This study has two arms: 1) cross-sectional observation on healthy participants, and 2)
multi-center, prospective study of 3 month duration (pre and post design) on obese
participants undergoing bariatric procedure.
Population study: Forty Emirati obese adults from UAE and 40 Lebanese obese adults from
Lebanon from both genders and planning to undergo bariatric procedure (irrelevant of the
study) will be recruited. All participants planning to conduct the surgery will be contacted;
the consenting ones will be recruited till target sample saturation. Afterwards, 40 healthy
counterparts from each country will be selected. Healthy participants will be recruited from
Zayed University or staff of Qassimi Hospital in Sharjah, UAE and from
staff/students/colleagues of the Middle East Institute of Health University Hopsital in
Lebanon.
Assessment and Data Collection: 2 Research assistants (one in each hospital) will be trained
by the principal investigator (PI) on the study instruments and data collection methods.
These assistants will administer 4 questionnaires for each participant (healthy and obese
per-operatively) at baseline(t0) and 4 questionnaires for the obese participants after the
bariatric procedure after 3 months (t1). For quality control purposes, each questionnaire
will be administered to all patients before the administration of the following
questionnaire. Furthermore, each questionnaire will be completed and reviewed prior to
administering the next. The assessment will take place in the specified clinic or hospital.
All of the parameters, except the demographics and initial screening questionnaire (collected
only at t0) and follow up post bariatric questionnaire (t1: at 3 months, after the bariatric
procedure), will be collected and monitored at 2 time points: Baseline (t0: at the beginning
of the study), and follow up for obese participants (t1: at 3 months, after the bariatric
procedure).
Assessment tools include:
Demographics
Questionnaires for:
i. Initial screening questionnaire ii. Follow up post bariatric questionnaire iii. 24 hour
recall iv. Anxiety and Stress Levels using the DASS v. Appetite questionnaire
All questionnaires that are originally not in Arabic, will be translated to Arabic (local
language), prior to study by translators whose first language is Arabic and back translated
to English to assure coherence with original version.
Biochemical evaluation
An overnight fast of at least 12 h for blood collection is required. Collection will be done
by a certified nurse at the Middle East institute of Health University Hospital and Qassimi
Hospital. The blood will be analyzed for the following parameters:
Lipid and glucose profile: serum triglyceride, total cholesterol, HDL-cholesterol, LDL-
cholesterol, fasting blood glucose,
Gut peptides: Total GLP-1, GLP-2, PYY, CCK, Ghrelin,
Hormones: fasting insulin and Leptin
The questionnaires will be administered during the participants' routine visits. And blood
draw will be taken during that visit (for obese participants,around 1 week prior to surgery)
And 3 months post bariatric surgery for obese individuals. For each time, for the complete
process, a total of 30 min will be needed per participant.
Nutritional Assessment • Anthropometric measurements will be assessed through a dietitian at
the Middle East institute of Health University Hospital in Lebanon and Qassimi Hospital in
sharjah, UAE. It will include body weight, body height, Body mass index (BMI), waist
circumference (WC). Body composition will be evaluated using bioelectrical impedance analysis
and energy expenditure using portable Indirect Calorimeter.
Fecal microbiota analysis.
• Participants will be given special collection kits followed by instructions on how to
collect the stool. They will be asked to inform the research team when the samples are ready,
so it will be collected within 24 hours. 2 samples will be collected from each participant,
where 1 will be analyzed and second kept for accuracy check. Stool microbiota analysis will
be done for all the participants at baseline and repeated at 3 months for the obese
participants post bariatric surgery. Using Polymerase Chain Reaction (PCR) products of the
V3-V4 region of 16S rRNA gene will be sequenced using a barcoded Illumina paired-end
sequencing technique. The primary composition of the microbiome in the stool samples will be
determined and analyzed by cluster analysis.
Sample size was determined according to change in Bacteroidetes/Firmicutes ratio, considering
it as the main objective outcome of this study. Calculations were based on the data retrieved
from Damms-Machado et al (2015) where serum Bacteroidetes/Firmicutes ratio changed
significantly from 5.9 ±2.1 to 10.4± 1.4 in 3 months post bariatric surgery.To generate a
similar significant effect of a sample size of 2 participants was estimated to achieve 80%
power at a 5% alpha. Expecting a drop in effect size in this protocol, a high attrition rate
among the samples at 3 months; we multiplied the number of participants in it by 20. Thus a
sample of 40 participants per groups was planned for this study.
Data will be analyzed through SPSS version 18. Correlations will be conducted through ANOVA.
Effect of the study will be analyzed by paired t test on continuous data and Chi square on
categorical data. Microbiota composition will be analyzed using QIIME, and alpha- and
beta-diversity will be determined.