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James A Hanley

Publications and source records attributed to James A Hanley.

At least 37 records · Page 2Linked to original sources
PubMed2005

Analysis of mortality data from cancer screening studies: looking in the right window.

BACKGROUND: Appropriate statistical analysis is required to measure the impact of early detection and treatment of cancer. The current practice of using cumulative mortality ignores both (1) the delay between early treatment and the time that any averted deaths would have otherwise occurred, and (2) cessation of these delayed benefits some time after screening is discontinued. METHODS: We use time-specific mortality density ratios to estimate the mortality ratio in the "window of influence." We then use time-specific incidence density ratios to assess the extent to which the removal of polyps and other possibly precancerous lesions detected by fecal occult blood screening reduces the incidence of colorectal cancer. RESULTS: Applied to a theoretical example, the current practice of using cumulative mortality substantially underestimates the reduction in mortality achievable by early treatment. If there is sufficient time for the full impact to emerge, time-specific mortality patterns provide a more accurate measure. In a previous analysis of the screening study, the reduction in cumulative incidence in the screened groups was just under 20%. In our reanalysis, yearly incidence density ratios indicate that had screening not been interrupted, there might have been a 40% reduction in incidence. CONCLUSIONS: Time-specific mortality ratios provide a more sensitive measure of the effects of early detection and treatment. Measures based on cumulative mortality are diluted by inclusion of deaths that occur soon after the initiation of screening as well as deaths that occur too long after the cessation of screening.

Colorectal Neoplasms↗
PubMed2005

The effect of a task-oriented walking intervention on improving balance self-efficacy poststroke: a randomized, controlled trial.

OBJECTIVES: To evaluate the efficacy of a task-oriented walking intervention in improving balance self-efficacy in persons with stroke and to determine whether effects were task-specific, influenced by baseline level of self-efficacy and associated with changes in walking and balance capacity. DESIGN: Secondary analysis of a two-center, observer-blinded, randomized, controlled trial. SETTING: General community. PARTICIPANTS: Ninety-one individuals with a residual walking deficit within 1 year of a first or recurrent stroke. INTERVENTION: Task-oriented interventions targeting walking or upper extremity (UE) function were provided three times a week for 6 weeks. MEASUREMENTS: Activities-specific Balance Confidence Scale, Six-Minute Walk Test, 5-m walk, Berg Balance Scale, and Timed "Up and Go" administered at baseline and postintervention. RESULTS: The walking intervention was associated with a significantly greater average proportional change in balance self-efficacy than the UE intervention. Treatment effects were largest in persons with low self-efficacy at baseline and for activities relating to tasks practiced. In the walking group, change in balance self-efficacy correlated with change in functional walking capacity (correlation coefficient=0.45, 95% confidence interval=0.16-0.68). Results of multivariable modeling suggested effect modification by the baseline level of depressive symptoms and a prognostic influence of age, sex, comorbidity, time poststroke, and functional mobility on change in self-efficacy. CONCLUSION: Task-oriented walking retraining enhances balance self-efficacy in community-dwelling individuals with chronic stroke. Benefits may be partially the result of improvement in walking capacity. The influence of baseline level of self-efficacy, depressive symptoms, and prognostic variables on treatment effects are of clinical importance and must be verified in future studies.

Adult↗
PubMed2004

Intestinal fatty acid binding protein and microsomal triglyceride transfer protein polymorphisms in French-Canadian youth.

Growing evidence suggests an association between lipid abnormalities and fatty acid binding protein (FABP) and microsomal triglyceride transfer protein (MTP) gene variants. Our objectives were to determine whether Ala54Thr FABP2 and G-493T MTP polymorphisms are associated with increased risks of insulin resistance syndrome (IRS) in youth and/or modify the expression of accompanying dyslipidemia. Our study of 1,742 French-Canadians aged 9, 13, and 16 years did not provide evidence of a potential predisposition to IRS related to either FABP2 or MTP genotypes. However, we observed a heterogeneity of the FABP2 effect by IRS status on total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), and apolipoprotein B (apoB) concentrations (P for interaction=0.045, 0.018, and 0.017, respectively). Among the metabolic components of IRS, only triglyceride (TG) displayed an interaction with FABP2 polymorphism: compared with Thr/Ala and Ala/Ala, the Thr/Thr genotype was associated with a steeper increase in TC, LDL-C, and apoB parallel to TG concentrations (P <0.001). IRS did not modify the associations between the MTP polymorphism and any of the biochemical parameters. Our study suggests that the effects of FABP2 allelic variations on lipid traits are context dependent, indicating that this variant may play an important role in cardiovascular pathogenesis in the presence of IRS or hypertriglyceridemia.

Adolescent↗
PubMed2004

Blood pressure and adiposity in children and adolescents.

BACKGROUND: Although obesity is associated with important hemodynamic disturbances, there are few data on population-wide blood pressure (BP) distribution in children and adolescents in this era of endemic pediatric obesity. METHODS AND RESULTS: We conducted a school-based survey of a representative sample of youth aged 9, 13, and 16 years in Quebec, Canada. Resting BP was measured with an oscillometric device in 3589 subjects (80% response). Additional measures included height, weight, and subscapular and triceps skinfold thickness, an age-appropriate questionnaire, and a fasting blood draw. Mean (SD) systolic/diastolic BP (SBP/DBP) levels in 9-, 13-, and 16-year-olds were 103 (9)/57 (6), 113 (12)/58 (7), and 124 (14)/61 (7) mm Hg in males and 103 (10)/57 (6), 111 (11)/60 (7), and 114 (11)/62 (7) mm Hg in females. The prevalence of high-normal or elevated SBP was 12%, 22%, and 30% among 9-, 13-, and 16-year-old males, respectively, and 14%, 19%, and 17% among same-aged females. The prevalence of high-normal or elevated DBP was <1%. In multiple linear regression analysis, body mass index was consistently associated with SBP and DBP in all age-gender groups. CONCLUSIONS: Mean SBP and the prevalence of high-normal and elevated SBP are elevated in children and adolescents. Public policy, public health programs, and clinical preventive measures are urgently needed to address the obesity epidemic and its hemodynamic consequences.

Adolescent↗
PubMed2004

C-reactive protein and features of the metabolic syndrome in a population-based sample of children and adolescents.

BACKGROUND: C-Reactive protein (CRP) is a risk marker for type 2 diabetes and cardiovascular diseases. In youth, limited data are available on the distribution of high-sensitivity CRP as well as on its association with components of the metabolic syndrome. METHODS: In 1999, we conducted a school-based survey of a representative sample of youths 9, 13, and 16 years of age in the province of Quebec, Canada. Standardized clinical measurements and fasting plasma lipid, glucose, insulin, and CRP concentrations were available for 2224 individuals. RESULTS: The distribution of CRP was positively skewed. The median and 95th percentile values by age and sex ranged from < 0.2 to 0.56 mg/L and from 2.72 to 6.28 mg/L, respectively. A total of 7.7% of 9-year-olds, 5.5% of 13-year-olds, and 12.8% of 16-year-olds had CRP concentrations > 3.0 mg/L, the threshold defining the adult high-risk category. We observed a strong relationship between CRP concentrations and both body mass index (BMI) and fasting insulin values. The association between CRP and insulin concentration was markedly attenuated after adjustment for BMI, whereas that between CRP and BMI remained unchanged after adjustment for insulin: a 1 SD increase in BMI was associated with a 52% increase in CRP concentration. An increased CRP concentration was independently associated with a worsening of the lipid profile, whereas the association between increased CRP values and high systolic blood pressure was no longer statistically significant after adjustment for BMI. CONCLUSIONS: The metabolic correlates of excess weight, including a state of low-grade systemic inflammation, are detectable early in life. Their health impact in adults remains to be fully examined.

Adolescent↗
PubMed2004

Health-related behavior and the use of hormone replacement therapy.

PURPOSE: To study health-related differences between hormone replacement therapy (HRT) users and nonusers among colorectal cases and women without diagnosed cancer. METHODS: Data from the Saskatchewan Health population-based databases were used to ascertain the use of HRT, oral contraceptives (OCs), cardiovascular system (CVS) drugs, central nervous system (CNS) drugs, prescribed NSAIDs and vitamins among 3338 women diagnosed with colorectal cancer and 13025 women without diagnosed cancer. Physician visits and sigmoidoscopy procedures were also determined. RESULTS: Among women without diagnosed cancer, HRT was associated with CVS drugs (OR = 1.23, 95%CI: 1.10-1.37), CNS drugs (OR = 1.96, 95% CI: 1.72-2.23), other hormones (OR = 1.12, 95% CI: 1.01-1.24), prescribed vitamins (OR = 1.37, 95% CI: 1.22-1.55), NSAIDs (OR = 1.41, 95% CI: 1.18-1.68), having had a sigmoidoscopy 3-5 years prior to index dates (OR = 1.33, 95% CI: 1.12-1.59) and 15 or more visits to physicians during the 5th year prior to assigned index date (OR = 2.0, 95% CI: 1.77-2.35). Similar results were observed among women diagnosed with colorectal cancer, but HRT use was not associated with having had a sigmoidoscopy. CONCLUSIONS: Health-related characteristics of HRT users and nonusers are identified and described. Some of these factors may contribute to selection bias in studies examining the health benefits of HRT.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Defining hormone replacement therapy in longitudinal studies: impact on measures of effect.

Data from a nested case-control study, designed to examine the effect of hormone replacement therapy (HRT) on colorectal cancer risk, were analyzed to determine the effect of exposure definition on the estimation of risk ratios (RR). A prescription drug plan database was used to ascertain HRT prescriptions dispensed prior to index dates to cases (n = 3059) and age-matched controls (n = 12,116). HRT exposure was defined as 'prescription' and 'tablet' counts, 'conjugated estrogen only' and a method based on proportions of minimum exposure to a number of estrogens (SUM-P3 and SUM-P12). The effect of HRT was described with reference to 'ever', <5 and > or = 5 years of HRT use. Conditional logistic regression was used to estimate ORs and 95% confidence intervals (CI). Adjusted ORs for 'ever use' of HRT ranged from 0.72 (95%CI: 0.60-0.88) to 0.86 (95%CI: 0.76-0.99); for <5 years use, from 0.70 (95%CI: 0.56-0.88) to 0.89 (95%CI: 0.78-1.01) and for >5 year of HRT use, from 0.74 (95%CI: 0.59-0.92) to 0.98 (95%CI: 0.42-2.26). Various methods used to define HRT exposure produce a range of estimated ORs that vary in magnitude similar to results reported in the literature from observational studies investigating the association between HRT and colorectal cancer.

Aged↗
PubMed2004

Response shift influenced estimates of change in health-related quality of life poststroke.

OBJECTIVE: The interpretability of changes in perceived health status over time is threatened if people experience a response shift. This study assessed whether the recovery process following stroke altered individuals' perceptions of past health status and the impact that change in internal standards (response shift) had on ratings over time. We hypothesized that individuals with stroke would experience changes in internal standards, not experienced by the control group. Two other hypotheses related to objective criterion measures also were tested. STUDY DESIGN AND SETTING: Individuals were recruited through a randomized trial of acute poststroke care. Health status was evaluated at baseline (within the first week poststroke), 6 and 24 weeks later using the EQ VAS. At 6 and 24 weeks, subjects were asked to retrospectively re-evaluate their health status for the preceding evaluation using the then test technique. RESULTS: The pattern of mean scores was indicative of changes in internal standards among individuals with stroke but not for the control group. Memory had an impact on estimates of response shift. Hypotheses related to the objective criterion measures were not supported. CONCLUSION: The results suggest that there was a change in internal standards, and that measures of improvement in health status are different based on prospective as compared to retrospective ratings. Further understanding of the impact of recall on the assessment of response shift using the then test is needed to validate the use of this technique.

Aged↗
PubMed2004

Validation of increasing prostate specific antigen as a predictor of prostate cancer death after treatment of localized prostate cancer with surgery or radiation.

PURPOSE: Many patients who undergo surgery or radiation therapy to treat localized prostate cancer experience an increase in serum prostate specific antigen (PSA) after treatment. This study documents patterns of PSA recurrence after surgery or radiation to treat localized prostate cancer and quantifies the extent to which an increasing PSA predicts death from prostate cancer. MATERIALS AND METHODS: Posttreatment PSA levels were measured on a population based cohort of 1136 men diagnosed with localized prostate cancer in community practice in Connecticut between 1990 and 1992, and treated within 6 months of diagnosis with surgery or radiation with or without androgen withdrawal therapy. The major outcome measure was death from prostate cancer. RESULTS: PSA recurrence followed a log-linear pattern over time. Patients who died of prostate cancer had a median PSA doubling time of 0.8 years (25th and 75th percentiles 0.5 to 1.4 years). Patients who did not die of prostate cancer within 10 years of diagnosis had either no posttreatment increase in serum PSA (40%) or had a PSA doubling time longer than 1 year (44%). CONCLUSIONS: Patients whose posttreatment PSA doubling times before the initiation of androgen withdrawal therapy are less than 1 year are at high risk of dying of prostate cancer within 10 years of diagnosis. Men with PSA recurrences that are doubling at rates greater than 1 year are at low risk of death from prostate cancer within 10 years of diagnosis.

Aged↗
PubMed2003

Effect of ultraviolet germicidal lights installed in office ventilation systems on workers' health and wellbeing: double-blind multiple crossover trial.

BACKGROUND: Workers in modern office buildings frequently have unexplained work-related symptoms or combinations of symptoms. We assessed whether ultraviolet germicidal irradiation (UVGI) of drip pans and cooling coils within ventilation systems of office buildings would reduce microbial contamination, and thus occupants' work-related symptoms. METHODS: We undertook a double blind, multiple crossover trial of 771 participants. In office buildings in Montreal, Canada, UVGI was alternately off for 12 weeks, then turned on for 4 weeks. We did this three times with UVGI on and three times with it off, for 48 consecutive weeks. Primary outcomes of self-reported work-related symptoms, and secondary outcomes of endotoxin and viable microbial concentrations in air and on surfaces, and other environmental covariates were measured six times. FINDINGS: Operation of UVGI resulted in 99% (95% CI 67-100) reduction of microbial and endotoxin concentrations on irradiated surfaces within the ventilation systems. 771 participants appeared to remain masked, and reported no adverse effects. On the basis of within-person estimates, use of UVGI was associated with significantly fewer work-related symptoms overall (adjusted odds ratio 0.8 [95% CI 0.7-0.99]), as well as respiratory (0.6 [0.4-0.9]) and mucosal (0.7 [0.6-0.9]) symptoms than was non-use. Reduction of work-related mucosal symptoms was greatest among atopic workers (0.6 [0.5-0.8]), and never-smokers (0.7 [0.5-0.9]). With UVGI on, never-smokers also had large reduction of work-related respiratory (0.4 [0.2-0.9]), and musculoskeletal symptoms (0.5 [0.3-0.9]). INTERPRETATION: Installation of UGVI in most North American offices could resolve work-related symptoms in about 4 million employees, caused by microbial contamination of heating, ventilation, and air-conditioning systems. The cost of UVGI installation could in the long run prove cost-effective compared with the yearly losses from absence because of building-related illness.

Adult↗
PubMed2003

Statistical analysis of correlated data using generalized estimating equations: an orientation.

The method of generalized estimating equations (GEE) is often used to analyze longitudinal and other correlated response data, particularly if responses are binary. However, few descriptions of the method are accessible to epidemiologists. In this paper, the authors use small worked examples and one real data set, involving both binary and quantitative response data, to help end-users appreciate the essence of the method. The examples are simple enough to see the behind-the-scenes calculations and the essential role of weighted observations, and they allow nonstatisticians to imagine the calculations involved when the GEE method is applied to more complex multivariate data.

Body Height↗
PubMed2003

Evolution of the caregiving experience in the initial 2 years following stroke.

Relationships between stroke survivor and family caregiver factors and the caregiver's health-related quality of life (HRQL) and overall quality of life (QoL) were examined in 97 dyads during the first and second years after stroke. Compared to age- and sex-matched population norms, caregivers scored significantly lower on the mental subscales of HRQL, and differences were greater for women than for men. Caregiver characteristics (older age, less burden, and fewer physical symptoms) were associated with better HRQL (mental summary scale) in the first year, with similar findings in the second year. Moderate stroke survivor physical impairment and caregiver characteristics (younger age and better HRQL) were associated with better QoL in the first year. During the second year poorer caregiver physical and mental health and caring for a stroke survivor with communication difficulties were associated with diminished QoL.

Aged↗
PubMed2003

Effect of nonsteroidal anti-inflammatory drugs on stage of colon cancer at diagnosis.

BACKGROUND AND OBJECTIVE: We investigated the effect of nonsteroidal anti-inflammatory drug (NSAID) use on stage of colon cancer and presence of distant metastases at diagnosis. METHODS: Cases of incident colon cancer diagnosed between 1981 and mid-1995 were selected from the Saskatchewan Cancer Registry. Cases with more extensive cancer at diagnosis were compared with cases with less extensive cancer (characterized using the Dukes system). NSAID exposure was assessed using the Saskatchewan Prescription Drug Plan database. RESULTS: Compared with non-users in the same period, nonmetastatic cancer was found to be less extensive in those with low NSAID use (odds ratio [OR] 0.67, 95% confidence interval [CI] 0.53-0.87) and high NSAID use (OR 0.55, 95%CI 0.36-0.84) during the 6 to 10 year periods preceding diagnosis, regardless of the cut-off used to define "more extensive cancer." NSAID use in the 2 to 5 year periods was also found to protect (although not statistically significantly) against the occurrence of distant metastasis. CONCLUSION: Results are consistent with the hypothesized mechanism of the action of NSAIDs, but confounding by healthy lifestyle cannot be ruled out.

Aged↗
PubMed2003

Physician and practice characteristics associated with the early utilization of new prescription drugs.

BACKGROUND: Prescription of new drugs contributes to substantial increases in annual drug expenditures. A small proportion of physicians appear to be early users of new prescription drugs and little is known about their characteristics. OBJECTIVE: To estimate the initial utilization rate of new prescription drugs among physicians, and the physician and practice characteristics associated with early use. DESIGN: Cumulative prospective assessment over a 5 year period (1989-1994) of new drug utilization rates in a randomly selected cohort of Quebec physicians. PARTICIPANTS: 1661 physicians and 669,867 elderly patients. OUTCOME: Prescribing rate of 20 new drugs, in 6 therapeutic categories, to elderly patients in the first 6 months after inclusion in the Quebec formulary. RESULTS: The 20 new drugs were prescribed by 1.3-22.3% of physicians, and there was an 8 to 17-fold difference in new drug utilization rates among prescribers. Characteristics associated with higher rates of utilization differed for general practitioners and specialists. Male general practitioners, and physicians graduating from the most recently established medical school in the province, had higher rates of new drug utilization, whereas recent graduation was only associated with higher utilization rates among specialists. Practice volume was associated with higher rates of utilization among GPs. For both GPs and specialists, having a high proportion of elderly in one's practice and a rural or remote practice location was associated with lower utilization rates. CONCLUSIONS: Physician sex, specialty, medical school, years since graduation, practice location, volume, and relative proportion of elderly in the physician's practice influence the utilization of new drugs.

Age Factors↗
PubMed2003

Factors associated with pattern of care before surgery for breast cancer in Quebec between 1992 and 1997.

BACKGROUND: Practice guidelines for breast cancer emphasize the importance of establishing an accurate diagnosis using a minimum number of procedures and selecting optimal treatment regimens. Understanding the determinants of waiting time is essential to develop optimum interventions to reduce delay. OBJECTIVES: The purpose of this study is to estimate the extent to which variability in 1) the number of procedures before surgery and 2) waiting time from initial procedure to surgery are explainable by factors related to the woman, to the provider, and to the care setting. RESEARCH DESIGN: Records of physicians' fee-for-service claims were obtained for 23,370 women undergoing breast cancer surgery in Quebec between 1992 and 1997. Multilevel logistic regression was used to determine predictors of having multiple procedures before surgery. Hierarchical linear regression models were used to identify predictors of waiting time, separately for women with lymph node involvement and without this involvement. RESULTS: Overall, 23% of the women had 3 or more procedures before surgery with significant variation found across hospitals and surgeons. Number of procedures was a strong predictor of waiting time. Waiting time also varied by stage, age, comorbidity, a history of benign disease, surgical setting, calendar time, month of initial procedure, and hospital teaching status. CONCLUSION: Although variability in waiting time was more strongly influenced by the characteristics of the women rather than by physician- or hospital-related factors, most variation remained unexplained by the factors included in this study. To reduce overall waiting time, strategies would need to be systemically applied.

Adult↗
PubMed2003

Distribution of fasting plasma insulin, free fatty acids, and glucose concentrations and of homeostasis model assessment of insulin resistance in a representative sample of Quebec children and adolescents.

BACKGROUND: Plasma fasting insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) are markers of IR, which, at least in part, mediates the relation of obesity to increased cardiovascular risk. Increased free fatty acids (FFAs) may be involved in the pathogenesis of IR. Our objectives were to describe the distributions of fasting plasma insulin, glucose, and FFAs and HOMA-IR in youth and to assess the relationship between FFAs and markers of IR. METHODS: Fasting plasma insulin, glucose, and FFAs were measured in a representative sample of Quebec youth comprising 2244 individuals 9, 13, and 16 years of age. RESULTS: In all age and sex groups, glucose exhibited remarkably tight distributions (median CV, 7.1%) in contrast to insulin, HOMA-IR, and FFAs (median CVs, 52%, 54% and 45%, respectively). For every percentile examined, 9-year-olds had lower insulin concentrations and HOMA-IR values than 13- and 16-year-olds. We observed strong correlations between insulin concentrations and HOMA-IR values, as well as close similarity in their rankings of individuals. The mean concentrations of glucose were higher in our population than in other Caucasian pediatric populations. No positive correlations were detected between FFAs and markers of IR. CONCLUSIONS: We report some of the first data on the distributions of fasting plasma insulin, HOMA-IR, and FFAs from a representative sample of youth. HOMA-IR does not appear more informative than fasting insulin as a marker of IR. Our findings on higher mean glucose concentrations in this population require confirmation in other representative samples of youth to assess whether the North American distribution of glucose concentrations is shifting positively.

Adolescent↗
PubMed2003

The Québec Child and Adolescent Health and Social Survey: design and methods of a cardiovascular risk factor survey for youth.

BACKGROUND: Although atherosclerosis begins in childhood, there are no recent Canadian data on cardiovascular risk factors in provincially or nationally representative samples of youth. OBJECTIVE: To describe the design and methods of the 1999 Québec Child and Adolescent Health and Social Survey, which assessed the prevalence and distribution of risk factors in a representative sample of Québec youth. METHODS: School-based, multistage, cluster sampling survey of youth aged nine, 13 and 16 years. Measures included height, weight, subscapular and tricipital skinfolds, blood pressure (measured with the Dinamap), a fasting blood draw for assessment of lipoproteins and glucose, an age-adapted youth questionnaire on lifestyles and a parent questionnaire. RESULTS: One thousand two hundred sixty-seven, 1186 and 1160 subjects aged nine, 13 and 16 years, respectively, responded to the questionnaire and had height, weight, skinfold thickness and blood pressure measured (response proportions of 83%, 79% and 78% respectively); 783, 818 and 874 subjects of the same age agreed to the blood draw (response proportions of 52%, 55% and 59%, respectively). Comparisons of characteristics of participants and nonparticipants in the blood draw showed few differences. The mean relative difference between lipoprotein and glucose values obtained at the study laboratory and a reference method varied from -0.3% to 6.1%. Design effects for means and proportions varied from 1.0 to 1.8. CONCLUSION: Despite its complexity, this survey was able to achieve a high level of precision for multiple measures. It will provide the most complete data on cardiovascular risk factors ever collected among children and adolescents in Canada.

Adolescent↗