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Background and Objective: Obesity plays an important role in the development of chronic diseases including diabetes, hyperlipidemia, and cardiovascular diseases (CVD). This study was conducted to evaluate the association of the age of onset of obesity with resting metabolic rate (RMR) in overweight and obese women during adulthood.
Methods: This descriptive-analytical study was done on 295 overweight and obese women aged 18-50 years in Tehran, Iran. The anthropometric measurements of all participants were measured. Dietary intake and total daily energy intake were assessed by using a semi-quantitative food-frequency questionnaire (FFQ) which the list including 147 food items. Resting metabolic rate was measured by indirect calorimetric method. In order to measure the physical activity International Physical Activity Questionnaire (IPAQ) was used. The questionnaire includes 7 items to assess the intensity of activities by the vigorous, medium, and light for at least 10 minutes during the last week.
Results: There was a significant difference between those whose age of onset of obesity was under 18 or over 18, in RMR per body weight (kg) (Beta: 0.16, CI: 0.11 to 0.00, P: 0.03). In addition, it was seen a significant inverse correlation between age of onset of obesity and body weight (Beta: -0.11, CI: -0.30 to 0.00, P: 0.005) and adipose tissue content (Beta: -0.13,
CI: -0.23 to -0.01, P: 0.02). After adjustment for confounders including (age, physical activities, and energy intake), the correlations still remain significant.
Conclusion: Age of onset of obesity was associated with increased weight and fat and decreased resting metabolic rate in adulthood. In fact, people with lower obesity age have higher body weight and fat and lower RMR.