BACKGROUND: Overt hypothyroidism has been found to be associated with
cardiovascular disease. Whether subclinical hypothyroidism and thyroid
autoimmunity are also risk factors for cardiovascular disease is
controversial. OBJECTIVE: To investigate whether subclinical
hypothyroidism and thyroid autoimmunity are associated with aortic
atherosclerosis and myocardial infarction in postmenopausal women. DESIGN:
Population-based cross-sectional study. SETTING: A district of Rotterdam,
The Netherlands. PARTICIPANTS: Random sample of 1149 women (mean age +/-
SD, 69.0 +/- 7.5 years) participating in the Rotterdam Study.
MEASUREMENTS: Data on thyroid status, aortic atherosclerosis, and history
of myocardial infarction were obtained at baseline. Subclinical
hypothyroidism was defined as an elevated thyroid-stimulating hormone
level (>4.0 mU/L) and a normal serum free thyroxine level (11 to 25 pmol/L
[0.9 to 1.9 ng/dL]). In tests for antibodies to thyroid peroxidase, a
serum level greater than 10 IU/mL was considered a positive result.
RESULTS: Subclinical hypothyroidism was present in 10.8% of participants
and was associated with a greater age-adjusted prevalence of aortic
atherosclerosis (odds ratio, 1.7 [95% CI, 1.1 to 2.6]) and myocardial
infarction (odds ratio, 2.3 [CI, 1.3 to 4.0]). Additional adjustment for
body mass index, total and high-density lipoprotein cholesterol level,
blood pressure, and smoking status, as well as exclusion of women who took
beta-blockers, did not affect these estimates. Associations were slightly
stronger in women who had subclinical hypothyroidism and antibodies to
thyroid peroxidase (odds ratio for aortic atherosclerosis, 1.9 [CI, 1.1 to
3.6]; odds ratio for myocardial infarction, 3.1 [CI, 1.5 to 6.3]). No
association was found between thyroid autoimmunity itself an
