BACKGROUND: The association between sex hormone-binding globulin (SHBG) and renal function has rarely been reported in men. We aimed to investigate the above association in a community-based Chinese population. METHODS: A total of 5027 men were included from the survey on prevalence for metabolic diseases and risk factors, which is a population-based study conducted from 2014 to 2016 in Eastern China. The estimated glomerular filtration rate (eGFR) was calculated according to the chronic kidney disease Epidemiology Collaboration equation. Low eGFR was defined as eGFR <60 mL·min -1 ·1.73 m -2 . RESULTS: After adjusting for age, smoking, metabolic factors, and testosterone, through increasing quartiles of SHBG, a significantly positive association between SHBG quartiles and eGFR was detected in men (Q1 vs. Q4, β -2.53, 95% confidence interval -3.89, -1.17, Ptrend < 0.001). Compared with the highest quartile of SHBG, SHBG in the lowest quartile was associated with 96% higher odds of low eGFR (odds ratio 1.96, 95% confidence interval 1.10, 3.48) in the model after full adjustment. According to the stratified analyses, the associations between a 1-standard deviation increase in serum SHBG and the prevalence of low eGFR were significant in men aged ≥60 years old, waist circumference <90 cm, diabetes (no), hypertension (yes), dyslipidemia (no), and nonalcoholic fatty liver disease (no). CONCLUSIONS Lower serum SHBG levels were significantly associated with lower eGFR and a higher prevalence of low eGFR in Chinese men independent of demographics, lifestyle, metabolic-related risk factors, and testosterone. Large prospective cohort and basic mechanistic studies are warranted in the future.
Humans ; Male ; Middle Aged ; China/epidemiology* ; Kidney/metabolism* ; Prospective Studies ; Sex Hormone-Binding Globulin/physiology* ; Testosterone ; Tomography, Emission-Computed, Single-Photon ; Glomerular Filtration Rate

With the generalized use of highly sensitive thyroid stimulating hormone (TSH) and free thyroid hormone assays, most thyroid function tests (TFTs) are straightforward to interpret and confirm the clinical impressions of thyroid diseases. However, in some patients, TFT results can be perplexing because the clinical picture is not compatible with the tests or because TSH and free T4 are discordant with each other. Optimizing the interpretation of TFTs requires a complete knowledge of thyroid hormone homeostasis, an understanding of the range of tests available to the clinician, and the ability to interpret biochemical abnormalities in the context of the patient's clinical thyroid status. The common etiologic factors causing puzzling TFT results include intercurrent illness (sick euthyroid syndrome), drugs, alteration in normal physiology (pregnancy), hypothalamic-pituitary diseases, rare genetic disorders, and assay interference. Sick euthyroid syndrome is the most common cause of TFT abnormalities encountered in the hospital. In hypothalamic-pituitary diseases, TSH levels are unreliable. Therefore, it is not uncommon to see marginally high TSH levels in central hypothyroidism. Drugs may be the culprit of TFT abnormalities through various mechanisms. Patients with inappropriate TSH levels need a differential diagnosis between TSH-secreting pituitary adenoma and resistance to thyroid hormone. Sellar magnetic resonance imaging, serum α-subunit levels, serum sex hormone-binding globulin levels, a thyrotropin-releasing hormone stimulation test, trial of somatostatin analogues, and TR-β sequencing are helpful for the diagnosis, but it may be challenging. TFTs should be interpreted based on the clinical context of the patient, not just the numbers and reference ranges of the tests, to avoid various pitfalls of TFTs and unnecessary costly evaluations and therapies.
Diagnosis ; Diagnosis, Differential ; Diagnostic Errors ; Euthyroid Sick Syndromes ; Homeostasis ; Humans ; Hyperthyroidism ; Hypothyroidism ; Magnetic Resonance Imaging ; Physiology ; Pituitary Neoplasms ; Rare Diseases ; Reference Values ; Sex Hormone-Binding Globulin ; Somatostatin ; Thyroid Diseases ; Thyroid Function Tests ; Thyroid Gland ; Thyrotropin ; Thyrotropin-Releasing Hormone