Thyroid disorders in older adults

Impaired Sensitivity to Thyroid Hormones Is Associated With Decreased Vitamin D Levels in the Euthyroid Population

CONTEXT

The relationship between vitamin D and thyroid profiles lacks consensus despite extensive investigations. Whether vitamin D levels correlate with thyroid hormone sensitivity remains largely unexplored.

OBJECTIVE

To explore the relationship between vitamin D levels and thyroid hormone sensitivity among euthyroid individuals.

METHODS

This study involved 6452 euthyroid participants. Clinical parameters, including TSH, free thyroxine, 25-hydroxyvitamin D [25(OH)D], and other relevant indicators were extracted from the National Health and Nutrition Examination Survey 2007-2012. To quantify thyroid hormone sensitivity, we calculated the Thyroid Feedback Quantile-based Index (TFQI), the TSH index (TSHI), and the thyrotropin thyroxine resistance index (TT4RI).

RESULTS

Subjects with impaired thyroid hormone sensitivity have decreased 25(OH)D levels (TFQI, TT4RI: P < 0.05; TSHI: P = .05574) following adjustment of confounding variables. Age-specific analysis found negative correlations between thyroid hormone sensitivity indices and 25(OH)D within the 20 to 60 years subgroup, turning positive in the 60 to 80 years subgroup. In females, thyroid hormone sensitivity indices and vitamin D levels were negatively linked, while in males, vitamin D's relationships with TFQI, TT4RI, and TSHI shifted from negative to positive when 25(OH)D levels exceeded 63.5 nmol/L, 56.7 nmol/L, and 56.7 nmol/L, respectively. Stratification by race revealed U-shaped curvilinear patterns resembling those found in the males. In body mass index (BMI) subanalysis, vitamin D had differing associations with thyroid hormone sensitivity indices: negative in the <25 kg/m2 and ≥30 kg/m2 subgroups and U-shaped in the 25-30 kg/m2 subgroup.

CONCLUSION

Impaired thyroid hormone sensitivity correlates with decreased vitamin D levels among euthyroid subjects, with associations varying by age, sex, race, and BMI.

Mechanistic advances in osteoporosis and anti-osteoporosis therapies

Osteoporosis is a type of bone loss disease characterized by a reduction in bone mass and microarchitectural deterioration of bone tissue. With the intensification of global aging, this disease is now regarded as one of the major public health problems that often leads to unbearable pain, risk of bone fractures, and even death, causing an enormous burden at both the human and socioeconomic layers. Classic anti-osteoporosis pharmacological options include anti-resorptive and anabolic agents, whose ability to improve bone mineral density and resist bone fracture is being gradually confirmed. However, long-term or high-frequency use of these drugs may bring some side effects and adverse reactions. Therefore, an increasing number of studies are devoted to finding new pathogenesis or potential therapeutic targets of osteoporosis, and it is of great importance to comprehensively recognize osteoporosis and develop viable and efficient therapeutic approaches. In this study, we systematically reviewed literatures and clinical evidences to both mechanistically and clinically demonstrate the state-of-art advances in osteoporosis. This work will endow readers with the mechanistical advances and clinical knowledge of osteoporosis and furthermore present the most updated anti-osteoporosis therapies.

Association Between Thyroid Dysfunction and Incident Dementia in the Atherosclerosis Risk in Communities Neurocognitive Study

BACKGROUND

Abnormal thyroid hormone levels (high or low) and autoimmunity from autoimmune thyroid disease (AITD) may increase dementia risk.

METHODS

We examined the associations of thyroid dysfunction or possible AITD in 1990 - 1992 with dementia through 2017 in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. Thyroid dysfunction (subclinical and overt hypo- or hyperthyroidism and euthyroidism) was categorized from serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) cut-points and AITD from anti-thyroid peroxidase (anti-TPO) antibody positivity. Dementia was identified primarily based on cognitive test performance, neuropsychological examinations and clinician review of suspected cases. Additional cases of dementia were ascertained through telephone interviews or relevant hospital and death certificate codes. Cox regression with multivariable adjustment was used for analysis.

RESULTS

After exclusions for missing data, 12,481 participants were included in the analysis (mean index exam age 57 ± 5.7 (44% male, 25% black)), and 2,235 incident dementia cases were identified. AITD was not significantly associated with dementia. Subclinical hypothyroidism was associated with a lower risk of dementia (hazard ratio (HR) (95% confidence interval (CI)): 0.74 (0.60 - 0.92)), while overt hyperthyroidism was associated with a higher risk of dementia (HR (95% CI): 1.40 (1.02 - 1.92)) compared to euthyroid participants. Participants with serum FT4 concentrations above the 95th percentile were at an increased risk of dementia compared to those in the middle 90% of FT4 (HR (95% CI): 1.23 (1.02 - 1.48)).

CONCLUSIONS

Subclinical hypothyroidism was associated with reduced risk of dementia, whereas overt hyperthyroidism, particularly very elevated FT4, was associated with increased risk of dementia. The association between subclinical hypothyroidism and reduced risk of dementia cannot be explained, but may have been an artifact due to change. By extrapolation, effective treatment of overt hyperthyroidism may modestly reduce dementia risk in older adults.

Sex Differences in the Associations of Obesity With Hypothyroidism and Thyroid Autoimmunity Among Chinese Adults

There is an intensive link between obesity and thyroid dysfunction, but this relationship in Asians is still unclear. This study was conducted to define the impact of obesity on risk of hypothyroidism and thyroid autoimmunity among Chinese adults. A population-based, cross-sectional study was carried out, which enrolled a total of 2,808 Chinese adults. To assess the associations of obesity with hypothyroidism and thyroid autoimmunity, odds ratio (ORs) with 95% confidence intervals (95%CIs) were calculated through logistic regression model, and the correlations of body mass index (BMI) with TPOAb and TGAb were also analyzed. Obese females had higher risk of hypothyroidism (22.7 vs. 15.0%; OR = 1.66, 95%CI 1.10–2.53; P = 0.02) and higher risk of subclinical hypothyroidism (22.1 vs. 13.4%; OR = 1.83, 95%CI 1.20–2.80; P = 0.005) than non-obese females. Multivariate logistic regression analysis found significant associations of obesity with hypothyroidism (Adjusted OR = 1.54, 95%CI 1.00–2.38; P = 0.05) and subclinical hypothyroidism (Adjusted OR = 1.69, 95%CI 1.09–2.63; P = 0.02) in females after adjustment for confounding factors. No association between obesity and hypothyroidism was observed in male participants. Spearman's correlation analysis suggested BMI was significantly and positively correlated with TPOAb (Spearman's r = 0.062, P = 0.022) in men but not in women. Linear regression analysis suggested an obviously positive correlation of BMI with TPOAb in men (β = 0.018, P = 0.015) and an obviously negative correlation of BMI with TGAb in women (β = −0.025, P = 0.012), respectively. The study suggests sex differences in the associations of obesity with hypothyroidism and thyroid autoimmunity among Chinese adults. Further studies are needed to better understand the exact mechanism of sex difference in the obesity-thyroid relationship.

Mid- and Deep-Zone Gastritis: A Histologic Pattern Associated With Autoimmune Disease but Distinct From Autoimmune Atrophic Gastritis

OBJECTIVES

We sought to characterize a histologic pattern of mid- and deep-zone gastritis, distinct from the typical pattern of Helicobacter pylori or autoimmune gastritis and to see if it had any clinicopathologic association(s).

METHODS

We analyzed inflammatory patterns and composition, excluded autoimmune gastritis using immunohistochemistry, and reviewed the medical record for demographics, medical/surgical history, presenting symptoms, endoscopic findings, and medications for 28 cases.

RESULTS

All cases had inflammation in the middle and/or deep mucosal zones with sparing of the superficial/pit compartment. Subfeatures included corpus or antral predominance, pangastric involvement, prominence of a subset(s) of inflammatory cells, and degree of epithelial injury. Of 28 patients, 13 had autoimmune disease(s), autoantibodies, or both. There was no other unifying clinical feature.

CONCLUSIONS

This unique pattern of gastritis should be distinguished from other entities such as H pylori and autoimmune gastritis. At least a subset may be an autoimmune condition different from classic autoimmune gastritis.

Treated hypothyroidism is associated with cerebrovascular disease but not Alzheimer's disease pathology in older adults

Thyroid hormone disease is common among older adults and is associated with cognitive impairment. However, pathologic correlates are not well understood. We studied pathologic and clinical factors associated with hypothyroidism, the most common manifestation of thyroid disease, in research subjects seen annually for clinical evaluations at U.S. Alzheimer's Disease Centers. Thyroid disease and treatment status were assessed during clinician interviews. Among autopsied subjects, there were 555 participants with treated hypothyroidism and 2146 without known thyroid disease; hypothyroidism was associated with severe atherosclerosis (odds ratio: 1.35; 95% confidence interval: 1.02, 1.79) but not Alzheimer's disease pathologies (amyloid plaques or neurofibrillary tangles). Among participants who did not undergo autopsy (4598 with treated hypothyroidism and 20,945 without known thyroid hormone disease), hypercholesterolemia and cerebrovascular disease (stroke and/or transient ischemic attack) were associated with hypothyroidism, complementing findings in the smaller autopsy sample. This is the first large-scale evaluation of neuropathologic concomitants of hypothyroidism in aged individuals. Clinical hypothyroidism was prevalent (>20% of individuals studied) and was associated with cerebrovascular disease but not Alzheimer's disease-type neuropathology.

Effect of Metformin on Hypothalamic-Pituitary-Thyroid Axis Activity in Elderly Antipsychotic-Treated Women With Type 2 Diabetes and Subclinical Hypothyroidism: A Preliminary Study

Metformin was found to reduce elevated serum thyrotropin levels, and this effect was partially determined by endogenous dopaminergic tone. The aim of this study was to compare the effect of metformin treatment on hypothalamic-pituitary-thyroid axis activity in elderly women with subclinical hypothyroidism treated with antipsychotic agents and not receiving this drug. The study population consisted of 34 elderly women with subclinical hypothyroidism, 16 of whom received antipsychotic drugs. Because of coexistent type 2 diabetes, these women were treated with metformin (2.55-3 g daily). Glucose homeostasis markers as well as serum levels of thyrotropin, free thyroid hormones and prolactin were measured at the beginning of the study and 6 months later. Thirty women completed the study. With the exception of prolactin, baseline serum levels of the assessed hormones were comparable in both study groups. Although metformin reduced serum thyrotropin levels in both groups, this effect was more pronounced in the antipsychotic-treated than in the antipsychotic-naive patients. The effect on serum prolactin was observed only in antipsychotic-treated patients. The impact on serum thyrotropin levels correlated with improvement in insulin sensitivity and with a reduction in prolactin levels. Free thyroxine and free triiodothyronine remained at a similar level throughout the study. The obtained results indicate that metformin reduces serum thyrotropin levels in elderly women, and this effect is particularly pronounced in women with diminished dopaminergic transmission.

Melatonin alleviates hyperthyroidism induced oxidative stress and neuronal cell death in hippocampus of aged female golden hamster, Mesocricetus auratus

Oxidative stress is a well known phenomenon under hyperthyroid condition that induces various physiological and neural problems with a higher prevalence in females. We, therefore investigated the antioxidant potential of melatonin (Mel) on hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain (cognition and memory centre) of aged female golden hamster, Mesocricetus auratus. Aged female hamsters were randomly divided into four experimental groups (n=7); group-I: control, group-II: Melatonin (5mgkg(-1)day(-1), i.p., for one week), group-III: Hyperthyroid (100μg kg(-1)day(-1), i.p., for two weeks) and group-IV- Hyper+Mel. Hormonal profiles (thyroid and melatonin), activity of antioxidant enzymes (SOD, CAT and GPX), lipid peroxidation level (TBARS) and the specific apoptotic markers (Bax/Bcl-2 ratio and Caspase-3) expression were evaluated. A significant increase in the profile of total thyroid hormone (tT3 and tT4) in hyperthyroidic group as compared to control while tT3 significantly decreased in melatonin treated hyperthyroidic group. However, Mel level significantly decreased in hyperthyroidic group but increased in melatonin treated hyperthyroidic group. Further, the number of immune-positive cells for thyroid hormone receptor-alpha (TR-α) decreased in the hippocampus of hyperthyroidic group and increased in melatonin treated hyperthyroidic group. Profiles of antioxidant enzymes showed a significant decrease in hyperthyroidic group with a simultaneous increase in lipid peroxidation (TBARS). Melatonin treatment to hyperthyroidic group lead to decreased TBARS level with a concomitant increase in antioxidant enzyme activity. Moreover, increased expression of Bax/Bcl-2 ratio and Caspase-3, in hyperthyroidic group had elevated neuronal cell death in hippocampal area and melatonin treatment reduced its expression in hyperthyroidic group. Our findings thus indicate that melatonin reduced the hyperthyroidism-induced oxidative stress and neuronal cell death in the hippocampus region of brain, suggesting a novel therapeutic approach of melatonin for management of cognition and memory function in females under hyperthyroid condition.

Ageing Is Associated with Decreases in Appetite and Energy Intake--A Meta-Analysis in Healthy Adults

It is not well recognized that in the elderly weight loss is more common than weight gain. The aim of this analysis was to determine the effect of ageing on appetite (hunger/fullness) and energy intake, after overnight fasting and in a postprandial state, by meta-analyses of trials that included at least two age groups (>18 years). We hypothesized that appetite and energy intake would be less in healthy older compared with younger adults. Following a PubMed-database systematic search up to 30 June 2015, 59 studies were included in the random-effects-model meta-analyses. Energy intake was 16%-20% lower in older (n = 3574/~70 years/~71 kg/~25 kg/m²) than younger (n = 4111/~26 years/~69 kg/~23 kg/m²) adults (standardized mean difference: -0.77 (95% confidence interval -0.90 to -0.64)). Hunger was 25% (after overnight fasting; weighted mean difference (WMD): -17 (-22 to -13) mm) to 39% (in a postprandial state; WMD: -14 (-19 to -9) mm) lower, and fullness 37% (after overnight fasting; WMD: 6 mm (95% CI: 1 to 11 mm)) greater in older than younger adults. In conclusion, appetite and energy intake are less in healthy older than younger adults, suggesting that ageing per se affects food intake.

Bone mineral density in geriatric patients with toxic nodular goiter

BACKGROUND AND AIMS

We aimed to assess bone mineral density (BMD) in geriatric patients with hyperthyroidism caused by TNG.

MATERIALS AND METHODS

Bone mineral density was measured at the lumbar spine and proximal femur, using dual-X-ray absorptiometry (DXA) in 90 patients with TNG (mean age; 69.2 ± 4.4 years) and compared with those in 42 age-matched healthy subjects (mean age; 68.40 ± 4.3 years). Serum levels of TSH, fT3, fT4, 25-OH vitamin D and PTH were measured.

RESULTS

BMD was significantly lower at total spine (0.904 ± 0.1 vs. 1.114 ± 0.1 g/cm(2)) and total hip (0.850 ± 0.1 vs. 1.079 ± 0.1 g/cm(2)) in male patients with TNG in comparison to the healthy men (p = 0.001, p < 0.001). Postmenopausal women with TNG had lower BMD measurements at total lumbar spine (0.754 ± 0.1 vs. 0.870 ± 0.2 g/cm(2), p < 0.001) and total hip (0.765 ± 0.1 vs. 0.831 ± 0.2 g/cm(2), p < 0.001) in comparison to the healthy women. T scores of total lumbar spine and hip were lower in patients with subclinical hyperthyroidism compared to the control group, respectively (-1.9 ± 1.7 vs -0.8 ± 1.8, p = 0.007; -1.09 ± 1.2 vs. -0.02 ± 1.6, p = 0.001). While serum levels of fT3 and fT4 revealed a negative correlation with T score of BMD measurements at the total spine and hip, TSH levels were positively correlated. We did not find a difference in serum calcium, phosphorus, 25-OH vitamin D and PTH levels between the two groups (p > 0.005).

CONCLUSION

Geriatric patients with hyperthyroidism secondary to TNG had reduced BMD at the total spine and hip. Thus, we suggest to investigate bone mineral density in geriatric patients with TNG.

Reversible morbidity markers in subclinical hypothyroidism

IMPORTANCE

Subclinical hypothyroidism (SCH) is a common clinical entity with a putative role in a wide range of disorders. The impact of SCH on mortality and markers of morbidity has been demonstrated, but studies have shown inconsistent results. Evidence regarding the effect of levothyroxine treatment on reversing morbidity markers is emerging, but the value of treatment is still unclear.

OBJECTIVE

The objectives of this review were to assess recent, high-quality studies evaluating the role of SCH in cardiovascular health, cognition, mood, pregnancy, anemia, and renal disease; to examine the effects of levothyroxine on reducing mortality or reversing markers of morbidity in these conditions; and to consider how new research insights may help guide clinical practice.

EVIDENCE REVIEW

A PubMed search was conducted (using 'subclinical hypothyroidism' [Title/Abstract] AND morbidity [MeSH Subheading] as search criteria) and was restricted to human studies published in the English language between 1990 and 2013. Subsequent searches of retrieved articles yielded further studies, which were included based on quality. Emphasis was given to large observational studies, well-conducted meta-analyses, and randomized controlled trials.

FINDINGS

The difficulty of diagnosing SCH, particularly in the elderly, may underlie many of the conflicting results seen in the literature. Increased understanding of the at-risk patient population will result in better selection of study subjects and, likely, unequivocal results. Regardless of the current confusion, emerging evidence suggests that certain markers of morbidity are reversed by levothyroxine therapy across the disorders examined here.

CONCLUSION AND RELEVANCE

Future large, well-controlled studies will not only clarify the role of SCH but also help identify patients for whom levothyroxine treatment will provide the most benefit.

Ethical issues in the management of thyroid disease

The focus of this article is on clinical ethics issues in the thyroid disease context. Clinical ethics is a subspecialty of bioethics that deals with bedside ethical dilemmas that specifically involve the provider-patient relationship. Such issues include consent and capacity; weighing therapeutic benefits against risks and side-effects; innovative therapies; end of life care; unintended versus intentional harms to patients or patient populations; and healthcare access. This article will review core ethical principles for practice, as well as the moral and legal requirements of informed consent. It will then discuss the range of unique and universal ethical issues and considerations that present in the management of autoimmune thyroid disease and thyroid cancer.

An update on subclinical hypothyroidism and subclinical hyperthyroidism

Subclinical thyroid dysfunction is characterized by normal levels of peripheral thyroid hormone, paired with a TSH level that is either lower than (subclinical hyperthyroidism) or higher than (subclinical hypothyroidism) the normal laboratory reference range. Slight shifts in peripheral hormone levels result in significant serum TSH changes. The exact upper limit of normal TSH and the management of subclinical hypothyroidism are still controversial. For those with TSH between high upper limit of normal and 10 mIU/L, the authors suggest selective use of thyroxine therapy. The authors agree with the general consensus in favor of therapy for those with serum TSH levels above 10 mIU/L. This recommendation is compatible with guidelines of American Thyroid Association and American Association of Clinical Endocrinologists. For subclinical hyperthyroidism persistent serum TSH <0.1 mIU/L should be treated particularly if the etiology is nodular toxic goiter. For serum TSH between 0.1 mIU/L and lower limit of normal, serum TSH co-morbidities such as cardiac risk factors and osteoporosis may favor therapy.