Showing 11 results for Case-Control Study
P Yavari, Ma Mosavizadeh, I B Sadrolhefaz, R Khodabakhshi, H Madani, Y Mehrabi,
Volume 1, Issue 3 (2-2006)
Abstract
Background & Objectives: Breast cancer is a common malignancy in women in many parts of the world. The incidence of breast cancer in Iranian women is growing. Iranian patients are relatively younger than their western counterparts. We conducted a case-control study to determine roles of reproductive factors for breast cancer among women in Iran.
Methods: A hospital based case-control study was conducted in 2004 at a teaching hospital in Tehran, Iran. A total of 303 cases of breast cancer and 303 healthy controls were interviewed. Cases were identified through the oncology department of a university hospital and controls were recruited from other wards or out-patients clinics at the same hospital. Controls were matched to cases on age. Demographic and reproductive data were ascertained by personal interview using a structured questionnaire. Informed consent was obtained from cases and controls. Odds ratios and 95% confidence intervals for breast cancer were derived using logistic regression analysis.
Results: Mean ±SD age of cases and controls was 48.8 ±9.8 and 50.2 ± 11.1 years, respectively (range 24-84). The final model constructed after multivariate analysis indicated that factors such as never being married, menopause, older age at first live birth, parity, use of oral contraceptives, and history of chest X-ray between adolescence and the age of 30 yrs were significantly associated with breast cancer. Variables such as higher education, early age at menarche, abortion, breast feeding and its duration did not constitute significant risk factors.
Conclusions: Marital status, history of chest X-ray between adolescence and the age of 30, number of live births, and age at first live birth, menopause, and oral contraceptive use seem to increase the risk of developing breast cancer among women in Iran.
R Chaman, A Shamshiri, K Kamali, Ghr Khalili, K Holakouie Naieni,
Volume 2, Issue 1 (3-2006)
Abstract
Background & Objectives: This investigation was prompted by the growing importance of nested case-control studies and the increasing frequency with which they are done in epidemiologic research. After a brief explanation of nested case-control studies, we evaluate the trends in research methodology over the last decade, especially with regard to cohort, case-control, and nested case-control designs.
Methods: Data for this study were extracted from the PubMed database, using these keywords: Nested Case-Control, Risk-Set Sampling and Density Sampling. The search was confined to the 10-year period from 1996 to the end of 2005. As for other methodologies, we used keywords Cohort and Case-Control for a search over the same time period. The search itself was performed on April 25, 2006.
Results: We found 2011 articles reporting nested case-control studies. There were 95 such articles in 1996 the number had increased to 289 in 2005. Case-control and cohort designs accounted for 68456 and 60479 articles, respectively.
The number of case-control articles rose from 4378 in 1996 to 10270 in 2005, while that of cohort articles increased from 2981 to 9771 over the same period.
Conclusions: The number of cohort and nested case-control articles followed similar upward trends over the last decade and their rate of increase was greater than that of simple case-control articles.
M Khabazkhoob, A Fotouhi, Mr Majdi, A Moradi, Z Haeri Kermani, M Seyed Nozadi,
Volume 3, Issue 1 (9-2007)
Abstract
Background & Objectives: To determine the risk factors for acute diarrhea disease in children.
Methods: This study involved 220 cases and 220 controls in Dr. Sheykh Hospital, a specialzed pediatric hospital in Mashhad. Cases were children seen in the emergency department with loose watery feces, diagnosed as acute diarrhea by the physician. The controls were selected from the same setting as the cases and included children with traumas, burns, acute respiratory complaints and other diseases.
Results: In univariate logistic regression, variables having a significant relationship with acute diarrhea disease included formula feeding in the first 6 months of life, antibiotic therapy over the preceding 15 days, mother's employment, mother's acquaintance with oral rehydration solutions, place of residence, and disruption in the water supply in the week before illness. We performed multiple logistic regression to examine the role of these variables as independent risk factors for acute diarrhea. Use of formulas before 6 months of age (OR=3.21, 95%CI: 1.77-5.79), and type of residence (OR=1.83, 95%CI: 1.24-2.71), and mother's employment (OR=2.48, 95%CI: 1.2-5.06) were the factors that remained in the multiple logistic model and had a significant relationship with the disease.
Conclusions: This study identified some environmental risk factors for acute diarrhea disease. High-risk groups and mothers of children under 5 years of age should be aware of these risk factors in order to prevent disease in their children. Prevention of acute diarrhea in children can significantly reduce the current burden on the health system.
R Chaman , M Yunesian , B Golestan , K Holakouie Naieni ,
Volume 3, Issue 3 (2-2008)
Abstract
Background and Objectives: A pregnancy can be considered high-risk if there are conditions that put the mother or the baby at higher-than-average risk of morbidity or mortality. Neonatal mortality rate is one of the most important indices of children's health status. The present study was conducted to evaluate the effects of high-risk states on neonatal mortality.
Methods: We performed a nested case-control study in the rural areas of Kohgiluyeh and Boyerahmad province. Within the study cohort, 97 cases and 97 controls were selected by a risk-set sampling method. Data were analyzed with univariate and multivariate conditional logistic regression models.
Results: Neonatal mortality was shown to increase significantly in high-risk pregnancies. There were no substantial differences between crude odds ratios and those adjusted for the presence of other risk factors (crude odds ratio decreased from 5.5 to an adjusted figure of 3.25 for pregnancies with one risk factor and from 5.21 to adjusted level of 4.80 for pregnancies with more than one risk factor).
Conclusions: High-risk pregnancies need great attention in family health and prenatal care programs, especially in remote rural areas. Within our rural health network there are potential cohorts for use in nested case-control studies, especially in the evaluation of neonatal mortality risk factors.
V Montazeri, F Jafarpour Sadegh , S Hosseinpour, Hr Mirzaei, E Akbari, M Ehsani, S Akbari, N Asadi, M Mahmoudinezhad, E Mirtaheri, Z Sanaat, S Pirouzpanah,
Volume 12, Issue 1 (6-2016)
Abstract
Background and Objectives: Reproductive factors are in close relationship with breast carcinogenesis. This matched case-control study was conducted to study the association of reproductive risk factors with the risk of breast cancer (BC) among women in Tehran and northwest of Iran.
Methods: This hospital-based case-control study was performed on a total of 432 patients diagnosed with BC with confirmed histopathology who were recruited from hospitals affiliated with Shahid Beheshti and Tabriz University of Medical Sciences between 2007 and 2012, and 543 regionally matched controls without a prior history of BC.
Results: The average number of pregnancy and breast-fed children were significantly higher in cases than controls (P<0.01). The duration of breast-feeding was longer in patients (18.0±8.4 months) than controls (16.0±9.1; P<0.001). Most of the patients were diagnosed with BC above the age of 48 years old which was higher than the mean age of the recruited matched controls. Older age was associated with a 3.87 higher risks of BC development (95% CI: 2.94-5.10). The higher frequency of lactation in patients was significantly associated with the elevated risk (OR=2.22, 95% CI 1.62-3.04). The duration of breast-feeding within14-24 months was correlated with OR=0.52 to protect BC development during the reproductive age
(<48 years) (95% CI: 0.32-0.86).
Conclusion: High frequency of pregnancy, lactation, and older ages at first pregnancy are associated with the risk of BC, while older age at puberty, menopause, and longer duration of breast-feeding (age above 48 years) have inverse associations with the risk of BC.
Z Torabi, Sh Nematollahi, E Ahmadnezhad, K Holakoie Naieni ,
Volume 14, Issue 2 (9-2018)
Abstract
Background and Objectives: Epidemics of diarrhea caused by contaminated food and water occur frequently worldwide, especially in developing countries. The aim of this study was to identify the factors contributing to the development and spread of diarrhea epidemics caused by Shigella flexneri in Isfahan in the spring of 2015.
Methods: Following the first reports and activation of the surveillance system, a matched case-control study was conducted in 360 cases with diarrhea and 360 controls. Data were gathered using a questionnaire, and conditional logistic regression was used to provide adjusted odds ratios and 95% confidence intervals.
Results: Consumption of contaminated fresh vegetable (OR=4.50, 95% CI=2.88-7.01) was the source of the epidemic. Contact with similar patients (OR=7.19, 95% CI=4.26-12.12), presence of similar patients in the family (OR=33.2, 95% CI=13.64-80.82), food consumption on special events (party, wedding ceremony, funeral, etc.) (OR=1.67, 95% CI=1.06-2.62), being a government employee (OR=3.08, 95% CI=1.64-5.78) and being illiterate (OR=2.91, 95% CI=1.10-7.67) were the risk factors of the spread of the epidemic.
Conclusion: In this study, consumption of fresh vegetable contaminated with Shigella flexneri was the source of the infection. According to the Epidemic Management Team, contamination occurred due to non-standard wastewater irrigation of agricultural lands. Therefore, it is important to consider the standards of agricultural production and compilation of a comprehensive program to improve the status of the wastewater purification system in the environmental sciences by the relevant organizations to prevent diarrhea epidemics.
B Moatamedizadeh, H Ansari, A Payandeh, Sm Tabatabae, A Ramazanpouramirdehi,
Volume 16, Issue 1 (6-2020)
Abstract
Background and Objectives: In addition to effective treatment, tuberculosis recurrence is a very important challenge regarding the treatment of this infection. This study was conducted to evaluate the risk factors associated with tuberculosis recurrence.
Methods: In this nested case-control study, 202 tuberculosis patients with recurrence and 202 matched controls in terms of age, sex and place of residence were studied. The cases and controls were selected from a cohort of tuberculosis patients in Sistan and Baluchestan province between 2011 and 2018. The data were collected using interviews and patients’ records. The independent t-test, chi-square and multiple conditional logistic regression were used to analyze the data.
Results: The drug abuse history (OR=6.1), 3+ smear positive (OR=3.03), chest X-ray suggestive of tuberculosis (OR=4.9), drug resistance (OR=7.3), low socioeconomic status (OR=3.9), weight loss (OR=3.1), chest pain (OR=3.2), history of digestive disease (OR=22.1), smoking (OR=6.1), and imprisonment (OR=3.7) significantly increased the chance of recurrence among tuberculosis patients (p<0.05). On the other hand, the chance of recurrence was significantly lower in patients with coughs (OR=0.29) and a small family size (OR=0.28).
Conclusion: According to the results, tobacco use, drug use, low socio-economic status, life conditions, and disease conditions are the most important determinants of tuberculosis recurrence. In general, epidemiologic factors related to tuberculosis recurrence are not similar in different regions; therefore, educational programs for patients and their families and prevention methods should be considered based on related factors in different regions.
M Karami, A Doosty Irani, Sj Battaei, L Rafati, M Javaheri, M Kheir Andish , M Farhadi, M Hashemi, K Mozafari, A Akhlagh, M Shojaeian, Ar Maleki, R Rostam Abadi , Sh Torkshavand, M Khodabakhshi,
Volume 16, Issue 3 (11-2020)
Abstract
Background and Objectives: Water and foodborne diseases are major causes of mortality worldwide. The aim of this study was to investigate the factors affecting an gastroenteritis outbreak in Hamadan county in summer of 2019.
Methods: This study was performed based on the outbreak investigation process. After producing hypotheses based on preliminary field studies, a case-control study was conducted on 45 cases and 45 controls to investigate the factors associated with the outbreak. New cases of the disease were included according to the case definition. A logistic regression model was used to investigate potential risk factors.
Results: A total of 171 people were affected in this outbreak from 25 June 2019 to 01 July 2019. The at-risk population in this outbreak was 3410 individuals. The attack rate was 5.1%. Abdominal pain, vomiting, and nausea were the most common symptoms with a prevalence of 77.8%, 73.3% and 68.9%, respectively. The results of the case-control study showed that the consumption of tap and spring/well water increased the odds of disease by 4.63 and 4.13 times compared to boiled water, although these relationships were not statistically significant. The odds of diseases were significantly lower in people aged 30-45 years and 46-85 years compared people aged 15 years old and younger.
Conclusion: Based on the results of this study, the outbreak was related to contaminated water consumption. Therefore, regular monitoring of drinking water status is very important for the local health system.
Hr Bahrami Taghanaki , E Mosa Farkhani , R Eftekhari Gol , P Bahrami Taghanaki , S Bokaei, A Taghipour, B Beygi,
Volume 16, Issue 3 (11-2020)
Abstract
Background and Objectives: Diabetes is considered as one of the most common endocrine disorders worldwide. The aim of this study was to investigate the factors associated with diabetic complications.
Methods: A case-control study was performed on the data of 70089 diabetic patients (4622 cases and 53613 controls) extracted from the SINA Electronic Health Record (SinaEHR®) in a population covered by Mashhad University of Medical Sciences in 2018. The effect of independent variables on the likelihood of diabetic complications was investigated using single-variable and multivariate logistic regression models with the control of the potential confounding effects.
Results: Using the multivariate logistic regression, the odds of developing diabetic complications were 0.35 (0.31-0.38) for living in the city, 0.73(0.67-0.79) for living in the suburbs and 0.31(0.28-0.33) for living in rural areas relative to the metropolises, 0.84 (0.78-0.91) for illiterate subjects, 0.70 (0.66-0.75) for physical activity, 1.51(1.34-1.71) for stage 1 hypertension and 1.87 (1.43-2.44) for stage 2 hypertension relative to normal blood pressure, 0.79(0.74-0.85) for uncontrolled low density lipoprotein and 1.42(1.33-1.51) for uncontrolled hemoglobin A1C.
Conclusion: Various risk factors were identified to increase the odds ratio of diabetic complications. The most important risk factors were uncontrolled glycosylated hemoglobin and stage 1 and 2 hypertension. Control of these factors can reduce the chance of diabetic complications in diabetic patients.
Mohammad Ali Derik, Mohammad Kakavand, Shahram Mamdohi, Mojgan Navabi, Elham Goodarzi, Hamid Mokhayeri, Zaher Khazaei,
Volume 17, Issue 2 (9-2021)
Abstract
Background and Objectives: Viral hepatitis is one of the most prevalent diseases and an important underlying cause of death and disability in the world. This case-control study was conducted to investigate the outbreak of hepatitis A in Boroujerd in 2019.
Methods: This case-control study was conducted to investigate the epidemic of hepatitis A in Boroujerd in 2019. Fifty hepatitis A patients were recruited. For each patient diagnosed, two controls with no history of the disease were selected from a neighboring village. Data were collected using a demographic questionnaire as well as the results of experiments. To investigate the association between the disease and risk factors, odds ratio and 95% confidence interval were used.
Results: In this study, the odds ratios were significant for a number of risk factors including washing fruits and vegetables with a source other than tap water [OR = 3.2], washing dishes with a source other than tap water [OR = 3.7], non-sanitary toilets [OR = 8.3], using sources other than tap water when there is no tap water [OR = 4.4], being unaware of the disease and its transmission methods [OR = 4.8] and water well dug less than 15 m from the sewage well (OR = 4.1).
Conclusion: Increased public awareness and improved health status of the environment and rural sewage can preclude similar epidemics in the study area and other regions.
Sa Hashemi, K Holakoui-Naeini, Ma Mansournia, R Akrami, M Nomali, T Valadbeigi, V Mennati, Ha Adineh, Mr Taghavi, M Ghafouri, S Poorbarat, A Hoseinzadeh, M Farahdel, Mr Armat, M Haresabadi,
Volume 17, Issue 3 (12-2021)
Abstract
Background and Objectives: COVID-19 is a new disease and little information is available on its risk factors. The aim of this study was to determine the mortality risk factors in patients with COVID-19 in the northeast of Iran.
Materials and Methods: A case-control study was conducted. Patients of both sexes with a confirmed diagnosis of Covid-19 infection who died during the study were studied as the case group and patients who were in good general health and ready for discharge were studied as the control group. Data analysis was performed with the STATA software version 14 using descriptive statistics and univariate and multiple logistic regression tests.
Results: Six hundred and eleven patients were studied (27% cases and 73% controls). Multiple logistic regression analysis showed that the odds of death were 2.8 times higher in patients over 80 years compared to patients aged 50-60 years. In addition, age under 40 years reduced the odds of mortality by 85% and living in rural areas increased odds of death by 2.2 times. Cough, general fatigue, pain, nausea and vomiting increased the odds of COVID19 survival.
Conclusion: The odds of mortality were higher in elder patients with COVID-19. In addition, living in rural areas increased the odds of mortality in patients. Cough and fatigue reduced mortality; however, it is needed to address other hidden factors for sound judgment.
