Computational protocol: Evaluation of vitamin D relationship with type 2 diabetes and systolic blood pressure

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Protocol publication

[…] Ethical approval to conduct the study was obtained from the University of the West Indies (UWI), St. Augustine, the South West Regional Health Authority (SWRHA), and the North Central Regional Health Authority (NCRHA) in Trinidad and Tobago. Subjects were randomly chosen at the Eric Williams Medical Sciences Complex (EWMSC) and San Fernando General Hospital (SFGH) in Trinidad. The sample size chosen for the study was 80 because of limitations in resources for assays. Both effect size and sample size with 80% power were estimated for future studies.Hospital records were used to select at random patients who were diagnosed with T2DM. From the hospital records, patients with T2DM had a history of having glycated hemoglobin (HbA1c) and fasting blood glucose (FBG) values of ≥6.5% and ≥120 mg/dL, respectively. Clinicians at the SFGH and the EWMSC screened patients with T2DM again, to ensure that the patients did have the condition of T2DM before they were allowed to participate in the study. Controls were selected from the hospitals at random and were included in the study provided that the controls did not fall into the exclusion criteria. Antihypertensive drugs used and information on kidney disorders were recorded. The exclusion criteria for both controls and patients with T2DM were: persons consuming more than 8 mL of ethanol per week; taking multiple antihypertensive medications; having any form of cancer or any condition that may raise inflammatory markers; having T1DM; having any form of liver disease; having thyroid or parathyroid problems; being pregnant; and being under the age of 18. Additionally, exclusion criteria for controls only were HbA1c or FBG values of ≥6.5% or ≥120 mg/dL, respectively.Subjects fasted and did not take any medication 8–10 hours before venous blood samples were drawn. On the morning of the blood draw, before venous samples were taken, the subjects’ height and mass were measured. SBP and diastolic BP (DBP) were measured using a digital BP monitor. Venous blood samples drawn into blood collection tubes were centrifuged at 2000 g and separated into serum and plasma fractions. All blood fractions and two whole blood samples were stored at −70°C subsequent to analysis. Plasma 25(OH)D was determined by ELISA (ADI-900-215, Enzo Life Sciences, USA). Serum cholesterol was assayed using an automated dry chemistry analyzer (Cobas 6000, Roche Diagnostics, USA). Four subjects were removed from the study because of blood sample hemolysis. The final sample size for the study was 76 subjects (24 males and 52 females).Software packages used for statistical analyses were IBM SPSS Statistics V.21, Minitab 16, and G*Power 3.1.7. Statistical analyses performed were Anderson-Darling test, independent t-test, Mann-Whitney U-test, Fisher's exact test, Spearman's correlation (rs), logistic regression, and general linear model (GLM) univariate analysis. A p value <0.05 meant a statistically significant result. SBP was transformed via natural logarithm (ln) in order for the requirements of the GLM to be met. […]

Pipeline specifications

Software tools SPSS, G*Power
Application Miscellaneous
Organisms Homo sapiens
Diseases Diabetes Mellitus, Hypotension
Chemicals Calcifediol, Cholesterol, Vitamin D