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Janet M Raboud

Publications and source records attributed to Janet M Raboud.

7 recordsLinked to original sources
PubMed2005

Light and exercise and melatonin production in women.

Melatonin may protect against breast cancer. Light and other factors influence melatonin, but the evidence is limited. The authors conducted a study to determine factors related to melatonin. Women volunteers recruited in Toronto, Canada, from 2002 to 2004 collected urine for three nights (winter and summer), took periodic light measurements, and recorded exposures in a diary. The relation of each variable to log-transformed creatinine-corrected 6-sulfatoxymelatonin in overnight urine was determined by use of generalized estimating equation linear regression. The final model was based on 1,054 measurement days from 213 participating women. None of the light variables was related to the log of 6-sulfatoxymelatonin. A significant interaction between season and day length was included in the final model. The most significant factor was duration of exercise (beta = 0.072; p = 0.004, two-tailed), which increased the amount of melatonin produced. Exercise duration later in the day was more significant (beta = 0.108; p = 0.0009, two-tailed). There was no difference between moderate or strenuous exercise. The failure to find a relation between light brightness and melatonin may be due to the difficulty of measuring this, as well as the importance of the light spectrum, which could not be measured. It is possible that the protective effect of exercise with respect to breast cancer may operate in part through an effect on melatonin.

Adult↗
PubMed2005

Nonfinancial factors associated with decreased plasma viral load testing in Ontario, Canada.

OBJECTIVE: To examine whether individual characteristics were associated with differential use of viral load testing when testing is available without charge to all HIV-positive patients with provincial health insurance. METHODS: Individuals enrolled in the HIV Ontario Observational Database with complete medication records and health insurance numbers for linkage were studied. Generalized estimating equation regression models were used to examine the relationship between time-varying covariates such as plasma viral load levels, CD4 counts, and antiretroviral regimen characteristics and the number of days between viral load tests and the occurrence of an interval of >or=6 or 9 months between tests. RESULTS: A total of 1032 individuals were included in the analysis with a median follow-up of 4.6 years and a median of 18 viral load tests. In multivariate analyses, clinically important gaps in viral load testing were more likely among injection drug users (odds ratio [OR]=1.86, P<0.0001), in more recent years (P<0.01) and for individuals not using antiretrovirals (OR=1.70, P<0.0001) and less likely among individuals using >4 antiretrovirals (OR=0.62, P<0.0001). Results were similar when the outcome was the number of days between tests. CONCLUSIONS: Injection drug users, younger individuals, and residents of Toronto used fewer viral load tests than other individuals, even when financial barriers to testing were removed.

Adult↗
PubMed2004

Implications of the age range in a population-based BRCA1 testing program with eligibility based on family history of breast and ovarian cancer.

The current options available to BRCA1 mutation carriers can be classified as either cancer risk reduction or increased disease surveillance. Risk reduction might be preferable to young women. Increased surveillance might be more attractive to women when their cancer risk is highest. The aim of this report is to estimate the sensitivity, specificity and ability to detect carriers for a population-based BRCA1 testing program with eligibility based on family history of cancer, and examine the effect of age on the program's performance. A computer model was used to simulate the incidence of breast and ovarian cancer in a woman's family, based on her BRCA1 mutation carrier status. Age-specific estimates of the sensitivity and specificity for family history as an indicator of mutation status were applied to local population figures. Sensitivity of the program increased with the age of the proband and the size of her family. Sensitivity ranged from 0.33 for 20-year-olds with small families, to 0.98 for 60-year-olds with large families. Specificity was greater than 0.95, regardless of a woman's age or family size. If 0.12% of people carry a BRCA1 mutation, a province-wide testing program for people aged 20-69 with referrals based only on family history would have a sensitivity of 0.55. Only 2% of the genetic test results would be positive. The acceptability of a genetic testing program depends on its sensitivity and specificity, and on the options available to women who are found to carry a mutation. Compared with variation due to family size, the program sensitivity and specificity does not differ substantially amongst the various age groups.

Adult↗
PubMed2004

Predictive value of HIV-1 protease genotype and virtual phenotype on the virological response to lopinavir/ritonavir-containing salvage regimens.

The predictive values of HIV-1 protease genotype and virtual phenotype (vPhenotype) results on the HIV-1 RNA response to lopinavir/ritonavir (LPV/r)-containing salvage regimens were assessed. Data were evaluated from patients with antiretroviral (ARV) resistance testing prior to initiating an LPV/r-containing salvage ARV regimen, from two independent cohorts from Toronto, Ontario and British Columbia, Canada. Multivariate logistic regression models controlling for previous non-nucleoside reverse transcriptase inhibitor use, baseline viral load and AIDS-defining illness were used to assess the impact of different protease genotypic mutations (individual and in combination) and lopinavir vPhenotyping on virological suppression to <50 copies/ml by 12 months. We confirmed that the 11-mutation 'lopinavir mutation score' (LMS) was significantly inversely associated with the probability of virological suppression within 12 months [odds ratio (OR)=0.91; P=0.02]. The only single specific protease mutation found to predict virological response in multivariate analyses was 461 (OR=0.55; P=0.02). The most predictive three-mutation combination was 10F/I/R/V, 461, 82A/F/T (OR=0.18; P=0.0004). We confirmed that a 10-fold increase of lopinavir IC50 is an appropriate clinical cut-off for lopinavir vPhenotype. In univariate analyses, a cut-off of the LMS as low as 3 was significantly associated with a lack of virological suppression (P=0.04). This finding, which is in contrast to those of other studies, may be due to the high degree of ARV experience of our population and lack of active agents in the salvage regimen. Selecting the 11 specific mutations to make the LMS is potentially arbitrary; we determined that when different combinations of 11 protease mutations were chosen randomly from a set of 30, similar associations with virological response were found, probably due to the co-linearity of these mutations.

Adult↗
PubMed2002

Consecutive rebounds in plasma viral load are associated with virological failure at 52 weeks among HIV-infected patients.

OBJECTIVES: To describe the characteristics and predictors of transient plasma viral load (pVL) rebounds among patients on stable antiretroviral therapy and to determine the effect of one or more pVL rebounds on virological response at week 52. METHODS: Individual data were combined from 358 patients from the INCAS, AVANTI-2 and AVANTI-3 studies. Logistic regression models were used to determine the relationship between the magnitude of an increase in pVL and the probability of returning to the lower limit of quantification (LLOQ: 20-50 copies/ml) and to determine the odds of virological success at 52 weeks associated with single and consecutive pVL rebounds. RESULTS: A group of 165 patients achieved a pVL nadir < LLOQ; of these, 85 patients experienced pVL rebounds within 52 weeks. The probability of a pVL rebound was greater among patients who did not adhere to treatment (68% vs 49%; P < 0.05). The probability of reachieving virological suppression after a pVL rebound was not associated with the magnitude of the rebound [odds ratio (OR), 0.86; P = 0.56] but was associated with triple therapy (OR, 2.22; P = 0.06) or non-adherence (OR, 0.40; P = 0.04). The probability of virological success at week 52 was not associated with an isolated pVL rebound but was less likely after detectable pVL at two consecutive visits. CONCLUSIONS: An isolated pVL rebound was not associated with virological success at 52 weeks but rebounds at two consecutive visits decreased the probability of later virological success. Given their high risk of short-term virological failure, patients who present with consecutive detectable pVL measurements following complete suppression should be considered ideal candidates for intervention studies.

Antiretroviral Therapy, Highly Active↗
PubMed2002

The effect of an education program on violence in the emergency department.

STUDY OBJECTIVE: We examine whether a specific educational effort reduces emergency department violence in the short term and quantify the amount of violence in the ED. METHODS: Cross-sectional prospective surveys were conducted at a tertiary referral center at baseline (1998) and at 3 and 6 months (1999) after the Prevention and Management of Aggressive Behavior Program (PMABP). ED staff on all shifts for 7 alternate days in a 2-week period were surveyed. We measured the total and mean number of physical and violent events per survey. A generalized estimating equation Poisson regression model examined the effect of the program on the numbers of physically and verbally violent events per shift per employee, after adjusting for other covariates. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. RESULTS: Physical violence events per survey at baseline, 3 months posttraining, and 6 months posttraining were 0.27, 0.10, and 0.21, respectively. The number of reported violent interactions at the same intervals were 49, 19, and 46 (adjusted OR 1.0, 0.35 [95% CI 0.15 to 0.84], and 0.79 [95% CI 0.48 to 1.40]), respectively. Verbal violence events per survey at baseline, 3 months posttraining, and 6 months posttraining were 0.85, 0.31, and 0.51, respectively. The number of reported interactions involving verbal violence at the same intervals were 154, 58, and 69 (adjusted OR 1.0, 0.31 [95% CI 0.21 to 0.46], and 0.47 [95% CI 0.33 to 0.66]), respectively. CONCLUSION: Violent events are frequent in the ED. Education programs may reduce the number of events at least temporarily but do not clearly reduce violence in the long term.

British Columbia↗