Background
Serum thyroid-stimulating hormone (TSH) levels change during body weight reduction. However, the changes that occur during short-term body weight control interventions remain controversial. Thus, this study aimed to evaluate the changes in TSH levels according to body fat reduction.
Methods
We performed a 3-month intervention study involving partial meal replacement. Forty-nine participants completed the study. Correlations between changes in TSH levels and other body composition parameters were determined. The subjects were divided into two groups according to their body fat reduction (>1 kg, n=20; <1 kg, n=29). The changes in metabolic parameters, including TSH levels, were compared. For significant values, a multivariate analysis was performed after adjustment to evaluate the relationship between TSH changes and body fat reduction.
Results
The 3-month intervention caused favorable changes in body proportions and metabolic parameters. TSH levels changed significantly only after changes in total body fat, showing a partial correlation. Changes in TSH levels were significantly different between groups (P=0.014). Moreover, the change in TSH levels was significantly different after adjustment (P=0.012).
Conclusion
A body fat reduction, especially >1 kg, can reduce serum TSH concentrations in subjects with metabolic syndrome after short-term body weight intervention.

Citations

• The impact of weight loss interventions on thyroid function: a systematic review and meta-analysis
  Sandeep Samethadka Nayak, Seyyed Mohammad Hashemi, Masum Patel, Nimra Shafi, Pubali Biswas, Sepide Javankiani, Padmavathi Jaladi, Sanjana B. Patil, Rahiq Rashid, Ehsan Amini-Salehi, Daniyal Ameen, Khushbu Viresh Janani, Anil Kumar Jonnalagadda, Kwame Boat
  Annals of Medicine & Surgery.2025; 87(7): 4484.     CrossRef

Background
: There are no agreement for abnormalities in serum lipid concentrations and lipoprotein(a) (Lp(a)) in patients with subclinical hypothyroidism. But there are no reports for consideration of postmenopausal state and hormone replacement therapy(HRT). Therefore, we anayzed serum Lp(a) and lipid concentrations in patients with subclinical hypothyroidism considering menopause and HRT and the correlation between serum Lp(a) level and thyroid-stimulating hormone (TSH) concentration.

Methods : We undertook this study in 99 patients with subclinical hypothyroidism (TSH>5uIU/mL) and 297 age- and sex-matched normal control. They and no abnormalities in liver and renal function, fasting blood glucose and medical and drug histories. We excluded who were receiving HRT. Serum free thyroxine, triiodothyronine, TSH were measured by radioimmune assay using commercial kits, and Lp(a), total cholesterol, TG and HDL by Latex and enzyme method, respectively.

Results : There were no significant differences of serum Lp(a), total cholesterol, LDL, TG, HDL concentrations in patients with subclinical hypothyroidism and control subjects, analyzing after dividing into men, premenopausal and postmenopausal women. In patients with subclinical hypothyroidism, there was no correlation between serum Lp(a) and TSH concentraions(r=0.06, P>0.05).

Conclusion : Considering menopause and HRT, there were no increase in serum Lp(a) and lipid concentrations in subclinical hypothyroidism. There was no correlation between serum Lp(a) and TSH concentration in patients with subclinical hypothyroidism.

Background
: Hypothyroidism may be involved in a significant portion of the causes of hypercholesterolemia in Korea. In this study, we determined the frequency of suspected hypothyroidism in hypercholesterolemic patients and compared the frequency of elevated thyrotropin levels among the groups with various total cholesterol levels.

Methods : The study subjects were healthy, asymptomatic people who visited Health Promotion Center of Seoul National University Hospital. We excluded subjects with history of hypertension, DM and hypothyroidism. The study subjects underwent physical examination and filled out a questionnaire on health risk factors. Also blood chemistry and thyroid function test were done.

Results : Among 6479 subjects, 194(2.99%) had elevated(>4.1μIU/ml) thyrotropin levels. Among the hypercholesterolemic(≥240mg/dl) patients(n=868), 40(4.60%) had elevated thyrotropin levels. And there was statistically significant difference between normal cholesterolemic and hypercholesterolemic subjects(P<0.05). Among the patients with total cholesterol above 280mg/dl (n=180), 15(8.33%) had elevated thyrotropin levels. As amount of the total cholesterol increased, the frequency of elevated thyrotropin levels increased(P=0.001). And this result was consistent following adjustment for age, sex, BMI, smoking and drinking status(P<0.01).

Conclusion : Practicing physicians should be aware of the possibility of secondary hypercholesterolemia due to hypothyroidism and keep in mind the importance of evaluating TSH level.