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Dive into the research topics where Ada O. Youk is active.

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Featured researches published by Ada O. Youk.


Transplantation | 1998

Comparative incidence of de novo nonlymphoid malignancies after liver transplantation under tacrolimus using surveillance epidemiologic end result data

A. Jain; Ld Yee; M. Nalesnik; Ada O. Youk; G Marsh; Jorge Reyes; Marsha Zak; Jorge Rakela; William Irish; John J. Fung

BACKGROUND An increased incidence of de novo nonlymphoid malignancies has been shown in immunocompromised patients. However, the true risk over time compared to the general population has not been determined. METHODS One thousand consecutive patients were carefully followed for an average of 77.8+/-11.1 (range, 56.3-96.3) months after primary liver transplantation at a single center. All de novo nonlymphoid malignancies were recorded. Each malignancy was compared with a standard Occupational Cohort Mortality Analysis Program population matched for age, sex, and length of follow-up using modified life table technique and surveillance epidemiology end result (SEER) data. RESULTS Fifty-seven patients accounted for de novo malignancies and contributed 4795.3 total person years, a mean+/-SD of 36+/-21 (median, 36; range, 6-74) months after liver transplantation. Twenty-two of these malignancies were skin malignancies including two melanomas. Oropharyngeal cancers (n=7) were found to be 7.6 times higher (P<0.05) and respiratory malignancies (n=8) were 1.7 times higher (P>0.05) compared to the SEER incidence rate. Female reproductive system malignancies including breast cancer (n=3) were 1.9 times lower (P>0.05) and genitourinary malignancies were (n=5) 1.5 times lower (P>0.05) than their matched cohorts. No differences was observed in gastrointestinal malignancies (n=5). There was a significant difference in survival of the patients after diagnosis of malignancy depending on the type of cancer. There were two Kaposis sarcomas, two metastatic unknown primaries, one thyroid, one brain, and one ophthalmic malignancies in the series. Mortality for Kaposis and metastatic disease of unknown primary was 100% within 5 months, while the 1-year mortality for oropharyngeal cancer was 57.1% and that for lung cancers was 62.5%. Long-term survival for skin cancer was highest: 86.4% at 3 years (P=0.015 by log-rank test). CONCLUSION An increased incidence of de novo cancers in the chronically immunocompromised patient demands careful long-term screening protocols which will help to facilitate the diagnosis at an early stage of the disease. This is particularly true for oropharyngeal cancers where the risk is more than 7 times higher compared to SEER incidence data matched for age, sex, and length of follow-up.


Journal of Occupational and Environmental Medicine | 1998

OCMAP-PLUS: a program for the comprehensive analysis of occupational cohort data.

Gary M. Marsh; Ada O. Youk; Roslyn A. Stone; Stephen Sefcik; Charles Alcorn

The Occupational Cohort Mortality Analysis Program (OCMAP) has been redesigned for optimal microcomputer use and extended to include new computing algorithms. The new program, OCMAP-PLUS, offers a comprehensive, flexible, and efficient analysis of incidence or mortality rates and standardized measures in relation to multiple and diverse work history and exposure measures. New features include executable code, minimization of memory requirements, disk file storage of person-day arrays, stratified analyses by geographic area, employment status and up to eight exposure variables, a data imputation algorithm for study members with unknown race, and enhanced algorithms for constructing several time-dependent exposure measures. New modules create grouped data files for Poisson and logistic regression and risk set files for use in relative risk regression analysis. The Mortality and Population Data System (MPDS) provides external comparison rates and proportional mortalities. Analysis from two recent cohort mortality studies illustrate several new features.


Occupational and Environmental Medicine | 1999

Mortality patterns among workers exposed to acrylamide: 1994 follow up.

Gary M. Marsh; Lorraine J Lucas; Ada O. Youk; Laura C. Schall

OBJECTIVE: To update the mortality experience of a cohort of 8508 workers with potential exposure to acrylamide at three plants in the United States from 1984-94. METHODS: Analyses of standardised mortality ratios (SMR) with national and local rates and relative risk (RR) regression modelling were performed to assess site specific cancer risks by demographic and work history factors, and exposure indicators for acrylamide and muriatic acid. RESULTS: For the 1925-94 study period, excess and deficit overall mortality risks were found for cancer sites of interest: brain and other central nervous system (CNS) (SMR 0.65, 95% confidence interval (95% CI) 0.36 to 1.09), thyroid gland (SMR 2.11, 95% CI 0.44 to 6.17), testis and other male genital organs (SMR 0.28, 95% CI 0.01 to 1.59), and cancer of the respiratory system (SMR 1.10, 95% CI 0.99 to 1.22); however, none was significant or associated with exposure to acrylamide. A previously reported excess mortality risk of cancer of the respiratory system at one plant remained increased among workers with potential exposure to muriatic acid (RR 1.50, 95% CI 0.86 to 2.59), but was only slightly increased among workers exposed or unexposed to acrylamide. In an exploratory exposure-response analysis of rectal, oesophageal, pancreatic, and kidney cancer, we found increased SMRs for some categories of exposure to acrylamide, but little evidence of an exposure-response relation. A significant 2.26-fold risk (95% CI 1.03 to 4.29) was found for pancreatic cancer among workers with cumulative exposure to acrylamide > 0.30 mg/m3.years; however, no consistent exposure-response relations were detected with the exposure measures considered when RR regression models were adjusted for time since first exposure to acrylamide. CONCLUSION: The contribution of 1115 additional deaths and nearly 60,000 person-years over the 11 year follow up period corroborate the original cohort study findings of little evidence for a causal relation between exposure to acrylamide and mortality from any cancer sites, including those of initial interest. This is the most definitive study of the human carcinogenic potential of exposure to acrylamide conducted to date.


Transplantation | 2000

Long-term follow-up after liver transplantation for alcoholic liver disease under tacrolimus.

Ashok Jain; Andrea DiMartini; Randeep Kashyap; Ada O. Youk; Susan Rohal; John J. Fung

BACKGROUND Liver transplantation (LTx) for alcohol-related liver disease (ALD) is an accepted modality of treatment and is one of the most common indications for LTx in the United States. The present report examines the long-term patient survival, graft survival, rates of recidivism, and development of de novo cancers in this group, and compares these results with a contemporaneous group of patients who were transplanted for non-ALD indications. METHODS Between August 1989 and December 1992, 185 adults received LTx for ALD (group I). During the same time interval, 649 adults received LTx for non-ALD (group II). The mean follow-up time was 94+/-10.7 months for group I vs. 92+/-11 months for group II. Kaplan-Meier survival estimates and the incidence of cancers using Surveillance Epidemiologic End Result data were compared in both groups. RESULTS At 5 years after orthotopic LTx, the overall patient survival and graft survival for group I were 72.0% and 66.5% vs. 66.5% and 60.3% for group II, respectively. After 5 years, the patient survival and graft survival for the alcoholic group were significantly lower (P=0.001) compared to the non-alcoholic group. The rate of de novo oropharyngeal cancer and lung cancer was 25.5 times and 3.7 times higher, respectively, in ALD group compared with the general population matched for age, sex, and length of follow-up (P=0.001), whereas this was not higher in the non-ALD group. Prior pretransplant length of sobriety and alcohol rehabilitation was not associated with the rate of post-LTx rate of recidivism, which was 20%. Out of 79 deaths in group I, only 1 was attributed to recidivism and 3 to noncompliance with recidivism. The other deaths occurred from de novo cancer (n=13), posttransplant lymphoproliferative disorder (n=5), age-related complications (n=23), and other infection or miscellaneous causes (n=34). CONCLUSIONS Patient and graft survival past 5 years after orthotopic LTx is significantly lower for ALD for a variety of reasons (P=0.001). The rate of upper airway malignances was significantly higher in ALD patients than for non-ALD post-LTx patients and the general public. Graft loss/death related to recidivism or chronic rejection was extremely low. More attention is needed for early diagnosis of de novo cancer and prevention of cardiorespiratory and cerebrovascular complications.


Psychological Medicine | 2009

Predictors of first lifetime episodes of major depression in midlife women

Joyce T. Bromberger; Howard M. Kravitz; Karen A. Matthews; Ada O. Youk; Charlotte Brown; W. Feng

BACKGROUND Little is known about factors that predict first lifetime episodes of major depression in middle-aged women. It is not known whether health-related factors and life stress pose more or less of a risk to the onset of clinical depression than does the menopausal transition. METHOD The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) was used to assess diagnoses of lifetime, annual and current major depression in a community-based sample of premenopausal or early perimenopausal African American and White women. Menstrual cycle characteristics, psychosocial and health-related factors, and blood samples for assay of reproductive hormones were obtained annually. Two hundred and sixty-six women without a history of major depression at baseline constituted the cohort for the current analyses. RESULTS Over 7 years of follow-up, 42 (15.8%) women met criteria for a diagnosis of major depression. Frequent vasomotor symptoms (VMS; hot flashes and/or night sweats) (HR 2.14, p=0.03) were a significant predictor of major depression in univariate analyses. After simultaneous adjustment for multiple predictors in Cox proportional hazards analyses, frequent VMS were no longer significant; lifetime history of an anxiety disorder (HR 2.20, p=0.02) and role limitations due to physical health (HR 1.88, p=0.07) at baseline and a very stressful life event (HR 2.25, p=0.04) prior to depression onset predicted a first episode of major depression. CONCLUSIONS Both earlier (e.g. history of anxiety disorders) and more proximal factors (e.g. life stress) may be more important than VMS in contributing to a first episode of major depression during midlife.


Journal of Bone and Mineral Research | 2012

Inflammatory markers and the risk of hip fracture: the Women's Health Initiative.

Kamil E. Barbour; Robert M. Boudreau; Michelle E. Danielson; Ada O. Youk; Jean Wactawski-Wende; Nancy Greep; Andrea Z. LaCroix; Rebecca D. Jackson; Robert B. Wallace; Douglas C. Bauer; Matthew A. Allison; Jane A. Cauley

Cytokines play a major role in bone remodeling in vitro and in animal models, with evidence supporting the involvement of inflammatory markers in the pathogenesis of osteoporosis. However, less is known about the longitudinal association of inflammatory markers with hip fracture. We tested whether high receptor levels of proinflammatory cytokines are associated with an increased risk of hip fracture in older women. We used a nested case‐control study design from the Womens Health Initiative Observational Study (WHI‐OS) and selected 400 cases with physician‐adjudicated incident hip fractures and 400 controls matched on age, race, and date of blood draw. Participants were chosen from 39,795 postmenopausal women without previous hip fractures, not using estrogens or other bone‐active therapies. Incident hip fractures (median follow‐up 7.1 years) were verified by review of radiographs and confirmed by blinded central adjudicators. Hip fractures with a pathological cause were excluded. In multivariable models, the risk of hip fracture for subjects with the highest levels of inflammatory markers (quartile 4) compared with those with lower levels (quartiles 1, 2, and 3) was 1.43 (95% confidence interval [CI], 0.98–2.07) for interleukin‐6 (IL‐6) soluble receptor (SR), 1.40 (95% CI, 0.97–2.03) for tumor necrosis factor (TNF) SR1, and 1.56 (95% CI, 1.09–2.22) for TNF SR2. In subjects with all three markers in the highest quartile, the risk ratio of fracture was 2.76 (95% CI, 1.22–6.25) in comparison with subjects with 0 or 1 elevated marker(s) (p trend = 0.018). Elevated levels of inflammatory markers for all three cytokine‐soluble receptors were associated with an increased risk of hip fractures in older women. Future clinical trials should test whether interventions to decrease inflammatory marker levels reduces hip fractures.


Environmental Research | 2012

Pesticide exposure as a risk factor for amyotrophic lateral sclerosis: A meta-analysis of epidemiological studies ☆: Pesticide exposure as a risk factor for ALS

Angela M. Malek; Aaron Barchowsky; Robert Bowser; Ada O. Youk; Evelyn O. Talbott

BACKGROUND Exposure to pesticides and agricultural chemicals has been linked to amyotrophic lateral sclerosis (ALS) although findings have been inconsistent. A meta-analysis of studies published through May, 2011 was conducted to investigate the association of pesticide exposure and risk of ALS. METHODS Six peer-reviewed studies that met criteria were included in a meta-analysis of men involving 1,517 ALS deaths from one retrospective cohort study and 589 ALS or motor neuron disease cases from five case-control studies. A random effects model was used to calculate sex-specific pooled odds ratios (ORs). RESULTS Evidence was found for an association of exposure to pesticides and risk of ALS in male cases compared to controls (OR=1.88, 95% CI: 1.36-2.61), although the chemical or class of pesticide was not specified by the majority of studies. CONCLUSION This meta-analysis supports the relationship of exposure to pesticides and development of ALS among male cases compared to controls. The weight of evidence links pesticide exposure to ALS; however, additional prospective studies with a target exposure group are necessary to better elucidate the relationship. Future research should focus on more accurate exposure assessment and the use of job exposure matrices.


Journal of Occupational and Environmental Medicine | 2001

Historical cohort study of US man-made vitreous fiber production workers: I. 1992 fiberglass cohort follow-up: initial findings.

Gary M. Marsh; Ada O. Youk; Roslyn A. Stone; Jeanine M. Buchanich; Mary Jean Gula; Thomas J. Smith; Margaret M. Quinn

This 1986 to 1992 update and expansion of an earlier historical cohort study examined the 1946 to 1992 mortality experience of 32,110 workers employed for 1 year or more during 1945 to 1978 at any of 10 US fiberglass (FG) manufacturing plants. Included are (1) a new historical exposure reconstruction for respirable glass fibers and several co-exposures (arsenic, asbestos, asphalt, epoxy, formaldehyde, polycyclic aromatic hydrocarbons, phenolics, silica, styrene, and urea); and (2) a nested, matched case-control study of 631 respiratory system cancer (RSC) deaths in male workers during 1970 to 1992 with interview data on tobacco smoking history. Our findings to date from external comparisons based on standardized mortality ratios (SMRs) in the cohort study provide no evidence of excess mortality risk from all causes combined, all cancers combined, and non-malignant respiratory disease. Also, excluding RSC, we observed no evidence of excess mortality risk from any of the other cause-of-death categories considered. For RSC among the total cohort, we observed a 6% excess (P = 0.05) based on 874 deaths. Among long-term workers (5 or more years of employment) we observed a not statistically significant 3% excess based on 496 deaths. Among the total cohort, we observed increases in RSC SMRs with calendar time and time since first employment, but these were less pronounced among long-term workers. RSC SMRs were not related to duration of employment among the total cohort or long-term workers. In an externally controlled analysis of male workers at risk between 1970 and 1992, we observed no association between RSC SMRs and increasing exposure to respirable FG. Our findings to date from internal comparisons based on rate ratios in the case-control study of RSC were limited to analyses of categorized study variables with and without adjustment for smoking. On the basis of these analyses, the duration of exposure and cumulative exposure to respirable FG at the levels encountered at the study plants did not appear to be associated with an increased risk of RSC. RSC risk also did not seem to increase with time since first employment. There is some evidence of elevated RSC risk associated with non-baseline levels of average intensity of exposure to respirable glass, but when adjusted for smoking this was not statistically significant, and there was no apparent trend with increasing exposure. This same pattern of findings was observed for duration of exposure, cumulative exposure, and average intensity of exposure to formaldehyde. None of the other individual co-exposures encountered in the study plants appeared to be associated with an increased risk of RSC. The primary focus of ongoing analyses is to determine the extent to which our present findings are robust to alternative characterizations of exposure.


Clinical Gastroenterology and Hepatology | 2014

Association Between Telephone Activity and Features of Patients With Inflammatory Bowel Disease

Claudia Ramos Rivers; Miguel Regueiro; Eric J. Vargas; Eva Szigethy; Robert E. Schoen; Michael Dunn; Andrew R. Watson; Marc Schwartz; Jason M. Swoger; Leonard Baidoo; Arthur Barrie; Anwar Dudekula; Ada O. Youk; David G. Binion

BACKGROUND & AIMS Telephone communication is common between healthcare providers and patients with inflammatory bowel disease (IBD). We analyzed telephone activity at an IBD care center to identify disease and patient characteristics associated with high levels of telephone activity and determine if call volume could identify individuals at risk for future visits to the emergency department (ED) or hospitalization. METHODS We performed a prospective observational study in which we categorized telephone calls received by nursing staff over 2 years at a tertiary care IBD clinic (2475 patients in 2009 and 3118 in 2010). We analyzed data on 21,979 ingoing and outgoing calls in 2009 and 32,667 calls in 2010 and assessed associations between clinical factors and logged telephone encounters, and between patterns of telephone encounters and future visits to the ED or hospitalization. RESULTS Telephone encounters occurred twice as frequently as office visits; 15% of the patients generated >10 telephone encounters per year and were responsible for half of all telephone encounters. A higher percentage of these high telephone encounter (HTE) patients were female, had Crohns disease, received steroid treatment, had increased levels of C-reactive protein and rates of erythrocyte sedimentation, had psychiatric comorbidities, and had chronic abdominal pain than patients with lower telephone encounters. The HTE patients were also more frequently seen in the ED or hospitalized over the same time period and in subsequent years. Forty-two percent of patients with >8 telephone encounters within 30 days were seen in the ED or hospitalized within the subsequent 12 months. CONCLUSIONS Based on an analysis of telephone records at an IBD clinic, 15% of patients account for half of all calls. These HTE patients are a heterogeneous group with refractory disease who are likely to visit the ED or be hospitalized.


Journal of Occupational and Environmental Medicine | 2001

Historical cohort study of US man-made vitreous fiber production workers : II. Mortality from mesothelioma

Gary M. Marsh; Mary Jean Gula; Ada O. Youk; Jeanine M. Buchanich; Andrew Churg; Thomas V. Colby

As part of our ongoing mortality surveillance program for the US man-made vitreous fiber (MMVF) industry, we examined mortality from malignant mesothelioma using data from our 1989 follow-up of 3478 rock/slag wool workers and our 1992 follow-up of 32,110 fiberglass workers. A manual search of death certificates for 1011 rock/slag wool workers and 9060 fiberglass workers revealed only 10 death certificates with any mention of the word “mesothelioma.” A subsequent review of medical records and pathology specimens for 3 of the 10 workers deemed two deaths as definitely not due to mesothelioma and one as having a 50% chance of being caused by mesothelioma. Two other deaths, for which only medical records were available, were given less than a 50% chance of being due to mesothelioma. Eight of the 10 decedents had potential occupational asbestos exposure inside or outside the MMVF industry. We also estimated the mortality risk from malignant mesothelioma in the cohort using two cause-of-death categorizations that included both malignant and benign coding rubrics. Using the more comprehensive scheme, we observed overall deficits in deaths among the total cohort and fiberglass workers and an overall excess among rock/slag wool workers. The excess in respiratory system cancer is largely a reflection of elevated lung cancer risks that we attributed mainly to confounding by smoking, to exposures outside the MMVF industry to agents such as asbestos, or to one or more of the several co-exposures present in many of the study plants (including asbestos). The second scheme, which focused on pleural mesothelioma in time periods when specific malignant mesothelioma coding rubrics were available, classified only one cohort death as being caused by malignant mesothelioma, compared with 2.19 expected deaths (local county comparison). We conclude that the overall mortality risk from malignant mesothelioma does not seem to be elevated in the US MMVF cohort.

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Gary M. Marsh

University of Pittsburgh

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Nurtan A. Esmen

University of Illinois at Chicago

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Eva Szigethy

University of Pittsburgh

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Kathleen J. Kennedy

University of Illinois at Chicago

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Roger P. Hancock

University of Illinois at Chicago

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Steven E. Lacey

University of Illinois at Chicago

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