Associations of testosterone and sex hormone binding globulin with adipose tissue hormones in midlife women.

OBJECTIVE: Regulators of adipose tissue hormones remain incompletely understood, but may include sex hormones. As adipose tissue hormones have been shown to contribute to numerous metabolic and cardiovascular disorders, understanding their regulation in midlife women is of clinical importance. Therefore, we assessed the associations between testosterone (T) and sex hormone binding globulin (SHBG) with leptin, high molecular weight (HMW) adiponectin, and the soluble form of the leptin receptor (sOB-R) in healthy midlife women. DESIGN AND METHODS: Cross-sectional analyses were performed using data from 1,881 midlife women (average age 52.6 (±2.7) years) attending the sixth Annual follow-up visit of the multiethnic Study of Women's Health Across the Nation. RESULTS: T was weakly negatively associated with both HMW adiponectin and sOB-R (r = -0.12 and r = -0.10, respectively; P < 0.001 for both), and positively associated with leptin (r = 0.17; P < 0.001). SHBG was more strongly and positively associated with both HMW adiponectin and sOB-R (r = 0.29 and r = 0.24, respectively; P < 0.001 for both), and more strongly and negatively associated with leptin (r = -0.27; P < 0.001). Adjustment for fat mass, insulin resistance, or waist circumference only partially diminished associations with HMW adiponectin and sOB-R, but attenuated associations with leptin. In conclusion, in these midlife women, lower SHBG values, and to a lesser extent, higher T levels, were associated with lower, or less favorable, levels of adiponectin and sOB-R, independent of fat mass. CONCLUSIONS: These data suggest that variation in these adipose hormones resulting from lower SHBG levels, and possibly, though less likely, greater androgenicity, may contribute to susceptibility for metabolic and cardiovascular outcomes during midlife in women.

The association of menopause status with physical function: the Study of Women's Health Across the Nation.

OBJECTIVE: The aim of this study was to determine whether postmenopause status is associated with self-reported limitations in physical function. METHODS: The Study of Women's Health Across the Nation is a multisite, multiethnic, longitudinal study of midlife women. Women aged 45 to 57 years (N = 2,566) completed the physical function scale of the Medical Outcomes Study Short-Form 36 on visit 4 (2000-2001). Scores created a three-category variable of physical function limitations: none (86-100), moderate (51-85), and substantial (0-50). In the Study of Women's Health Across the Nation, menopause status is a five-category list variable based on menstrual bleeding patterns and gynecological surgery. Premenopausal and perimenopausal women using hormones (n = 284) or missing physical function scores (n = 46) were excluded. Multinomial logistic regression was used to relate physical function and menopause status after adjustment for age, ethnicity, site, education, body mass index (BMI), and self-reported diabetes, hypertension, arthritis, depressive symptoms, smoking, and hormone use among postmenopausal women. RESULTS: Of 2,236 women, 8% were premenopausal, 51% were early perimenopausal, 12% were late perimenopausal, 24% were naturally postmenopausal, and 5% were surgically postmenopausal. In the full model, substantial limitations in physical function were higher in postmenopausal women, whether naturally postmenopausal (odds ratio, 3.82; 95% CI, 1.46-10.0) or surgically postmenopausal (odds ratio, 3.54; 95% CI, 1.15-10.84), than in premenopausal women. These associations were attenuated by higher BMI and depressive symptoms but remained significant. Moderate limitations in physical function were not significantly related to menopause status. CONCLUSIONS: Women experiencing surgical or naturally occurring postmenopause report greater limitations in physical function compared with premenopausal women, independent of age and only partly explained by higher BMI and depressive symptoms. This suggests that physiological changes in menopause could contribute directly to limitations in physical function.

Cognitive functioning is related to physical functioning in a longitudinal study of women at midlife.

BACKGROUND: Studies have reported declines with age in cognitive or physical functioning, but rarely identify whether these are parallel or linked events in the same study. Furthermore, most research in this area has focused on persons in late life rather than midlife. OBJECTIVE: The objective of the study was to determine (1) if cognitive functioning was related to physical functioning and whether this relationship persisted after adjustment for age, menopause status, metabolic status, depression and socioeconomic resources, and (2) if changes in physical functioning were associated with changes in cognitive functioning over a 4-year follow-up period. METHODS: Data were from the Study of Women's Health Across the Nation (SWAN), a multi-site, longitudinal study of women aged 46-56 years at follow-up examination 4. Three follow-up examinations (study years 04, 06 and 08) included measures of physical functioning perception (MOS SF-36) and cognitive functioning [Symbol Digit Modality Test (SDMT), Digit Span Backward Test (DSBT), and East Boston Memory Test (EBMT)] (n = 2,405). RESULTS: Women with lower cognitive functioning scores also had lower perceived physical functioning scores. While adjustment for covariates attenuated the association between perceived physical functioning and both the SDMT and EBMT cognitive measures, these associations remained statistically significant. Additionally, the 4-year change in perceived physical functioning was significantly associated with the 4-year change in the EBMT. CONCLUSIONS: At midlife, there were associated declines in cognitive and perceived physical functioning scores, commencing at midlife in women.

Assessment of physical functioning: a conceptual model encompassing environmental factors and individual compensation strategies.

Commonly studied physical functions include activities such as walking and climbing stairs. Despite the acknowledged role of environmental factors and behavioral strategies to compensate for reduced performance capacity or environmental barriers in characterizing physical functioning, most assessments do not take these factors into account. This article presents a new conceptual model for assessment of relevant physical functioning while accounting for habitual environmental factors and compensation strategies.

Race and financial strain are independent correlates of sleep in midlife women: the SWAN sleep study.

STUDY OBJECTIVES: To examine racial differences in sleep in a large cohort of midlife women and to evaluate whether indices of socioeconomic status (SES) are associated with racial differences in sleep. DESIGN: Cross-sectional study. SETTING: Participants' homes. PARTICIPANTS: Caucasian (n=171), African American (n=138) and Chinese women (n=59). INTERVENTIONS: None. MEASUREMENTS: Sleep quality was assessed with the Pittsburgh Sleep Quality Index. Polysomnographically assessed sleep duration, continuity, architecture, and NREM electroencephalograhic (EEG) power were calculated over multiple nights. Sleep disordered breathing and periodic leg movements were measured on a separate night. Linear regression analysis was used to model the independent and synergistic effects of race and SES on sleep after adjusting for other factors that impact sleep in midlife women. Indices of SES were self-reported educational attainment and financial strain. RESULTS: Sleep was worse in African American women than Caucasian participants as measured by self-report, visual sleep stage scoring, and NREM EEG power. Slow wave sleep differences were also observed between Chinese and Caucasian participants. Racial differences persisted after adjustment for indices of SES. Although educational attainment was unrelated to sleep, financial strain was associated with decreased sleep quality and lower sleep efficiency. Financial strain-by-race interactions were not statistically significant, suggesting that financial strain has additive effects on sleep, independent of race. CONCLUSIONS: Independent relationships between race and financial strain with sleep were observed despite statistical adjustment for other factors that might account for these relationships. Results do not suggest that assessed indices of SES moderate the race-sleep relationship, perhaps due to too few women of low SES in the study.

Reproductive hormones in the early menopausal transition: relationship to ethnicity, body size, and menopausal status.

We measured serum reproductive hormone concentrations in a community-based, multiethnic population of premenopausal and early perimenopausal women to determine whether there are ethnic differences in hormones that can be explained by host factors. We studied 2930 participants in the Study of Women's Health Across the Nation who were aged 42-52 yr and self-identified as African-American (27.6%), Caucasian (47.1%), Chinese (7.4%), Hispanic (8.8%), or Japanese (9.0%) at 7 clinical sites. Outcome measures from this baseline assessment of a longitudinal study were serum estradiol (E2), FSH, testosterone (T), dehydroepiandrosterone sulfate, and SHBG concentrations and calculated estimates of free steroid availability, free testosterone index, and free E2 index from serum collected primarily in the early follicular phase of a spontaneous menstrual cycle. The primary explanatory variables were race/ethnicity, menopausal status, age, body mass index, day of the cycle, smoking, alcohol use, and physical activity. Chinese women had lower unadjusted E2 and SHBG levels, and Hispanic women had lower unadjusted T levels than other ethnic groups. Unadjusted serum FSH levels did not differ by race/ethnicity. E2 levels adjusted for host characteristics, particularly body size, did not differ by race/ethnicity. Adjusted FSH levels were higher, and adjusted T levels were lower in African-American and Hispanic women. Serum E2 and FSH concentrations were highly variable. Serum FSH levels, but no other hormone concentrations, were positively correlated with menopausal status. Serum dehydroepiandrosterone sulfate levels were negatively correlated with age, but not menopausal status. All hormone concentrations were significantly correlated with body mass index. We conclude that serum sex steroid, FSH, and SHBG levels vary by ethnicity, but are highly confounded by ethnic disparities in body size.