TY - JOUR
T1 - Subclinical hypothyroidism in obese patients: Relation to resting energy expenditure, serum leptin, body composition, and lipid profile
AU - Tagliaferri, M
AU - Berselli, M E
AU - Calo, G
AU - Minocci, A
AU - Savia, G
AU - Petroni, M L
AU - Viberti, G C
AU - Liuzzi, A
PY - 2001/3
Y1 - 2001/3
N2 - Objective: To evaluate whether subclinical hypothyroidism (SH) affects resting energy expenditure (REE) as well as body composition, lipid profile, and serum leptin in obese patients. Research Methods and Procedures: A total of 108 obese patients with SH defined as normal free thyroxine levels and thyroid-stimulating hormone (TSH) values of >4.38 muU/ml (mean +/- 2 SD of the values of our reference group of obese patients with normal thyroid function) were compared with a group of 131 obese patients matched for age, sex, and body mass index (BMI) but with normal TSH levels. We assessed estimated daily caloric intake by 7-day recall, REE by indirect calorimetry, body composition by bioelectrical impedance analysis, serum leptin by radioimmunoassay, and lipid profile (i.e., total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides). Results: All of the variables measured were not different between the euthyroid obese patients and those with SH. In a multiple regression model with REE expressed for kilo-grams of fat free: mass (REE/kgFFM) as a dependent variable and percentage of fat mass, BMI, waist-to-hip ratio, age, TSH, free thyroxine, serum leptin, and caloric intake as independent variables, only percentage of fat mass was significantly correlated with REE/kgFFM in both groups. Tn the SH group only, BMI, waist-to-hip ratio, age, and TSH were related to REE/kgFFM and explained 69.5% of its variability. After dividing the patients with SH using a cutoff TSH value of 5.7 muU/ml, which represents 3 SD above the mean of TSH levels of the group of obese patients with normal thyroid function, only REE/kgFFM was significantly different and lower in the group of more severely hypothyroid patients. Discussion: In patients with obesity, SH affects energy expenditure only when TSH: is clearly above the normal range; it does not change body composition and lipid profile. We suggest that, at least in obese patients, evaluation of TSH levels may be useful to rule out a possible impairment of resting energy expenditure due to a reduced peripheral effect of thyroid hormones.
AB - Objective: To evaluate whether subclinical hypothyroidism (SH) affects resting energy expenditure (REE) as well as body composition, lipid profile, and serum leptin in obese patients. Research Methods and Procedures: A total of 108 obese patients with SH defined as normal free thyroxine levels and thyroid-stimulating hormone (TSH) values of >4.38 muU/ml (mean +/- 2 SD of the values of our reference group of obese patients with normal thyroid function) were compared with a group of 131 obese patients matched for age, sex, and body mass index (BMI) but with normal TSH levels. We assessed estimated daily caloric intake by 7-day recall, REE by indirect calorimetry, body composition by bioelectrical impedance analysis, serum leptin by radioimmunoassay, and lipid profile (i.e., total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides). Results: All of the variables measured were not different between the euthyroid obese patients and those with SH. In a multiple regression model with REE expressed for kilo-grams of fat free: mass (REE/kgFFM) as a dependent variable and percentage of fat mass, BMI, waist-to-hip ratio, age, TSH, free thyroxine, serum leptin, and caloric intake as independent variables, only percentage of fat mass was significantly correlated with REE/kgFFM in both groups. Tn the SH group only, BMI, waist-to-hip ratio, age, and TSH were related to REE/kgFFM and explained 69.5% of its variability. After dividing the patients with SH using a cutoff TSH value of 5.7 muU/ml, which represents 3 SD above the mean of TSH levels of the group of obese patients with normal thyroid function, only REE/kgFFM was significantly different and lower in the group of more severely hypothyroid patients. Discussion: In patients with obesity, SH affects energy expenditure only when TSH: is clearly above the normal range; it does not change body composition and lipid profile. We suggest that, at least in obese patients, evaluation of TSH levels may be useful to rule out a possible impairment of resting energy expenditure due to a reduced peripheral effect of thyroid hormones.
UR - http://www.scopus.com/inward/record.url?scp=0035289396&partnerID=8YFLogxK
U2 - 10.1038/oby.2001.21
DO - 10.1038/oby.2001.21
M3 - Article
VL - 9
SP - 196
EP - 201
JO - Obesity Research
JF - Obesity Research
IS - 3
ER -