Impact of Lifestyle Modification on Thyroid Axis in Obese Adults: A quasi-experimental longitudinal study

Obesity is a complex and chronic disease characterized by the accumulation of fat in the body, which negatively impacts the thyroid axis, which controls basal metabolic rate and energy expenditure. The study aims to investigates the mechanisms correlating obesity with thyroid disorders, focusing on its impact on metabolic indicators, lipid profile at baseline, and assessing changes in hormonal balance resulting from health intervention. A quasi-experimental longitudinal controlled study was done on 100 participants from Ramadi city, Iraq, including 50 healthy individuals and 50 obese participants.  All participants were initially assessed to classify them into healthy and obese groups. The obese group then followed a healthy lifestyle program for six months. Thyroid hormones were measured for the healthy and obese groups pre- and post-intervention, while the metabolic indicators and lipid profile were assessed at baseline for the obese groups only. The results showed a significant improvement in thyroid hormones post-intervention, with TSH and free T3 concentrations decreasing, and free T4 levels increasing, although they remained below normal levels. Baseline data revealed significant metabolic and lipid abnormalities among obese participants. Results of the current study indicate that a healthy lifestyle improves thyroid parameters in obese individuals, but restoring full hormonal balance may require a longer period. Baseline metabolic and lipid profile measurements highlight their importance as diagnostic tools for characterizing the metabolic effects of obesity.