Thyroid function and perimenopausal lipid and weight changes: the Thyroid Study in Healthy Women (TSH-W).

We designed a prospective observational trial to study the relationship of thyroid function to cholesterol and weight changes at menopause. Subjects were participants in the ongoing Healthy Women Study, a prospective study of cardiovascular risk factor change through menopause. Healthy premenopausal women were recruited from a random sample of licensed drivers in selected ZIP codes of Allegheny County, Pennsylvania. Participants had to be 42-50 years of age, have menstruated within the last 3 months, not have had surgical menopause, have diastolic blood pressure < 100 mm Hg, and not be taking medications (including insulin, estrogen, lipid-lowering drugs, or thyroid or antihypertensive medications) at the baseline examination. The substudy included three groups of women who were premenopausal at baseline and were categorized according to change noted at follow-up regarding menopausal status and use of hormone replacement therapy (HRT). The groups comprised 95 women who remained premenopausal, 96 postmenopausal women not on HRT, and 61 postmenopausal women using HRT. The main outcome measures were baseline and follow-up measurements for serum levels of thyroid-stimulating hormone (TSH), thyroid peroxidase, and thyroglobulin, as well as serum cholesterol, total high-density lipoprotein (HDL) cholesterol, triglycerides, and calculated low-density lipoprotein (LDL) cholesterol, height, and weight. Covariates included cigarette smoking and alcohol intake. The prevalence of thyroid antibodies in this healthy population was high at both time points (range 27%-31%) and did not differ by menopausal status. The presence of thyroid antibodies was associated with increased TSH concentration. Women with antibodies at both time points had lower levels of total and LDL cholesterol compared with those with no antibodies, significant only for those women who remained premenopausal during the follow-up period. Thyroid function during menopause in this healthy population is unlikely to account for the observed changes in levels of serum lipoprotein and body weight. The presence of thyroid antibodies may be associated with lower total and LDL cholesterol, possibly through an underlying inflammatory disorder.

Urinary markers of estrogen metabolism 2- and 16 alpha-hydroxylation in premenopausal women.

There is considerable scientific interest in whether measurement of the major estrogen metabolites 2- and 16 alpha-hydroxyestrone will shed light on the role of estrogen in the risk of breast cancer. These have been difficult to measure in large numbers because of the need for radiolabeled tracers, but a new assay is able to utilize spot urine samples. The main objective of this study was to assess the reliability of a newly developed enzyme immunoassay (EIA) for the measurement of 2- and 16 alpha-hydroxyestrone in urine samples collected from a large group of healthy premenopausal women enrolled in a clinical trial A secondary objective was to assess the impact of several factors such as body weight on the urinary estrogen metabolite ratios. The study cohort included 174 women aged 44-50, who were enrolled in the Cardiovascular Risk Factors and Menopause Trial, also referred to as the Women's Healthy Lifestyle Project (WHLP), an ongoing 5-year clinical trial of 535 premenopausal women randomized either to an intensive dietary life-style intervention group or to an assessment-only control group. Measurements of 2- and 16 alpha-hydroxyestrone showed a high intraclass correlation for blind duplicate urine samples (R = 0.94 and R = 0.80), cross-sectionally and over time (R = 0.79 and R = 0.62), in this population of healthy premenopausal women. The intervention diet (of 25% of total calories from fat) did not appear to influence the estrogen metabolite ratio. This new estrogen metabolite EIA demonstrates good reliability and thus may be appropriate for use in large epidemiologic studies of estrogen-related diseases. There was no relation between dietary fat reduction, weight loss, and increased exercise and change in the ratio among premenopausal women in this study.

Effects of fluoridated drinking water on bone mass and fractures: the study of osteoporotic fractures.

To determine if optimal fluoridation of public water supplies influences bone mass and fractures, we studied 2076 non-black women, all aged > or = 65 years recruited into the Study of Osteoporotic Fractures at the Pittsburgh clinic. Information on fluoride exposure was limited to community water supplies. The variable used in the analysis was years of exposure to fluoridated water in community drinking water supplies. Bone mineral density (BMD) was measured at the spine and hip using dual energy X-ray absorptiometry and at the midpoint and ultradistal radius and calcaneus using single photon absorptiometry. Prevalent and incident vertebral fractures were determined by morphometry. Incident nonspine fractures were ascertained every 4 months and confirmed by radiographic report. Exposure to residential fluoridated water had no effect on bone mass. Women exposed to fluoride for > 20 years had similar axial and appendicular bone mass to women not exposed or women exposed for < or = 20 years. There was some suggestion that women exposed to fluoride for > 20 years had a lower relative risk of nonspine fractures (relative risk, RR, = 0.73; 95% confidence interval [CI] 0.48-1.12), osteoporotic fractures, RR = 0.74 (CI 0.46-1.19), and hip fractures, RR = 0.44 (CI 0.10-1.86), compared with women not exposed, but none of these relative risks was statistically significant. There was no association with wrist or spinal fractures. Our results do not support the findings from recent ecological studies which showed an increased risk of hip fracture among individuals exposed to fluoridated public water.

Prevalence of thyroid antibodies among healthy middle-aged women. Findings from the thyroid study in healthy women.

Autoimmune thyroiditis is the most common cause of subclinical hypothyroidism in North America, is more common in women than men, and is a risk factor for the development of coronary heart disease (CHD). We measured thyroid-stimulating hormone (TSH) and two thyroid antibodies, thyroid peroxidase and thyroglobulin, in stored sera of the participants (aged 44 to 54 years) of the Healthy Women Study. We selected 254 samples from the premenopausal baseline examination in 1983 to 1985 and from a follow-up examination that occurred an average of 5.7 years later (range, 3 to 7.7 years). At follow-up, 95 women remained premenopausal, 98 had ceased menstruating for at least 12 months, and 61 were taking postmenopausal hormone therapy. Overall, the prevalence of the thyroid antibodies in this healthy population was high at both time points (21 to 26%). Women with antibodies had higher TSH concentrations than did those with no antibodies (2.68 +/- 1.3 versus 1.51 +/- .73 mU/L, P < 0.001); this relationship was statistically significant even after excluding those with subclinical hypothyroidism (TSH > 6.0 mU/L). TSH and antibody levels did not differ by menopausal status or hormone therapy use at follow-up. Given the high prevalence of thyroid antibodies among healthy middle-aged women, long-term follow-up is warranted to ascertain whether the presence of antibodies is associated with subsequent excess risk of disease, in particular, CHD.