The Effect Of Low-Fat And Low-Cholesterol Dietary Intervention On LDL Sub-Groups In Turkısh Dyslipidemic Patients
Condition: Dyslipidemias
MeSH terms: Dyslipidemias
Study type: Interventional

Summary: 
      The aim of this study is to compare LDL sub-group concentration before and after a diet with
      low-fat and low-cholesterol prescribed to dyslipidemic patients for 12 weeks.
    

Detailed description: 
      The study was conducted between January 2018-July 2019 in Erciyes University Health
      Application and Research Center. This study was planned as a clinical trial for treatment and
      47 patients were included. All participants were given written consent. The study was
      evaluated to be ethically appropriate by Erciyes University Faculty of Medicine Clinical
      Research Ethics Committee.

      A low-fat (<30% of total energy), and low-cholesterol (<200 mg/day) diet was planned for the
      participants at the baseline, according to the gender, lifestyle, working conditions,
      nutritional habits, BMI, concomitant diseases and risk conditions. The patients were called
      for monthly controls and followed up for a total of 12 weeks. When the patients admitted at
      the first and second months, Body Impedance Analyzer (BIA) measurements were performed and
      dietary adherence was controlled. If necessary, the energy requirements of the patients were
      re-calculated and their diets were re-newed and if the patients had any questions on the
      diet, they were answered. Blood samples were taken from the patients at the baseline and
      after 12 weeks and the effects of a low-fat, low-cholesterol diet on biochemical and
      anthropometric measurements were evaluated. Energy restricted diet were planed for overweight
      and obese patients (~ 500-1000 kcal/day). In addition, patients were recommended to walk at a
      moderate speed for at least 30-40 min per day.

      Data Collection A questionnaire including socio-demographic characteristics, nutritional
      habits, physical activity status, and comorbid diseases was filled by the researcher. The
      food consumption frequency of the participants was evaluated by dividing the frequencies into
      four groups as consuming 5-6 times daily, consuming every other day, consuming 1-2 times a
      week and consuming 1-2 times a month or never at all. Food consumption records were also
      taken from each patient. Physical activity was questioned by the 'International Physical
      Activity Questionnaire (short form).

      Statistical analysis The suitability of the data for normal distribution was evaluated by
      histogram, q-q graphs and Shapiro-Wilk test. Variance homogeneity was tested with Levene
      test. Two groups independent samples t-test and Mann-Whitney U-tests were used for
      quantitative variables. In the qualitative data, two repeated measurement comparisons were
      used with McNemar-Bowker test. The paired t-test and Wilcoxon tests were used in the
      quantitative data for two repeated measurements. Spearman analysis was used to evaluate the
      relationship between quantitative variables. Data analysis was performed by Turcosa Cloud
      (Turcosa Ltd Co) statistical software. Significance level was accepted as p<0.05.

      Anthropometric measurements After the completing the questionnaire, anthropometric
      measurements were taken. Body weight: When the patient was in fasting state in the morning
      measured with thin clothes. While measuring body weight, the individual was asked to remove
      his heavy clothes (coats, jackets, etc.), belongings in the pockets (wallet, key ring, phone,
      address book etc.) and shoes. Attention is given to place the feet on the balance and to
      ensure a balanced distribution of body weight to the two feet. The individual was asked to
      stand upright and without moving. The measurement was made with a sensitivity of 0.1 kg (100
      g). Height: The height was measured with a stadiometer while the feet were side-by-side and
      the head was in the Frankfort plane. Body mass index (BMI): BMI was calculated by dividing
      subjects body weight by square of his/her height. [BMI = Body weight (kg)/height (m)²]. Waist
      circumference: The waist circumference was measured with a non-elastic tape measuring the
      mid-point between the lower rib and the crista iliac crest. Waist-to height ratio: It was
      calculated by the division of waist circumference (cm) into height (cm). Neck circumference:
      Neck circumference was measured with a non-elastic plastic band from the middle of the neck
      height between the middle cervical spine and the middle anterior neck with a sensitivity of
      0.1 cm. In men with Adam's apple, it was measured just below the protrusion. BIA
      measurements: Body composition of the participants was determined with Tanita BC-418 MA
      (Tanita Corporation of America, Inc., Arlington Heights, IL) device. In order to make
      accurate measurements; metal jewelery on individuals, socks, clothes that will affect the
      measurement excessively were removed and information about the person's age, height, gender
      and whether they are dealing with regular sports activities were entered into the device.
      Then, individuals were removed from the instrument with their heels on the electrodes and the
      measurement was made. It was taken into consideration that participants did not perform
      intensive physical activity 24-48 hours before the measurement. It was observed that
      individuals did not have heavy physical activity 24-48 hours before the measurement, they
      were fasted for at least 4 hours, no alcohol was used 24 hours before, and they did not
      consume too much beverages (tea, coffee) before the measurement (at least 4 hours).

      Biochemical parameters In the Endocrinology polyclinic; the patients were diagnosed with
      dyslipidemia by an endocrinologist and their fasting blood glucose (mg/dL), triglycerides
      (mg/dL), total cholesterol (mg/dL), HDL-cholesterol (mg/dL), LDL-cholesterol (mg/dL) levels
      were evaluated. Patients were selected according to the inclusion criteria and blood was
      drawn after fasting for at least 10-12 hours. Very low density lipoprotein (VLDL (mg/dL)),
      large-LDL (mg/dL), small-LDL (mg/dL) medium density lipoprotein (IDL (mg/dL)) (Mid A, B, C)
      values. After centrifugation, blood samples were kept in the freezer at -80°C in Erciyes
      University Endocrinology Service until analysis period. For patients who were not initially
      evaluated for insulin (mg/dL), some blood was collected and delivered to Erciyes University
      Blood Collection Department and studied at the Central Biochemistry Laboratory of Erciyes
      University. Fasting blood glucose, triglyceride, total cholesterol, HDL-cholesterol and
      LDL-cholesterol levels were measured by spectrophotometric method using Roche Diagnostics
      (Basel, Switzerland). Insulin was measured by the ECLIA study method using the Roche
      Diagnostics (Mannheim, Germany). LDL subgroups were measured in serum samples using a
      Lipoprint System (Quantimetrix Inc., Redondo Beach, CA, USA). This system separates
      lipoproteins in a non-denaturing gel gradient of polyacrylamide based on net surface charge
      and size. The dye binds proportionally to the relative amount of cholesterol in each
      lipoprotein. After the electrophoresis, densitometric analyzes and proportional
      concentrations of lipoprotein classes and subclasses were calculated on the Lipoware
      software. In this system, VLDL, IDL corresponding to 3 midbands (Mid A, B, C) and 7 LDL
      subgroups: LDL-1 to -2 (large, bouyant, pattern A); LDL-3 to -7 (small, dense; pattern B).
      The system also gives the average LDL particle size. Type A if particle size was ≥268Â,
      medium level if particle size was 265-268Â, type B if particle size was ≤265Â.
    

Intervention name(s): Low-fat and low-cholesterol diet
Intervention type(s): Behavioral
Intervention description(s): Low-fat (<30% of total energy) and low-cholesterol (<200mg/day) diet total of 12 weeks
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Supportive Care
Keywords: Dyslipidemia, Low-Fat Low-Cholesterol Diet, LDL Sub-groups