In a 2010 clinical abstract posted to PubMed and originally published in the Expert Review of Cardiovascular Therapy, researchers concluded that hypothyroidism should be recognized as a cause of secondary hypertension. This acknowledgement was based on a prior 2007 study in which 100 individuals who were recently diagnosed for hypothyroidism and who had never been treated before with antihypertensive treatment or received drugs for hypothyroidism demonstrated elevated blood pressure values.
All participants underwent around-the-clock “ambulatory” blood pressure monitoring, meaning that blood pressure was monitored at all levels of activity throughout a 24-hour day. The control group consisted of 100 healthy volunteers matched to hypothyroid patients of the same gender and age. Clinical systolic and diastolic blood pressures were significantly higher in patients with hypothyroidism compared to the blood pressure of volunteers.
Based on the findings, the researchers were able to conclude that hypothyroidism may be an important predictor of cardiovascular target organ damage. Specifically, elevated blood pressure values include a higher mean 24-h systolic blood pressure, 24-h pulse pressure, and 24-h systolic blood pressure variability. Lastly, serum cholesterol tended to be marginally higher in patients with hypothyroidism compared with volunteers, while fasting serum triglycerides were significantly higher.
Lipid abnormalities, or dyslipidemia, are common findings in patients with thyroid disease. This is explained by the effects of thyroid hormones in nearly all steps of lipid metabolism. For instance, total and LDL cholesterol (less often HDL cholesterol), triglycerides, lipoprotein (a), apolipoprotein A1, and apolipoprotein B can each be affected. Many of my patients have been asked by their doctors to do extensive testing for cardiovascular disease, and are often told to begin taking statins (and blood pressure medications) based on the results. But, as the research would indicate, thyroid is a critical component.
Thyroid hormones regulate the expression of enzymes involved in all steps of lipid metabolism. Lipoproteins themselves prevent infections, protect against toxins and inflammation. The most common underlying reasons for dyslipidemia are chronic inflammation, immune dysfunction, and oxidative stress of the vascular system. The underlying lesson is that lipid abnormalities coexist with other metabolic abnormalities, including, hypertension, insulin resistance, and oxidative stress, all of them being risk factors for cardiovascular disease. And, as is probably already evident to thyroid sufferers, the same root causes (chronic infections, accumulation of toxins such as heavy metals, POPs, etc, and chronic inflammatory reactions to foods) will cause negative vascular response.