Serum Leptin Level in Patients with Type 2 Diabetes Mellitus: . • A Nutritional and Biochemical Study

Abstract

Type 2 diabetes is a chronic heterogenous disorder with a well recognized polygenic basis. The underlying determinants and etiological factors for . this epidemic sweeping the globe have been a subject of much controversy over the last decade, and many questions in this respect have been at least partly answered following a substantial increase in research. Since the cloning of leptin, the adipocyte derived hormone, several studies have been carried out to suggest that leptin might be one of the triggers that cause the development of type 2 diabetes mellitus especially in obese subjects, however the causal pathway by which leptin may be associated with increased diabetes risk in humans remains unknown. The general aim of the present study was to study serum leptin levels in patients with type 2 diabetes (newly diagnosed) and compare them with that in controls in an attempt to determine whether leptin represents a risk in the development of diabetes. The specific aim was to demonstrate the correlation between serum leptin level and different variables including age, obesity indices (BMI, waist circumference, WIH ratio, TSFT), blood pressure (systolic and diastolic), fasting insulin and fasting glucose. Also to investigate the effect of sex and lifestyle habits (smoking and physical activity) on serum leptin level, and finally to study relationships with dietary data including total energy intake as well as diet composition. During a period of one year, a case control study was conducted in the Diabetes Clinic of the Alexandria Main University Hospital and EL-Pharaana Health Insurance diabetes center. Newly diagnosed cases of type 2 DM in the age group 35-65 years from both sexes, before receiving any medications (oral antidiabetic agents or insulin) were selected. As for the controls, non diabetic subjects were selected in the same age group and also from both sexes. All subjects were interviewed to answer a pre-designed structured questionnaire which included demographic and socioeconomic data, medical and family history, reproductive history (for females) and data on lifestyle habits. Anthropometric measurements were recorded including weight, height, waist circumference, hip circumference and triceps skinfold thickness, then body mass index and WaistiHip ratio were calculated. Blood pressure was also measured. Blood samples were taken after 12 hours overnight fast. Glucose was determined immediately from the serum after its separation, while serum leptin and insulin were measured in batches at the end of the study from the aliquots that had been stored at -20°C. All subjects were also interviewed to answer a pre-designed quantitative food frequency questionnaire. It included data about the different food groups, as well as additional information about the type of fat/oil added to food items or used in cooking and also the preferred methods of cooking. After completion of data collection, data were fed to the computer using the Foxpro • for windows data base program. Then, after checking and correction of the data, the data base file was transferred to the SPSS program version 11 software for tabulation and statistical analysis. A nutrient database and analysis program was designed using Foxpro for windows software to calculate nutrient intakes.