Age-specific serum thyrotropin reference range for the diagnosis of subclinical hypothyroidism and its association with lipid profiles in the elderly population

Lipoprotein alterations in endocrine disorders - a review of the recent developments in the field

Dyslipidemia is one of the most common disorders worldwide, which, if left untreated, results in a multitude of complications. Thus proper diagnostics, which includes identifying of secondary causes of dyslipidemia is crucial. Endocrine disorders are an important cause of secondary dyslipidemia. This paper aims to review the publications on lipoprotein alterations in endocrine disorders from the past two years and provide an overview of the recent discoveries in this dynamically developing and large field. Significant changes in lipoprotein serum concentrations are present in most endocrinological diseases and can be modified with proper treatment. Some lipoproteins have also been proposed as markers in some endocrine diseases, e.g., thyroid carcinoma. From the scope of endocrine disorders, the largest number of studies explored the lipoprotein changes in polycystic ovary syndrome and in women during the menopausal and peri-menopausal period. Even though the association of thyroid disorders with dyslipidemia is already well studied, new research has delivered some exciting findings about lipoprotein alterations in euthyroid patients with either positive antithyroid peroxidase antibodies or reduced sensitivity to thyroid hormones. The problem of the adverse metabolic profile, including dyslipidemia in hypoprolactinemia has been recognized. Moreover, this review describes other significant discoveries encompassing lipoprotein alterations in disorders of the adrenals, thyroid, parathyroid glands, pituitary, and gonads. The up-to-date knowledge of the influence of endocrine disorders and hormonal changes on serum lipoproteins is prudent as it can significantly impact therapeutic decisions.

Correlation of subclinical hypothyroidism with sarcopenia and its components in the Chinese older adults

OBJECTIVE

To identify the correlation of thyroid function and subclinical hypothyroidism (SCH) with sarcopenia and its components in the older Chinese adults.

METHODS

Older adults were recruited and divided into SCH group and non-SCH group. Free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured by electrochemiluminescence. Appendicular skeletal muscle mass (ASM) was measured, and skeletal muscle index (SMI) was further calculated. Grip strength was measured. Physical performance was graded by the Short Physical Performance Battery (SPPB) scores of the gait speed test, chair stand test and balance test.

RESULTS

Of the 240 older adults included, 48 (20.00%) presented with SCH. The prevalence of sarcopenia in SCH group was higher than that in non-SCH group (33.33% v.s. 18.75%). Grip strength was significantly lower in patients with SCH than those without sarcopenia. In terms of physical performance, 6-meter gait speed and SPPB score were lower in subjects with SCH than those without SCH, while 5 sit-to-stand movements was longer score in subjects with SCH than those without SCH. SCH was significantly correlated with sarcopenia, while FT3, FT4, and TSH levels were not. SCH was significantly correlated with low muscle strength and low muscle mass, but not with low physical performance. FT3 level was positively correlated with grip strength and SMI. TSH level was negatively correlated with grip strength, 6-meter gait speed, and SPPB score, but positively correlated with the time of 5 sit-to-stand movements.

CONCLUSION

SCH is a risk factor for sarcopenia in the older adults and correlated with low muscle strength and low muscle mass, but not with low physical performance. FT3, FT4 and TSH levels are associated with sarcopenia components, but not with sarcopenia.

Age-specific association between thyroid autoimmunity and hypothyroidism in Chinese adults aged over 65 years: a cross-sectional study

Background

The correlation between thyroid autoimmune (TAI) disease and hypothyroidism in the elderly of different ages remains unclear. This study aimed to investigate the epidemiological characteristics of hypothyroidism, including subclinical hypothyroidism (Shypo) and overt hypothyroidism (Ohypo) in those aged ≥65 years from iodine-adequate areas and reveal the correlation between TAI and hypothyroidism in the elderly of different ages.

Methods

It was a cross-sectional study involving 2,443 subjects aged ≥65 years from two iodine-adequate areas in China by cluster sampling. They were assigned to the 65-69-, 70-79-, and ≥80-year-old age group. All subjects were surveyed by questionnaires and received physical examinations, laboratory testing, and thyroid ultrasound. Epidemiological characteristics of thyroid diseases in the elderly were compared among the three groups. Risk factors for hypothyroidism were predicted by binary logistic regression analysis.

Results

The median urinary iodine level was 238.70 (197.00, 273.70) μg/L. Thyroid peroxidase antibody or thyroglobulin antibody positivity (11.87%) and Shypo (9.13%) were common in the elderly. The prevalence of hypothyroidism in the elderly increases with age. TAI was a risk factor for Shypo (OR, 1.94; 95% CI, 1.35, 2.80; p < 0.01) and Ohypo (OR, 7.64; 95% CI, 3.40, 17.19; p < 0.01) in elderly Chinese. There was an age-specific correlation between TAI and hypothyroidism in the elderly. However, a significant correlation was not identified between TAI and hypothyroidism in ≥80-year-old age group (p > 0.05).

Conclusion

Hypothyroidism, particularly Shypo, is common in the elderly from iodine-adequate areas in China. TAI serves as a risk factor for hypothyroidism in the elderly, with an age-specific correlation with hypothyroidism.