Obesity epidemic is a major health-care
problem. The thyroid hormone affects weight status
through modulation of the Resting Energy Expenditure.
This is done through the adaptive thermogenesis, the
Na/K pump, glucose entry through GLUT-4 transporter,
and through effects on the cardiac muscle. Studies
conflict on the effect of obesity on the thyroid hormone
function; some studies found a positive correlation even
after excluding thyroid disorders, but others did not.
Although obesity can explain the co-occurrence of
coronary artery disease and diabetes mellitus, the
influence of the thyroid hormone needs further
clarification. In this study, we explore the association
between obesity and thyroid hormone levels and the
effect of the thyroid hormone on comorbidities.
Methodology: This is a retrospective cross-sectional
study that included hospitalized patients in the
Endocrinology department of King Fahd Hospital
between January 2016 and January 2017. Patient files
were searched for age, gender, co-morbidities, chronic
medications, TSH, free T3, free T4, and BMI. Patient
with endocrinologic disease, thyroid disease, cancer; and
women who are pregnant or on Oral Contraceptive Pills
were excluded from the study. Data was analyzed using
SPSS version 23. Frequencies, descriptive statistics and
multiple linear regression were performed looking for
statistically significant associations.
Results: We studied 334 Saudi Arabian participants,
66.7% of whom were females. The mean age among our
patients was 49 years. Twenty five percent of our
patients had a normal BMI, 30.8% were overweight, and
42.8% were obese. Sixty three percent of our
participants had abnormal TSH level, 22% had
abnormal T3, and 21.5% had abnormal T4. About half
of our patients had at least one comorbidity. Multiple
linear regression analysis was done, with BMI as the
outcome variable and TSH, T3, and T4 as the predictive
variables. It did not reveal any significant association.
Discussion: Although many studies report an association
between obesity and the thyroid function, many others,
including our study, did not. This can be attributed to
different laboratories, methodologies and sample sizes.
Our studied population was leaner on average than
other studies. Although it is not clear whether different
obesity levels have different effect on the thyroid
function, an association was detected in more obese