Purpose: To proceed effectively with clinical research requires an understanding of the fundamental principles of study design and biostatistical methods. In this article, we identified and summarized basic clinical research designs and some of the key biostatistical methods that have been commonly used in clinical research. Materials and Methods: In an observational study, cross-sectional, case- control and Cohort designs were illustrated and compared. In a clinical trial study, parallel group design and cross-over designs were described according to their characteristics. Also, the biostatistical methods for their usages classified and summarized. Results: Understanding and evaluating research design are part of the process researchers must use to determine both the quality and usefulness of their research. Adequate applications to biostatistical methods are need; i.e., descriptive statistics, Student's t-test, ANOVA, nonparametrics, categorical data analysis, correlation and regression, and survival analysis. Conclusions: Research findings are used by clinical researcher to guide their practice and reduce their uncertainty in clinical decision making. However, to understand how to interpret research results, it is important to be able to understand basic statistical concepts and types of study design. Clinicians should also appropriately choose the biostatistical methods to suit their purposes.
Biostatistics ; Cohort Studies ; Cross-Over Studies ; Decision Making ; Observational Study ; Research Design* ; Statistics as Topic ; Uncertainty

PURPOSE: Obesity has been known to be a cause of insulin resistance and dyslipidemia, and along with coronary artery disease and diabetes, is associated with metabolic syndrome(MS). This study aimed to ascertain the cause and prevalence of MS in obese children and adolescents. METHODS: Two hundred and seventy-seven school children, who showed more than a 95th percentile of body mass index(BMI) for age and sex, underwent oral glucose tolerance tests; fasting plasma lipid profiles, leptin, and CRP were measured; and ultrasonography was done. RESULTS: Out of 277 obese children, the prevalence of MS was 37.5%, with 38.7% occurring in males and 35.2% in females. The prevalence was 20.8% in primary school children and 50.3% in middle school children. MS was present in 25.2% of mildly obese children, 43.9% of moderate and 71.4% of highly obese children, showing increased occurrence among the severer degrees of obese groups. Increased prevalence was observed in males with high blood pressure, and females with high triglyceride levels. The ratio of children satisfying more than one, more than two, more than three, more than four and all of the five criteria for diagnosis of MS were 90.6%, 63.5%, 37.5%, 8.3%, and 0.4%, respectively. Aside from diagnostic criteria for MS, a statistically significant difference was present between obese patients with or without the syndrome in such items as weight, BMI, degree of obesity, visceral fat thickness, ratio of body fat, leptin, and adiponectin, fasting and 2 hour post prandial insulin concentration. CONCLUSION: The prevalence of MS is currently on the rise among children, due to the rapidly increasing rate of obesity, westernized diet, higher calorie intake and reduced exercise. The prevalence of MS in obese children was 37.5% - higher than US results - after implementation of modified pediatric criteria established by ATP III Asia-Pacific standard in 2003. It would therefore be necessary to establish an acceptable universal standard for the diagnosis of MS, and extend the study to the general pediatric population in order to acquire more accurate data on the prevalence of the disease.
Adenosine Triphosphate ; Adiponectin ; Adipose Tissue ; Adolescent ; Child* ; Coronary Artery Disease ; Diagnosis ; Diet ; Dyslipidemias ; Fasting ; Female ; Glucose Tolerance Test ; Humans ; Hypertension ; Insulin ; Insulin Resistance ; Leptin ; Male ; Obesity ; Obesity, Abdominal ; Plasma ; Prevalence* ; Triglycerides ; Ultrasonography

PURPOSE: It is known that insulin resistance is important because it may precede the development of Diabetes Mellitus. We evaluated the gender difference of insulin resistance in obese children & adolescents. METHODS: 92 obese children and 187 adolescents (age:5-16 y, >95th percentile of the body mass index [BMI] for age and sex) were included in this study. The abdominal fat, abdominal circumference, and intraabdominal fat depth (IAFD), plasma fasting insulin, leptin, adiponectin, lipid profiles and high sensitive-C reactive protein (hs-CRP) were measured, and a two-hour oral glucose tolerance test with insulin measurement were performed. RESULTS: The plasma total cholesterol, leptin, fasting insulin & HOMA-IR levels of obese females were higher than those of obese males. The sex, waist circumference, IAFD & adiponectin levels were strongly correlated with HOMA-IR by multiple linear regression analysis (P<0.05). CONCLUSION: Adolescent females may have specific fat distribution and were expressed to have higher leptin and relatively lower adiponectin concentration compared to adolescent males, developing higher insulin resistance, even though having lesser abdominal fat and waist size. Further investigation is required to verify the gender difference of insulin resistance in obese children and adolescents.
Abdominal Fat ; Adiponectin ; Adolescent* ; Body Mass Index ; Child* ; Cholesterol ; Diabetes Mellitus ; Fasting ; Female ; Glucose Tolerance Test ; Humans ; Insulin Resistance* ; Insulin* ; Leptin ; Linear Models ; Male ; Obesity ; Plasma ; Waist Circumference

PURPOSE: Stroke is the second leading cause of death and a major cause of morbidity and mortality worldwide. Evidence of variations in adiponectin(AdipoQ) genes that are associated with ischemic stroke has not been consistent, and it is unclear whether the same loci contribute to these associations in the Korean population. Using a Korean population, we tested ischemic stroke-associated AdipoQ markers. MATERIALS AND METHODS: In a preliminary genome-wide association study using 320 250 k Affymetrix NSP chips, AdipoQ was found to be associated with ischemic stroke in Koreans. To study of AdipoQ, a further 673 ischemic stroke patients and 267 unrelated individuals without a history of stroke or transient ischemic attack were examined in a case-control study. RESULTS: Six polymorphisms (rs182052G > A, rs16861205G > A, rs822391T > C, rs822396A > G, rs12495941G > T and rs3774261A > G) that had a minor allele frequency of over 1% were strongly associated with stroke (p < 0.05). Two of these, rs822391T > C and rs822396A > G showed this association on both dominant and additive logistic regression analysis after adjusting for age and sex. The haplotypes ht 1 (AGGCGG and AAGTAG) were significantly associated with susceptibility to stroke. CONCLUSION: Our findings show that polymorphisms in AdipoQ are associated with risk for ischemic stroke in the Korean population. This study lends further support to the putative role of AdipoQ in stroke.
Adiponectin/*genetics ; Aged ; Asian Continental Ancestry Group ; Female ; Genetic Predisposition to Disease/genetics ; Haplotypes ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide/genetics ; Stroke/epidemiology/*genetics