Thyroid stimulating hormone levels and geriatric syndromes: secondary nested case-control study of the Mexican Health and Aging Study

Evaluation of the risk of hypothyroidism and its clinical manifestations using the Zulewski scale

Background

Globally, clinical hypothyroidism affects an estimated 0.5 to 5% of the population, while subclinical hypothyroidism affects 5-20%. Limited data is available on the prevalence of thyroid disease within the Mexican population. The objective of this study was to describe the characteristics of people screened for hypothyroidism in Mexico during 2022 using the Zulewski scale.

Methods

A cross-sectional analysis was conducted using data obtained from a digital survey administered by an e-Health platform. This study included participants of all genders, aged 18 years and older (n = 31,449). Descriptive statistics (frequencies and percentages) were sued to describe the data. Differences between groups were assessed through the chi-square or Fischer's exact test. Information gathered was subjected to hierarchical segmentation analysis to explore trends and patterns. Statistical significance was set as <0.05.

Results

Among the participants, 87.7% were women, and 80% fell within the age group 18 and 44 years. According to the Zulewski scale, 27% of the participants had a low risk of hypothyroidism, 37.4% were classified as having an intermediate risk, and 35.6% were at a high risk. In people at high risk of hypothyroidism, the most common symptom was constipation (29.2%) whereas the most common sign was decreased speed of movement (26.2%). Inquiry of slow movements, dry skin, and facial edema allowed the identification of 90.2% of participants at high risk of hypothyroidism.

Conclusions

In Mexico, a significant portion of the population is at an intermediate or high risk of hypothyroidism, requiring confirmatory diagnostic tests.

Aging under endocrine hormone regulation

Aging is a biological process in which the environment interacts with the body to cause a progressive decline in effective physiological function. Aging in the human body can lead to a dysfunction of the vital organ systems, resulting in the onset of age-related diseases, such as neurodegenerative and cardiovascular diseases, which can seriously affect an individual's quality of life. The endocrine system acts on specific targets through hormones and related major functional factors in its pathways, which play biological roles in coordinating cellular interactions, metabolism, growth, and aging. Aging is the result of a combination of many pathological, physiological, and psychological processes, among which the endocrine system can achieve a bidirectional effect on the aging process by regulating the hormone levels in the body. In this paper, we explored the mechanisms of growth hormone, thyroid hormone, and estrogen in the aging process to provide a reference for the exploration of endocrine mechanisms related to aging.

[Hypothyroidism and aging: the search for protective factors]

Searching for aging key points is one of the main problems in geriatrics. More and more research in recent years has been devoted to the study of geroprotective mechanisms, the impact of various conditions and diseases on aging in general. Of particular importance is the determination of age-related involutive processes in the human body, whether they are part of normal aging or a condition that needs to be corrected to improve the functioning of organs and systems. An important mechanism of aging starts is a change in hormonal activity of endocrine glands, in particular in hormonal activity of thyroid. Frequency of hypothyroidism in advanced age explains relevance of the chosen topic. The aim of the review was to find out the role hypothyroidism in aging. The main task was to define, whether thyroid hormones decrease in older age was a protective factor or pathological process. A review of the literature over the past 10 years on subclinical treatment was carried out and we identified the most pressing issues associated with hypothyroidism and aging. We studied data on the relationship between hypothyroidism and major geriatric syndromes, with special attention paid to cognitive diseases and emotional disorders.

Association between gestational blood lipids and TSH levels and pregnancy outcome of patients with subclinical hypothyroidism

Objective

To investigate the association between gestational blood lipids and thyroid stimulating hormone (TSH) levels and pregnancy outcomes of patients with subclinical hypothyroidism (SCH).

Methods

In this retrospective observational study, we analyzed the clinical data of 82 patients (case group) with gestational SCH treated in our hospital from January 2021 to January 2022 at gestational weeks 25-33 and grouped them according to whether SCH was well controlled by treatment (case Group-A: well controlled, n=55; case Group-B: poorly controlled, n=27), and the clinical data of 41 pregnant women (control group) undergoing physical examination during the same period. After comparing the blood lipids and TSH levels of the three groups, we compared their adverse pregnancy outcomes to assess the possible correlations between blood lipids and TSH levels and pregnancy outcomes.

Results

The levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and TSH in the case Group-B were significantly higher than those in the case Group-A and the control group (P<0.05). Compared with case Group-B and the control group, the incidence of premature delivery, abortion and neonatal growth restriction was higher in case Group-A (P<0.05). Among 82 patients in the case group 42 presented adverse pregnancy outcomes. The levels of TC, TG, LDL-C and TSH in mothers and infants in the adverse outcome group were significantly higher than those in the favorable outcome group (P<0.05). Our Pearson analysis results showed that the levels of TC, TG and LDL-C were positively correlated with the TSH levels and the pregnancy outcomes, and that TSH was positively correlated with pregnancy outcomes (P<0.05).

Conclusion

The levels of TC, TG, LDL-C and TSH in patients with poorly controlled SCH were increased during pregnancy, and were associated with the pregnancy outcomes and positively correlated with each other.

Free thyroxine but not TSH levels are associated with decline in functional status in a cohort of geriatric outpatients

PURPOSE

To assess the associations between TSH and free thyroxine (FT4) levels and decline in functional status in euthyroid older patients at risk of frailty.

DESIGN

Longitudinal prospective study.

METHODS

Participants from the geriatric outpatient clinic of a university hospital, who fulfilled the criteria for frailty or were at risk of frailty, were recruited. Only those euthyroid, defined by age-specific reference range of TSH, were included. Serum was collected during enrollment and at the third and sixth years of follow-up to assess the mean value of all follow-up levels of serum TSH and FT4. Functional status assessing activities of daily living (ADL) and instrumental ADL were evaluated using the Katz Index and the Health Assessment Questionnaire, respectively. Functional decline was defined by a positive variation in any of the applied scales in the absence of disagreement between the scales or if the patient was institutionalized.

RESULTS

Of the 273 participants (72.5% females) enrolled (mean age 80 years old), 48 died and 102 presented functional decline at the end of follow-up (mean 3.6 ± 1.7 years). Each 0.1 ng/dL increase in baseline and mean follow-up serum FT4 levels increased the risk of functional decline by 14.1% and 7.7%, respectively. The risk of functional decline was 9 times greater with baseline FT4 levels in the fourth and fifth quintiles (p = 0.049) and 50% lower with baseline FT4 levels in the first quintile (p = 0.046). No association between TSH and the outcome was found.

CONCLUSIONS

Higher and lower FT4 levels were, respectively, a risk and a protective factor for the decline in functional status in a cohort of euthyroid older adults at risk of frailty.