Vitamin D Status and Lipid Profile in Obese Adults With Type 2 Diabetes

**Detailed Description**

This prospective, single-center, cross-sectional observational study is designed to investigate the association between serum 25-hydroxyvitamin D [25(OH)D] status and lipid profile parameters among obese adults with established type 2 diabetes mellitus (T2DM).

The study will recruit adult participants with obesity and T2DM attending an outpatient diabetes clinic in Cairo, Egypt. Eligible participants will undergo a baseline clinical and laboratory assessment after providing written informed consent.

The primary objective of this study is to evaluate whether serum 25(OH)D concentrations are associated with lipid profile parameters, including total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C).

Secondary objectives include evaluating the association between serum vitamin D status and glycemic characteristics, including fasting blood glucose, postprandial blood glucose, glycated hemoglobin (HbA1c), and serum insulin levels.

During the study visit, demographic and clinical data will be collected, including age, sex, diabetes duration, body mass index (BMI), and relevant medical history. Anthropometric measurements and blood pressure assessment will be performed. Fasting blood samples will be collected for biochemical analyses, including serum 25(OH)D concentration, glucose parameters, insulin, and lipid profile measurements.

Participants will be categorized according to their serum 25(OH)D status based on predefined criteria. Statistical analyses will be performed to assess differences between vitamin D status groups and to evaluate correlations between serum 25(OH)D concentrations and cardiometabolic parameters.

No intervention, medication assignment, or vitamin D supplementation will be administered as part of this study. The study is observational in nature and aims to identify associations between vitamin D status and metabolic characteristics among obese adults with T2DM.

All procedures will be conducted according to the approved study protocol and ethical principles for research involving human participants. Written informed consent will be obtained from all participants before enrollment.

Inclusion criteria

• Adults aged 18 years or older.
• Established diagnosis of type 2 diabetes mellitus (T2DM) according to standard diagnostic criteria.
• Obesity based on body mass index (BMI) criteria.
• Availability of serum 25-hydroxyvitamin D [25(OH)D] measurement.
• Availability of lipid profile and glycemic laboratory parameters.
• Ability and willingness to provide written informed consent.

Exclusion criteria

• Type 1 diabetes mellitus.
• Pregnancy.
• Known chronic kidney disease.
• Chronic liver disease.
• Active malignancy.
• Acute infection or inflammatory disease.
• Conditions affecting gastrointestinal absorption.
• Use of medications or supplements that substantially alter vitamin D metabolism (when applicable).