Objective. Observational studies show the correlation between thyroid dysfunction and risk of venous thromboembolism. However, the causal effects remain uncertain. Our study was conducted to evaluate whether thyroid function and dysfunction were causally linked to the risk of venous thromboembolism. Methods. Publicly available summary data of thyrotropin (TSH) and free thyroxine (FT4), hypothyroidism, and hyperthyroidism were obtained from the ThyroidOmics Consortium and the UK Biobank. With single nucleotide polymorphisms (SNPs) as instrumental variables, the casual effects of genetically predicted TSH and FT4 and hypo- and hyperthyroidism on venous thromboembolism outcome were estimated through Mendelian randomization analysis methods (inverse variance weighted (IVW), MR-Egger, weighted median, simple mode, and weighted mode). Cochran’s Q test was performed to evaluate the heterogeneity and horizontal pleiotropy. Results. Our study selected 15 FT4-, 36 TSH-, 3 hyperthyroidism-, and 79 hypothyroidism-associated SNPs as instrumental variables. The IVW analysis results showed that the odds ratio of venous thromboembolism for hyperthyroidism was 1.124 (95% confidence interval: 1.019-1.240; p = 0.019 ), demonstrating the casual effect of hyperthyroidism not FT4, TSH, and hypothyroidism on venous thromboembolism. No heterogeneity or horizontal pleiotropy was observed according to Cochran’s Q test. Conclusion. Our Mendelian randomization analysis supports the causal effect of hypothyroidism on risk of venous thromboembolism. There is no evidence that genetically predicted TSH, FT4, and hypothyroidism have casual effects on venous thromboembolism. Future studies should be conducted to elucidate the underlying pathophysiological mechanisms.

Purpose To investigate the changes of cough sensitivity in patients with metabolic syndrome and its possible mechanisms. Method A total of 29 metabolic syndrome (MetS) patients with OSAHS (group-1), 22 MetS patients without OSAHS (group-2), and 25 healthy controls (group-3) were included. All participants underwent a routine physical examination and completed the gastroesophageal reflux disease questionnaire (GerdQ), and the inflammatory mediator profile were determined. The cough threshold for capsaicin, induced sputum cell count and cell classification, and inflammatory mediators in induced sputum supernatants were compared. The correlation between capsaicin cough sensitivity and various indicators in the MetS population was analyzed. Results The minimum concentration of inhaled capsaicin needed to induce ≥ 5 coughs (C5) was significantly different among three groups (H = 14.393, P = 0.001) and lower for group-1 and group-2 than it for group-3 (P = 0.002, P = 0.005). The percentage of neutrophils in induced sputum and the concentrations of calcitonin gene-related peptide (CGRP), substance P (SP), and interleukin 8 (IL-8) in the sputum supernatant of group-1 and group-2 were significantly higher than those of group-3. Besides, the pepsin concentrations were significantly different among the 3 groups (F = 129.362, P < 0.001), which significantly was highest in group-1 (P < 0.001) and lowest in group-3 (P < 0.001). Triglycerides, AHI, pepsin concentration and BMI were risk factors of increased capsaicin cough sensitivity. Conclusion Increased capsaicin cough sensitivity in MetS patients is closely related to sleep apnea and gastroesophageal reflux. For patients in MetS patients without OSAHS, gastroesophageal reflux is an important factor for increased capsaicin cough sensitivity. Airway inflammation, especially airway neurogenic inflammation, may also play a role in the pathogenesis of increased capsaicin cough sensitivity. Trial registration The protocol was registered in the Chinese Clinical Trials Register (http://www.chictr.org.cn/) (ChiCTR1800014768). Written informed consent was obtained from all participants before enrollment.

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