Cancer patterns in Canada.

Data from a cross-sectional survey of the health of Ontario children carried out in 1983 were used to provide estimates of the prevalence, patterns and sociodemographic correlates of the use of tobacco, alcohol and illicit drugs (substance use) among adolescents aged 12 to 16 years. Ninety-one percent of selected households participated. The prevalence rates of all categories of substance use, except use of inhalants, increased with increasing age. Among children aged 14 to 16 years the rates for girls were higher than those for boys for all categories of substance use except use of other, nondefined drugs. The prevalence rates of substance use tended to be higher in small urban areas except for use of marijuana (more prevalent in large urban areas) and use of inhalants (more prevalent in rural areas). The strongest evidence of clustering of substance use within families was found for smoking. Children who used less prevalent drugs (e.g., "hard" drugs) also tended to use the more prevalent ones (e.g., marijuana, tobacco and alcohol). Associations between substance use and low socioeconomic status suggested a positive relation with smoking and a negative relation with use of alcohol. The findings highlight the need for preventive programs aimed at specific subgroups in the adolescent population.     

Comparison of avalanche survival patterns in Canada and Switzerland

Background

Current recommendations for rescue and resuscitation of people buried in avalanches are based on Swiss avalanche survival data. We analyzed Canadian survival patterns and compared them with those from Switzerland.

Methods

We extracted relevant data for survivors and nonsurvivors of complete avalanche burials from Oct. 1, 1980, to Sept. 30, 2005, from Canadian and Swiss databases. We calculated survival curves for Canada with and without trauma-related deaths as well as for different outdoor activities and snow climates. We compared these curves with the Swiss survival curve.

Results

A total of 301 people in the Canadian database and 946 in the Swiss database met the inclusion criteria. The overall proportion of people who survived did not differ significantly between the two countries (46.2% [139/301] v. 46.9% [444/946]; p = 0.87). Significant differences were observed between the overall survival curves for the two countries (p = 0.001): compared with the Swiss curve, the Canadian curve showed a quicker drop at the early stages of burial and poorer survival associated with prolonged burial. The probability of survival fell quicker with trauma-related deaths and in denser snow climates. Poorer survival probabilities in the Canadian sample were offset by significantly quicker extrication (median duration of burial 18 minutes v. 35 minutes in the Swiss sample; p < 0.001).

Interpretation

Observed differences in avalanche survival curves between the Canadian and Swiss samples were associated with the prevalence of trauma and differences in snow climate. Although avoidance of avalanches remains paramount for survival, the earlier onset of asphyxia, especially in maritime snow climates, emphasizes the importance of prompt extrication, ideally within 10 minutes. Protective devices against trauma and better clinical skills in organized rescue may further improve survival.A valanches make winter outdoor travel in mountainous terrain a hazardous activity. A total of 881 people died from avalanches in open terrain in Europe and North America over the six winters from 2003/04 to 2008/09.¹ The survival pattern of complete avalanche burials (coverage of the person’s head and chest, impairing breathing) in open terrain in Europe has been depicted in the avalanche survival curve,^2,3 which displays probability of survival as a function of burial time. The curve exhibits a characteristic shape, with four distinct phases. The probability of survival remains above 91% during the first 18 minutes of burial (“survival phase”). This phase is followed by a precipitous drop to 34% between 19 and 35 minutes because of asphyxiation of most people (“asphyxia phase”). Between 35 and 90 minutes, the survival curve levels out (“latent phase”) because of the survival of people with patent airways.⁴ Thereafter, survival drops again as those buried eventually succumb to lethal hypothermia complicated by progressive hypoxia and hypercapnia.⁵This avalanche survival model forms the foundation for current international recommendations for rescue and resuscitation^3,4 as well as the rationale for safety and rescue devices.⁶ However, the existing survival curve was calculated solely from Swiss data. Therefore, the universal validity of the survival curve and recommendations derived from it remains unknown.We analyzed survival curves for Canada and compared them with the survival curve in Switzerland. A better understanding of the factors affecting survival during an avalanche burial will provide important background for improvements in rescue, resuscitation and avalanche safety measures in Canada and elsewhere.     

Effect of medicolegal liability on patterns of general and family practice in Canada.

As part of the Federal/Provincial/Territorial Review on Liability and Compensation Issues in Health Care, in 1988 we surveyed Canadian general practitioners and family physicians to determine the effect of liability concerns on their practices in the previous 5 years. Questionnaires were sent to a random, stratified national sample of 1295 physicians, with a response rate of 64.6%. However, a high proportion of the returned questionnaires were ineligible because the physicians were not in general or family practice, were not involved in direct patient care, or had died or moved; thus, the corrected response rate was 50.8%. The newsletter of the Canadian Medical Protective Association was the source of information on liability most frequently cited (by 88.1% of the physicians) and most influential (to 62.4%). Only 15.5% of the physicians cited personal involvement with medicolegal issues as a source of information; the rate was higher for Ontario physicians and those in urban areas generally. A total of 74.6% of the respondents had altered their style of practice in the previous 5 years, and 56.3% reported changes in the scope of their practice. Concern about litigation was the most important reason for changing style of practice and reducing or eliminating administration of anesthesia, whereas lifestyle and other issues along with liability concerns most influenced decisions to reduce obstetric care and emergency department work. Our findings suggest that physicians'' perceptions of liability issues have had a profound influence on primary care practice in Canada in the past several years.     

An Analysis of the Increase in Lung Cancer in Canada

Lung cancer mortality in Canada over the period 1936-1964 is reviewed and a forecast is presented of future trends in the death rates, based on cohort analyses. Since 1936 the annual increases in mortality have been greater among individuals over 65 years of age, but in this group no single five-year age-group has contributed the major part to the general increase. Cohort analyses show (a) that the rate of increase of lung cancer has been much slower in generations born after 1906, (b) that the actual death rate will rise more slowly in the future, and (c) that the death rate may become stable within 15 years.     

Lung Cancer Mortality Trends in Canada, 1931-1960

Trends in mortality due to lung cancer in Canada since 1931 were reviewed and data for 1960 presented. In 1960, 2223 male deaths were due to lung cancer. In each five-year age group over 45, there has been a distinct increase in male lung cancer death rates since 1931. The greatest increase occurred between the ages of 65 and 79. The age group 70-74, where the lung cancer mortality rates increased from 10.7 in the period 1931-33 to 173.5 in 1958-60, indicates the trend. Between 1931 and 1960, the proportion of male lung cancer deaths to all male cancer deaths increased from 3% to 18.8%. Female deaths due to lung cancer numbered 321 in 1960. Between 1931 and 1960 the proportion of female lung cancer deaths to all female cancer deaths increased only from 1.4% to 3.2%.