Ft3 is Higher in Males than in Females and Decreases Over the Lifespan

Strich, David; Karavani, Gilad; Edri, Shalom; Chay, Cherut; Gillis, David

doi:10.4158/ep171776.or

Cited by 18 publications

(11 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, the findings confirm the hypothesis put forward in the introduction, that is, that the FT3/FT4 ratio increases with increasing TSH into the pathological range and that FT4 therapy is associated with lower FT3/FT4. As we have described for physiological states [2,3,13], the FT3/FT4 ratio increased as TSH increased. The effect was much more pronounced in the extremely high TSH range (above 50 mIU/l) and was more pronounced in younger age groups (▶Fig.…”

Section: Discussionsupporting

confidence: 73%

Levothyroxine Therapy Achieves Physiological FT3/FT4 Ratios at Higher than Normal TSH Levels: A Novel Justification for T3 Supplementation?

et al. 2018

Self Cite

View full text Add to dashboard Cite

In euthyroidism, as thyroid Stimulating hormone (TSH) levels increase, the free triiodothyronine (FT3) to free thyroxine (FT4) ratio increases. The aim of this study was to assess if beyond the euthyroid range of TSH levels FT3/FT4 ratio continues to increase and if levothyroxine treatment reduces this ratio, possibly through TSH suppression. This cross sectional retrospective study included a total of 77 832 patients [age 22.76±15.17 years (4 days to 112 years)] evaluated and treated in community clinics between January 2009 and September 2013. Blood samples drawn in community clinics for which TSH, FT4, FT3, age, and gender were available were included. Tests with TSH below 0.5 IU/l were excluded as were samples taken during pregnancy. The FT3/FT4 ratio continued to increase significantly even with TSH above 50 mIU/l (p for trend<0.001) with an increase of more than 50% over the entire TSH range. With increasing age and female gender, the phenomenon was less prominent (p<0.001). Levothyroxine treated patients had significantly lower FT3/FT4 ratios in comparison to untreated patients up to TSH levels of 5.0 mIU/l. In conclusion, increasing TSH increases FT3/FT4 ratio even with severe hypothyroidism, less so with aging. With levothyroxine therapy, a ratio similar to untreated patients is achieved at TSH of above 5.0 mIU/l. Since T3 suppresses TSH better than T4, administration of T3 would likely normalize the FT3/FT4 ratio at a lower, ostensibly more physiological, TSH level. This could be seen as a rationale for add-on T3 therapy.

show abstract

Section: Discussionsupporting

confidence: 73%

Levothyroxine Therapy Achieves Physiological FT3/FT4 Ratios at Higher than Normal TSH Levels: A Novel Justification for T3 Supplementation?

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…Whether there is a causal relationship between Hcy concentration and thyroid function needs further investigation. It is interesting that the average fT3 level of men is higher than that of women 36 , but the higher fT3 levels do not help men have a lower Hcy level than women. It may be that other factors that increase Hcy in men mask this effect.…”

Section: Discussionmentioning

confidence: 98%

Gender- and age-related differences in homocysteine concentration: a cross-sectional study of the general population of China

Huang

Wang

et al. 2020

Sci Rep

View full text Add to dashboard Cite

The primary goals of this study were to evaluate the gender- and age-related differences in homocysteine concentration in the general population of China and possible influencing factors. A total of 7872 subjects, divided into male and female groups, participated in this retrospective study. The average homocysteine level, prevalence of hyperhomocysteinemia, and independent factors affecting homocysteine concentration were analyzed. The homocysteine level was significantly higher in males than in females in each age range (aged 20–30, aged 30–40, aged 40–50, aged 50–60, aged 60–80, aged over 80) (P < 0.0001), and the trend did not abate with age. The homocysteine concentration first decreased and then increased, being lowest at 30–50 years of age and significantly increased after 50 years of age. Factors associated with homocysteine concentration in males were smoking status (current smokers versus ex-smokers: β: 0.112), estimated glomerular filtration rate (β = − 0.192), blood urea nitrogen (β = − 0.14), diastolic blood pressure (β = − 0.113), free triiodothyronine (β = − 0.091), serum potassium (β = − 0.107) and cystatin C (β = 0.173). In females, independent factors associated with homocysteine concentration were cystatin C (β = 0.319), albumin (β = 0.227), free thyroxine (β = 0.179), age (β = 0.148), free triiodothyronine (β = − 0.217) and serum potassium (β = − 0.153). The homocysteine level was significantly higher in males than in females and increased markedly after 50 years of age in both groups. The independent factors associated with increased homocysteine concentration differed between males and females.

show abstract

“…Another limitation is the absence of patient stratification according sex. Strich et al [ 52 ] showed reliable data on the characteristics of the hormonal level depending on age and sex. FT3 decreases throughout life and is significantly higher among women.…”

Section: Discussionmentioning

confidence: 99%

Body Fat Parameters, Glucose and Lipid Profiles, and Thyroid Hormone Levels in Schizophrenia Patients with or without Metabolic Syndrome

et al. 2020

View full text Add to dashboard Cite

In this study, we aim to investigate associations between body fat parameters, glucose and lipid profiles, thyroid-stimulating hormone (TSH), and thyroid hormones (THs) levels in Tomsk-region schizophrenia patients depending upon the presence or absence of metabolic syndrome (MetS). A total of 156 psychiatric inpatients with schizophrenia who had been treated with antipsychotics for at least six months before entry were studied: 56 with and 100 without MetS. Reference groups consisted of general hospital inpatients with MetS and without schizophrenia (n = 35) and healthy individuals (n = 35). Statistical analyses were performed using the Mann–Whitney U-test, chi-square test, Spearman’s rank correlation coefficient, multiple regression analyses, and descriptive statistics. Patients with schizophrenia and MetS had significantly higher levels of free triiodothyronine (FT3) and thyroxine (FT4) compared to schizophrenia patients without MetS (3.68 [3.25; 5.50] vs. 3.24 [2.81; 3.66], p = 0.0001, and 12.68 [10.73; 15.54] vs. 10.81 [9.76; 12.3], p = 0.0001, in pmol/L, respectively). FT3 maintained an association with MetS (p = 0.0001), sex (p = 0.0001), age (p = 0.022), and high-density lipoproteins (p = 0.033). FT4 maintained an association with MetS (p = 0.0001), sex (p = 0.001), age (p = 0.014), and glucose (p = 0.009). The data obtained showed body fat parameters, glucose and lipid profiles, and THs levels in Western-Siberian schizophrenia patients depending on MetS presence or absence.

show abstract

Ft3 is Higher in Males than in Females and Decreases Over the Lifespan

Cited by 18 publications

References 19 publications

Levothyroxine Therapy Achieves Physiological FT3/FT4 Ratios at Higher than Normal TSH Levels: A Novel Justification for T3 Supplementation?

Levothyroxine Therapy Achieves Physiological FT3/FT4 Ratios at Higher than Normal TSH Levels: A Novel Justification for T3 Supplementation?

Gender- and age-related differences in homocysteine concentration: a cross-sectional study of the general population of China

Body Fat Parameters, Glucose and Lipid Profiles, and Thyroid Hormone Levels in Schizophrenia Patients with or without Metabolic Syndrome

Contact Info

Product

Resources

About