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Dive into the research topics where Imke Janssen is active.

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Featured researches published by Imke Janssen.


JAMA Internal Medicine | 2008

Menopause and the Metabolic Syndrome: The Study of Women’s Health Across the Nation

Imke Janssen; Lynda H. Powell; Sybil L. Crawford; Bill L. Lasley; Kim Sutton-Tyrrell

BACKGROUND Cross-sectional studies suggest that prevalence of the metabolic syndrome (MetS) increases from premenopause to postmenopause in women, independent of age. Little is known about why. We hypothesized that the incidence of the MetS increases with progression through menopause and that this increase is explained by the progressive androgenicity of the hormonal milieu. METHODS This longitudinal, 9-year study of 949 participants in the Study of Womens Health Across the Nation investigates the natural history of the menopausal transition. Participants of 5 ethnicities at 7 geographic sites were recruited when they were premenopausal or early perimenopausal and were eligible for this study if they (1) reached menopause during the study; (2) had never taken hormone therapy, and (3) did not have diabetes mellitus or the MetS at baseline. The primary outcome was the presence of MetS using National Cholesterol Education Program Adult Treatment Panel III criteria. Secondary outcomes were the components of the MetS. RESULTS By the final menstrual period, 13.7% of the women had new-onset MetS. Longitudinal analyses, centered at the final menstrual period, were adjusted for age at menopause, ethnicity, study site, marital status, education, body mass index, smoking, and aging. Odds of developing the MetS per year in perimenopause were 1.45 (95% confidence interval, 1.35-1.56); after menopause, 1.24 (95% confidence interval, 1.18-1.30). These odds were significantly different (P < .001). An increase in bioavailable testosterone or a decrease in sex hormone-binding globulin levels increased the odds. CONCLUSIONS As testosterone progressively dominates the hormonal milieu during the menopausal transition, the prevalence of MetS increases, independent of aging and other important covariates. This may be a pathway by which cardiovascular disease increases during menopause.


Pediatrics | 2005

The Impact of School Daily Schedule on Adolescent Sleep

Martha Hansen; Imke Janssen; Adam Schiff; Phyllis C. Zee; Margarita L. Dubocovich

Objectives. This study was initiated to examine the impact of starting school on adolescent sleep, to compare weekday and weekend sleep times, and to attempt to normalize the timing of the circadian sleep/wake cycle by administering bright light in the morning. This was a collaborative project involving high school students and their parents, as well as high school and university faculty members, for the purpose of contributing information to the scientific community while educating students about research processes and their own sleep/wake cycles and patterns. Methods. Sixty incoming high school seniors kept sleep/wake diaries beginning in August and continuing through 2 weeks after the start of school in September. Sleep diaries were also kept for 1 month in November and 1 month in February. Early-morning light treatments were given to 19 students in the last 2 weeks of November and the last 2 weeks of February. Neuropsychologic performance was measured with computer-administered tests. Paper-and-pencil tests were used for assessment of mood and vigor. A testing period consisted of 2 consecutive days at the beginning and end of November and at the beginning and end of February. Tests were given 3 times per day, ie, in the morning before school (6:30–8:00 am), during midday lunch periods (11:30 am to 1:00 pm), and in the afternoon (3:00–4:30 pm), on each of the test days. Results. Adolescents lost as much as 120 minutes of sleep per night during the week after the start of school, and weekend sleep time was also significantly longer (∼30 minutes) than that seen before the start of school (August). No significant differences were found between weekday sleep in the summer and weekend sleep during the school year. Early-morning light treatments did not modify total minutes of sleep per night, mood, or computer-administered vigilance test results. All students performed better in the afternoon than in the morning. Students in early morning classes reported being wearier, being less alert, and having to expend greater effort. Conclusions. The results of this study demonstrated that current high school start times contribute to sleep deprivation among adolescents. Consistent with a delay in circadian sleep phase, students performed better later in the day than in the early morning. However, exposure to bright light in the morning did not change the sleep/wake cycle or improve daytime performance during weekdays. Both short-term and long-term strategies that address the epidemic of sleep deprivation among adolescents will be necessary to improve health and maximize school performance.


Archives of Physical Medicine and Rehabilitation | 2008

Lateral Balance Factors Predict Future Falls in Community-Living Older Adults

Marjorie Johnson Hilliard; Katherine M. Martinez; Imke Janssen; Beatrice J. Edwards; Marie Laure Mille; Yunhui Zhang; Mark W. Rogers

OBJECTIVE To prospectively determine the capacity of measures of mediolateral (ML) protective stepping performance, maximum hip abduction torque, and trunk mobility, in order to predict the risk of falls among community-living older people. DESIGN Cross-sectional study. SETTING A balance and falls research laboratory. PARTICIPANTS Medically screened and functionally independent community-living older adult volunteers (N=51). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Measures included: (1) protective stepping responses: percentage of trials with multiple balance recovery steps and sidestep/crossover step recovery patterns, and first step length following motor-driven waist-pull perturbations of ML standing balance; (2) hip abduction strength and axial mobility: (3) peak isokinetic hip abduction joint torque and trunk functional axial rotation (FAR) range of motion; and (4) fall incidence: monthly mail-in reporting of fall occurrences with follow-up contact for 1 year post-testing. One- and 2-variable logistic regression analysis models determined which single and combined measures optimally predicted fall status. RESULTS The single variable model with the strongest predictive value for falls was the use of multiple steps in all trials (100% multiple steps) (odds ratio, 6.2; P=.005). Two-variable models, including 100% multiple steps and either hip abduction torque or FAR variables, significantly improved fall prediction over 100% multiple steps alone. The hip abduction and FAR logistic regression optimally predicted fall status. CONCLUSIONS The findings identify new predictor variables for risk of falling that underscore the importance of dynamic balance recovery performance through ML stepping in relation to neuromusculoskeletal factors contributing to lateral balance stability. The results also highlight focused risk factors for falling that are amenable to clinical interventions for enhancing lateral balance function and preventing falls.


JAMA | 2010

Self-management Counseling in Patients With Heart Failure: The Heart Failure Adherence and Retention Randomized Behavioral Trial

Lynda H. Powell; James E. Calvin; DeJuran Richardson; Imke Janssen; Carlos F. Mendes de Leon; Kristin J. Flynn; Kathleen L. Grady; Cheryl Rucker-Whitaker; Claudia Eaton; Elizabeth Avery

CONTEXT Motivating patients with heart failure to adhere to medical advice has not translated into clinical benefit, but past trials have had methodological limitations. OBJECTIVE To determine the value of self-management counseling plus heart failure education, compared with heart failure education alone, for the primary end point of death or heart failure hospitalization. DESIGN, SETTING, AND PATIENTS The Heart Failure Adherence and Retention Trial (HART), a single-center, multiple-hospital, partially blinded behavioral efficacy randomized controlled trial involving 902 patients with mild to moderate heart failure and reduced or preserved systolic function, randomized from the Chicago metropolitan area between October 2001 and October 2004 and undergoing follow-up for 2 to 3 subsequent years. INTERVENTIONS All patients were offered 18 contacts and 18 heart failure educational tip sheets during the course of 1 year. Patients randomized to the education group received tip sheets in the mail and telephone calls to check comprehension. Patients randomized to the self-management group received tip sheets in groups and were taught self-management skills to implement the advice. MAIN OUTCOME MEASURE Death or heart failure hospitalization during a median of 2.56 years of follow-up. RESULTS Patients were representative of typical clinical populations (mean age, 63.6 years; 47% women, 40% racial/ethnic minority, 52% with annual family income less than


Obesity | 2010

Testosterone and Visceral Fat in Midlife Women: The Study of Women's Health Across the Nation (SWAN) Fat Patterning Study

Imke Janssen; Lynda H. Powell; Rasa Kazlauskaite; Sheila A. Dugan

30,000, and 23% with preserved systolic function). The rate of the primary end point in the self-management group was no different from that in the education group (163 [40.1%)] vs 171 [41.2%], respectively; odds ratio, 0.95 [95% confidence interval, 0.72-1.26]). There were no significant differences on any secondary end points, including death, heart failure hospitalization, all-cause hospitalization, or quality of life. CONCLUSIONS Compared with an enhanced educational intervention alone, the addition of self-management counseling did not reduce death or heart failure hospitalization in patients with mild to moderate heart failure. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00018005.


Physical Therapy | 2010

Effectiveness of Particle Repositioning Maneuvers in the Treatment of Benign Paroxysmal Positional Vertigo: A Systematic Review

Janet Odry Helminski; David S. Zee; Imke Janssen; Timothy C. Hain

Visceral fat (VF) increases with the menopause and is an independent predictor of the metabolic syndrome, diabetes, and cardiovascular disease (CVD) in women. Little is known about how hormonal changes during the menopausal transition are related to the increase in VF. We aimed to determine the relationship between bioavailable testosterone and VF in middle‐aged women at various stages of the menopausal transition and whether this relationship is independent of age and other CVD risk factors. The Study of Womens Health Across the Nation (SWAN) is a longitudinal, community‐based study. This report uses baseline data from a population‐based longitudinal ancillary study at the Chicago site to examine the cross‐sectional relationship between testosterone and computed tomography (CT)–assessed VF in women at different stages of the menopausal transition. Included are 359 women (47.2% black), aged 42–60 years, who were randomly selected from a complete community census in which a 72% participation rate was achieved. In multivariate models, bioavailable testosterone was associated with VF independent of age, race, percent total body fat, and other cardiovascular risk factors. Bioavailable testosterone was a stronger predictor than estradiol and was interchangeable in its strength of association with sex hormone–binding globulin (SHBG). As bioavailable testosterone was associated with VF even after adjusting for insulin resistance, this suggests that it plays an important role in regional fat distribution. Our findings may have direct implications in explaining the effect of menopause‐related testosterone predominance on VF accumulation and subsequent cardiovascular risk.


American Journal of Epidemiology | 2011

Self-reported Experiences of Discrimination and Visceral Fat in Middle-aged African-American and Caucasian Women

Tené T. Lewis; Howard M. Kravitz; Imke Janssen; Lynda H. Powell

Background Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo. Purpose The purpose of this systematic review was to determine whether patients diagnosed with posterior canal (PC) BPPV, based on positional testing, and treated with a particle repositioning maneuver will show the resolution of benign paroxysmal positional nystagmus (BPPN) on the Dix-Hallpike Test performed 24 hours or more after treatment. Data Sources Data were obtained from an electronic search of the MEDLINE, EMBASE, and CINAHL databases from 1966 through September 2009. Study Selection The study topics were randomized controlled trials (RCTs), quasi-RCTs, the diagnosis of PC BPPV, treatment with the particle repositioning maneuver, and outcome measured with a positional test 24 hours or more after treatment. Data Extraction Data extracted were study descriptors and the information used to code for effect size. Data Synthesis In 2 double-blind RCTs, the odds in favor of the resolution of BPPN were 22 times (95% confidence interval=3.41–141.73) and 37 times (95% confidence interval=8.75–159.22) higher in people receiving the canalith repositioning procedure (CRP) than in people receiving a sham treatment. This finding was supported by the results reported in 8 nonmasked quasi-RCTs. Studies with limited methodological quality suggested that a liberatory maneuver (LM) was more effective than a control intervention; there was no significant difference in the effectiveness of the LM and the effectiveness of the CRP; the self-administered CRP was more effective than the self-administered LM; and the CRP administered together with the self-administered CRP was more effective than the CRP administered alone. The Brandt-Daroff exercises were the least effective self-administered treatments. Limitations The limitations included the methodological quality of the studies, the lack of quality-of-life measures, and confounding factors in reporting vertigo. Conclusions Randomized controlled trials provided strong evidence that the CRP resolves PC BPPN, and quasi-RCTs suggested that the CRP or the LM performed by a clinician or with proper instruction at home by the patient resolves PC BPPN. There were no data on the effects of the maneuvers on outcomes relevant to patients.


Obstetrics & Gynecology | 2010

Lactation and Maternal Measures of Subclinical Cardiovascular Disease

Eleanor Bimla Schwarz; Candace K. McClure; Ping G. Tepper; Rebecca C. Thurston; Imke Janssen; Karen A. Matthews; Kim Sutton-Tyrrell

The authors examined the association between self-reported experiences of discrimination and subtypes of abdominal fat (visceral, subcutaneous) in a population-based cohort of African-American and Caucasian women. Prior studies examining associations between discrimination and abdominal fat have yielded mixed results. A major limitation of this research has been the reliance on waist circumference, which may be a poor marker of visceral fat, particularly for African-American women. Participants were 402 (45% African-American, 55% Caucasian) middle-aged women from the Chicago, Illinois, site of the Study of Womens Health Across the Nation. Visceral and subcutaneous fat were assessed via computed tomography scans between 2002 and 2005. Linear regression models were conducted to test associations among discrimination and visceral and subcutaneous fat. After adjustment for age and race, every one-point increase on the discrimination scale was associated with a 13.03-cm(2) higher amount of visceral fat (P = 0.04). This association remained significant after further adjustments for total body fat and relevant risk factors, including depressive symptoms. Discrimination was not associated with subcutaneous fat in minimally (P = 0.95) or fully adjusted models. Associations did not differ by race. Findings suggest that visceral fat may be one potential pathway through which experiences of discrimination increase cardiovascular risk.


American Journal of Public Health | 2014

Mexican American Trial of Community Health Workers: A Randomized Controlled Trial of a Community Health Worker Intervention for Mexican Americans With Type 2 Diabetes Mellitus

Steven K. Rothschild; Molly A. Martin; Susan M. Swider; Carmen M. Tumialán Lynas; Imke Janssen; Elizabeth Avery; Lynda H. Powell

OBJECTIVE: To examine the relationship between lactation and subclinical cardiovascular disease in a population free of clinical cardiovascular disease. METHODS: We conducted a cross-sectional analysis of 297 women who reported at least one live birth on enrollment in the Study of Women Across the Nation–Heart Study. Participants were mothers aged 45–58 years who were free of clinical cardiovascular disease. History of lactation was self-reported. Electron beam tomography was used to assess coronary and aortic calcification. B-mode ultrasonography was used to assess carotid adventitial diameter, intima–media thickness, and carotid plaque. Multivariable linear and logistic regression models were used to estimate whether lactation was independently associated with markers of subclinical cardiovascular disease. RESULTS: In unadjusted models, compared with mothers who had breastfed all of their children for at least 3 months, mothers who had not breastfed were more likely to have coronary artery calcification (17% compared with 32%), aortic calcification (17% compared with 39%), carotid plaque (10% compared with 18%), and larger carotid adventitial diameters (mean±standard deviation 6.63±0.59 compared with 6.87±0.60 mm). After adjusting for measures of socioeconomic status and lifestyle and family history variables, mothers who had not breastfed remained more likely to have aortic calcification (odds ratio [OR] 3.85, 95% confidence interval [CI] 1.47–10.00) and coronary artery calcification (OR 2.78, 95% CI 1.05–7.14) than mothers who had consistently breastfed. After further adjustment for body mass index and traditional risk factors for cardiovascular disease, mothers who had not breastfed remained more likely to have aortic calcification than mothers who had consistently breastfed (OR 5.26, 95% CI 1.47–20.00). CONCLUSION: Mothers who do not breastfeed their infants seem to be at increased risk of vascular changes associated with future cardiovascular disease. LEVEL OF EVIDENCE: II


American Heart Journal | 2011

Depressive symptoms are related to progression of coronary calcium in midlife women: The Study of Women's Health Across the Nation (SWAN) Heart Study

Imke Janssen; Lynda H. Powell; Karen A. Matthews; John F. Cursio; Steven M. Hollenberg; Kim Sutton-Tyrrell; Joyce T. Bromberger; Susan A. Everson-Rose

OBJECTIVES We assessed whether community health workers (CHWs) could improve glycemic control among Mexican Americans with diabetes. METHODS We recruited 144 Mexican Americans with type 2 diabetes between January 2006 and September 2008 into the single-blinded, randomized controlled Mexican American Trial of Community Health Workers (MATCH) and followed them for 2 years. Participants were assigned to either a CHW intervention, delivering self-management training through 36 home visits over 2 years, or a bilingual control newsletter delivering the same information on the same schedule. RESULTS Intervention participants showed significantly lower hemoglobin A1c levels than control participants at both year 1 Δ = -0.55; P = .021) and year 2 (Δ = -0.69; P = .005). We observed no effect on blood pressure control, glucose self-monitoring, or adherence to medications or diet. Intervention participants increased physical activity from a mean of 1.63 days per week at baseline to 2.64 days per week after 2 years. CONCLUSIONS A self-management intervention delivered by CHWs resulted in sustained improvements in glycemic control over 2 years among Mexican Americans with diabetes. MATCH adds to the growing body of evidence supporting the use of CHWs to reduce diabetes-related health disparities.

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Lynda H. Powell

Rush University Medical Center

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Howard M. Kravitz

Rush University Medical Center

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Rasa Kazlauskaite

Rush University Medical Center

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Bradley M. Appelhans

Rush University Medical Center

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Sheila A. Dugan

Rush University Medical Center

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