Southeastern Ontario Research Articles

Pain and Self‐Reported Health in Canadian Children

Despite increasing attention to the epidemiology of pain, relatively little is known about the association between pain and health in children. In particular, no studies have examined this relationship in the general population of children in Canada. To assess the association between self-reported pain experiences and health in school children in southeastern Ontario. Health measures included perceived health status, psychological complaints and satisfaction with school. A total of 495 nine- to 13-year-old school children completed the Pain Experience Interview -- Short Form and health-related questions from the Health Behaviour in School-aged Children questionnaire. Of the 495 children in the present study, 8% rated their health as 'fair' to 'poor', 56% reported experiencing at least one of four psychological symptoms more than once a week and 24% said they disliked school. The strongest associations existed between headaches and poor self-rated health (OR=10.1; 95% CI 1.3 to 78.3), recurrent pain and psychological outcomes (OR=3.6; 95% CI 2.0 to 6.3), and recurrent pain and disliking school (OR=3.6; 95% CI 1.9 to 6.7). These findings indicate that common childhood pains are associated with childhood health. Further studies are needed to assess the causal relationship between pain and health in children, to obtain a more comprehensive understanding of the personal and economic impact of childhood pain, and to monitor changes in the lives of children living with chronic pain.

Prospects for nuclear energy in Canada, the USA and Mexico

Recent years have seen a growing interest in the possibility of building new nuclear power plants in Canada and the USA. Electricity generating companies, especially in the south-eastern USA and Ontario, announced plans during 2005 and 2006 which could lay the groundwork for future decisions to construct commercial reactors that could come on line as early as 2015. The possibility of new nuclear power construction is also being examined in Mexico. This growing interest is driven by less expensive technologies, concerns regarding the environmental impacts of generation using fossil fuels and more favourable attitudes toward nuclear power from national and regional governments.

Wetland soil and vegetation bismuth content following experimental deposition of bismuth pellets

Bismuth pellets have been approved as a non-toxic alternative to lead pellets in Canada since 1997 but, to our knowledge, there is little literature for soil and vegetation bismuth content in areas of bismuth pellet deposition. The present study addresses this shortcoming by measuring wetland soil and vegetation bismuth content following experimental deposition of bismuth pellets under ambient and experimentally increased acidic deposition conditions. We manipulated 24 plots in a fully factorial design (bismuth shot x soil acidification) in a south-eastern Ontario freshwater wetland during 1999-2003. Soil pH (range 6.5-7.3) increased significantly (p = 0.001) during the experimental period but there were no significant differences amongst treatments (p = 0.79). Significantly (p < 0.05) greater bismuth concentrations were measured in soil receiving bismuth pellets (mean +/- SE, n = 6; with acidification = 2.55 +/- 1.02 microg Bi g(-1) dry mass [DM]; without acidification = 6.40 +/- 2.23 microg Bi g(-1) DM) compared to plots that were not seeded with bismuth pellets (without acidification = 0.42 +/- 0.09 microg Bi g(-1) DM; with acidification = 0.39 +/- 0.10 microg Bi g(-1) DM). Nevertheless, bismuth levels in 20 of 24 aboveground tissue samples from the Carex lacustris-Agrostis scabra community were below detection levels (0.057 microg Bi g(-1) DM); the other samples ranged from 0.065 to 0.095 microg Bi g(-1) DM, similar to global background levels. Primary productivity in plots receiving bismuth pellets and soil acidification was not significantly (p = 0.15) different to vegetation in plots that were not manipulated. The results suggest bismuth mobilization from bismuth pellets into soil but not to aboveground vegetation.

Detection of European Peristenus digoneutis loan in mirid populations in southern Ontario

Lygus spp. Hahn (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. A European parasitoid, Peristenus digoneutis Loan (Hymenoptera: Braconidae), released in the northeastern USA for the biological control of Lygus, has successfully established in nine states and in eastern Canada, including southeastern Ontario, southern Quebec and Nova Scotia. To determine the extent to which P. digoneutis has dispersed and established in mirid populations in Ontario, a single-step multiplex PCR assay, designed to differentiate European species P. digoneutis and P. relictus from native North American Peristenus species, was used to identify parasitoid larvae dissected from field-collected Miridae. A total of 222 parasitoid larvae were analysed with the multiplex assay. Most (172) were identified as members of the P. pallipes Curtis complex; however, three from the Niagara region were identified as P. digoneutis. Specimens that did not amplify using the Peristenus multiplex PCR assay were screened with a PCR primer set designed to detect Leiophron (Hymenoptera: Braconidae) species, and most were confirmed to be Leiophron larvae. This study confirms the presence of P. digoneutis species in southern Ontario, and is another example of the utility of molecular methods for the detection of newly introduced or dispersed parasitoids. The presence of exotic P. digoneutis in southern Ontario may expedite future releases to augment already-established populations. Following such releases, the Peristenus multiplex PCR assay will be a useful component of post-release studies to evaluate the success of the biological control programme for Lygus plant bugs in Canada.

Effect of road density on abundance of white-footed mice

While several studies have demonstrated that roads can act as barriers to small mammal movement, the relationship between road density and small mammal abundance has not yet been investigated. In southeastern Ontario, Peromyscus leucopus (white-footed mice) suffer high over-winter mortality rates, resulting in small springtime populations and frequent local extinctions. Peromyscus leucopus movement is known to be inhibited by roads, which should result in lower rates of immigration into and recolonization of habitats in landscapes with high road density. We tested two predictions: (1) Forest sites situated in landscapes with high road densities have a higher chance of P. leucopus being absent during the early spring than forest sites situated in landscapes with low road densities and (2) P. leucopus populations during the summer are smaller in forest sites situated in landscapes with high road densities than in landscapes with low road densities. We sampled P. leucopus in focal patches within nineteen landscapes (7 rural, low-road-density landscapes; 7 rural, high-road-density landscapes; 5 urban landscapes). There was no significant relationship between road density and the presence/absence of P. leucopus during the early spring. We found a significant positive effect of road density on P. leucopus relative abundance during the summer, even when we excluded the urban landscapes and based the analysis on only the 14 rural landscapes. Our results suggest that any negative effect of roads on P. leucopus populations, created by their inhibition to moving across roads, is far outweighed by some positive effect of roads on P. leucopus abundance. We suggest that the two most likely explanations are that roads are positively correlated with an important as-yet-undetermined component of habitat quality, or that roads positively affect P. leucopus by negatively affecting their predators.

Prostate Cancer among Canadian Men: A Transcultural Representation

Health services should consider the masculine representation of disease that underlies men’s health behaviors. This study presents a transcultural view of Prostate Cancer (PC) among Canadian men of European descent. Nine men who were enrolled in a PC support group in Southeastern Ontario comprised the sample. Data were collected through interviews, genograms and ecomaps. The contrasting-ideas method guided analysis and interpretation of the findings. Healthcare providers must assist men to understand that an immediate investment of time is imperative to adequately decode and understand medical information, consider available therapies, and reflect on the potential outcome of their decisions.

45. Education at distance: Broadcasting ECG rounds to Southeastern Ontario (BESO Project). An innovative approach for teaching electrocardiography

Electrocardiography (ECG) interpretation is an essential skill for physicians as well as for many other health care professionals. Continuing education is necessary to maintain these skills. The process of teaching and learning ECG interpretation is complex and involves both deductive mechanisms and recognition of patterns for different clinical situations (“pattern recognition”). The successful methodologies of interactive sessions and real time problem based learning have never been evaluated with a long distance education model.&#x0D; To evaluate the efficacy of broadcasting ECG rounds to different hospitals in the Southeastern Ontario region; to perform qualitative research to determine the impact of this methodology in developing and maintaining skills in ECG interpretation.&#x0D; ECG rounds are held weekly at Kingston General Hospital and will be transmitted live to Napanee, Belleville, Oshawa, Peterborough and Brockville. The teaching methodology is based on real ECG cases. The audience is invited to analyze the ECG case and the coordinator will introduce comments to guide the case through the proper algorithm. Final interpretation will be achieved emphasizing the deductive process and the relevance of each case. An evaluation will be filled out by each participant at the end of each session.&#x0D; Videoconferencing works through a vast array of internet LANs, WANs, ISDN phone lines, routers, switches, firewalls and Codecs (Coder/Decoder) and bridges. A videoconference Codec takes the analog audio and video signal codes and compresses it into a digital signal and transmits that digital signal to another Codec where the signal is decompressed and retranslated back into analog video and audio. This compression and decompression allows large amounts of data to be transferred across a network at close to real time (384 kbps with 30 frames of video per second). Videoconferencing communication works on voice activation so whichever site is speaking has the floor and is seen by all the participating sites. A continuous presence mode allows each site to have the same visual and audio involvement as the host site. A bridged multipoint can connect between 8 and 12 sites simultaneously.&#x0D; This innovative methodology for teaching ECG will facilitate access to developing and maintaining skills in ECG interpretation for a large number of health care providers. &#x0D; Bertsch TF, Callas PW, Rubin A. Effectiveness of lectures attended via interactive video conferencing versus in-person in preparing third-year internal medicine clerkship students for clinical practice examinations. Teach Learn Med 2007; 19(1):4-8.&#x0D; Yellowlees PM, Hogarth M, Hilty DM. The importance of distributed broadband networks to academic biomedical research and education programs. Acad Psychaitry 2006;30:451-455

Implementation of a novel prehospital advance directive protocol in southeastern Ontario

Do not resuscitate (DNR) orders are commonly accepted in most health care settings, but are less widely recognized in the prehospital setting. We describe the implementation of and satisfaction with a prehospital DNR protocol that allows paramedics to honour verbal and non-standard written DNR requests. This prospective observational study reviewed all cardiac arrests in southeastern Ontario between March 1, 2003 and September 31, 2005. Following a verbal or non-standard written DNR request, paramedics completed a questionnaire and a follow-up structured telephone interview was conducted with surrogate decision makers (SDMs). There were 1890 cardiac arrests during the study period, of which 86 met our inclusion criteria. Paramedic surveys were available for 82 cases (95%), and surrogate decision makers (SDMs) were successfully contacted in 50 (58%) of them. Two SDMs declined to be interviewed. The mean patient age was 72.7 (standard deviation 13.8) years and 65% were male. Sixty-three (73%) of DNR requests were verbal, and 23 (27%) were written. The mean paramedic comfort was rated 4.9 on a 5-point Likert scale (with 5 being "very comfortable") (95% confidence interval [CI] 4.9-5.0). The mean SDM comfort was rated by paramedics as 4.9 (95% CI 4.8-4.9). SDMs reported comfort in withholding CPR in 47 of 48 cases (98%), and with paramedic care in all cases. One SDM stated that although it was consistent with the patient's wishes, she was uncomfortable having to make the DNR request. Satisfaction with this novel prehospital DNR protocol was uniformly high among paramedic and SDM respondents. It appears that such a protocol is feasible and acceptable for the prehospital setting. Our conclusions are limited by a small sample size, the lack of a comparison group, and limited follow-up.

Evaluating the relationship between floristic quality and measures of plant biodiversity along stream bank habitats

Abstract Measures used to describe the floristic structure of a habitat can vary in their ability to express trends in plant composition along anthropogenic disturbance gradients. This study was based on a survey of vascular plant biodiversity performed along stream bank habitats within an agricultural landscape in southeastern Ontario, Canada. The accuracy of several measures of plant biodiversity – including those related to a regional floristic quality assessment system – was examined to compare their ability to recognize a gradient of anthropogenic disturbance and associated floristic quality along the stream bank habitats. The floristic quality assessment system is a scheme in which all vascular plants of a region have been assigned a score corresponding to a qualitative conservation value based on habitat fidelity and tolerance of disturbance (native species), and on invasiveness (non-native species). Data were collected from a priori designated disturbed, moderate, and pristine zones along 27 stream sections exhibiting a length-wise disturbance gradient. A detrended correspondence analysis (DCA) was used to isolate the plant compositional gradient present along the stream sections. The measures of plant biodiversity recorded in the different study sites were then ranked by the degree to which they were linearly correlated with the identified compositional gradient of the DCA. The “% non-native plant species” measure was most effective at expressing the gradient, though it incorporated nothing about the fidelity and sensitivity of native plant species present in individual zones. Several measures associated with the floristic quality assessment system – including the mean coefficient of “conservatism” (mCC) – were also effective in identifying the gradient, and had the additional benefit of considering the contribution of each native species in a plot. The simple measure of “total plant species richness” proved to be a poor linear indicator due to a quadratic trend across the whole of the compositional gradient. The floristic quality assessment system proved to be a valuable tool for assessing conservation values of the selected sites. It should be extended to include further regions in Canada and North America in general. Our results further suggest that stream banks associated with open non-crop agricultural property are highly susceptible to colonization by non-native upland plants and species of low conservation interest, and that the presence of wooded areas surrounding these same streams is associated with higher numbers of native and disturbance sensitive plant species present in the bank habitats.

Decreased dose density of standard chemotherapy does not compromise survival for ovarian cancer patients

For women diagnosed with ovarian cancer, the standard practice of surgery followed by adjuvant platinum-taxane combination chemotherapy, with cycles administered every 3 weeks, is based on randomized control trials. However, a substantial number of patients require delays or reductions on this schedule. The Cancer Centre of Southeastern Ontario (CCSEO) has historically administered chemotherapy every 4 weeks. We analyzed survival outcomes of our cohort. All ovarian cancer patients treated with chemotherapy at the CCSEO from 1995 to end-2002 were included in this study. Overall survival and progression-free survival were calculated from initiation of chemotherapy using the Kaplan-Meier technique and log-rank tests. Cox regression analysis was used to adjust for age and disease stage. A total of 171 patients were treated with chemotherapy (cisplatin-paclitaxel or carboplatin-paclitaxel), of which 144 received chemotherapy every 4 weeks and 27 every 3 weeks. Median progression-free survival was 19.2 months for the group treated every 4 weeks vs 13.2 months for the 3-weekly group. Median overall survival was 36.5 months compared to 27.1 months, respectively. Trends favored treatment every 4 weeks. In early-stage disease, 5-year overall survival was 74% and 5-year progression-free survival was 68%. Administration of platinum-paclitaxel chemotherapy every 4 weeks did not reduce survival of ovarian cancer patients. Importantly, median survival is favorable compared to results from landmark trials where patients were treated every 3 weeks. These results suggest that decreasing the frequency of chemotherapy cycles does not decrease survival. Prospective trials would be required to compare quality of life and cost-effectiveness.

Ontario, Canada: Using Networks to Integrate Palliative Care Province-Wide

Ontario, a Canadian province, identified the lack of coordination, integration, and consistency of end-of-life care services as barriers to quality palliative care. To address these barriers, various governmental, organizational, and community-level initiatives were implemented. The Ministry of Health and Long-Term Care enacted an End-of-Life Care Strategy in 2005 aimed at shifting care from acute settings to appropriate alternate settings of care; enhancing client-centered and interdisciplinary service capacity; and improving access, coordination, and consistency of services. Crucial to accomplishing the strategy was the establishment of End-of-Life Networks within health care planning regions. The networks were instrumental in developing end-of-life care service delivery models in the various regions, bringing key stakeholders together toward a common vision, and building strong collaborations across providers and settings. Cancer Care Ontario, an organization dedicated to improving cancer care at the regional and provincial levels, also leads improvements in palliative care through the implementation of a palliative strategy for cancer patients aimed at improved measurement of quality indicators, increased use of evidence and standards, and increased efficiency and access to care. A regional network of organizations in Southeastern Ontario created a quality improvement project, the Palliative Care Integration Project (PCIP), which disseminated common symptom assessment tools, collaborative care plans, and evidence-based guidelines across the continuum of care. The PCIP was embraced by key stakeholders across the province as a model intervention to better coordinate, integrate, and standardize palliative care service delivery, and is currently being spread across all regions of the province.

Notes on Succession in Old Fields in Southeastern Ontario: the Herbs

Vegetation in abandoned hayfields was monitored during 1976-1998. An earlier successional stage followed ploughing. Changes in tree, shrub and vine populations have been reported earlier and showed expected increases in species richness and cover. Highest species richness of herbs occurred three years after ploughing. Non-woody species richness trended irregularly downward, while non-woody cover was variable, peaking in 1987. Within the herbaceous community, year-to-year changes in cover and frequency of species in the following selected groups are reported here: 18 grasses including sown and adventive species; 13 legumes including two sown species; 14 macroforbs of the Compositae, including a goldenrod, Solidago canadensis, which dominated parts of the fields; a rosette weed, Taraxacum officinalis; sedges, horsetails and some other minor components. Grasses and goldenrods were grazed, sometimes intensively and repeatedly, by insects; grasses were impacted by skipper larvae (Thymelicus lineola), and goldenrods by beetle larvae (Trirhabda spp.). Effects of repeated outbreaks on host plant cover are shown for two plots (100 m2) matching the scale of outbreaks.

Hydrogen isotopic variation in migratory bird tissues of known origin: implications for geographic assignment

Continent-wide variation in hydrogen isotopic composition of precipitation is incorporated into animal diets, providing an intrinsic marker of geographic location at the time of tissue growth. Feathers from migratory birds are now frequently analyzed for stable-hydrogen isotopes (deltaD) to estimate the location of individuals during a preceding molt. Using known-origin birds, we tested several assumptions associated with this emerging technique. We examined hydrogen isotopic variation as a function of age, sex, feather type and the timing of molt in a marked population of American redstarts (Setophaga ruticilla) breeding in southeastern Ontario. We measured deltaD in feathers and blood from individuals that bred or hatched at our study site during the year in which those tissues were grown. Juvenile tissues from 5- to 10-day-old birds had more negative deltaD values than those from adults, which most likely reflected age-related differences in diet. Within adults, primary feathers had more negative deltaD values than contour feathers. The mean deltaD value in adult primary feathers was relatively consistent among years and with the value expected for our study population. However, among-individual variation in deltaD corresponded to an estimated latitudinal range of 6-8 degrees (650-900 km). We conclude that feathers sampled from recently hatched juveniles may not provide a reliable estimate of expected local isotopic signatures for comparison with adult feathers of unknown origin. Furthermore, we urge researchers to use caution when using deltaD values in feathers to infer geographic origin, and suggest that the best approach is to assign individuals to broad geographic zones within a species' potential molting range.

Effect of small-scale forest management on fungivorous Coleoptera in old-growth forest fragments in southeastern Ontario, Canada

AbstractFungivorous Coleoptera were sampled from old-growth and managed (selectively logged in 1999) hemlock–hardwood forests in southeastern Ontario to examine the effect of small-scale forest management on fungivore diversity in forest fragments. Sampling using flight-intercept traps and trunk-window traps for 22 weeks in 2003 yielded 11 888 beetles representing 73 species in 11 target families (Anthribidae, Cerylonidae, Endomychidae, Erotylidae, Leiodidae, Mycetophagidae, Scaphidiidae, Sphindidae, Tenebrionidae, Trogossitidae, and Zopheridae). The leiodid subfamily Leiodinae was the dominant taxon (10 386 individuals, 38 species). While old-growth stands had no recent logging and had higher volumes of coarse woody debris, species diversity and composition of fungivorous Coleoptera were similar between forest types, suggesting that the stand differences measured (recent logging history, volume of coarse woody debris) did not have a significant effect on beetle diversity in this study. Indicator species analysis showed that Triplax macra LeConte (Erotylidae) was strongly associated with old-growth stands, while Anisotoma blanchardi (Horn), Anogdus obsoletus (Melsheimer), Agathidium sp. 1 (Leiodidae), and Mycetina perpulchra (Newman) (Endomychidae) were associated with managed stands. The lack of difference observed between stand types may be related to the small size of the forest fragments or the relatively small scale of the disturbance.

Ecological risk assessment of lead contamination at rifle and pistol ranges using techniques to account for site characteristics

Spent ammunition at outdoor rifle and pistol (RP) firing ranges creates a characteristic pattern of contamination, whereby small areas surrounding backstop berms exhibit extremely high soil lead (Pb) concentrations. We characterized sources, pathways and uncertainty in contaminant accumulation for receptors at two RP ranges in southeastern Ontario. Based on these results, we performed risk calculations using kriging to estimate risk across "worst-case" species foraging ranges. Range-normalized hazard quotients (RNHQ) were then calculated to estimate risk across each receptor's foraging range. Monte Carlo simulation was used to provide +2 standard deviation (SD) risk estimates, in order to account for uncertainty in risk parameters. The American robin was found to be most at risk (RNHQ=4.10; +2SD=9.24), followed by the short-tailed shrew (RNHQ=0.113; +2SD=0.243) and the eastern cottontail (RNHQ=0.109; +2SD=0.703). Elevated risk for the American robin and short-tailed shrew was due to their small foraging ranges and habit of eating earthworms, which bioaccumulate Pb. Elevated risk for the eastern cottontail was due to vegetation accumulating Pb to levels that were considerably higher than conventional bioaccumulation models would indicate. The results of this study clearly emphasize the importance of specific characteristics of RP ranges, such as contamination patterns, dust accumulation on plant tissues, and contaminant bioaccessibility. These characteristics should be accounted for, not only in performing risk assessments, but also in choosing remedial options and in routine management practices.

Use of clinical placements as a means of recruiting health care students to underserviced areas in Southeastern Ontario: Part 1 – Student perspectives

This two-part study examines the present gap between financial and educational incentives required and the recruitment strategies used to draw health science students to underserviced areas in Southeastern Ontario. Part 1 explores the impact of offering travel stipends, rent-free accommodation and interprofessional educational opportunities to health science students on their willingness to participate in clinical placements in underserviced areas. Mixed-method two-part study using a self-administered questionnaire. Canadian university campus. Four hundred and sixty-eight senior level medical, nursing, occupational therapy, physical therapy and X-ray technology students from a Canadian university and affiliated professional school. The influence of currently established incentives on student willingness to complete a clinical placement in designated underserviced communities in Southeastern Ontario. Based on a 75% response rate, the results demonstrate that, in general, students agree that they are more willing to complete a clinical placement in an underserviced community if provided travel stipends (75%), rent-free housing (92%) and interprofessional educational opportunities (65%). Students also identified 15 additional factors influencing willingness. Students are more willing to complete clinical placements in underserviced communities if provided incentives. The findings of this study support an interprofessional clinical education and recruitment enhancement program in Southeastern Ontario.

Use of clinical placements as a means of recruiting health care professionals to underserviced areas in Southeastern Ontario: Part 2 – Community perspectives

Part 2 of this two-part study identifies current recruitment strategies and existing incentives used by underserviced communities to recruit health science students during the clinical placement stage. Discussion surrounding current gaps in recruitment strategies and potential funding sources are explored. Mixed-method two-part study using a self-administered questionnaire. Six community hospitals and one private practice. Community resource contact from seven underserviced communities in Southeastern Ontario. Level of community agreement that current recruitment strategies include travel stipends, rent-free accommodation and interprofessional education opportunities. A 100% response rate established that one sample community provides travel stipends, three provide rent-free accommodation, and four offer interprofessional education opportunities. These incentives were frequently offered exclusively to medical students. When considering the results from part 1 of the study, there is a substantial gap between financial incentives students deem important in the creation of an appealing clinical placement opportunity and the provisions offered to them by the sample communities. The findings of this study support the need for a recruitment enhancement program in Southeastern Ontario.

Petrogenesis of the Leo Lake and Lyndhurst plutons, Frontenac terrane, Central Metasedimentary Belt, southeastern Ontario, Canada

The 1167 ± 2 Ma Leo Lake pluton, located at the southern part of the Frontenac terrane in Central Metasedimentary Belt of southeastern Ontario, is a bimodal pluton that is dominated by olivine gabbro, gabbro, syenite, and lesser monzonite. The adjoining 1166 ± 3 Ma Lyndhurst pluton is composed of syenite and granite, and exhibits magma mingling. Even though geochemical data from both plutons suggest fractional crystallization as the main crystallization process, magma mingling is evident in the Lyndhurst pluton. Hornblende from the Leo Lake syenite yields a 40Ar–39Ar age of 1120 ± 6 Ma and titanite from the adjacent St. Lawrence skarn yields a U–Pb age of 1147 ± 8 Ma. The 40Ar–39Ar age indicates that the pluton cooled to 550 °C at a rate of ca. &lt;2 °C/Ma following emplacement. The two plutons are similar in petrology to several other granitic, syenitic, and monzonitic intrusions of the Frontenac suite in the Frontenac terrane. Moreover, the spatial distribution, textural features, and geochemistry indicate that the plutons are coeval. The present data indicate that the two plutons may have been produced from evolved mantle-derived melts, and may have assimilated varying proportions of crustal melts.

Site-Index Curves and Growth Intercepts for Young White Spruce Plantations in North Central Ontario

Abstract Site-index (heightߝgrowth) curves, site-index prediction equations, and growth intercepts were developed from internode measurements and stem-analysis data using dominant trees in 69 plots located in white spruce plantations aged 19 to 32 years total age. Site-index curves were based on breast-height (1.3 m) age because our analyses show that height growth below breast height is slow and erratic and is poorly related to site index (dominant height at 15 years breast-height age). The most precise model for computing heightߝgrowth curves was a Newnham constrained polymorphic expression (Newnham, R.M. 1988. A modification of the Ek-Payandeh nonlinear regression model for site-index curves. Can. J. For. Res. 18:115ߝ120) of the Ek nonlinear regression model (Ek, A.R. 1971. A formula for white spruce site-index curves. University of Wisconsin For. Res. Note 161. 2 p). Comparisons showed that site-index curves in North Central Ontario were comparable to site-index curves for white spruce plantations in southeastern Ontario. The first three to five internodes above 2.0 m gave the most precise estimates of site index based on growth intercepts. North. J. Appl. For. 23(4):257–263.

Adequacy of Glycemic Control in Hemodialysis Patients With Diabetes

We sought to measure the prevalence of inadequate glycemic control in prevalent hemodialysis patients with diabetes and to examine independent predictors of inadequate glycemic control in these patients. This is a cross-sectional study of prevalent hemodialysis patients with diabetes in southeastern Ontario (n = 100). Data were collected by chart review and interview. The outcome variable was inadequate glycemic control defined as HbA1c (A1C) >0.07. Other measured variables were diabetes type, diabetes duration, diabetes physician, blood glucose monitoring, diabetes medications, BMI, time on dialysis, and other demographic, clinical, and laboratory variables. Fifty-four patients had A1C >0.07. In bivariate analysis, these patients had a longer diabetes duration (23.6 vs. 14.7 years, P < 0.001), higher proportion with insulin use (81.5 vs. 58.7%, P = 0.012), higher proportion with microvascular complications (66.7 vs. 43.5%, P = 0.017), and lower erythropoietin (EPO) dose (7.0 vs. 11.9 x 10(3) units/week, P < 0.01) than patients with adequate glycemic control. There was no difference between the two groups in terms of macrovascular complications (59.3 vs. 65.2%, P = 0.54). In multiple logistic regression controlling for age and diabetes type, the diabetes duration (odds ratio 1.09 [95% CI 1.04-1.15], P < 0.001), EPO dose (0.90 [0.85-0.97], P < 0.01), and blood glucose monitoring (10.06 [1.03-98.74], P = 0.05) were the only significant independent predictors of A1C >0.07. A high proportion of hemodialysis patients with diabetes had inadequate glycemic control, particularly those with longstanding disease. Patients with inadequate glycemic control had a significantly higher burden of microvascular complications.