فهرست مطالب elham mohebbi

 The inflammatory potential of diet may affect carcinogenesis. This study aimed to determine the association between dietary inflammatory index (DII) and the risk of head and neck cancer (HNC), as well as the interaction between DII and cigarette smoking in HNC development within the Iranian population.

Study Design: 

This is a case-control study.

 In this multicenter case-control study, participants’ dietary intake was assessed using a validated 130-item food frequency questionnaire, from which DII was computed. The study recruited 876 new cases from referral hospitals across 10 provinces and 3409 healthy controls who were frequency-matched based on age, gender, and residential place. Logistic regression was used to obtain odds ratios (ORs) for HNC across tertiles of DII, which were adjusted for confounding variables.

 A higher pro-inflammatory diet was associated with an increased risk of all HNC (OR T3 vs. T1 [95% CI]: 1.31 [1.06, 1.62]; P-trend=0.013). There was a significant association between lip and oral cavity cancers and DII (OR T3 vs. T1 [95% CI]: 1.56 [1.16, 1.66]; P-trend=0.004). Furthermore, an inflammatory diet was associated with an increased risk of pharynx cancer (OR T3 vs. T1 [95% CI]: 2.08 [1.14, 3.79]; P-trend=0.02). Additionally, no significant association was observed between DII and larynx cancer, while an interaction was found between DII and tobacco use on the risk of HNC (OR T3 vs. T1 [95% CI]: 2.52 [1.78, 3.57]; P-interaction=0.03).

 DII was positively associated with HNC risk. There was a significant association between DII and the risk of lip, oral cavity, and pharynx cancers. Additionally, there was an interaction between tobacco use and DII in determining the risk of HNC.

Mental health is integral to public health in adolescents. Although previous studies have shown that low socioeconomic status (SES) is associated with mental disorders (MD), it is unclear which mental health domains are most important. Thus, our study aimed to investigate the associations between 5 domains of mental disorder and SES inequality in adolescents. 

We conducted a cross-sectional study among adolescents (N = 1724). Associations between SES inequality with mental disorders, such as emotional symptoms, conduct problems, hyperactivity, peer relationship problems, and prosocial behavior, were examined. We used the concentration index (CI) to determine inequality. The gap between the low and high socioeconomic groups was decomposed into its determinants using the Blinder-Oaxaca decomposition method.  

Mental health's overall CI was –0.085 (P ˂ 0.001). The emotional problem was primarily caused by SES inequality (–0.094 [P = 0.004]). Decomposition of the gap between the 2 economic groups showed that physical activity, school performance, exercise, parents' smoking status, and gender were the most important determinants of inequality.  

SES inequality plays a vital role in adolescents' mental health. It seems that the emotional problem domain of mental health might be more amenable to interventions than other domains.

Most of previous studies have investigated the association of specific food or nutrient with risk of breast cancer (BC) rather than overall diet and there is lack of evidence regarding dietary pattern in BC development. This study aims to examine the association between dietary patterns and risk of BC among Iranian women.

This case–control study was carried out on 453 BC women and 496 healthy controls. A reliable and valid FFQ was used to evaluate usual dietary intake. Factor analysis was also applied to address the most major dietary patterns which were known as the healthy and unhealthy dietary patterns.

Those in the highest quartile of healthy dietary pattern had lower risk of BC (P = 0.001). However, being in the highest quartile of unhealthy pattern was associated with 2.04-fold increase of BC risk (P = 0.004) compared to the lowest quartile. In premenopausal women, risk of BC in upper quartile of healthy pattern was lower than the lowest quartile (OR = 0.47; CI = 0.26 – 0.83,
P = 0.004). More adherence to the unhealthy dietary pattern was associated with higher risk of BC (OR = 2.85; 95% CI = 1.57- 5.17, P < 0.0001).  No significant association was observed between the healthy or unhealthy dietary patterns among postmenopausal women.

The findings indicated that the healthy dietary pattern could be considered as a protective factor in terms of BC in women and particularly among premenopausal women.

The purpose of this study is to investigate the mediating role of job engagement and trust in relation to organizational culture with job satisfaction of teachers in Sama schools in Fars province. The present study is descriptive and correlational in terms of applied purpose and method. The statistical population of the present study was all teachers in Sama schools in Fars province (1025 people). According to Cochran's formula, a sample size of 205 people was obtained. To collect information from questionnaires job satisfaction of Minnesota (2009), Hofstede Organizational Culture (1991), Payne Organizational Trust (2003), and Schaufeli job engagement (2003) were used. Content validity and reliability of the questionnaires were checked and confirmed. SPSS21 and SmartPLS3 software were used to analyze the data. The results showed that there is a relationship between job engagement, organizational trust and organizational culture with job satisfaction. job engagement and trust also mediate the relationship between organizational culture and teachers 'job satisfaction.

There are relatively scant data to determine whether hospital visitors could serve as a proper source of controls in case-control studies of illicit drug use. The aim of this study was to evaluate using neighborhood versus hospital visitor controls in reporting opium use. 

We used data from 2 independent case-control studies of cancer in Iran. In the first study, controls were selected from neighborhoods of the patients. For the second one, controls were selected from among hospital visitors. In the latter study, hospital visitors were companions of the patients or others visiting the hospital for reasons other than disease treatment. We used stata (version 12; Stata Corp( for all analyses and with a significance level of 0.05.

Data from 616 of neighborhood controls and 414 of hospital visitor controls were analyzed. Opium point prevalence among men was significantly higher in hospital visitors than neighborhood controls (43.3% vs 32.2%; P = 0.047), while the prevalence of cigarette smoking was very similar in both control groups (46.3% vs 47.2%; P = .847). Using a logistic regression analysis, in an unadjusted analysis, neighborhood controls were less likely to report opium use in both genders, with (unadjusted OR = 0.77; 95% CI: 0.59,1). After adjusting for potential confounders, the differences of opium use between the 2 control groups became more pronounced (Adjusted OR = 0.26; 95% CI: 0.10, 0.69).

Because of the similarity of reporting cigarette smoking among neighborhood controls but substantially lower reporting of opium use among them, we concluded that neighborhood controls underreport opium use—a sensitive question— and that using neighborhood control biases the findings in case-control studies. Hospital visitor controls may be more appropriate than neighborhood controls for case-control studies of illicit drugs.

The International Agency for Research on Cancer (IARC) recently classified opium use as a Group 1 carcinogen. However, much remains to be studied on the relation between opium and cancer. We designed the Iranian Opium and Cancer (IROPICAN) study to further investigate the association of opium use and cancers of the head and neck, bladder, lung, and colon and rectum. In this paper, we describe the rationale, design, and some initial results of the IROPICAN Study.

The IROPICAN is a multi-center case-control study conducted in 10 provinces of Iran. The cases were all histologically confirmed and the controls were selected from hospital visitors who were free of cancer, were not family members or friends of the cancer patients, and were visiting the hospital for reasons other than their own ailment. The questionnaires included detailed questions on opium use (including age at initiation, duration, frequency, typical amount, and route), and potential confounders, such as tobacco use (e.g., cigarettes, nass and water-pipe), and dietary factors. Biological samples, including blood and saliva, were also collected.

The validation and pilot phases showed reasonably good validity, with sensitivities of 70% and 69% for the cases and controls, respectively, in reporting opium use. The results also showed excellent reliability, with intra-class correlation coefficients of 0.96 for ever opium use and 0.88 (95% CI: 0.80, 0.92) for regular opium use. In the main phase, we recruited 3299 cancer cases (99% response rate) and 3477 hospital visitor controls (89% response rate). The proportion of ever-use of opium was 40% among cases and 18% among controls.

The IROPICAN study will serve as a major resource in studies addressing the effect of opium on risk of cancers of the head and neck, bladder, lung, and colon and rectum.

Several epidemiological studies have reported that regular use of opium can be associated with an increased risk of developing cancers, including oesophageal, laryngeal, bladder, lung, and gastric cancer. In this systematic review, we aimed at investigating whether experimental studies support this finding and, if yes, how opium consumption can cause cancer. Most of the articles that have studied opium or its derivatives have found it as a carcinogen. However, due to the complex composition, different forms, and various ways of opium use, further comprehensive experimental studies are required. Using modern genomic and epigenomic methods seems to help determine the molecular mechanisms underlying opium carcinogenicity.

Measuring the amount of opium use is a challenge in epidemiologic studies. Self-report of amount of opium use at each consumption, widely used in the literature, usually fails to provide a good estimate. The purpose of this study is to systematically study the perceived weight units of reported opium use in Iran, and compare them to the standardized units of weight measurement.

An exploratory descriptive study was conducted in six major cities of Iran. Study participants were interviewed and asked to use a Play-Doh-like material to demonstrate the amount of opium they use. To obtain an estimate of the weight of the material used, we multiplied the volume by the density of the opium product. We experimentally determined the density of the commonly used opium products. We used medians and inter-quartile ranges (IQRs) to report the typical amount of each unit.

A total of 108 individuals participated in this study. The most frequently reported unit was "gram"; the median perceived weight for one gram (g) of opium was 0.24 (IQR: 0.16) g. The second most commonly used unit was nokhod with a median of 0.16 (IQR: 0.16) g, followed by mesghaal and hab/habeh, which were 1.28 (IQR: 0.81) and 0.16 (IQR: 0.16) g, respectively. The median perceived weight of mesghaal and gram in the studied cities was less than the expected standardized values.

In conclusion, the reported amount of opium use is highly inaccurate and unreliable, and is mainly subject to underestimation.

Estrogen is a risk factor for the development of breast cancer. The effect of estrogen is primarily mediated by estrogen receptor alpha 1 (ESR1). In this study, we investigated the association between breast cancer risk and the frequency of alleles and genotypes for two ESR1 single nucleotide polymorphisms (SNPs) in breast cancer patients and a healthy control group.      A total of 98 female patients with pathologically confirmed breast cancer and 93 age-matched healthy female controls who were selected from among the visitors of the general hospital were recruited in the study. Two ESR1 candidate polymorphisms; +2464 C/T (rs3020314) and -4576A/C (rs1514348) were selected. The frequency of alleles and genotypes was determined using Quantitative Real-Time PCR assay. Linkage disequilibrium (LD) was assessed for each pair of markers. Using logistic regression, genotype frequencies were estimated as Odds Ratios with 95% confidence intervals. There was no significant difference in the genotype and allele distributions of ESR1 for SNPs +2464 C/T and SNP -4576A/C between patients and controls. The frequency of the ESR1 +2464 T/T genotype in case and control groups was 31.6% vs 29.0%, (OR TT/TC: 1.13, 95%CI: 0.58, 2.20; P = 0.69). The frequency of the +2464C allele was 33.9% vs 35.2%, (OR C/T: 0.94, 95%CI: 0.60, 1.47; P =0.79). The frequency of the ESR1 -4576C/C genotype in case and control groups was 37.75% vs 33.36 %, OR CC/AC: 1.02, 95%CI: 0.51, 1.97; P =0.98). The frequency of the -4576A allele was 36.2% vs 43.6 %, (OR C/A: 0.73, 95%CI: 0.47, 1.13; P =0.14). The results indicated that ESR1 polymorphism does not show any significant association with breast cancer risk among female Iranian adults.

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. 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. 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. 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.

Failing heart has been described as the main mechanism of an unsuccessful separation the mechanical ventilator after cardiac surgery. Brain natriuretic peptide (BNP) is a specific marker for cardiac dysfunction. We aimed to evaluate the relationships between BNP levels and the duration of mechanical ventilation and the length of stay at the intensive care unit (ICU) after pediatric cardiac surgery. In this observational study, 52 infants aged between 2 and 50 months who underwent cardiac surgery were enrolled. Anesthesia and cardiopulmonary bypass methods were similar, and the weaning protocol in the ICU was the same in all the patients. The levels of pro-BNP and plasma lactate were recorded before surgery; at the time of ICU admission; and 24, 48, and 72 hours afterward. At the end of the study, the relationships between the levels of BNP and plasma lactate and the duration of mechanical ventilation and the length of stay at the ICU were assessed. Of the 52 patients, 35 (67.3%) were male. The mean age and weight were 17.14±12.50 months and 9.01±2.98 kg, respectively. The mean duration of cardiopulmonary bypass was 191.25±34.15 minutes, and the mean aortic cross-clamp time was 75.48±31.88 minutes. The mean duration of mechanical ventilation was 21.78±18.78 minutes, and the mean length of stay at the ICU was 133.67±97.68 hours. The results showed that there was no significant relationship between the pro-BNP level and the duration of mechanical ventilation (P>0.05). The levels of pro-BNP at the time of ICU admission and 24 and 48 hours after surgery had a direct relationship with the duration of ICU stay (P<0.05). In the present study, higher serum pro-BNP levels at the time of ICU admission and 24 and 48 hours after admission were related to a prolonged ICU stay. However, the serum BNP level was not correlated with the duration of mechanical ventilation after pediatric cardiac surgery. (Iranian Heart Journal 2018; 19(4): 40-46)

The prevalence of alcohol consumption in Iran cannot be estimated because large variations have been observed in the reported prevalences of alcohol consumption. The main aim of this study was to assess the methodological challenges in estimation of the life time prevalence of alcohol consumed in Iran. By the same token we provided a standard approach for future researches in this regard. Published articles were reviewed systematically. Using the risk of bias tool, 49 out of 600 articles met the eligibility criteria. Based on the population of alcohol consumers, the included studies were categorized into 5 groups: general populations, patients, school students, university students, and specific population (first relatives of opium addicts and women who were faced with epistemic violence). There was a paucity of reliable information in about 40% of provinces. Almost all studies applied the direct size estimation methods, but 11 studies used face to face interview and 38 studies used self-administered questionnaires. The non-response bias seemed prominent in entire studies except those on school students. It is important to mention that 97% of papers in general population did not represent any information about the non-response rate. The reported prevalence ranged from 1.37% in university students to 88.8% in patient population. Even among university students, the prevalence varied considerably (1.37% to 34.7%). The observed huge variations in the reported prevalence of alcohol consumption, due to the methodological consideration, appear largely in Iran. Therefore, it is necessary to develop a standard protocol for data collection and sampling to harmonize the findings in future studies. In addition, it is recommended to assess the frequency of alcohol use by indirect methods such as the Network Scale Up method.

Awake oral flexible fiberoptic intubation (AFOI) is used in patients with expected difficult airways. Different drugs have been used for sedation and yet we need to define ideal drug with proper sedation and safety, less changes in hemodynamic stability and less airway compromise. We aimed to compare the efficacy of dexmedetomidine with fentanyl and midazolam during AFOI. In this randomized clinical trial, 52 patients undergoing elective surgery and candidate for AFOI were randomly allocated to two groups. First group received 1mcg/kg of dexmedetomidine in 10 minutes and then infusion of 0.5 mcg/kg/h and second group received 2 mcg/kg fentanyl and then 1 mg midazolam. Hemodynamic variables, O2 saturation (SpO2) were evaluated before and after sedation and after intubation. Ramsey sedation scale (RSS) and patient’s tolerance were evaluated during bronchoscopy and intubation. Lower heart rate after intubation (p=0.008) and higher SpO2 before sedation (p<0.001) and after intubation (p=0.02) were observed in dexmedetomidine group compared to fentanyl group. The need for propofol for further sedation was comparable between groups (11.5% vs. 7.7%, respectively; p=0.63). Both groups had comparable RSS and tolerance during intubation. Dexmedetomidine compared to fentanyl and midazolam had comparable sedation with better hemodynamic stability and O2 saturation during AFOI.

This study aimed to evaluate the diagnostic value of outer dense fiber 4 (ODF4), melanoma-associated antigen A3 (MAGEA3), and MAGEAB4 mRNAs in transitional cell carcinoma (TCC), using a small amount of cell reverse transcriptase-polymerase chain reaction (RT-PCR) on urinary exfoliated cells.
We recruited a total of 105 suspected TCC patients and 54 sex- and age-matched non-TCC controls. The candidates’ genetic expression patterns were investigated with RT-PCR, while reverse transcription quantitative PCR was applied to quantify and compare each mRNA level between cases and control groups.
The sensitivity of ODF4, MAGEA3, and MAGEAB4 RT-PCR was 54.8%, 63%, and 53.4%, whereas the specificity was 73.7%, 86%, and 94.7%, respectively. Combining ODF4, MAGEA3, and MAGEAB4 RT-PCR offered a relatively higher sensitivity (83.6%).
RT-PCR with ODF4, MAGEA3, and MAGEAB4 on urinary exfoliated cells could provide clinicians with a promising method to improve TCC diagnosis, especially in the case of gross hematuria and catheterization. The method used here is non-invasive, simple and convenient, and unlike cytology, it does not rely directly on expert professional opinions. These features can be of particular importance to the management of TCC patients in whom regular and lifelong surveillance is required.

Burden of cancer is increasing worldwide, especially in the low and middle income countries (LMICs), including Iran. Several reports have been published about cancer statistics in Iran, although they had shortcomings and provided variable results. We reported the most valid cancer statistics about Iran.
We used Globocan database and reported age standardize incidence rate (ASR), mortality rate (ASMR), and five-year prevalence of cancer in Iran in 2012, and compared it with the results of 2008. We also provided the projection of cancer incidence for 2035 and estimated the life time cancer risks by age 75.
ASRs per 100,000 were 134.7 for men and 120.1 for women. The most common cancers were breast (ASR 28.1), colorectal (ASR 10.5), stomach (ASR 9.7) cancers in women and stomach (ASR 20.6), bladder (ASR 13.2), prostate (ASR 12.6) cancers in men. The ASR was about 19% higher in 2012 (127.7/100,000) compared to 2008 (107.3/100,000). ASR of all cancer sites will increase about 2.17 times by 2035. ASMR was about 20% higher in men (90.4/100,000) than women (72.7/100,000) in 2012. The highest ASMRs was observed for breast cancer (9.9/100,000) in women and stomach cancer (17.3/100,000) in men. Five-year prevalence of all cancers was 79,194 for men and 90,521 for women in 2012. Lifetime risk of occurrence of all types of cancer was 25%. In other words, 1 in 4 Iranian people will be diagnosed with cancer before the age of 75 years.
Stomach and breast cancers were the most common cancers in Iranian men and women, respectively. Iran and other LMICs will experience major increase in the incidence and mortality of cancer in the next decades. They need to collocate further resources for cancer surveillance system and monitor the cancer statistics for evidence based cancer control program.

Waterpipe smoking is a growing public health threat worldwide. The aim of this study was to assess waterpipe smoking prevalence and its associated factors among Iranian adults.
This cross-sectional study was conducted in Kerman, Iran, recruiting 1090 adult participants using multistage sampling in 2016. A self-reported researcher-designed questionnaire was used. The socio-demographic characteristics and waterpipe smoking behaviors such as pattern, duration, and the most common place of waterpipe use, the type of tobacco, and the concurrent use of alcohol and substances were assessed. Data analyses were performed using chi-square, independent t-test, and multiple logistic regression.
Findings: The prevalence of ever, current and daily waterpipe smoking were 43.8%, 28.8%, and 7.2%, respectively. Men initiated to use waterpipe in more early ages than women (P The present study revealed that men, high level of education, younger age and unemployment were associated with waterpipe smoking. Therefore, we need to design and implement more effective interventions, especially for vulnerable target groups.

Vascular endothelial growth factor (VEGF) is a key mediator of angiogenesis and as a result acts in tumor invasion. In this study, we investigate the frequency of alleles, genotypes and haplotypes for three VEGF single nucleotide polymorphisms (SNP) in female breast cancer patients and healthy control group.
We performed a case–control study including 214 female patients with pathologically proven breast cancer and 220 female age-matched healthy control subjects. We selected three VEGF candidate polymorphisms -634C/G (rs2010963), -460C/T (rs833061) and -1154A/G (rs1570360). Frequency of alleles and genotypes was determined by TaqMan real-time PCR allelic discrimination assay.
There was not a significant difference in genotype and allele distributions of the VEGF -460T/C and VEGF -1154A/G between patients and controls. For -634C/G SNP, the frequency of -634G allele was significantly higher in patients than control group (P =0.0003). However the frequency of -634C allele was significantly higher in control group than patients (P =0.0003). When we stratified patient and control groups by age, we observed that the frequency of VEGF -634G/G genotype was significantly higher in patients older than 40 years compared with respective controls (P =0.003).
These findings suggest the association of -634G allele with the presence of breast cancer in our female population. Female carriers with -634C allele show a protective effect against the development of this malignancy and women more than 40 years old with -634G/G genotype might be at increased risk of the disease. Further large-scale studies are required to confirm these findings.

Leishmaniasis is a parasitic infection that may lead to a variety of manifestations. In Iran, cutaneous leishmaniasis (CL) has a high prevalence. There are many treatment modalities for CL. The use of oral terbinafine in the treatment of CL has recently been considered. The aim of this study was to compare combination of oral terbinafine plus cryotherapy versus systemic meglu­mine antimoniate plus cryotherapy in CL. Patients with proven direct smear for CL were divided randomly in 2 groups of 40 cases. For the first group systemic glucantime prescribed (IM, 15 mg/kg/day) for 3 weeks. For the second group oral terbinafine as two folds of usual dose in the treatment of fungal diseases prescribed [125 mg/day for body weight (BW) <20 kg, 250 mg/day for BW 20-40 kg, 500 mg/day for BW>40 kg] for 4 weeks. Both groups received cryotherapy every 2 weeks for 4 weeks. The patients were followed monthly for 3 months after the treatment. Partial (HR= 0.55, CI 95%= 0.3-1.1) and complete (HR= 0.53, CI 95%= 0.3-0.98) clinical improvement in terbinafine group was much slower than glucantime group, although at the end of treatment protocols no signifi­cant difference between groups were statistically observed (P=0.27). Considering more convenient suitable route of administration and approximately comparable results, it seems that terbinafine can be used as an alternative treatment, especially in the case of allergy or resistance to systemic glucantime.

More than a billion people have some form of disabilities worldwide. Persons living with a disability have many needs (including physically, mentally, and socially needs). Estimating the size of disabled population is a challenge in health systems. An innovative indirect method to estimate the size of populations is network scale up (NSU) having widely used for hidden populations. The method is based-on the social network of individuals. We assessed the capability of NSU to estimate persons living with a disability being a middle population (neither non-hidden nor hidden populations) in the Southeast of Iran (Kerman City, southeast Iran). A total of 3052 of Kermanian people over 20 year old were interviewed by simple random sampling. We asked them whether they knew acquaintances with complete blindness, severe visual impairment, deafness, severe hearing impairment, limb defects, and mental retardation, if yes; we wanted them to count them. Based on the network scale up method, the prevalence of the populations was estimated at 5.21/1000 in Kerman City where severe visual impairment was 1.35, mental retardation was 1.039, severe hearing impairment was 1.005, limb defects was 0.78, deafness was 0.59, and complete blindness was 0.56 (per 1000 inhabitants). The results were not exactly comparable to previous studies using different methods such as surveys. Although the method has some limitations, considering its easiness and cost-effectiveness, modified NSU could be used when direct methods are not practicable.

The main purpose of medical researches is to answer a research question or to solve a problem to promote the health of a society. The first objective is to answer the research question correctly with minimal errors. The second objective is the publication of the results in order to generalize them to a population and use in a wider dimension. To achieve these objectives, using biostatistics is necessary. Despite the importance of biostatistics in medical research, researchers have limited understanding of it or due to its complications they refrain from its use. Statistics help the researcher in different levels of research including writing a proposal and interpretation of other papers. Moreover, biostatisticians and epidemiologists also play a very important role in the preparation of manuscripts for publication. The present article has eloquently described the most important statistical tests in medical research with applied examples.

Chronic functional constipation is an epidemic problem in children that has effects on the growth status.. The aim of this study is to evaluate the growth parameters in children with chronic functional constipation and compare them with healthy individuals.. Patients and One hundred children with chronic functional constipation (defined as Rome III criteria) referred to Pediatric Gastroenterology Clinic enrolled in this study. Control group was consisted of 100 children who referred for well-child visits، without constipation. Weight، height، body mass index (BMI) and z-score weight، z-score height and z-score BMI was calculated for each patient and control group.. Both case and control groups were consisted of the same age (P = 0. 725) and gender (P = 0. 777) individuals. The BMI (P < 0. 0001) and BMI z-scores (P < 0. 0001) of constipated children was significantly higher than the control group. Also، weight (P = 0. 004) and weight z-scores (P < 0. 0001) were significantly higher in the study group. There was no significant difference in height between two groups (P = 0. 1)، but constipated children had higher height z-scores than control group (P = 0. 027). The rate of obesity (define as BMI z-score > 2) in children with chronic constipation was 40% that was significantly higher than normal control group (11%) (P < 0. 0001).. We found a higher obesity rate and also higher BMI and weight z-scores in functionally constipated children compared with healthy control group. The reasons for the association between obesity and constipation are not clear and multifactor including diet، activity level، or hormonal influences، are involved that required additional studies..