Towards a methodology to formulate sustainable diets for livestock: accounting for environmental impact in diet formulation.

The objective of this study was to develop a novel methodology that enables pig diets to be formulated explicitly for environmental impact objectives using a Life Cycle Assessment (LCA) approach. To achieve this, the following methodological issues had to be addressed: (1) account for environmental impacts caused by both ingredient choice and nutrient excretion, (2) formulate diets for multiple environmental impact objectives and (3) allow flexibility to identify the optimal nutritional composition for each environmental impact objective. An LCA model based on Canadian pig farms was integrated into a diet formulation tool to compare the use of different ingredients in Eastern and Western Canada. By allowing the feed energy content to vary, it was possible to identify the optimum energy density for different environmental impact objectives, while accounting for the expected effect of energy density on feed intake. A least-cost diet was compared with diets formulated to minimise the following objectives: non-renewable resource use, acidification potential, eutrophication potential, global warming potential and a combined environmental impact score (using these four categories). The resulting environmental impacts were compared using parallel Monte Carlo simulations to account for shared uncertainty. When optimising diets to minimise a single environmental impact category, reductions in the said category were observed in all cases. However, this was at the expense of increasing the impact in other categories and higher dietary costs. The methodology can identify nutritional strategies to minimise environmental impacts, such as increasing the nutritional density of the diets, compared with the least-cost formulation.

Accounting for uncertainty in the quantification of the environmental impacts of Canadian pig farming systems.

The objective of the study was to develop a life cycle assessment (LCA) for pig farming systems that would account for uncertainty and variability in input data and allow systematic environmental impact comparisons between production systems. The environmental impacts of commercial pig production for 2 regions in Canada (Eastern and Western) were compared using a cradle-to-farm gate LCA. These systems had important contrasting characteristics such as typical feed ingredients used, herd performance, and expected emission factors from manure management. The study used detailed production data supplied by the industry and incorporated uncertainty/variation in all major aspects of the system including life cycle inventory data for feed ingredients, animal performance, energy inputs, and emission factors. The impacts were defined using 5 metrics-global warming potential, acidification potential, eutrophication potential (EP), abiotic resource use, and nonrenewable energy use-and were expressed per kilogram carcass weight at farm gate. Eutrophication potential was further separated into marine EP (MEP) and freshwater EP (FEP). Uncertainties in the model inputs were separated into 2 types: uncertainty in the data used to describe the system (α uncertainties) and uncertainty in impact calculations or background data that affects all systems equally (ß uncertainties). The impacts of pig production in the 2 regions were systematically compared based on the differences in the systems (α uncertainties). The method of ascribing uncertainty influenced the outcomes. In eastern systems, EP, MEP, and FEP were lower (P < 0.05) when assuming that all uncertainty in the emission factors for leaching from manure application was ß. This was mainly due to increased EP resulting from field emissions for typical ingredients in western diets. When uncertainty in these emission factors was assumed to be α, only FEP was lower in eastern systems (P < 0.05). The environmental impacts for the other impact categories were not significantly different between the 2 systems, despite their aforementioned differences. In conclusion, a probabilistic approach was used to develop an LCA that systematically dealt with uncertainty in the data when comparing multiple environmental impacts measures in pig farming systems for the first time. The method was used to identify differences between Canadian pig production systems but can also be applied for comparisons between other agricultural systems that include inherent variation.

Injury outcome indicators: the development of a validation tool.

BACKGROUND: Researchers have previously expressed concern about some national indicators of injury incidence and have argued that indicators should be validated before their introduction. AIMS: To develop a tool to assess the validity of indicators of injury incidence and to carry out initial testing of the tool to explore consistency on application. METHODS: Previously proposed criteria were shared for comment with members of the International Collaborative Effort on Injury Statistics (ICE) Injury Indicators Group over a period of six months. Immediately after, at a meeting of Injury ICE in Washington, DC in April 2001, revised criteria were agreed over two days of meetings. The criteria were applied, by three raters, to six non-fatal indicators that underpin the national road safety targets for Canada, New Zealand, and the United Kingdom. Consistency of ratings were judged. CONSENSUS OUTCOME: The development process resulted in a validation tool that comprised criteria relating to: (1) case definition, (2) a focus on serious injury, (3) unbiased case ascertainment, (4) source data for the indicator being representative of the target population, (5) availability of data to generate the indicator, and (6) the existence of a full written specification for the indicator. On application of these criteria to the six road safety indicators, some problems of agreement between raters were identified. CONCLUSION: This paper has presented an early step in the development of a tool for validating injury indicators, as well as some directions that can be taken in its further development.

Youth injury data in the Canadian Hospitals Injury Reporting and Prevention Program: do they represent the Canadian experience?

OBJECTIVE: Injuries to Canadian youth (11-15 years) identified from a population based health survey (World Health Organization-Health Behaviour in School-Aged Children Survey, or WHO-HBSC) were compared with youth injuries from a national, emergency department based surveillance system. Comparisons focused on external causes of injury, and examined whether similar rankings of injury patterns and hence priorities for intervention were identified by the different systems. SETTING: The Canadian version of the WHO-HBSC was conducted in 1998. The Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP) is the national, emergency room based, surveillance program. Two hospitals involved in CHIRPP collectively provide population based data for Kingston, Ontario. METHOD: Numbers of injuries selected for study varied by data source: WHO-HBSC (n=3673); CHIRPP (n=20,133); Kingston CHIRPP (n=1944). WHO-HBSC and Kingston CHIRPP records were coded according to four variables in the draft International Classification of External Causes of Injury. Existing CHIRPP codes were available to compare Kingston and other CHIRPP data by five variables. Males and females in the three datasets were ranked according to the external causes. Data classified by source and sex were compared using Spearman's rank correlation statistic. RESULTS: Rank orders of four variables describing external causes were remarkably similar between the WHO-HBSC and Kingston CHIRPP (p>0.78; p<0.004) for mechanism, object, location, and activity). The Kingston and other CHIRPP data were also similar (p>0.87; p<0.001) for the variables available to describe external causes of injury (including intent). CONCLUSION: The two subsets of the CHIRPP data and the WHO-HBSC data identified similar priorities for injury prevention among young people. These findings indicate that CHIRPP may be representative of general youth injury patterns in Canada. Our study provides a novel and practical model for the validation of injury surveillance programs.

Community-acquired needle stick injuries in Canadian children: Review of Canadian Hospitals Injury Reporting and Prevention Program data from 1991 to 1996.

OBJECTIVE: To review community-acquired needle stick injuries (CANSIs) in children reported to a Canadian emergency room-based injury surveillance program. DESIGN: Analysis of 1991 to 1996 CANSI records followed by chart review to determine use of prophylactic interventions and outcome information. SETTING: The Canadian Hospitals Injury Reporting and Prevention Program network of 10 paediatric and six general hospitals. PATIENTS: Nonoccupational injuries to patients younger than age 20 years involving used needles were reviewed. MAIN RESULTS: Of 116 children injured, most were male (74%); the median age was 6.6 years. Needles were picked up before injury in 77% of the cases. Most injuries (78%) were from needles presumed to have been discarded by an injection drug user. Parks were the most common site of injury (21%). Six per cent of injuries occurred in medical settings. Treatment information was obtained for 71 (61%) patients. Only 1.7% had been immunized against hepatitis B virus before injury. Hepatitis B immune globulin and hepatitis B virus vaccine were given to 78% and 76% of children, respectively. None received human immunodeficiency virus prophylaxis. CONCLUSIONS: Programs teaching needle avoidance may help prevent many CANSIs. The safety of outdoor, home and medical environments also needs to be ensured. Treatment guidelines for CANSIs will help ensure appropriate postinjury management.

Influenza vaccine match with circulating strains and indicators of influenza strain impact - Canada 1980 to 1992.

OBJECTIVES: To determine the similarity between influenza vaccine antigens and viruses associated with laboratory-confirmed infections by virus type/subtype, strain and influenza season; to correlate pneumonia and influenza hospitalization and mortality rates with the number of laboratory-confirmed influenza infections in an influenza season; and to develop predictive indicators of the likely incidence of current strains in the following season. DESIGN: Ecological study using national laboratory, pneumonia and influenza hospitalization and mortality data. SETTING: Canada, influenza seasons from 1980 to 1992. POPULATION STUDIED: Individuals with laboratory-confirmed influenza infections, pneumonia and influenza hospitalizations or deaths. INTERVENTION: Influenza immunization. MAIN RESULTS: Similarity of circulating strains and vaccine antigens was 99% for A(H1N1), 65% for A(H3N2) and 65% for B strains. During outbreaks, pneumonia and influenza hospitalization, and mortality rates increased 19% or less and 21% or less for A(H1N1), respectively; 28% or less and 51% or less for A(H3N2), and 19% or less and 16% or less for B strains. There were usually fewer than 25 laboratory-confirmed A(H1N1) infections with a particular strain in a season if there had been more than 25 infections with similar strains the previous season. For A(H3N2), the figure was 100, and for B it was 150. CONCLUSIONS: Matches were excellent for A(H1N1) and good for A(H3N2) plus B strains. Hospitalization and mortality rates increased substantially during outbreaks, eg, estimated 1609 excess deaths during a widespread A(H3N2) outbreak. This study identifies relationships that provide some ability to predict the incidence of a particular influenza strain in a coming season based on the incidence of strains similar to it in the previous season.

Air guns: the main cause of enucleation secondary to trauma in children and young adults in the greater Ottawa area in 1974-93.

OBJECTIVES: To determine the proportion of enucleation procedures attributable to injuries from air guns in people aged 18 years or less and to identify the associated pathological findings. DESIGN: Case series. SETTING: Ophthalmic Pathology Registry, University of Ottawa, and affiliated Children's Hospital of Eastern Ontario (Ottawa), Ottawa General Hospital and Ottawa Civic Hospital. In addition, information on air gun injuries from April 1990 to December 1993 was obtained from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP) database, with data from 10 pediatric and 5 general hospitals across Canada. PATIENTS: All patients aged 18 years or less who underwent enucleation between Jan. 1, 1974, and Dec. 31, 1993. RESULTS: Eighty-five patients were identified as having undergone enucleation. Trauma accounted for 51 cases (60%), of which 13 (25%) were caused by air guns, the largest single cause of enucleation secondary to trauma. Overall, air gun injuries accounted for 15% of enucleation procedures, whereas retinoblastoma accounted for 21%. All air gun injuries were in boys (median age 14 years, range 9 to 16 years). Of the 13 eyes with air gun injuries 7 had ocular perforation and 6 had ocular penetration. In all cases the intraocular structures were severely disrupted. The CHIRPP database included 165 air gun injuries; 32 were to the eye or ocular adnexa, resulting in 26 hospital admissions. CONCLUSIONS: Air guns were the largest single cause of enucleation secondary to trauma in our study. These guns are widely available in Canada and are unrestricted at muzzle velocities capable of causing death or serious injury, especially to the eye. We feel that air guns should be licensed only to people aged 16 to 18 years or older and that education in their use should be mandatory.

An investigation of report bias in a case-control study of pregnancy outcome.

The role of report (recall) bias in case-control studies of possible reproductive hazards was investigated in a study of women who gave birth at the Royal Victoria Hospital, Montreal from September 1983 to May 1985. Women were questioned twice (early in pregnancy; after delivery) about exposures that might influence pregnancy outcome. The two sets of responses of case mothers, control mothers, and mothers of infants of intermediate health status were then compared. Similar inconsistencies in the reporting of 39 exposure variables were common in all three groups, with postdelivery deletion of previous reports more frequent than addition of new information. Changes in reporting were not associated with pregnancy outcome, maternal concern about the baby or maternal sociodemographic characteristics. Odds ratios of exposure estimated from the two sets of data did not differ importantly. Moreover, there was no postdelivery trend to increases, or decreases, in the estimates of the odds ratios. The data do not provide evidence of biased reporting of exposures.