OBJECTIVES: To determine the trends in overall and age-specific rates of coronary artery bypass grafting (CABG) in Ontario from 1981 to 1989 and to assess whether relative resource scarcity, as manifested in waiting lists, resulted in obvious age-related or sex-related changes in utilization. DESIGN: Computerized compilation of hospital discharge abstracts from the Hospital Medical Records Institute. All separations for every other year from Apr. 1, 1981, to Mar. 31, 1990, were included. Procedures rather than patients were the unit of analysis (repeat procedures were double-counted if associated with separate hospital admissions). SETTING: Ontario acute care hospitals offering CABG. PATIENTS: People aged 20 years and over who underwent one or more CABG procedures. RESULTS: The overall rate of CABG increased by 31% in the study period, plateauing only between 1983 and 1985. By 1989-90 the rate was 66.03 per 100,000. The highest annual increase in the rate was among people aged 65 to 74 years, at 17.61 procedures per 100,000, as compared with 4.64 per 100,000 among people 75 years and over. In 1989-90 those aged 65 and over represented 37% of the total caseload. The overall male:female ratio did not change significantly throughout the study period. CONCLUSIONS: Since the CABG utilization rate continues to increase in Ontario...

In 1977 the rate of death from testicular cancer in Ontario began to decline following a long period of relative stability. This coincided with the addition of cisplatin to the chemotherapeutic regimens used in the treatment of disseminated germ-cell testicular cancer. A study was carried out to determine whether the decline has been similar for the two major histologic subgroups, seminoma and nonseminoma. By means of Ontario Cancer Registry data, histologic type was determined for all testicular cancers causing death in Ontario residents between 1964 and 1982, and death rates were calculated for seminoma and nonseminoma germ-cell testicular cancer. The rates of death from nonseminoma exceeded those from seminoma for the entire study period. Although the death rates for both subgroups declined by about 50% after 1976, the reduction in the overall rate of death from testicular cancer is primarily attributable to the decline in the rate for nonseminoma germ-cell testicular cancer. The increased overall rate of death from testicular cancer (all types) between 1980 and 1984 is cause for concern and indicates the need for continued monitoring of the trends in rates of death from this disease.

OBJECTIVES. Our objectives were (1) to describe an analysis of the spatial pattern of cancer incidence in Ontario and (2) to discuss the quality of data in the Ontario Cancer Registry with respect to the accuracy of local cancer rates. METHODS. Cancer incidence rates were calculated for 22 cancer sites in 49 counties of Ontario during 1976 to 1986. Capture-recapture methods were used to estimate completeness of case registration, and completeness of residence information was also assessed. Spatial autocorrelation was used in measuring the geographic pattern of incidence rates. Comparisons were also made between sexes and with earlier data from 1966 to 1975. RESULTS. The quality of the geographic data in the registry appeared good, and corrections for incomplete or inaccurate registration had little impact. About one third of the sex-site combinations showed some evidence of spatial patterning in the cancer rate. Particularly strong regional variation was noted for cancers of the stomach, lung, uterus, and prostate. CONCLUSIONS. The analysis revealed a number of cancers with significant spatial patterning of risk. Further work is needed to relate the cancer data to other information on potential life-style and environmental factors.

A serological study was undertaken to determine whether dogs in Ontario are being exposed to Borrelia burgdorferi, the etiological agent of Lyme disease. This study consisted of a survey of randomly selected dogs and testing of diagnostic submissions from candidate Lyme disease cases. The survey of 1,095 dogs, bled between January 1988 and August 1989, revealed a total of 65 (5.9%) enzyme-linked immunosorbent assay (ELISA) reactors, of which 22 had immuno-fluorescent antibody assay (IFA) titers ≥1:32. All but one of the IFA-positive and 10 of the ELISA-positive, IFA-negative sera were further tested by western blot. Eight western blot positive and three equivocal reactors were obtained. Three of the eight confirmed reactors had visited areas known to be endemic for Lyme disease, leaving five reactors that might have been infected in previously undocumented areas for B. burgdorferi activity in Ontario. Diagnostic submissions of sera from 223 dogs were received between August 1987 and February 1992. Test results revealed 21 (9.4%) IFA reactors, of which only six had significant titers (≥1:256) and were reactive by an immunodot Borrelia test. All six dogs had travelled to known Lyme endemic areas. Based on results obtained from this study...

To determine the feasibility of wholly referral practice in internal medicine within a prepaid health service, the practice profiles of 694 internists in metropolitan, nonmetropolitan urban, and rural areas of Ontario were delineated by analysis of data from questionnaires and health-insurance billing. The questionnaire showed that two thirds of internists, chiefly younger practitioners, confined themselves to a referral consultant practice; the other one third included primary care. Subspecialists practised predominantly in metropolitan areas; most general internists in such areas provided primary care, whereas most general internists elsewhere had an entirely referral practice. This pattern of practice is greatly different from that in the United States but probably similar to that in other provinces in Canada. Extension of wholly referral practice to all internists in Ontario appears feasible, provided the numbers entering residency training are controlled. The present Ontario curricula for internal medicine and its subspecialties appear suitable for such a pattern of practice.

We assessed population-based trends in incidence and survival rates for epithelial ovarian cancer in Ontario in two time periods. Our population-based study cohort included all women with epithelial ovarian cancer treated initially with abdominal surgery in Ontario for January 1996 through December 2001. Incident surgical cases were documented by hospital contact data and the Ontario Cancer Registry. Patient characteristics (age, for example) were obtained from electronic administrative data records. Regression analyses were used to assess the influence of time period on survival while controlling for age, comorbidity, and other factors associated with this outcome.

We carried out a cross-sectional study to investigate antimicrobial resistance patterns of Campylobacter coli isolated from Ontario grower-finisher pigs. From January to June 2004, 1200 samples were collected from 80 farms by obtaining a constant number (15) of fecal samples per farm. Susceptibility of the isolates to 11 antimicrobial drugs was determined by the agar-dilution technique. The overall prevalence of resistance to 1 or more antimicrobials among the isolates was 99.2%. High levels of resistance were observed for azithromycin, clindamycin, erythromycin, streptomycin, and tetracycline: 91.7%, 82.5%, 81.4%, 70.7%, and 63.7%, respectively. For sulfamethoxazole, ampicillin, and nalidixic acid, resistance was observed in 40.3%, 26.6%, and 22.7% of the isolates, respectively. Although at very low levels, resistance was observed for ciprofloxacin (a fluoroquinolone), chloramphenicol, and gentamicin: in 2.4%, 1.7%, and 0.2%, respectively. Many of the isolates (29.7%) were resistant to 5 antimicrobials, the most common being azithromycin, clindamycin, erythromycin, streptomycin, and tetracycline. Isolates from the same farm showed at least 5 patterns of resistance. Results from this study indicate high levels of resistance to the antimicrobial drugs most commonly used in the Canadian swine industry (macrolides...

The molecular diversity of rumen methanogens in feedlot cattle and the composition of the methanogen populations in these animals from two geographic locations were investigated using 16S rRNA gene libraries prepared from pooled PCR products from 10 animals in Ontario (127 clones) and 10 animals from Prince Edward Island (114 clones). A total of 241 clones were examined, with Methanobrevibacter ruminantium accounting for more than one-third (85 clones) of the clones identified. From these 241 clones, 23 different 16S rRNA phylotypes were identified. Feedlot cattle from Ontario, which were fed a corn-based diet, revealed 11 phylotypes (38 clones) not found in feedlot cattle from Prince Edward Island, whereas the Prince Edward Island cattle, which were fed potato by-products as a finishing diet, had 7 phylotypes (42 clones) not found in cattle from Ontario. Five sequences, representing the remaining 161 clones (67% of the clones), were common in both herds. Of the 23 different sequences, 10 sequences (136 clones) were 89.8 to 100% similar to those from cultivated methanogens belonging to the orders Methanobacteriales, Methanomicrobiales, and Methanosarcinales, and the remaining 13 sequences (105 clones) were 74.1 to 75.8% similar to those from Thermoplasma volcanium and Thermoplasma acidophilum. Overall...

This study evaluated the impact of province-wide treatment guidelines on consistency of adjuvant therapy for node-negative breast cancer. A retrospective population-based cohort study was conducted in the Canadian provinces of British Columbia, which has province-wide guidelines, and Ontario, which does not. All eligible 1991 incident cases of node-negative breast cancer in British Columbia (n = 942) and a similar number of randomly selected 1991 incident cases in Ontario (n = 938) were reviewed. Consistency of adjuvant therapy received was evaluated by stratifying cases into discrete diagnostic groups using several grouping systems, and by then comparing the distribution of treatments received within each diagnostic group in the two provinces. Recursive partitioning was also performed. We observed that patterns of pathology reporting were consistent with awareness of the factors used in the British Columbia guidelines to define indications for adjuvant therapy. Consistency of care was greater in British Columbia than in Ontario by all diagnostic grouping systems and by recursive partitioning (P < 0.001), and the observed patterns in British Columbia corresponded to the British Columbia guidelines. We conclude that population-based treatment guidelines can play a role in promoting consistent patterns of adjuvant therapy for women with node-negative breast cancer.

OBJECTIVE: To compare the medical services provided in small hospitals in Ontario in 1995 with those provided in 1988. DESIGN: Mailed survey questionnaire. SETTING: Small hospitals in Ontario. PARTICIPANTS: Chiefs of Staff of the hospitals. MAIN OUTCOME MEASURES: Hospital size and location; numbers of physicians; availability of obstetric, anesthesia, and general surgery services; and other medical services available. The 1995 questionnaire was identical to the 1988 one, except for addition of questions on midwives and deletion of the detailed emergency medicine section. RESULTS: Sixty hospitals responded in both years. In these hospitals, there were significantly fewer acute care beds and births in 1995 than in 1988. Availability of general anesthesia and general surgery was significantly reduced, although general anesthesia was administered and general surgeries were performed more often. There were significantly fewer GP anesthetists and significantly fewer family physicians who attended births, although there were slightly more family physicians overall. There were fewer specialists. CONCLUSION: These are negative trends, particularly for women giving birth and patients needing emergency surgery in rural Ontario.

OBJECTIVE: To compare obstetric services provided in small Ontario hospitals in 1995 with those provided in 1988. DESIGN: Mailed survey questionnaire. SETTING: Small hospitals in Ontario. PARTICIPANTS: Chiefs of Staff of the hospitals. MAIN OUTCOME MEASURES: Hospital size and location; numbers of physicians; availability of obstetric, anesthesia, and general surgery services; and other medical services. The 1995 questionnaire was identical to the 1988 one, except for addition of questions on midwives and deletion of the detailed emergency medicine section. RESULTS: A study group of 35 hospitals that provided active obstetric care in both years had significantly fewer births, fewer family physicians attending births, and fewer GP anesthetists in 1995 than in 1988. There were fewer cesarean births, but a similar number of epidural anesthetics. Availability of anesthetic, epidural, and cesarean services was significantly lower in 1995 than in 1988 in these 35 hospitals. Also, 11 other hospitals that had provided active obstetric care (defined as more than 25 births yearly) in 1988 no longer did so in 1995. CONCLUSION: By almost all measures, obstetric services in these rural Ontario hospitals were less available in 1995 than they had been in 1988.

Thirty-six Ontario physicians who entered a treatment process for alcohol and drug problems were systematically assessed prior to treatment. The demographic and medical practice characteristics of this sample are delineated and, where possible, are compared to those of all Ontario physicians. Physicians with alcohol and drug problems were both similar to and different from all Ontario physicians. Further study is needed to explore the similarities and differences between the two groups, with a view to improving treatment, prevention and professional goverance.

Thirteen preclinical medical students spent the summer of 1970 working with family physicians throughout Ontario. The program was a joint undertaking of the Ontario Chapter of the College of Family Physicians of Canada and the Department of Health of the Province of Ontario.

Infectious bronchitis (IB) is an economically important viral disease with worldwide distribution. Every country with an intensive poultry industry has infectious bronchitis virus (IBV). The virus rapidly spreads from bird to bird through horizontal transmission by aerosol or ingestion. Sentinel bird studies were carried out in southern Ontario and IBV has been isolated from layer flocks. Genetic analysis of the S1 region of the strains showed that they were not vaccine related. The pathogenicity of selected Ontario variants of IBV isolates was studied and the subsequent work was to determine the degree of protection against field isolates provided by a commonly used vaccine MILDVAC-Ma5 in Ontario. The protection was evaluated by challenging immunized chickens with the respiratory (IBV-ON1) and nephropathogenic (IBV-ON4) viruses. The mean vaccine efficacy for IBV-ON1 was 66.7% indicating that a Massachusetts serotype vaccine would provide some protection against IBV field isolates.

Two sediment cores collected from Lake Ontario and Lake Erie were sectioned, dated, and analyzed for five polycyclic musk fragrances and two nitro musk fragrances. The polycyclic musk fragrances were HHCB (Galaxolide), AHTN (Tonalide), ATII (Traseolide), ADBI (Celestolide), and AHMI (Phantolide). The nitro musk fragrances were musk ketone and musk xylene. Chemical analysis was performed by gas chromatography/mass spectrometry (GC/MS) and results from Lake Erie were confirmed using gas chromatography/triple-quadrupole mass spectrometry (GC/MS/MS). The chemical signals observed at the two sampling locations were different from each other due primarily to large differences in the sedimentation rates at the two sampling locations. HHCB was detected in the Lake Erie core while six compounds were detected in the Lake Ontario core. Using measured fragrance and 210Pb activity, the burden of synthetic musk fragrances estimated from these sediment cores is 1900 kg in Lake Erie and 18000 kg in Lake Ontario. The input of these compounds to the lakes is increasing. The HHCB accumulation rates in Lake Erie for 1979-2003 and 1990-2003 correspond to doubling times of 16 ± 4 yr and 8 ± 2 yr, respectively. The results reflect current U.S. production trends for the sum of all fragrance compounds.

The objective of this study was to determine the association between space allowance and in-transit loss of finishing pigs going to select abattoirs in Ontario during summer weather conditions. The study included data from 2- or 3-tiered trailers transporting ≥ 130 pigs in June, July, and August 2003 to 3 packers that processed 76% of Ontario market pigs. Daily in-transit loss data were merged with packer data to determine the number of pigs on each trailer. Space allowance (in square meters per pig) was estimated from the percentage of each trailer’s capacity that was filled by the load size. Actual pig weights were not available. Hourly temperature and relative humidity were obtained from 2 local Ontario weather stations. In-transit loss increased with environmental temperature, by 6.6 times at temperatures between 28°C and 34.2°C compared with < 17°C. At space allowances between 0.44 and 0.43 m2/pig compared with ≥ 0.515 m2/pig, in-transit losses increased 2.12 times when environmental temperatures were < 21°C. Temperature is likely a more important determinant of in-transit loss than space allowance. However, in-transit losses in hot weather are likely to be reduced by increasing space allowance or by adding a cooling device.

Effects of socioeconomic status on the long-term survival of 808 women with node-negative breast cancer in Canada and the United States were observed. Ontario and California samples diagnosed between 1988 and 1990 were followed until 2006. Socioeconomic data were taken from population censuses. Compared with their California counterparts, residents of low-income urban areas in Ontario experienced a significant 15-year survival advantage (RR = 1.66 [95% CI: 1.00, 2.76]). In these and other vulnerable, lower-middle- to working-class neighborhoods, significantly more Ontario residents gained access to adjuvant radiation therapy (RR = 1.75 [1.21, 2.53]) which seemed associated with better long-term survival (RR = 1.36 [0.99, 1.86]). This stage-adjusted, historical cohort analysis suggests much greater cancer care equity in Canada than in the United States.

Few antimicrobials are licensed for use in sheep in Canada, and the range of indications is narrow. Treatment in an “extra-label” manner may be ineffective. In addition, potentially harmful drug residues in food-animal products and antimicrobial resistance in bacteria may be associated with extra-label drug use (ELDU). No data had been documented on drug use, specifically antimicrobial use (AMU), in Ontario sheep, although it was thought that much use was extra-label. This study investigated AMU and ELDU on 49 lamb-producing Ontario sheep farms. Data were prospectively collected over 12 months from the participating farms, and farm-level practices were ascertained with a questionnaire. Treatment-level and farm-level variables were investigated for associations with rates of AMU by means of Poisson rate regression models fit with a generalized estimating equation to control for clustering at the farm level. Antimicrobials with high mean exposure rates included chlortetracycline (in feed), penicillins, and oxytetracycline. The exposure rate in lambs was significantly lower (P < 0.01) with antimicrobial treatment of systemic signs, respiratory disease, or wound or injury than with treatment of other reported diseases or conditions; it was also significantly lower with 3 or more lambing periods per year (α = 0.05). The exposure rate in adult sheep was significantly lower with treatment of 5 of the 6 most prevalent diseases or conditions (α = 0.05) and significantly higher with producer decision to treat and producer experience of 20 y or greater. Rates of using antimicrobials not licensed for use in sheep were high...

Traits that converge in appearance under similar environmental conditions among phylogenetically independent lineages are thought to represent adaptations to local environments. We tested for convergence in nest morphology and composition of birds breeding in two ecologically different locations in Canada: Churchill in northern Manitoba and Elgin in southeastern Ontario. We examined nests from four families of passerine birds (Turdidae: Turdus, Parulidae: Dendroica, Emberizidae: Passerculus and Fringillidae: Carduelis) where closely related populations or species breed in both locations. Nests of American Robins, Yellow Warblers, and Carduelis finches had heavier nest masses, and tended to have thicker nest-walls, in northern Manitoba compared with conspecifics or congenerics breeding in southeastern Ontario. Together, all species showed evidence for wider internal and external nest-cup diameters in northern Manitoba, while individual species showed varying patterns for internal nest-cup and external nest depths. American Robins, Yellow Warblers, and Carduelis finches in northern Manitoba achieved heavier nest masses in different ways. American Robins increased all materials in similar proportions, and Yellow Warblers and Common Redpolls used greater amounts of select materials. While changes in nest composition vary uniquely for each species...

In 1999, Ontario implemented a policy to offer HIV counseling and testing to all pregnant women and undertook measures to increase HIV testing. We evaluated the effectiveness of the new policy by examining HIV test uptake, the number of HIV-infected women identified and, in 2002, the HIV rate in women not tested during prenatal care. We analyzed test uptake among women receiving prenatal care from 1999 to 2010. We examined HIV test uptake and HIV rate by year, age and health region. In an anonymous, unlinked study, we determined the HIV rate in pregnant women not tested. Prenatal HIV test uptake in Ontario increased dramatically, from 33% in the first quarter of 1999 to 96% in 2010. Test uptake was highest in younger women but increased in all age groups. All health regions improved and experienced similar test uptake in recent years. The HIV rate among pregnant women tested in 2010 was 0.13/1,000; in Toronto, the rate was 0.28 per 1,000. In the 2002 unlinked study, the HIV rate was 0.62/1,000 among women not tested in pregnancy compared to 0.31/1,000 among tested women. HIV incidence among women who tested more than once was 0.05/1,000 person-years. In response to the new policy in Ontario, prenatal HIV testing uptake improved dramatically among women in all age groups and health regions. A reminder to physicians who had not ordered a prenatal HIV test appeared to be very effective. In 2002...