Factors Influencing Longitudinal Stair Climb Performance from Midlife to Early Late Life: The Study of Women's Health Across the Nation Chicago and Michigan Sites.

OBJECTIVES: To quantify the longitudinal change in stair climb performance (a measure indicative of both physical function and muscle power), determine whether physical activity is related to slower decline in performance, and to identify factors that modify the longitudinal change in performance among women from midlife to late life. DESIGN: Longitudinal cohort study with up to 15 study visits. SETTING: Two sites of the Study of Women's Health Across the Nation. PARTICIPANTS: Black (n=411) and white (N=419) women followed from median age 47.0 (44.6-49.6) to 62.0 (55.8-65.3) years. INTERVENTIONS: N/A. MEASUREMENTS: Performance on a stair climb test (ascend/descend 4 steps, 3 cycles) was timed. Physical activity (PA) was assessed using the Kaiser Physical Activity Survey (KPAS; possible range 0-15 points). Sociodemographic and health factors were assessed via self-report. BMI was calculated with measured height and weight. Mixed-effects regression modeled longitudinal change in stair climb performance. RESULTS: Average baseline stair climb time was 18.12 seconds (95% CI: 17.83-18.41), with 0.98% (95% CI: 0.84%-1.11%) annual slowing. In fully adjusted models, higher levels of PA were associated with faster stair climb times (2.09% faster per point higher, 95% CI: -2.87%- -1.30%), and black women had 5.22% (95% CI: 2.43%-8.01%) slower performance compared to white women. Smoking, financial strain, diabetes, osteoarthritis, fair/poor health, and stroke were associated with 3.36% (95% CI: 0.07%-6.65%), 7.56% (95% CI: 4.75%-10.37%), 8.40% (95% CI: 2.89%-13.92%), 8.46% (95% CI: 5.12%-11.79%), 9.16% (95% CI: 4.72%-13.60%), and 16.94% (95% CI: 5.37%-28.51%) slower performance, respectively. In separate models, higher BMI (per 1-unit), osteoarthritis, fair/poor health, and diabetes, were each associated with 0.06% (95% CI:0.04%-0.08%), 0.48% (95% CI:0.12%-0.84%), 0.81% (95% CI:0.35%-1.28%), and 0.84% (95% CI:0.22%-1.46%), additional slowing per year over time. CONCLUSION: Significant declines in function were evident as women transitioned from midlife to early late life. Declines were amplified by indicators of poor health, emphasizing the importance of health in midlife for promoting healthy aging.

A bone resorption marker as predictor of rate of change in femoral neck size and strength during the menopause transition.

We assessed whether a bone resorption marker, measured early in the menopause transition (MT), is associated with change in femoral neck size and strength during the MT. Higher levels of bone resorption were associated with slower increases in femoral neck size and faster decreases in femoral neck strength. PURPOSE: Composite indices of the femoral neck's ability to withstand compressive (compression strength index, CSI) and impact (impact strength index, ISI) forces integrate DXA-derived femoral neck width (FNW), bone mineral density (BMD), and body size. During the menopause transition (MT), FNW increases, and CSI and ISI decrease. This proof-of-concept study assessed whether a bone resorption marker, measured early in the MT, is associated with rates of change in FNW, CSI and ISI during the MT. METHODS: We used previously collected bone resorption marker (urine collagen type I N-telopeptide [U-NTX]) and femoral neck strength data from 696 participants from the Study of Women's Health Across the Nation (SWAN), a longitudinal study of the MT in a multi-ethnic cohort of community-dwelling women. RESULTS: Adjusted for MT stage (pre- vs. early perimenopause), age, body mass index (BMI), bone resorption marker collection time, and study site in multivariable linear regression, bone resorption in pre- and early perimenopause was not associated with transmenopausal decline rate in femoral neck BMD. However, each standard deviation (SD) increase in bone resorption level was associated with 0.2% per year slower increase in FNW (p = 0.03), and 0.3% per year faster declines in CSI (p = 0.02) and ISI (p = 0.01). When restricted to women in early perimenopause, the associations of bone resorption with change in FNW, CSI, and ISI were similar to those in the full sample. CONCLUSIONS: Measuring a bone resorption marker in pre- and early perimenopause may identify women who will experience the greatest loss in bone strength during the MT.

Association between changes in oestradiol and follicle-stimulating hormone levels during the menopausal transition and risk of diabetes.

AIM: To investigate the association between changes in oestradiol and follicle-stimulating hormone levels during the menopausal transition and incident diabetes. METHODS: We followed 1407 pre-menopausal women, aged 42-52 years at baseline, who experienced natural menopause, from baseline to the 12th annual follow-up visit in the Study of Women's Health Across the Nation (SWAN). Diabetes was defined based on fasting glucose level, medication use and self-report of physician diagnosis. Cox proportional hazards regression was used to evaluate the associations of incident diabetes with three components of the rate of change in hormones: the intercept (pre-menopausal levels) and two piece-wise slopes representing change during the early and late transition, respectively. RESULTS: During 15 years of follow-up, 132 women developed diabetes. After adjusting for potential confounders, a higher oestradiol intercept, but not its rate of change, was borderline significantly associated with lower risk of diabetes [hazard ratio for an interquartile range increase (75.2 pmol/L) 0.53, 95% CI 0.27-1.06]. For follicle-stimulating hormone, a greater rate of increase in the early transition, but not the intercept or late transition, was significantly associated with lower risk of diabetes [hazard ratio for an interquartile range increase (5.9 IU/L/year) 0.31, 95% CI 0.10-0.94]. CONCLUSIONS: Lower pre-menopausal oestradiol levels and a slower rate of follicle-stimulating hormone change during the early transition were associated with higher risk of developing diabetes. Given that obesity plays an important role in diabetes risk and in the levels and changes in oestradiol and follicle-stimulating hormone over the menopausal transition, weight control in earlier mid-life is important to prevent future diabetes development.

Socioeconomic status in relation to incident fracture risk in the Study of Women's Health Across the Nation.

UNLABELLED: We examined baseline and annual follow-up data (through annual follow-up visit 9) from a cohort of 2,234 women aged 42 to 52 years at baseline. Independent of financial status, higher educational level was associated with lower fracture incidence among non-Caucasian women but not among Caucasian women. INTRODUCTION: This study was conducted to determine the associations of education and income with fracture incidence among midlife women over 9 years of follow-up. METHODS: We examined baseline and annual follow-up data (through annual follow-up visit 9) from 2,234 participants of the Study of Women's Health Across the Nation, a cohort of women aged 42 to 52 years at baseline. We used Cox proportional hazards regression models to examine the associations of socioeconomic predictors (education, family-adjusted poverty-to-income ratio, and difficulty paying for basics) with time to first incident nontraumatic, nondigital, noncraniofacial fracture. RESULTS: Independent of family-adjusted poverty-to-income ratio, higher educational level was associated with decreased time to first incident fracture among non-Caucasian women but not among Caucasian women (p(interaction) 0.02). Compared with non-Caucasian women who completed no more than high school education, non-Caucasian women who attained at least some postgraduate education had 87% lower rates of incident nontraumatic fracture (adjusted hazard ratio 0.13, 95% confidence interval [CI] 0.03-0.60). Among non-Caucasian women, each additional year of education was associated with a 16% lower odds of nontraumatic fracture (adjusted odds ratio 0.84, 95% CI 0.73-0.97). Income, family-adjusted poverty-to-income ratio, and degree of difficulty paying for basic needs were not associated with time to first fracture in Caucasian or non-Caucasian women. CONCLUSIONS: Among non-Caucasian midlife women, higher education, but not higher income, was associated with lower fracture incidence. Elucidation of the mechanisms underlying the possible protective effects of higher educational level on nontraumatic fracture incidence may allow us to better target individuals at risk of future fracture.

Racial/ethnic differences in hepatic steatosis in a population-based cohort of post-menopausal women: the Michigan Study of Women's Health Across the Nation.

AIMS: The prevalence of hepatic steatosis may differ between post-menopausal African-American women and non-Hispanic white women and by sex hormone binding globulin level. We examined prevalence of hepatic steatosis by race/ethnicity and associations with sex hormone binding globulin. METHODS: Participants included post-menopausal women who underwent hepatic ultrasound (n = 345) at the Michigan site of the Study of Women's Health Across the Nation, a population-based study. We examined hepatic steatosis prevalence by race/ethnicity and used logistic regression models to calculate the odds of hepatic steatosis with race/ethnicity and sex hormone binding globulin, after adjustment for age, alcohol use, waist circumference, high density lipoprotein cholesterol, triglycerides, systolic blood pressure and use of medications reported to lower intrahepatic fat. RESULTS: Fewer African-American women than non-Hispanic white women had hepatic steatosis (23 vs. 36%, P = 0.01). African-American women had lower triglyceride and low-density lipoprotein cholesterol levels, but higher blood pressure and follicle-stimulating hormone levels (P < 0.05). In the optimal-fitting multivariable models, women in the highest tertile of sex hormone binding globulin (60.2-220.3 nmol/l) had a lower odds of hepatic steatosis (odds ratio 0.43, 95% CI 0.20-0.93) compared with women in the lowest tertile of sex hormone binding globulin (10.5-40.3 nmol/l). There was an interaction between race/ethnicity and medication use whereby non-Hispanic white women using medications had three times higher odds of hepatic steatosis compared with African-American women not using medications (odds ratio 3.36, 95% CI 1.07-10.58). Interactions between race/ethnicity and other variables, including sex hormone levels, were not significant. CONCLUSIONS: Hepatic steatosis on ultrasound may be more common in post-menopausal non-Hispanic white women than African-American women and was associated with lower levels of sex hormone binding globulin.

Sex dimorphism in the association of cardiometabolic characteristics and osteophytes-defined radiographic knee osteoarthritis among obese and non-obese adults: NHANES III.

OBJECTIVE: To examine the relationship of knee osteoarthritis (OA) with cardiovascular and metabolic risk factors by obesity status and gender. METHODS: Data from 1,066 National Health and Nutrition Examination Survey III participants (≥60 years of age) was used to examine relationships of osteophytes-defined radiographic knee OA and cardiovascular and metabolic measures. Analyses were considered among obese [body mass index (BMI)≥30 kg/m(2)] and non-obese (BMI<30 kg/m(2)) men and women. RESULTS: The prevalence of osteophytes-defined radiographic knee OA was 34%. Leptin levels and homeostatic model assessment-insulin resistance (HOMA-IR), a proxy measure of insulin resistance, were significantly associated with knee OA; those with knee OA had 35% higher HOMA-IR values and 52% higher leptin levels compared to those without knee OA. The magnitude of the association between HOMA-IR and knee OA was strongest among men, regardless of obesity status; odds ratios (ORs) for HOMA-IR were 34% greater among non-obese men (OR=1.18) vs obese women (OR=0.88). Among obese women, a 5-µg/L higher leptin was associated with nearly 30% higher odds of having knee OA (OR=1.28). Among men, ORs for the association of leptin and knee OA were in the opposite direction. CONCLUSIONS: Cardiometabolic dysfunction is related to osteophytes-defined radiographic knee OA prevalence and persists within subgroups defined by obesity status and gender. A sex dimorphism in the direction and magnitude of cardiometabolic risk factors with respect to knee OA was described including HOMA-IR being associated with OA prevalence among men while leptin levels were most important among women.

Post-discharge tobacco cessation rates among hospitalized US veterans with and without diabetes.

AIMS: Smoking is a major risk factor for cardiovascular complications among patients with diabetes. Hospitalization has been shown to enhance cessation rates. The purpose of this study was to compare 6-month post-hospitalization tobacco cessation rates among US veterans with and without diabetes. METHODS: This was a longitudinal study among inpatient veterans who used tobacco in the past month (n = 496). Patients were recruited and surveyed from three Midwestern Department of Veterans Affairs hospitals during an acute-care hospitalization. They were also asked to complete a follow-up survey 6 months post-discharge. Bivariate- and multivariable-adjusted analyses were conducted to determine differences in tobacco cessation rates between patients with and without a diagnosis of diabetes. RESULTS: The mean age of patients was 55.2 years and 62% were white. Twenty-nine per cent had co-morbid diabetes. A total of 18.8% of patients with diabetes reported tobacco cessation at 6 months compared with 10.9% of those without diabetes (P = 0.02). Cotinine-verified cessation rates were 12.5 vs. 7.4% in the groups with and without diabetes, respectively (P = 0.07). Controlling for psychiatric co-morbidities, depressive symptoms, age, self-rated health and nicotine dependence, the multivariable-adjusted logistic regression showed that patients with diabetes had three times higher odds of 6-month cotinine-verified tobacco cessation as compared with those without diabetes (odds ratio 3.17, P = 0.005). CONCLUSIONS: Post-hospitalization rates of smoking cessation are high among those with diabetes. Intensive tobacco cessation programmes may increase these cessation rates further.

Ethnicity predicts perceptions of smoking and smoking cessation among veterans.

The objective of this study was to determine if race/ethnicity predicts motivation to quit smoking and preferences for cessation services among smokers serviced by a primarily psychiatric Veterans Affairs hospital. A self-administered survey was given to a convenience sample of smokers (n=146) at the Battle Creek Veterans Affairs Medical Center. Univariate, bivariate and multivariate regression analyses were calculated to determine the association between race/ethnicity and motivation to quit smoking. Forty-two per cent of the sample was non-white. Non-white patients smoked significantly less cigarettes per day as compared with white patients (P=0.002). In the multivariate analyses, compared with whites, non-whites had 3.5 times greater odds of thinking that quitting smoking was extremely/very important to health (P= 0.01), 4.0 times greater odds of thinking of quitting using tobacco products in the next 30 days (P=0.004) and 3.4 times greater odds of being interested in receiving smoking cessation services (P=0.007). Yet, non-white patients were less likely to be interested in intensive nurse counselling and cessation medications. As the number of non-whites continues to increase in the military, novel strategies may be needed to capitalize on the high motivation to quit smoking and preference for non-traditional interventions among non-white smokers treated in Veterans Affairs hospitals.

Longitudinal changes of serum COMP and urinary CTX-II predict X-ray defined knee osteoarthritis severity and stiffness in women.

OBJECTIVE: To ascertain the predictive role of longitudinally acquired biochemical measures of cartilage turnover in relation to X-ray defined knee osteoarthritis (OAK), knee pain and functioning. METHODS: This is a feasibility study based on 72 enrollees of the Michigan site of Study of Women's Health Across the Nation (SWAN), a longitudinal, population-based cohort study with 11 annual visits to characterize health at the mid-life. At visits in 1996, 1998 and 2007, radiographs were evaluated for the presence of OAK [>or=2 on the Kellgren and Lawrence (K-L) scale]. Knee pain and stiffness were assessed by interview. Functioning was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Cartilage oligomeric matrix protein (COMP) and Type II collagen telopeptides (CTX-II) were assayed in serum and urine samples collected on alternate years from 1997 to 2006. We related trajectories of the cartilage biochemical markers from these five time points to OAK severity (no OAK, K-L score<2; mild OAK, K-L score=2; moderate/severe OAK, K-L score=3 or 4), pain, stiffness, or functioning, using longitudinal non-linear mixed modeling. RESULTS: The 2007 prevalence of X-ray defined OAK was 50% in these 72 women. Upward trajectories of COMP (P=0.02) and CTX-II (P=0.006) were associated with increased OAK severity and body size. COMP trajectories were associated with pain and stiffness, but not functioning. CTX-II trajectories were associated with stiffness scores, but not knee pain or functioning scores. CONCLUSION: Multiple, biennial measures of COMP or CTX-II taken over a 10-year period were predictive of subsequent OAK and knee stiffness.

Testosterone, sex hormone-binding globulin and free androgen index among adult women: chronological and ovarian aging.

BACKGROUND: In this study, levels and rates of change in total testosterone (T), sex hormone-binding globulin (SHBG) and free androgen index (FAI) were related to chronological age and to the final menstrual period (FMP) as an indicator of ovarian aging. METHODS: Data were annually acquired over a 15-year period in 629 women of the Michigan Bone Health and Metabolism Study cohort. Data were censored for hormone therapy use. Endogenous androgen patterns over time were described with stochastic processes and bootstrapping. RESULTS: With ovarian aging, T levels rose from a mean of 18 ng/dl commencing 10 years prior to the FMP to 27 ng/dl at the FMP. Over the 20-year period encompassing the FMP, modeled mean SHBG levels changed from 58 to 34 nM and the FAI ratio increased from 1.6 to 2.9 in a non-linear manner. With chronological aging, total T levels increased (P < 0.0001) from 43 to 50 years, but not thereafter. SHBG declined steadily with age with a modestly greater rate of change between 49 and 54 years. The FAI increased from 1.3 to 2.5 from 34 to 58 years. CONCLUSIONS: T increased from approximately age 40 until the FMP whereas SHBG had rate of change patterns reflecting both chronological and ovarian aging components. These data provide new insight into the endogenous androgen patterns at mid-life.

BMI vs. body composition and radiographically defined osteoarthritis of the knee in women: a 4-year follow-up study.

OBJECTIVE: To elucidate the role of body mass index (BMI) and knee osteoarthritis (OAK) by evaluating measures of body composition including fat mass and skeletal muscle mass (SMM). METHODS: Data are from 541 women enrolled in the Michigan Bone Health Study, a longitudinal, population-based study. At visits in 1998 and 2002, radiographs were taken of both knees and were evaluated for the presence of OAK (>or=2 on the Kellgren-Lawrence (K-L) scale). Joint space width (JSW) was measured with electronic calipers. Fat mass and SMM were determined using bioelectrical impedance analysis. RESULTS: In 2002, the prevalence of OAK was 11% in this population of women whose mean age was 47 years. Fat mass, lean mass, SMM, waist circumference and BMI were greater in women with OAK compared to those without OAK. In multiple variable analyses adjusted for age, fat mass and SMM explained OAK prevalence and increasing OAK severity better than models with BMI; further SMM explained more variation than did fat mass. SMM was positively associated with level of left and right medial JSW while there was no consistent association of JSW and BMI or fat mass. CONCLUSION: Fat mass and SMM were associated with K-L OAK score and the amount of joint space, with more variation explained by SMM. SMM was highly associated with JSW. Therefore, though obesity, frequently characterized by BMI, is a frequently reported risk factor for OAK, this mis-attribution may mean that interventions that focus on weight loss as treatment for osteoarthritis should be aware that this may negatively impact muscle mass.