A case control study is a type of observational study. In this study design, participants are selected to participate depending on their outcome status. Cases are participants with outcome of interest whereas controls are participants who do not have the outcome of interest. These studies estimate the odds ratio or the odds between the exposure and health outcome, however they cannot prove causality. Advantages of case control studies include the following: inexpensive, easy to design and implement, and are used to study rare outcomes. Case control studies are prone to certain research bias but can be addressed by the investigator through careful designing and planning. This paper describes the case control studies, their advantages, bias in case control studies and how to address them, and discuss the steps in how to conduct this type of study design.

OBJECTIVE: To investigate the effects of the B7-H4 gene rs10754339 and miR-125a gene rs12976445 on cancer susceptibility through a case-control study and meta-analysis. METHODS: A total of 1,490 cancer patients (lung/gastric/liver/: 550/460/480) and 800 controls were recruited in this case-control study. The meta-analysis was performed by pooling the data from previous related studies and the present study. RESULTS: The results of this study showed that in the Hubei Han Chinese population, the rs10754339 gene was significantly associated with the risk of lung and gastric cancer but not liver cancer, and the rs12976445 gene was significantly associated with the risk of lung cancer but not liver or gastric cancer. The meta-analysis results indicated that rs10754339 and rs12976445 contributed to cancer susceptibility in the Chinese population and also revealed a significant association between rs10754339 and breast cancer risk, as well as between rs12976445 and lung cancer risk. CONCLUSION The B7-H4 gene rs10754339 and miR-125a gene rs12976445 may be the potential genetic markers for cancer susceptibility in the Chinese population, which should be validated in future studies with larger sample sizes in other ethnic populations.
Humans ; MicroRNAs/genetics* ; Stomach Neoplasms/genetics* ; Case-Control Studies ; Lung Neoplasms/genetics* ; Risk

Humans ; Beijing/epidemiology* ; Case-Control Studies ; COVID-19/epidemiology* ; SARS-CoV-2 ; Risk Factors

PURPOSE: This study aimed to investigate the possible association between psychological disorders and risky driving behavior (RDB) in Iran. METHODS: This case-control study conducted in Shiraz, Iran in 2021. The case group included drivers with psychological disorders and the control group included those without any disorders. The inclusion criteria for selecting patients were: active driving at the time of the study, being 18 - 65 years old, having a driving license, having a psychological disorder including depression, bipolar disorder, anxiety spectrum disorder, or psychotic disorder spectrum confirmed by a psychiatrist, and completing an informed consent form. The exclusion criterion was the existence of conditions that interfered with answering and understanding the questions. The inclusion criteria for selecting the healthy cases were: active driving at the time of the study, being 18 - 65 years old, having a driving license, lack of any past or present history of psychiatric problems, and completing an informed consent form. The data were gathered using a researcher-made checklist and Manchester driving behavior questionnaire. First, partition around medoids method was used to extract clusters of RDB. Then, backward logistic regression was applied to investigate the association between the independent variables and the clusters of RDB. RESULTS: The sample comprised of 344 (153 with psychological disorder and 191 without confirmed psychological disorder) drivers. Backward elimination logistic regression on total data revealed that share of medical expenditure ≤ 10% of total household expenditure (OR = 3.27, 95% CI: 1.48 - 7.24), psychological disorder (OR = 3.08, 95% CI: 1.67 - 5.70), and substance abuse class (OR = 6.38, 95% CI: 3.55 - 11.48) were associated with high level of RDB. CONCLUSION Substance abuse, psychological illnesses, and share of medical costs from total household expenditure were found to be main predictors of RDB. Further investigations are necessary to explain the impact of different psychological illnesses on driving behavior.
Humans ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Automobile Driving ; Iran ; Case-Control Studies ; Mental Disorders/epidemiology* ; Surveys and Questionnaires ; Risk-Taking

OBJECTIVES: To explore the association between maternal gestational diabetes mellitus (GDM) exposure and the development of autism spectrum disorder (ASD) in offspring. METHODS: A case-control study was conducted, recruiting 221 children with ASD and 400 healthy children as controls. Questionnaires and interviews were used to collect information on general characteristics of the children, socio-economic characteristics of the family, maternal pregnancy history, and maternal disease exposure during pregnancy. Multivariate logistic regression analysis was used to investigate the association between maternal GDM exposure and the development of ASD in offspring. The potential interaction between offspring gender and maternal GDM exposure on the development of ASD in offspring was explored. RESULTS: The proportion of maternal GDM was significantly higher in the ASD group compared to the control group (16.3% vs 9.4%, P=0.014). After adjusting for variables such as gender, gestational age, mode of delivery, parity, and maternal education level, maternal GDM exposure was a risk factor for ASD in offspring (OR=2.18, 95%CI: 1.04-4.54, P=0.038). On the basis of adjusting the above variables, after further adjusting the variables including prenatal intake of multivitamins, folic acid intake in the first three months of pregnancy, and assisted reproduction the result trend did not change, but no statistical significance was observed (OR=1.94, 95%CI: 0.74-5.11, P=0.183). There was an interaction between maternal GDM exposure and offspring gender on the development of ASD in offspring (P<0.001). Gender stratified analysis showed that only in male offspring of mothers with GDM, the risk of ASD was significantly increased (OR=3.67, 95%CI: 1.16-11.65, P=0.027). CONCLUSIONS Maternal GDM exposure might increase the risk of ASD in offspring. There is an interaction between GDM exposure and offspring gender in the development of ASD in offspring.
Child ; Female ; Pregnancy ; Humans ; Male ; Diabetes, Gestational/etiology* ; Autism Spectrum Disorder/etiology* ; Case-Control Studies ; Gestational Age ; Mothers

OBJECTIVE: To explore lung ultrasound radiomics features which related to extravascular lung water index (EVLWI), and to predict EVLWI in critically ill patients based on lung ultrasound radiomics combined with machine learning and validate its effectiveness. METHODS: A retrospective case-control study was conducted. The lung ultrasound videos and pulse indicated continuous cardiac output (PiCCO) monitoring results of critically ill patients admitted to the department of critical care medicine of the First Affiliated Hospital of Guangxi Medical University from November 2021 to October 2022 were collected, and randomly divided into training set and validation set at 8:2. The corresponding images from lung ultrasound videos were obtained to extract radiomics features. The EVLWI measured by PiCCO was regarded as the "gold standard", and the radiomics features of training set was filtered through statistical analysis and LASSO algorithm. Eight machine learning models were trained using filtered radiomics features including random forest (RF), extreme gradient boost (XGBoost), decision tree (DT), Naive Bayes (NB), multi-layer perceptron (MLP), K-nearest neighbor (KNN), support vector machine (SVM), and Logistic regression (LR). Receiver operator characteristic curve (ROC curve) was plotted to evaluate the predictive performance of models on EVLWI in the validation set. RESULTS: A total of 151 samples from 30 patients were enrolled (including 906 lung ultrasound videos and 151 PiCCO monitoring results), 120 in the training set, and 31 in the validation set. There were no statistically significant differences in main baseline data including gender, age, body mass index (BMI), mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), cardiac index (CI), cardiac function index (CFI), stroke volume index (SVI), global end diastolic volume index (GEDVI), systemic vascular resistance index (SVRI), pulmonary vascular permeability index (PVPI) and EVLWI. The overall EVLWI range in 151 PiCCO monitoring results was 3.7-25.6 mL/kg. Layered analysis showed that both datasets had EVLWI in the 7-15 mL/kg interval, and there was no statistically significant difference in EVLWI distribution. Two radiomics features were selected by using LASSO algorithm, namely grayscale non-uniformity (weight was -0.006 464) and complexity (weight was -0.167 583), and they were used for modeling. ROC curve analysis showed that the MLP model had better predictive performance. The area under the ROC curve (AUC) of the prediction validation set EVLWI was higher than that of RF, XGBoost, DT, KNN, LR, SVM, NB models (0.682 vs. 0.658, 0.657, 0.614, 0.608, 0.596, 0.557, 0.472). CONCLUSIONS The gray level non-uniformity and complexity of lung ultrasound were the most correlated radiomics features with EVLWI monitored by PiCCO. The MLP model based on gray level non-uniformity and complexity of lung ultrasound can be used for semi-quantitative prediction of EVLWI in critically ill patients.
Humans ; Extravascular Lung Water/diagnostic imaging* ; Retrospective Studies ; Critical Illness ; Case-Control Studies ; Bayes Theorem ; China ; Lung/diagnostic imaging*

OBJECTIVE: To explore the predictive value of diaphragmatic thickening fraction (DTF) combined with Medical Research Council-score (MRC score) on the outcome of weaning from mechanical ventilation in ICU-acquired weakness (ICU-AW) patients. METHODS: A retrospective case-control study was conducted. The clinical data of mechanically ventilated patients with an MRC score of less than 48 admitted to the department of critical care medicine of the First Affiliated Hospital of Wannan Medical College from January 2022 to March 2023 were collected, including general information, ultrasound indicators, MRC scores, main clinical outcomes, and weaning outcomes. Patients were divided into successful weaning group and failed weaning group according to whether the patient could maintain effective autonomous breathing for at least 48 hours without using an invasive or non-invasive ventilator. The clinical data of the two groups were compared. Receiver operator characteristic curve (ROC curve) was plotted to analyze the predictive value of DTF and MRC score alone or in combination for successful weaning of patients. RESULTS: A total of 87 patients were enrolled, of which 58 were successful weaning and 29 were failed weaning. There were no statistically significant differences in general data such as gender, age, underlying disease, heart rate (HR), mean arterial pressure (MAP), pH value, blood lactic acid (Lac), oxygenation index (PaO₂/FiO₂), and severity scores between the two groups. Compared with the failed weaning group, the DTF and MRC scores of patients in the successful weaning group were significantly increased [DTF: (26.02±2.68)% vs. (22.79±5.40)%, MRC score: 38.90±2.78 vs. 33.24±3.78, both P < 0.05]. The duration of mechanical ventilation and the length of ICU stay of patients in the successful weaning group were significantly shorter than those in the failed weaning group [duration of mechanical ventilation (hours): 102.21±32.60 vs. 113.14±41.34, length of ICU stay (days): 6.48±2.18 vs. 10.11±4.01, both P < 0.05], and the re-intubation rate and ICU hospitalization cost were significantly lowered [re-intubation rate: 6.90% (4/58) vs. 27.59% (8/29), ICU hospitalization cost (10 000 RMB): 4.99±0.87 vs. 7.85±2.45, both P < 0.05]. ROC curve analysis showed that the area under the ROC curve (AUC) of DTF and MRC score for predicting successful weaning in ICU-AW mechanical ventilation patients was 0.839 [95% confidence interval (95%CI) was 0.746-0.931] and 0.799 (95%CI was 0.701-0.899), respectively. Using DTF ≥ 25.01% as the optimal cut-off value to predict successful weaning, the sensitivity was 82.76%, and the specificity was 72.41%. Predicting successful weaning based on an optimal cut-off value of MRC score of ≥ 35.50 had a sensitivity of 79.31% and a specificity of 70.69%. Based on the DTF ≥ 25.01% combined with MRC score ≥ 35.50, it was predicted that the weaning would be successful, with an AUC of 0.887 (95%CI was 0.812-0.962), sensitivity increased to 89.70%, and specificity increased to 79.30%. CONCLUSIONS The DTF and MRC score have good guiding value for the selection of weaning timing and predicting the weaning outcomes in ICU-AW patients. Compared with independent DTF and MRC score, the combination of DTF and MRC score improves the predictive value of successful weaning in ICU-AW patients.
Humans ; Respiration, Artificial ; Ventilator Weaning ; Case-Control Studies ; Retrospective Studies ; Intensive Care Units

OBJECTIVE: To explore the effect of thrombocytopenia on the prognosis of patients with septic shock and its mechanism in leading to death. METHODS: A retrospective case-control study was conducted. Patients with septic shock admitted to emergency intensive care unit (EICU) and intensive care unit (ICU) in Peking University People's Hospital from April 1, 2015 to January 31, 2023 were enrolled. Patients were divided into the thrombocytopenia group and the non-thrombocytopenia group, according to whether the minimum platelet count was less than 100×10⁹/L within 24 hours after admission to ICU. The outcome index was the mortality during ICU stay. The baseline data, hospitalization information and laboratory test results of the two groups were compared, and the risk factors of in-hospital death were analyzed by Logistic regression, and the mediation effect was performed by Bootstrap method. RESULTS: A total of 301 patients with septic shock were enrolled, of which 172 (57.1%) had thrombocytopenia and 129 (42.9%) did not. There were significant differences between the two groups in age, mortality, disseminated intravascular coagulation (DIC), continuous renal replacement therapy, and level of creatinine, urea nitrogen, total bilirubin, white blood cell count, lymphocyte count, prothrombin time (PT) and activated partial thromboplastin time (APTT). Univariate Logistic regression analysis showed thrombocytopenia [odds ratio (OR) = 4.478], continuous renal replacement therapy (OR = 4.601), DIC (OR = 6.248), serum creatinine (OR = 1.005), urea nitrogen (OR = 1.126), total bilirubin (OR = 1.006) and PT (OR = 1.126) were risk factors of death during hospitalization in patients with septic shock (all P < 0.05). Multivariate Logistic regression analysis showed that thrombocytopenia [OR = 3.338, 95% confidence interval (95%CI) was 1.910-5.834, P = 0.000], continuous renal replacement therapy (OR = 3.175, 95%CI was 1.576-6.395, P = 0.001) and PT (OR = 1.077, 95%CI was 1.011-1.147, P = 0.021) were independent risk factors for in-hospital mortality in patients with septic shock. Mediation analysis showed that 51% of the deaths due to thrombocytopenia in patients with septic shock were due to coagulopathy. CONCLUSIONS Thrombocytopenia is a powerful predictor of death in septic shock patients, and half of all thrombocytopenia-related deaths may be due to abnormal coagulation function.
Humans ; Shock, Septic ; Retrospective Studies ; Case-Control Studies ; Hospital Mortality ; Prognosis ; Thrombocytopenia ; Intensive Care Units ; Bilirubin ; Nitrogen ; Urea ; Sepsis

Objective: To summarize the clinical, radiological characteristics, and prognosis of infectious sacroiliitis in children. Methods: A case-control study was conducted, including 12 cases of infectious sacroiliitis diagnosed in the Rheumatology and Immunology Department of the Children's Hospital affiliated with the Capital Institute of Pediatrics from June 2018 to June 2023. These cases comprised the case group. Concurrently, 28 cases of pediatric idiopathic arthritis involving the sacroiliac joint in the same department served as the control group. Basic patient information, clinical features, laboratory parameters, and clinical treatment outcomes for both groups were collected and analyzed. Independent sample t-tests and chi-squared tests were used for inter-group comparisons. Results: Among the 12 cases in the case group, there were 5 males and 7 females, with a disease duration of 0.8 (0.5, 1.2) months. Nine patients presented with fever, and 1 patient had limping gait. Human leukocyte antigen (HLA)-B27 positivity was observed in 1 case, and there was no family history of ankylosing spondylitis. In the control group of 28 cases, there were 19 males and 9 females, with a disease duration of 7.0 (3.0, 17.0) months. One patient (4%) had fever, and 14 cases (50%) exhibited limping gait. HLA-B27 positivity was found in 18 cases (64%), and 18 cases (64%) had a family history of ankylosing spondylitis. The case group had higher white blood cell count (WBC), neutrophil ratio, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels, as well as a higher proportion of unilateral involvement on magnetic resonance imaging and bone destruction on CT compared to the control group ((11.1±6.2)×10⁹ vs. (7.3±2.3)×10⁹/L, 0.64±0.10 vs. 0.55±0.12, 72 (34, 86) vs. 18 (5, 41) mm/1 h, 24.6 (10.1, 67.3) mg/L vs. 3.6 (0.8, 15.0) mg/L, 11/12 vs. 36% (10/28), 9/12 vs. 11% (3/28), t=2.90, 3.07, Z=-2.94, -3.28, χ²=10.55, 16.53, all P<0.05). Conclusions: Pediatric infectious sacroiliitis often presents as unilateral involvement with a short disease history. Elevated WBC, CRP, and ESR, as well as a high rate of bone destruction, are also common characteristics.
Male ; Female ; Humans ; Child ; Sacroiliitis/diagnostic imaging* ; Spondylitis, Ankylosing/diagnosis* ; Case-Control Studies ; Sacroiliac Joint/diagnostic imaging* ; Radiography ; Magnetic Resonance Imaging ; Fever

Objective: To investigate the characteristics of salivary microbiota in patients with laryngopharyngeal reflux (LPR). Methods: A case-control study was applied to enroll 60 patients and healthy subjects who were outpatients of the Department of Otorhinolaryngology Head and Neck Surgery of the Eighth Medical Center of the PLA General Hospital from December 2020 to March 2021, including 35 males and 25 females, aged from 21 to 80 (33.75±11.10) years. Thirty patients with suspected laryngopharyngeal reflux were selected as study group and thirty healthy volunteers without pharyngeal symptoms were selected as control group. Their salivary samples were collected, and the salivary microbiota was detected and analyzed by 16S rDNA sequencing. SPSS 18.0 software was used for statistical analysis. Results: There was no significant difference in the diversity of salivary microbiota between the two groups. At the phylum classification level, the relative abundance of Bacteroidetes in the study group was higher than that in the control group[37.86(31.15, 41.54)% vs 30.24(25.51, 34.18)%,Z=-3.46,P<0.01]. And the relative abundance of Proteobacteria in the study group was lower than that in the control group [15.76(11.81, 20.17)% vs 20.63(13.98, 28.82)%, Z=-1.98,P<0.05]. At the genus level, the relative abundance of Prevotella, Lactobacillus, Parascardovia and Sphingobium in the study group was higher than that in the control group(Z values were-2.92, -2.69, -2.05, -2.31, respectively, P<0.05).And the relative abundance of Streptococcus, Cardiobacterium, Klebsiella and Uruburuella of study group was lower than that of control group(Z values were -2.43, -2.32, -2.17, -2.32, respectively, P<0.05). LEfSe difference analysis showed that there were 39 bacteria with significant differences between the two groups, including Bacteroidetes, Prevotellaceae and Prevotella, which were enriched in the study group, and Streptococcaceae, Streptococcus and other taxa, which were enriched in the control group(P<0.05). Conclusion: The changes of the microflora in the saliva between LPR patients and healthy people suggest that the dysbacteriosis might exist in LPR patients, which may play an important role in the pathogenesis and development of LPR.
Male ; Female ; Humans ; Laryngopharyngeal Reflux/diagnosis* ; Case-Control Studies ; Microbiota ; Outpatients ; Saliva/microbiology*