The incidence of hypothyroidism among dyslipidemic hypertensive minority patients in an inner-city clinic

Among studied white populations, 6-13% with hypercholesterolemia are hypothyroid. However, the relationship between thyroid dysfunction and hypercholesterolemia in non-whites has not been well documented. African Americans (AA) have a lower prevalence of hypothyroidism than whites, but are also less likely to be screened for thyroid disorders. We examined the incidence of hypothyroidism, employing an ultrasensitive thyroid-stimulating hormone (TSH) assay, among 160 hypertensive patients with a fasting total cholesterol level ≥ 200 mg/dl. Patients with diabetes mellitus or any history of thyroid disorders were excluded. The percentages of patients in each group with elevated (> 5.0 mU/L) and depressed (< 0.32 mU/L) TSH levels are shown below. Group N Age, years Females:males % up double arrow sign TSH % down double arrow sign TSH AA 131 55.5± 8.4* 103:28 0.8*** 7.6 Latino 29 52.0 ± 10.7 21:8 10.3 3.4 Group Total Cholesterol LDL-C HDL-C Triglyercides AA 242.3 ± 33.6 163.9 ± 37.0 55.5 ± 19.2** 124.8 ± 69.1 Latino 241.0 ± 29.3 161.5 ± 28.5 47.3 ± 11.0 163.0 ± 61.7*** All lipid values are in mg/dl. Lipid values and age are presented as mean values with one standard deviation. * P <0.05; ** P < 0.01, *** P < 0.005. The demographic features of our population are those typically associated with hypothyroidism-mean age in the fifth decade, hypertensive, and predominately female. The Latino patients had an incidence rate of hypothyroidism that was comparable to those of previously studied white individuals with hypercholesterolemia. However, in contradistinction, our AA patients displayed an extremely low incidence of hypothyroidism-only one-twelfth of that of the Latino group. It appears that there are ethnic differences in the incidence of hypothyroidism when hypercholesterolemia is used as the screening parameter.