Biyoistatistik/Makale Koleksiyonu
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe Retrospective Evaluation of Serum Zinc Levels in Patients with Protein-Energy Malnutrition(Selçuk Üniversitesi, 2023 Haziran) Özen, Hasan; Emiroğlu, Halil Haldun; Emiroğlu, Melike; Akdam, Neriman; Yorulmaz, AlaaddinAim: In this study, we aimed to investigate the frequency of serum zinc deficiency in children with protein-energy malnutrition and to show the relationship between the degree of malnutrition and serum zinc level. Methods: Methods: This retrospective study was conducted at the Pediatric Gastroenterology, Hepatology, and Nutrition clinic in Selçuk University Hospital, and included 506 patients aged between 1 and 18 years who were diagnosed with protein-energy malnutrition according to the Waterlow classification. Results: The prevalence of serum zinc deficiency was 61.1% in patients with protein-energy malnutrition. The mean serum zinc levels of patients aged 1-5 were significantly lower than those of patients aged 5-12 and 12-18. There was no difference between malnutrition degrees calculated according to Waterlow criteria and mean serum zinc levels. Although the relationship between the degree of malnutrition calculated according to the BGA scale and the mean serum zinc level was not statistically significant, the mean decrease in serum zinc levels was remarkable in contrast to the increase in the level of malnutrition. Conclusion: It is important to routinely measure serum zinc levels in patients with PEM and to provide zinc supplementation if deficiency is detected.Öğe Comparison of test statistics of nonnormal and unbalanced samples for multivariate analysis of variance in terms of Type-I error rates(HINDAWI LTD, 2019) Ateş, Can.; Kaymaz, Özlem.; Kale, H. Emre.; Tekindal, Mustafa Agah.In this study, we investigate how Wilks' lambda, Pillai's trace, Hotelling's trace, and Roy's largest root test statistics can be affected when the normal and homogeneous variance assumptions of the MANOVA method are violated. In other words, in these cases, the robustness of the tests is examined. For this purpose, a simulation study is conducted in different scenarios. In different variable numbers and different sample sizes, considering the group variances are homogeneous (sigma(12) = sigma(22) == sigma(g2)) and heterogeneous (increasing) (sigma(12) < sigma(22) < ... < sigma(g2)), random numbers are generated from Gamma(4-4-4; 0.5), Gamma(4-9-36; 0.5), Student's t(2), and Normal(0; 1) distributions. Furthermore, the number of observations in the groups being balanced and unbalanced is also taken into account. After 10000 repetitions, type-I error values are calculated for each test for alpha=0.05. In the Gamma distribution, Pillai's trace test statistic gives more robust results in the case of homogeneous and heterogeneous variances for 2 variables, and in the case of 3 variables, Roy's largest root test statistic gives more robust results in balanced samples and Pillai's trace test statistic in unbalanced samples. In Student's t distribution, Pillai's trace test statistic gives more robust results in the case of homogeneous variance and Wilks' lambda test statistic in the case of heterogeneous variance. In the normal distribution, in the case of homogeneous variance for 2 variables, Roy's largest root test statistic gives relatively more robust results and Wilks' lambda test statistic for 3 variables. Also in the case of heterogeneous variance for 2 and 3 variables, Roy's largest root test statistic gives robust results in the normal distribution. The test statistics used with MANOVA are affected by the violation of homogeneity of covariance matrices and normality assumptions particularly from unbalanced number of observations.Öğe Assessment of subclinical atherosclerosis in vitamin D deficiency(LIPPINCOTT WILLIAMS & WILKINS, 2019) Aydın, Elçin; Altın, Cihan; Söylev, Gözde Özcan; Tekindal, Mustafa Agah; Ağıldere, MuhteşemPurpose Patients with vitamin D deficiency (VDD) have potential to have increased cardiovascular morbidity and mortality. In this study, we aimed to discover the findings of early atherosclerosis in patients with VDD by measuring carotid intima-media thickness (CIMT) and epicardial fat thickness (EFT). Materials and Methods The study population includes 52 patients with VDD (n = 30 [57% female], mean +/- SD age 54.28 +/- 8.77 years, mean +/- SD serum 25-hydroxyvitamin D (25 [OH] D) 11 +/- 2.4 ng/mL) and 82 participants for control group (n = 52 [63.4% female], mean +/- SD age 56.40 +/- 7.90 years, mean +/- SD serum (25 [OH] D) 53 +/- 4.2 ng/mL) who have no cardiovascular disease. Carotid intima-media thickness was assessed by using ultrasonography, and EFT was measured on the free wall of the right ventricle at end diastole from the parasternal long-axis views by standard transthoracic 2-dimensional echocardiography. Results Both CIMT and EFT were significantly higher in patients with VDD compared with controls (0.75 +/- 0.16 mm vs 0.68 +/- 0.21 mm, P < 0.05, and 0.66 +/- 0.15 cm vs 0.56 +/- 0.15 cm, P < 0.001). Conclusions Patients with VDD seem to have increased CIMT and EFT, which are predictors of atherosclerotic process. Further studies are needed to confirm these results.Öğe Usefulness of grayscale inverted images in addition to standard images in digital mammography(BIOMED CENTRAL LTD, 2017) Altunkeser, Ayşegül; Körez, M. KazımBackground: Mammography is essential for early diagnosis of breast cancer, which is the most common type of cancer in females that is associated with a high mortality rate. We investigated whether evaluation of the grayscale inverted images of mammograms would aid in increasing the diagnostic sensitivity of the mammographic imaging technique. Methods: Our study included 636 mammograms of 159 women who had undergone digital mammography. Standard, grayscale inverted, and standard plus grayscale inverted images were sequentially examined three times, at 15-day intervals, for the presence or assessment of pathological changes in the skin, calcification, asymmetric density, mass lesions, structural distortions, and intramammary and axillary lymph nodes. To determine whether grayscale inverted image assessment improved detection rates, the results of the three assessment modes were compared using Cochran's Q test and the McNemar test (p < 0.05 was considered statistically significant). Results: The average age of 159 patients was 50.4 years (range, 35-80 years). There were significant differences among the three assessment modes with respect to calcification and intramammary lymph nodes (p < 0.05); however, no significant differences were observed for the detection of other parameters. Conclusions: Assessment of grayscale inverted images in addition to standard images facilitates the detection of microcalcification.
