Roy C. Ziegelstein, MD, Department of Medicine, Division of Cardiology, Johns Hopkins Bayview Medical Center, Johns Hopkins University School of Medicine, Baltimore, MD.

Depressed mood is common after a myocardial infarction and is associated with increased mortality risk. Although mild forms of depression often resolve without specific treatment, moderate to severe depression is typically longer lasting. Depression is particularly unlikely to resolve spontaneously in those who are socially isolated, a common problem in older individuals. Patients may be screened for depression using one of several short and valid instruments. If antidepressant treatment is indicated, a selective serotonin reuptake inhibitor is preferred and should be combined with efforts to improve social support, to address medication adherence issues and to encourage participation in a cardiac rehabilitation program.
Key words: depression, myocardial infarction, screening, social support, antidepressants.

David C.W. Lau, MD, PhD, FRCPC, Professor of Medicine, Biochemistry and Molecular Biology; Director, Julia McFarlane Diabetes Research Centre, University of Calgary, Calgary, AB.

As the population ages, the diagnosis of Type 2 diabetes is expected to skyrocket over the next two decades. Diabetes is diagnosed by a fasting venous plasma glucose level of equal to or greater than 7mmol/L or, in the presence of classic symptoms of hyperglycemia, a casual plasma glucose value greater than 11.1mmol/L. Early diagnosis, screening and prevention of diabetes in the elderly will greatly reduce the burden of this serious chronic disease that is associated with increased morbidity and mortality.
Key words: impaired glucose tolerance, diagnosis, screening, prevention, Type 2 diabetes

The Diabetes Epidemic
Diabetes is now reaching epidemic proportions in Canada and the U.

Peter G. Rossos MD, FRCP(C)
Elaine Yeung MD
Division of Gastroenterology, University Health Network
University of Toronto, Toronto, ON.

Introduction
Colorectal cancer (CRC) is the third most common cause of cancer and second leading cause of cancer death in Canada. It is estimated that there were 17,200 new cases and 6,400 deaths from colorectal cancer in Canada in 2001. When both women and men are considered together, colorectal cancer is the second most frequent cause of death from cancer among Canadians.¹ Most CRC occurs in average risk individuals for whom there are no accepted guidelines for screening.² Higher risk categories include those who have a family history of CRC, a personal history of CRC, colonic adenomas or inflammatory bowel disease, and the familial syndromes including familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC).³ This discussion will focus on average risk older adults, who comprise almost all CRC cases in patients 65 years of age or older.

Epidemiologic Considerations
Although age-standardized incidence and mortality rates have been declining for CRC since 1985, the number of new cases has continued to rise steadily and significantly among both men and women as a result of the growth and aging of the population. Recent data from the National Cancer Institute of Canada is displayed in Figures 1 and 2.

Michael A. Gardam MSc, MD, CM, FRCPC
Medical Director, Tuberculosis Clinic
Associate Hospital Epidemiologist
University Health Network

What is a Skin Test and How is it Administered?
Tuberculin skin testing is the most established method of diagnosing tuberculosis infection, that is both active disease and asymptomatic latent infection. Different skin testing techniques have been developed over the past 70 years. The Mantoux test, however, is the standard procedure in North America. The Mantoux test involves the intradermal injection of 0.1 ml of purified protein derivative (PPD--a precipitate prepared from filtered heat-sterilized cultures of Mycobacterium tuberculosis). The only absolute contraindication to administering the test is a history of anaphylaxis induced by any of the components. Those with a history of BCG vaccination may be skin tested.

The test is usually administered in an area that is free of blood vessels, hair or edema, on the flexor surface of the forearm, but it may also be administered on the upper chest or back. The needle should be inserted just under the skin with the bevel facing up until the bevel is fully inserted. A bleb should be raised when the PPD is injected. If this is not accomplished, or the PPD leaks out onto the skin, the test should be readministered in a different site. The test must be read at 48 to 72 hours by a trained healthcare professional.

Genetic Identification Promises Individually-tailored Treatments

Julia Krestow, BSc MSc

Mental illness is a term describing a group of disorders, all of which profoundly affect an individual's ability to think, feel, and act, and which result in a substantially diminished capa-city to cope with the ordinary demands of life. Mental illness can strike irrespective of age, gender, or race.¹ Although mental disorders were recognized as illnesses in the mid-18th century, suspicion and fear often overshadowed understanding. Gradually, advances in the fields of psychiatry, behavioural science, neuroscience, biology, and genetics have replaced trepidation with knowledge. Some common mental illnesses are schizophrenia, bipolar affective disorder and depression.

Researchers and clinicians have worked for decades to reduce the suffering of those with disabling disorders, and current treatments can alleviate symptoms for many. Unfortunately, there is no curative treatment, and the treatments which do exist can have side effects. Research has long shown that the risk of developing mental illness increases if another family member is similarly affected; this suggests a strong hereditary component. Exciting developments in molecular genetics and the neurosciences explain the cautious optimism in terms of insight gained into the causes of mental disorders.

D'Arcy Little, MD, CCFP
York Community Services, Toronto and
Department of Family Medicine, Sunnybrook Campus of Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario

Epidemiology
Diabetes mellitus, a metabolic disease characterized by hyperglycemia secondary to defective insulin secretion and/or action, is an extremely common, chronic illness with a high burden of potentially preventable complications. It is a leading cause of coronary artery disease, peripheral vascular disease, kidney failure, peripheral neuropathy and new-onset blindness. A full five percent of Canadians have been diagnosed with the disease, and this percentage is predicted to translate into 2.2 million cases by the year 2000. However, statistics from the United States suggest that for every person diagnosed with diabetes, another has the disease and remains undiagnosed. Appropriate screening for diabetes provides the means to identify those undiagnosed individuals who may benefit from earlier intervention.

Valerie Ha, BSc

In the past ten years, public campaigning on behalf of breast cancer has raised awareness to new heights. Despite an increase in the incidence of breast cancer over the past twenty years (most likely due to better detection of disease), we have seen a plateau and even more recently a decline in the mortality rates in both Canada and the United States. This is likely due to our ability to diagnose disease earlier through breast screening and our improvements in treatment.

Breast Screening is indeed a major player in our fight against breast cancer. It is estimated that a significant reduction in breast cancer mortality can be achieved in Ontario if 70% of women between the ages of 50-69 were to participate in a program of early detection.

Breast cancer screening involves participation in biennial mammograms, monthly self-examination and regular breast examination by a trained professional; a regimen that should be followed during the years that the woman is most likely to be affected.