Previous research updated the mortality experience of North American synthetic rubber industry workers during the period 1944-1998, determined if leukemia and other cancers were associated with several employment factors and carried out Poisson regression analysis to examine exposure-response associations between estimated exposure to 1,3-butadiene (BD) or other chemicals and cancer. The present study used Cox regression procedures to examine further the exposure-response relationship between several unlagged and lagged, continuous, time-dependent BD exposure indices (BD parts per million (ppm)-years, the total number of exposures to BD concentrations >100 ppm ("peaks") and average intensity of BD) and leukemia, lymphoid neoplasms and myeloid neoplasms. All three BD exposure indices were associated positively with leukemia. Using continuous, untransformed BD ppm-years the regression coefficient (beta) from an analysis that controlled only for age was 2.9 x 10(-4) (p
1,3-Butadiene has been assessed as a Priority Substance under the Canadian Environmental Protection Act. The general population in Canada is exposed to 1,3-butadiene primarily through ambient air. Inhaled 1,3-butadiene is carcinogenic in both mice and rats, inducing tumors at multiple sites at all concentrations tested in all identified studies. In addition, 1,3-butadiene is genotoxic in both somatic and germ cells of rodents. It also induces adverse effects in the reproductive organs of female mice at relatively low concentrations. The greater sensitivity in mice than in rats to induction of these effects by 1,3-butadiene is likely related to species differences in metabolism to active epoxide metabolites. Exposure to 1,3-butadiene in the occupational environment has been associated with the induction of leukemia; there is also some limited evidence that 1,3-butadiene is genotoxic in exposed workers. Therefore, in view of the weight of evidence of available epidemiological and toxicological data, 1,3-butadiene is considered highly likely to be carcinogenic, and likely to be genotoxic, in humans. Estimates of the potency of butadiene to induce cancer have been derived on the basis of both epidemiological investigation and bioassays in mice and rats. Potencies to induce ovarian effects have been estimated on the basis of studies in mice. Uncertainties have been delineated, and, while there are clear species differences in metabolism, estimates of potency to induce effects are considered justifiably conservative in view of the likely variability in metabolism across the population related to genetic polymorphism for enzymes for the critical metabolic pathway.
The purpose of this study was to investigate the 5-year outcome following transcatheter aortic valve implantation (TAVI).
Little is known about long-term outcomes following TAVI.
The 5-year outcomes following successful TAVI with a balloon-expandable valve were evaluated in 88 patients. Patients who died within 30 days after TAVI were excluded.
Mean aortic valve gradient decreased from 46 ± 18 mm Hg to 10 ± 4.5 mm Hg after TAVI and 11.8 ± 5.7 mm Hg at 5 years (p for post-TAVI trend = 0.06). Mean aortic valve area increased from 0.62 ± 0.17 cm(2) to 1.67 ± 0.41 cm(2) after TAVI and 1.40 ± 0.25 cm(2) at 5 years (p for post-TAVI trend
The purpose of the study was to examine the 7-year stability of systolic (SBP) and diastolic (DBP) blood pressures in the Canadian population.
The sample included 1,503 participants 7-69 years of age from the 1981 Canada Fitness Survey who were remeasured in Campbell's Survey of 1988. Both SBP and DBP were adjusted for the effects of body mass index (BMI) using regression procedures.
Interage correlations from baseline to follow-up ranged from -0.17 to 0.61 for SBP and from -0.22 to 0. 51 for DBP. With few exceptions, correlations were positive and significant, and were highest and most consistent in adulthood. Further, between 27 and 39% of participants in the upper or lower quintiles in 1981 remained there in 1988. There were few differences in adiposity between those who remained in the upper or lower quintiles and those who did not. One exception was that males who remained in the upper quintile of SBP had greater values for BMI, sum of skinfolds, and waist circumference at baseline. Among adults, the best predictor of future blood pressure was baseline blood pressure, which accounted for between 12 and 34% of the variance in follow-up blood pressure, followed by age, follow-up BMI, and, in females, baseline physical activity levels.
Blood pressure demonstrated low to moderate stability over 7 years in Canada, and baseline level of adiposity was related to the stability of SBP in males.
p-Phenylenediamine (PPD) is an important allergen; 5.0% of patients tested positive to PPD when patch-tested, according to the North American Contact Dermatitis Group. Hair dyes are the main source of exposure.
To assess the significance of PPD allergy at the Ottawa Patch Test Clinic.
We assessed the epidemiology of PPD allergies and determined the cross-reactivity with other para-amino compounds. Charts of patients visiting the Ottawa Patch Test Clinic between May 1997 and July 2009 were reviewed.
One hundred thirty-four patients were found to have a contact allergy to PPD; 75.4% were female, 24.6% were male, 13.4% were hairdressers, 18.7% had a history of atopy, 90.3% were sensitized by hair dye, 2.2% were sensitized by henna tattoos, and 7.5% were sensitized by other sources. Positive patch-test reactions to textile dyes were seen in 24.6%, 7.5% reacted to benzocaine, 6.0% reacted to sulfa drugs, 1.5% reacted to isopropyl-para-phenylenediamine, and 1.5% reacted to para-aminobenzoic acid.
PPD is an important source of allergic contact allergy. Our results show a significant relationship of PPD with other related para-amino compounds.
While a number of studies have documented higher period prevalence rates of depression among single as compared to married mothers, all of the data have been based upon community surveys of mental illness. In Canada, all of the published work comes from Ontario. As a result, we do not know whether these results hold true for other regions of the country. Using a nationally representative sample, we find, consistent with previous work, that single mothers have almost double the 12-month prevalence rates of married mothers (15.4% versus 6.8%). As well, there are no significant differences in rates of depression between single and married mothers by region/province of the country. Our findings are compared with other epidemiologic data on the mental health of single mothers from Ontario.
The aim of this study was to provide a temporal-spatial reference of adverse pregnancy outcomes (APO) and examine whether endometriosis promotes APO in the same population. Among the 31?068 women who had a pregnancy between 1997 and 2008 in Eastern Townships of Canada, 6749 (21.7%) had APO. These APO increased significantly with maternal age and over time (r(2?)=?0.522, p?=?0.008); and were dominated by preterm birth (9.3%), pregnancy-induced hypertension (8.3%) including gestational hypertension (6.5%), low birth weight (6.3%), gestational diabetes (3.4%), pregnancy loss (2.2%) including spontaneous abortion (1.5%) and stillbirth (0.6%), intrauterine growth restriction (2.1%) and preeclampsia (1.8%). Among the 31?068 pregnancies, 784 (2.5%) had endometriosis and 183 (23.3%) had both endometriosis and APO. Endometriosis has been shown to increase the incidence of fetal loss (OR?=?2.03; 95% CI?=?1.42-2.90, p?