Gender and Age Impact on the Association Between Thyroid-Stimulating Hormone and Serum Lipids

The relationship between thyroid-stimulating hormone (TSH) and hyperlipidemia is still a topic of debate. We aimed to explore the impact of gender and age on the association between serum TSH and lipid profile in a large cohort of Chinese. This cross-sectional study enrolled 13,915 participants (8565 male, 5350 female), who self-reported as healthy without any known previous diseases. Clinical data including anthropometric measurements, thyroid function, and other serum parameters were collected. The associations between TSH and hyperlipidemia of males and females were analyzed separately after dividing TSH and age into subgroups. Odds ratio for hyperlipidemia was calculated by binary logistic regression models. Young males had significantly higher prevalence of hypercholesterolemia, hypertriglyceridemia, and high serum low-density lipoprotein-cholesterol than females, yet after menopause, females had higher prevalence than males. TSH was positively associated with hyperlipidemia independent of thyroid hormones. Males showed more reduced risks of hyperlipidemia in low TSH concentrations, while females demonstrated more enhanced risks of hyperlipidemia in high TSH concentrations. For instance, if TSH was lower than 0.3 μIU/mL, the risks of developing hypercholesterolemia and hypertriglyceridemia in males were only 0.198 (P < 0.01) and 0.425 (P < 0.05) of the reference TSH risks (between 2.0 and 3.0 μIU/mL), while in females the risks were 0.553 (P < 0.05) and 0.642 (P > 0.05), respectively. If TSH was higher than 4.0 μIU/mL, women displayed significantly higher risks of developing hypertriglyceridemia than the reference TSH risks (P < 0.05), yet, men did not demonstrate such significances. Our results showed thyroid hormone independent positive associations between serum TSH and lipids, which were substantially influenced by gender and age. Males demonstrated more protective effects of low TSH against hyperlipidemia, while females showed more detrimental effects of high TSH on hyperlipidemia.