Association between thyroid-stimulating hormone and blood pressure in adults: an 11-year longitudinal study

BACKGROUND: The results of longitudinal studies on the association between thyroid function and blood pressure (BP) are divided. This study aimed to investigate this association in cross-sectional and longitudinal settings in a nationwide, random sample representative of the Finnish adult population aged 30 and over. METHODS: The study sample was randomly drawn from the population register. A total of 5655 participants were included in the baseline analyses and 3453 in the 11-year prospective analyses. The associations between baseline TSH and (i) BP and BP change over time; and (ii) prevalent and incident hypertension were assessed using linear and logistic models, adjusted for age, gender, smoking and body mass index. RESULTS: A positive association (β ± standard error) was observed between TSH and diastolic (0·36 ± 0·12, P = 0·003) but not systolic BP (0·16 ± 0·21, P = 0·45) at baseline. TSH was negatively associated with 11-year BP change in men (systolic: -0·92 ± 0·41, P = 0·03; diastolic: -0·66 ± 0·26, P = 0·01) but not in women (P ≥ 0·09 for systolic and diastolic BP change). Participants in the highest TSH tertile within the TSH reference interval (0·4-3·4 mU/L), as compared with the lowest, had increased odds of prevalent (odds ratio 1·22, 95% confidence interval 1·05-1·43, P = 0·01) but not incident hypertension (odds ratio 0·93, 95% confidence interval 0·73-1·19, P = 0·58). CONCLUSIONS: A modest association was found between increasing TSH and prevalent but not incident hypertension. TSH was inversely associated with BP change in men in our study. These findings contest an independent role of thyroid function at normal to near-normal levels in the pathogenesis of hypertension.</p

Association of thyroid-stimulating hormone with lipid concentrations: an 11-year longitudinal study

BACKGROUND:Scant data exist on the longitudinal association between thyroid function and lipid concentrations. We investigated associations of TSH and lipid concentrations cross-sectionally and longitudinally in a nationwide population sample.METHODS:A total of 5205 randomly sampled participants representative of Finns aged ≥30 years were examined in 2000-2001 and included in cross-sectional analyses. A total of 2486 were re-examined 11 years later and included in longitudinal analyses. With linear regression models adjusted for age, gender, smoking and body mass index, we assessed the associations of baseline TSH and TSH categories (low, reference range and high) with total, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol; apolipoprotein A1 and B; and triglycerides at baseline and follow-up.RESULTS:At baseline, higher TSH associated with higher total cholesterol (β = 0·025, standard error [SE] = 0·007, P < 0·001), LDL cholesterol (β = 0·020, SE = 0·007, P = 0·002), apolipoprotein B (β = 0·006, SE = 0·002, P < 0·001) and log triglycerides (β = 0·008, SE = 0·003, P = 0·004), but not with other lipid outcomes. Higher baseline TSH associated with higher total cholesterol (β = 0·056, SE = 0·026, P = 0·033), LDL cholesterol (β = 0·057, SE = 0·023, P = 0·015) and apolipoprotein B (β = 0·012, SE = 0·006, P = 0·028) at follow-up in women, but not with any lipid outcomes in men. Participants with high TSH at baseline had a 0·22 mmol/l (95% confidence interval 0·02-0·41 mmol/l) higher LDL cholesterol at follow-up (P = 0·028) than participants with TSH in the reference range (0·4-3·4 mU/l). However, exclusion of participants with high-risk baseline lipid values rendered these positive longitudinal associations nonsignificant (P ≥ 0·098).CONCLUSIONS:We could confirm a modest association between higher TSH and an adverse lipid profile cross-sectionally but not indisputably longitudinally.</p