Relationship of gender and age on thyroid hormone parameters in a large Chinese population

Abstract

Objective: This study aimed to present the impact of age and gender on thyroid hormone levels in a large Chinese population with sufficient iodine intake. Subjects and methods: A total of 83643 individuals were included and were stratified by age and gender. The median, 2.5th and 97.5th of thyrotropin (TSH), free triiodothyronine (FT3), free thyroxine (FT4) and FT3/FT4 ratio were calculated for both genders for every decade from 18 to over 80 years. TSH, FT3, FT4, FT3/FT4 distribution in each age group was evaluated for females and males using smoothing splines in the generalized additive models (GAM). TSH concentrations were compared in the different age groups in gender. Results: In the over 80s age group, the TSH level (median: 2.57 mIU/L, 2.5th-97.5th: 0.86-7.56 mIU/L) was significantly higher than other age groups, irrespective to gender (P<0.001). Females had a higher TSH value than males in all age groups (P<0.001). Results of the smoothing curves showed that TSH increased with age, FT3 concentration was higher in males than in females and the tendency of the FT3/FT4 ratio was basically similar to that of FT3. TSH concentration in the 50s age group (median 2.48 mIU/L for females versus 2.00 mIU/L for males) was significantly higher than that in the 30s age group (median 2.18 mIU/L for females versus median 1.85 mIU/L for males). Conclusions: In accord with increasing TSH values during aging, females and older adults have lower FT3 values and lower FT3/FT4 ratios, while the FT4 values remain stable.

Age- and sex-related reference interval for free thyroxine: An indirect approach

“…Quality control was run in duplicate at the beginning and end of each day and met the laboratory precision goals for this assay. 3,4 Table 1 summarizes our findings. Reproducibility of duplicate measurements was unpredictable; unacceptable precision is highlighted in the table.…”

“…For example, the imprecision observed the 99th percentile cut-offs may be discordant with respect to other cardiac troponin assays and the clinical diagnosis, even when imprecision from duplicate analysis is acceptable. 4 As part of a stability study assessing Ortho hsTnI concentrations in both EDTA plasma and lithium heparin plasma over 24 h, we have observed that this interference is random and not related to time on cells. Briefly, samples were collected into paired lithium heparin and potassium EDTA vacutainers (Becton, Dickinson, and Company, NJ, USA), i.e.…”

“…We speculate that this might be in part linked to the reduced conversion of T4 to T3 in older age. 4 Indeed, the ratio fT3/fT4, measured in the 6958 cases in which fT3 were requested, progressively decreases with age (data not shown).…”

The interactive effects of pre-pregnancy body mass index, thyroid function, and blood lipid levels on the risk of gestational diabetes mellitus: a crossover analysis

“…To our knowledge, it is the rst study to explore these interactions by using crossover methodology. Second, we chose FT3/FT4 ratio as an indicator of thyroid hormone status, which has been demonstrated to be a stable and better predictor of insulin resistance and metabolic syndrome [49 ]. Third, we used the interaction presentation table recommended by Knol et al [50] to report OR value, AP values, RERI interaction indices, and 95% CI.…”

Age-related Changes in Computed Tomography Density of Thyroid Gland in Children: A Single-Center Retrospective Study in Northern China

“…1,2 Recently, several studies have reported that thyroid function changes were associated with age in the general population. 3,4 However, it is unclear whether thyroid gland CT density is related to age during childhood.…”