Cleansing and preparation of data for statistical analysis: A step necessary in oral health sciences research

In many published articles, there is still no mention of quality control processes, which might be an indication of the insufficient importance the researchers attach to undertaking or reporting such processes. However, quality control of data is one of the most important steps in research projects. Lack of sufficient attention to quality control of data might have a detrimental effect on the results of research studies. Therefore, directing the attention of researchers to quality control of data is considered a step necessary to promote the quality of research studies and reports. We have made an attempt to define the processes of cleansing and preparing data and determine its position in research protocols. An algorithm was presented for cleansing and preparing data. Then, the most important potential errors in data were introduced by giving some examples, and their effects on the results of studies were demonstrated. We made attempts to introduce the most important reasons behind errors of different natures; the techniques used to identify them and the techniques used to prevent or rectify them. Subsequently, the procedures used to prepare the data were dealt with. In this section, techniques were introduced which are used to manage the relationships established between the premises of statistical models before carrying out analyses. Considering the widespread use of statistical models with the premise of normality, such premises were focused on. Techniques used to identify lack of normal distribution of data and methods used to manage them were presented. Cleansing and preparation of data can have a significant effect on promotion of quality and accuracy of the results of research studies. It is incumbent on researchers to recognize techniques used to identify, reasons for occurrence, methods to prevent or rectify different kinds of errors in data, learn appropriate techniques in this context and mention them in study reports. KEYWORDS: Cleaning; Preparation; Statistics; Data; Quality Contro

Prevalence, Incidence and Ecological Determinants of Diabetic Retinopathy in Iran: Systematic Review and Meta-analysis

Purpose: To estimate the pooled prevalence and incidence of diabetic retinopathy (DR) in Iran and to investigate their correlations with the Human Development Index (HDI), healthcare access (i.e., density of specialists and sub-specialists), and methodological issues. Methods: Electronic databases such as PubMed, Embase, Scopus, Web of Science, Google Scholar, and local databases were searched for cohort and cross-sectional studies published prior to January 2018. Prevalence and incidence rates of DR were extracted from January 2000 to December 2017 and random effects models were used to estimate pooled effect sizes. The Joanna Briggs Institute critical appraisal tool was applied for quality assessment of eligible studies. Results: A total of 55,445 participants across 33 studies were included. The pooled prevalence (95% CI) of DR in diabetic clinics (22 studies), eye clinics (4 studies), and general population (7 studies) was 31.8% (24.5 to 39.2), 57.8% (50.2 to 65.3), and 29.6% (22.6 to 36.5), respectively. It was 7.4% (3.9 to 10.8) for proliferative DR and 7.1% (4.9 to 9.4) for clinically significant macular edema. The heterogeneity of individual estimates of prevalence was highly significant. HDI (P < 0.001), density of specialists (P = 0.004), subspecialists (P < 0.001), and sampling site (P = 0.041) were associated with heterogeneity after the adjustment for type of DR, duration of diabetes, study year, and proportion of diabetics with controlled HbA1C. Conclusion: Human development and healthcare access were correlated with the prevalence of DR. Data were scarce on the prevalence of DR in less developed provinces. Participant recruitment in eye clinics might overestimate the prevalence of DR

Awareness and Attitude Towards Opioid and Stimulant Use and Lifetime Prevalence of the Drugs: A Study in 5 Large Cities of Iran

Background: Providing population-based data on awareness, attitude and practice of drug and stimulant use has policy implications. A national study was conducted among Iranian general population to explore life time prevalence, awareness and attitudes toward opioids and stimulant use.Methods:We recruited subjects from 5 provinces with heterogenic pattern of drug use. Participants were selected using stratified multistage cluster sampling. Data were collected using a validated self-administered questionnaire. Logistic regression model was applied to identify the variables that are associated with drug and stimulant use. Results:In total 2065 respondents including 1155 men (33.96 ± 10.40 years old) and 910 women (35.45 ± 12.21 years old) were recruited. Two-third of respondents had good awareness about adverse effects of opioid use. Corresponding figure in terms of stimulants was 81.4%. Almost 95% of participants reported a negative attitude towards either opioid or stimulant use. The lifetime prevalence of opioid use and stimulant use were 12.9% (men: 21.5%, women: 4.0%) and 7.3% (men: 9.6%, women: 4.9%), respectively. Gender (adjusted odds ratio [AOR]M/W =6.92; 95% CI: 2.92, 16.42), education (AORundergraduate/diploma or less = 0.49; 95% CI: 0.26, 0.90), and marital status (AORothers/single = 2.13; 95% CI: 1.36, 3.33) were significantly related with opioid use. With respect to stimulant use, age was negatively associated with the outcome (AOR60+/20-29 years = 0.08: 95% CI; 0.01, 0.98) and men were 2 times more likely than women to use stimulants (ORM/W=2.15: 95% CI: 0.83, 5.56). In addition, marital status (AOROthers/singles = 3.45; 95% CI: 1.09, 10.93), and awareness (AORWeak and moderate/good = 0.40; 95% CI: 0.25, 0.61) were independently correlated with stimulants use. Conclusion: While the attitude of Iranian adults toward opioid and stimulant use was negative, their awareness was not that adequate to prevent the drug use. Men and those with lower socio-economic status (SES) should be the focus of health promotion programs regarding opioid use. However, regarding stimulants use, promotion programs should target younger age groups and those with higher SES status

Lung Cancer Prevalence in Iran by Histologic Subtypes

Background: Prevalence statistics are essential for cancer control in addition to incidence and mortality data. As we know, there is no published report regarding lung cancer (LC) prevalence in Iran. Herein, we provide model-based estimates of limited time LC prevalence in Iran, 2015. Materials and Methods: Incidence numbers of LC were extracted from Iranian National Cancer Registry reports for 2003–2009. Trends were analyzed by joinpoint regression, assuming a logarithmic poisson model. Incidence numbers were projected up to 2015, using linear regression models which were trained by corrected annual percentage changes. A Monte Carlo-based model was generated, and absolute survival rates, number of incident cases, and incompleteness of Iranian cancer registry for LC were included into it. Limited-time prevalence (within 1, 2–3, and 4–5 years from diagnosis) and its respective 95% uncertainty level (UL) were estimated by age, gender, and histopathological type. Results: Five-year prevalence was estimated to be 4.21 (95% UL: 3.37–5.38) per 100,000 adult person, with a male:female ratio of 2.01. Estimated number of patients within 1, 2–3, and 4–5 years from diagnosis were 1871 (1497–2392), 993 (770–1285), and 420 (322–550), respectively. Most prevalent form of LC were squamous cell carcinoma (802; 579–999) and adenocarcinoma (319; 230–389) in males and females, respectively. Conclusion: According to our results, the most plausible estimates of number of alive LC patients within initial treatment, clinical follow-up, and cure phases were 2392, 1285, and 550 cases in Iran in 2015

Individual and Environmental determinants of Health Related Quality of Life in Iranian patients with type II diabetes

Abstract Background: In recent two past decades prevalence of Type II diabetes has increased dramatically. Despite its financial costs, one of its consequence outcomes is decreasing quality of life of Diabetic patients. So it seems to be more useful to evaluate the influential personal and also environmental factors on patient’s quality of life. The purpose of this study was to assess effects of personal and environmental factors on Health Related Quality of Life (HRQoL) of Iranian type II diabetic patients. Material and Methods: We worked on some parts of data form a national cross sectional study conducted in 2006. Sampling technique was random cluster sampling. Data collection method was face to face interview based on EQ-5D questionnaire. Interview form, also measured personal factors include: gender, age, duration of diseases from diagnosis, educational and family economic status. We collected our environmental factors such as literacy rate, urbanization rate, number of medical clinics and endocrinologists from latest national census, 1385. For data analysis we used multilevel regression analysis by Ml-win software. Results: Available data were analyses for 3472 diabetic patients. Gender, age, duration of disease, economic status and educational level in personal level and urbanization rate as an environmental factor were statistically significant factors in relation with health related quality of life. Conclusion: Based on study results, gender, and age, duration of illness, family economic and educational status of patients and the rate of urbanization affect on the HRQoL of type II diabetic patients

Estimation and Projection of Prevalence of Colorectal Cancer in Iran, 2015–2020

Background: Population aging and more prevalent westernized lifestyle would be expected to result in a markedly rising burden of colorectal cancer (CRC) in the future years. The aim of this study is to estimate the limited-time prevalence of CRC in Iran between 2015 and 2020. Materials and Methods: Aggregated CRC incidence data were extracted from the Iranian national cancer registry (IR.NCR) reports for 2003–2009 and from GLOBOCAN-2012 database for 2012. Incidence trends were analyzed by age groups, genders, histopathologic, and topographic subtypes to estimate annual percentage changes. Incidence was projected for 2020. The prevalence was estimated applying an adopted version of a previously introduced equation to estimate limited–time prevalence based on the incidence and survival data. Monte Carlo sensitivity analyses were applied to estimate 95% uncertainty levels (ULs). In each scenario, incidence, survival, annual percentage changes, and completeness of case ascertainment at IR.NCR were replaced under pre-assumed distributions. Results: Number of estimated within 1, 2-3 and 4-5-year CRC patients in 2015 were 13676 (95% UL: 10051–18807), 20964 (15835–28268), and 14485 (11188–19293), respectively. Estimated 5-year prevalence for 2020 (99463; 75150–134744) was 2.03 times of that for 2015. Highest 5-year prevalence was estimated in ages 55–59 for females and 75 + for males. Adenocarcinoma (41376; 31227 55898) was the most prevalent histologic subtype. The most prevalent tumor location was colon (30822, 23262–41638). Conclusion: A substantial growth in the prevalence of CRC survivors is highly expected for future years in Iran. Establishment of specialized institutes is highly recommended to provide medical and especially social supports for Iranian CRC survivors

Prevalence of obesity and overweight and their related factors among the adults of Mazandaran Province, Iran, in 2010

Background: Obesity is an unpleasant outcome of changes in the behavior and lifestyle, and it leads to premature inability and loss of job in most cases. This study aimed at determining the prevalence of obesity and overweight conditions and some related factors among the adults in Mazandaran Province, Iran. Methods: This cross-sectional study was conducted in 2010. The data collection tool was a standard questionnaire provided by the World Health organization (WHO).The sample of this study was selected from all people in the age range of 15 to 64 who lived in the urban and rural areas of Mazandaran Province. The researchers studied 1000 people (500 males and 500 females). The data were analyzed using mean, standard deviation, chi-squared, linear regression, and Logistic regression in SPSS version 16 software. Results: The average and the standard deviation of Body Mass Index (BMI) of the participants was 27.36±6.04 (25.76±4.5 for males and 28.95±6.9 for females), and the average prevalence of overweight was 34% (males: 35.8%, females: 32.2%); the average incidence of obesity was 28.4% (males: 17.8%, females: 39%).It was found that age groups of 35-44 (OR: 3.1, CI: 95%: 1.7-5.8), 45-54 (OR: 3.1, CI: 95%: 1.7-5.8), and 55-64 (OR: 4.02, CI: 95%: 2.1-7.5) and being a housewife (OR: 2.3, 95% CI: 1.03-5.1) were predictive of BMI values equal to or greater than 30. Conclusion: The results of this study showed that the prevalence of overweight and obesity was significant among people of Mazandaran Province. Therefore, it is recommended that educational-research centers and health authorities look for appropriate strategies to reduce the prevalence of this problem

Visual Impairment Prevalence, Causes, and Role of Healthcare Access: A Systematic Review and Meta-Analysis in Iran

Purpose. Healthcare access is one of the determinants of visual impairment (VI), as a public health problem. The objective of this study was to estimate VI prevalence, related causes, and its correlation with access to physicians in Iran. Methods: This systematic review and meta-analysis include observational studies published in Iran. PubMed, Web of Science, Scopus, Google Scholar, and local databases were systematically searched by using the MeSH headings. Data on the provincial distribution of physicians, as an index of access to healthcare, was retrieved. A random-effect meta-analysis was performed to assess. Results. Eight articles were included. The pooled prevalence of blindness, low vision, and VI was 0.80% (95% CI: 0.61–0.99%), 2.92% (95% CI: 2.40–3.44%), and 5.57% (95% CI: 4.71–6.43%). Refractive errors were the most common causes of VI based on PVA with the pooled prevalence of 54.6% (95% CI: 43.4–65.8%). Based on BCVA, we found that the pooled prevalence of cataracts was 37.4% (95% CI: 29.5–45.3%) as the most common cause of VI. The results of metaregression showed that the greater number of general practitioners (GPs) (P value=0.01) and pharmacists (P value=0.024) per population were associated with a lower prevalence of blindness. Conclusion. Some of the main causes of visual impairment in Iran are preventable. Access to healthcare services may lead to early diagnosis of preventable causes of VI. Further well-designed studies and national surveys should be conducted to provide accurate data from different regions of Iran

Determinants of cancer visibility and disclosing behavior of cancer patients.

<p>Determinants of cancer visibility and disclosing behavior of cancer patients.</p