screening by 16 times (OR: 16.438, P = 0.001) than no family history of OC.
The findings were analyzed using Poisson regression with robust variance, as shown in Table 5. According to our model, the probabilities of going for OC screening were essentially zero if all other factors remained the same (OR: 0.012, P < 0.000). Four additional significant variables were also obtained by the Poisson model with robust variance. When compared to people who had never used tobacco, individuals who had a history of tobacco use had 5 (OR: 5.403, P = 0.05) times higher odds of OC screening. Additionally, former smokers had 2-fold higher likelihood of receiving an OC screening compared to non-users (OR: 2.342; P = 0.08 at the 10% significant level). Furthermore, our data showed that there were no odds of OC screening among those who occasionally visited the dentist for a checkup (Reason 2) (OR: 0.000, P = 0.000). Finally, having a family history of OC increased the odds of OC screening by 9 (OR: 9.544, P < 0.001) times that of those who had no family history of OC. It is evident that the findings of the Poisson regression and the Poisson regression with robust variance were the same, but they differed in the variance, standard error, and confidence interval of the estimates.
For better understanding and to find out the optimal model, we compared the odds and confidence interval of the odds ratio as represented in Table 6. The Poisson model produced significantly less standard error and provided narrower confidence intervals than the binary logistic regression, making it clear that it outperformed the latter by a wide margin. However, it becomes clear that the robust Poisson model performed significantly better than both the Poisson and the logistic regression models when compared to the Poisson model with robust variance.
Table 6 shows that the confidence interval for the odds of past tobacco user is 0.934-31.266 for Poisson regression and 1.170-51.057 for logistic regression, but it becomes much narrower for robust Poisson regression at 0.988-29.552, indicating a better estimate interval. Additionally, the Poisson regression’s confidence interval for past “smoking” was 0.476-11.521, whilst the logistic regression’s range was 0.465-14.927. However, robust Poisson regression yielded a significantly narrower interval than those two, at 0.888-6.18. Likewise, the range of the logistic regression was 3.082-87.671, while the range of the Poisson regression’s confidence interval for FHO was 2.256-40.367. However, robust Poisson regression produced an interval that was 2.402-37.921, which was noticeably narrower than those two.
Robust Poisson regression yielded a substantially lower standard error and a much smaller confidence interval for the estimate for each of the relevant examples.
Finding from this survey aimed at reporting the tend of OC screening and assessing risk factors associated with ever OC examination. Our findings indicate a lower rate of OC screening, with only 2.4% of respondents indicating that they had ever received OC screening. This finding is lower than the estimated 6.8% in Sudan,6 28% in India,24 and 30% in the USA.25 We found more than half of the patients visited the dentist twelve months ago, and seventy-three percent of patients reported that they visit the dentist when they have trouble with their teeth. These findings give a possible cause for concern as low levels of awareness of oral health may affect the chances of early presentation of OC. A greater emphasis should be placed on patient education regarding OC risk and detection, as there is no population screening program for this condition. A surprising result of this study was that 90% of patients had heard of OC screening. Even though this report indicates that participants are aware of screening for OC, it also exhibits a negative attitude or ignorance of its existence because only 2.4% of participants underwent OC screenings. This is the same situation that has been reported that only a few participants had ever received OC screenings despite hearing about OC screening before in different places.6,15 This gives cause for concern as low levels of OC screening will affect the chances of early detection of OC. It also highlights that extensive population-based surveys, awareness programs and establishing health literacy may need to be targeted more closely to encourage people to OC screening gradually.
There is a substantial body of evidence linking tobacco use as one of the leading causes of cancer and its death5; in that same way, using smokeless tobacco products, such as dipping and chewing tobacco, also leads to cancer mouth, esophagus, and throat cancers.8 According to data, compared to people who had never used smokeless tobacco, individuals with a history of smokeless tobacco use had five times higher odds of OC screening. The results of this study support previous studies suggesting that tobacco users had a significantly more positive attitude toward screening than non-tobacco users.14,15 The reason might be that continued anti-tobacco focus strategies such as advertising bans, higher taxes and prices, and restrictions contribute to behavioral changes in Bangladesh, although the country’s implementing smokeless tobacco control policies is insufficient.7 This study also observes that similar to the former smokeless tobacco users, former smokers had a 2-fold higher likelihood of receiving an OC screening than non-users which is in stark agreement with a prior study that reported that smoking was a significant determinant of receiving an OC screening.4,15 On the contrary, previous studies reported that former smokers were not a significant determinant of having a positive attitude or undergoing OC screening.4,14 A probable explanation for our finding might be that former smokers have a positive attitude toward OC screenings, and therefore, it is likely that opportunistic OC screening during dental checkups will yield positive results.
A previous study indicated that regular visits to dentists or check-ups do not affect the uptake of OC screening.15 This result in line with our findings that there were no odds of OC screening among those who occasionally visited the dentist for a checkup. This result suggests that using the opportunity a dental appointment may provide to raise awareness may be increasingly vital to encouraging OC screening, and a previous study emphasised it.6 However, our study also suggests promoting public awareness concerning OC as a risk factor. The risk of many cancers is higher in subjects with a family history of cancer at a concordant site. It was also evident that OC had increased risks of family history at discordant sites.9 This present study demonstrated that having a family history of OC increased the odds of OC screening by nine times that of those with no family history of OC. This result is in line with a previous study conducted in India among women.13 The possible reason might be people with a family history of cancer/OC are better aware of cancer as a disease and hence participate more in OC screening.
Of note, we observed a strong influence of the use of smokeless tobacco and smoking in the uptake of OC screening services. As shown in Table 5, the odds of having OC screening were higher among former smokeless tobacco users and former smokers. The findings in the present study concerning current smokeless tobacco users and smokers’ attitudes related to OC suggest strongly that awareness programs for OC screening are indispensable for them. Raising oral cancer awareness during dental appointments may be increasingly crucial to encouraging early detection. While anti-tobacco strategies such as advertising bans, higher taxes and prices, and restrictions continue to be implemented in Bangladesh, smokeless tobacco control policies remain inadequate.7 Therefore, policymakers must evolve and introduce new effective smokeless tobacco control policies. Additionally, this study revealed that visits to dentists or check-ups do not affect the uptake of OC screening. It concerns that low awareness among people and dentists is likely to hinder early presentation. To address this barrier, dental professionals and patients may need educational initiatives like training programs to improve health literacy surrounding OC risk factors. As well, general dentists’ confidence, expertise, and knowledge in conducting future OC screenings may need to be improved by implementing theory-based interventions.
To our knowledge, this study is the first to assess the tend and associated factors of OC screening among dental patients in Bangladesh. As well this is the first paper to compare OC screening ratios and confidence intervals from different strategies to a suitable reference. In this study, we particularly examined the odds ratio produced by several models. This research is among the first to compare different regression models while comparing their findings about OC screening in Bangladesh. Although qualitative studies are prevalent in OC screening, model comparison and model selection are less focused. So, we presented a different point of view when discussing OC screening. In order to initiate early treatment and avoid OC in its later stages, we used a variety of parameters in this study to determine the likelihood of OC screening. This research also emphasises already established factors (i.e., smoking and using tobacco) responsible for OC and further interpret the findings for the OC screening scenario in Bangladesh. Due to the nature of the study, we employed non-probability sampling for procuring and extracting the findings.
While this research makes several contributions to understanding OC screening, there are some limitations. In this study, we used convenience sampling, which is a non-probability sampling method. So, the samples are not chosen by random selection. We collected samples that were readily available to us. So, it is only possible to generalise for some of the population. Due to the nature of the sampling method, the research may be subject to under-coverage bias and observer bias.
This study disclosed the tend and associated risk factors of OC screening among Bangladeshi dental patients using a model comparison approach. This study has found that only 2.4% of dental patients underwent OC screening before the study period. We also have found that former smokeless tobacco users and past smokers are more likely to uptake OC screening than non-users. In addition, patients having a family history of OC increased the odds of receiving OC screening than subjects without a family history of OC. The lack of OC screening in Bangladesh highlights the need to implement a national-level screening program to help with the early diagnosis of OC and its prevention.
Open Science Framework. Association between Mediterranean diet adherence and dyslipidemia among diabetes mellitus patients. DOI: https://osf.io/2zh6y/.
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Is the work clearly and accurately presented and does it cite the current literature?
Partly
Is the study design appropriate and is the work technically sound?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Yes
If applicable, is the statistical analysis and its interpretation appropriate?
I cannot comment. A qualified statistician is required.
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Are the conclusions drawn adequately supported by the results?
Partly
References
1. Gaballah K, Kujan O: The Impact of Educational Intervention on Junior Dentists' Capacity to Detect Oral Mucosal Lesions and Suspect Malignant Potential.Asian Pac J Cancer Prev. 2022; 23 (11): 3673-3676 PubMed Abstract | Publisher Full TextCompeting Interests: No competing interests were disclosed.
Reviewer Expertise: oral cancer, early detection, prevention , oral precancer
Is the work clearly and accurately presented and does it cite the current literature?
Yes
Is the study design appropriate and is the work technically sound?
Yes
Are sufficient details of methods and analysis provided to allow replication by others?
Partly
If applicable, is the statistical analysis and its interpretation appropriate?
I cannot comment. A qualified statistician is required.
Are all the source data underlying the results available to ensure full reproducibility?
Yes
Are the conclusions drawn adequately supported by the results?
Partly
Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Oral cancer, oral medicine, oral pathology, molecular pathology.
Alongside their report, reviewers assign a status to the article:
Invited Reviewers | ||
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Version 1 25 Jul 23 |
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