Sheldon Singh, BSc
Toronto, ON and

George Fantus, MD, FRCPC,
Diabetology
Mount Sinai Hospital
Toronto, ON and
Director, Banting & Best Diabetes Centre Core Lab

In the USA, the prevalence of type 2 Diabetus Mellitus (T2DM), in individuals over 65 is estimated to be 10%. This is twice the prevalence of the overall USA population. The worldwide prevalence of T2DM is steadily increasing due to factors such as an increase in the elderly population, obesity, and decreased physical activity.

Multiple mechanisms are involved in the pathogenesis of T2DM including impaired insulin secretion by pancreatic b-cells, increased hepatic gluconeogenesis, and reduced glucose uptake by muscles and adipose tissue (see figure 1). These factors lead to hyperglycemia and in the long term, micro- and macrovascular complications. Available evidence indicates that improved glycemic control will decrease the complications of diabetes; this may be achieved with a combination of dietary, exercise and pharmacologic interventions.

Current pharmacologic agents used to treat T2DM include sulphonylureas (glibenclamide, gliclazide), biguanides (metformin), alpha-glucosidase inhibitors (acarbose), or insulin.

Neil Fam, BSc, MSc

Heart failure can be defined as a pathophysiological syndrome in which the heart fails to pump an adequate flow of blood to meet the metabolic demands of the body. This condition carries extremely high morbidity and mortality, with a five year survival rate of 50%. It is also one of the most common reasons for hospital admission in Canada. As our population ages, heart failure is becoming increasingly prevalent, placing serious strain on health care resources. In the past decade, medications such as angiotensin converting enzyme (ACE) inhibitors have been shown to improve survival in patients with heart failure. However, mortality has remained high. New research has focused on the use of b-blockers, a class of drugs traditionally used in the treatment of angina and myocardial infarction. Recently, two large randomised trials, the Cardiac Insufficiency Bisoprolol Study II (CIBIS-II) and the Metoprolol CR/XL Randomized Intervention Trial in Congestive Heart Failure (MERIT-HF) clearly demonstrated a survival benefit in heart failure patients taking b-blockers. This article summarizes the main findings of these studies and outlines the practical use of b-blockers in heart failure.

An understanding of the pathophysiology underlying heart failure is helpful in the selection of appropriate medical therapy.

Alexandra Nevin, BSc

Type II diabetes is a complicated, multifactorial disease process characterized by a relative insulin insensitivity leading to prolonged hyperglycemia. In comparison with type I diabetes, which is primarily due to the auto-immune-mediated destruction of the insulin producing beta cells of the pancreas, type II diabetes is the more predominant, generally adult- onset form, which predisposes individuals to pathological complications, and is more amenable to lifestyle modifications.

Senior citizens are the population most susceptible to type II diabetes. The Canadian Heart Health Survey reported that 13.2% of men and 12.0% of women between the ages of 65 and 74 have diabetes. In light of the aging population in Canada, researchers continue to investigate the intertwined role of genetics and the environment in the pathogenesis of type II diabetes in an effort to better understand and, ideally, to devise true preventative therapy measures to combat the disease.

Pathogenesis
Two fundamental defects underlie the pathogenesis of type II diabetes. The primary problem is the development of insulin resistance. In an attempt to compensate for the increased blood glucose load, a period of relative maladaptive hyperinsulinemia occurs.

Leora Horn, BSc, MSc

Over three hundred thousand Canadians currently suffer from Alzheimer's disease (AD) and the related dementias. AD is a degenerative disorder associated with a progressive decline in cognitive function. There is significant neuronal loss and impairment of metabolic activity in the cerebral cortex, hippocampus and subcortical structures affecting memory, language and emotion. At present, there are limited drugs used to treat the symptoms associated with the disease but there is no cure. In a recent Nature publication, Schenk et al., reported results that take the treatment of AD in a new direction by raising the possibility of vaccination as prevention against disease development. In two separate sets of experiments scientists were able to prevent the occurrence or reduce the presence of Alzheimer-like pathology in genetically engineered mice immunized with one of the proteins that may be responsible for disease evolution.¹

According to the Alz-heimer's Association of Canada, AD is the fourth leading cause of death in adults. The prevalence of AD increases exponentially with age. AD affects 1 in 100 Canadians between the ages of 65 and 74, 1 in 14 Canadians between the ages of 75 and 84 and 1 in 4 Canadians over 85. Symptoms of AD range from forgetfulness to disorientation to people, time and place resulting in an inability to function without assistance.

Geoff Fernie, PhD, PEng, CCE
Centre for Studies in Health and Aging,
Sunnybrook Hospital and Women's College Hospital
North York, Ontario

It would obviously be safer and easier if we all lived on one level as we got older. This is not the reality and we are likely to have to use some form of assistive technology to make the change in elevation possible, less tiring or perhaps, simply less hazardous. For those who are no longer able to climb stairs, options include the installation of elevators and stair-climbing platforms. We will address these in a later article.

The focus of this article is on how to specify and install handrails that will reduce the risk of a falling accident as much as possible. Good sturdy rails will also provide significant assistance for many people in climbing the stairs.

The greatest dangers are of falling while descending the stairs. Catching the heel on the edge of a tread (under stepping), missing a step (overstepping) or simply losing balance may result in toppling forward down the stairs. Note that a tread is the surface of a step, whereas the vertical board is called the riser (i.e. each step consists of a tread and a riser). Studies in Dr.

Sheldon Singh, BSc

Hypothyroidism (thyroid hormone deficiency) can affect all body systems; the degree of severity can range from mild and unrecognized to a state of striking myxedema. In the elderly, hypothyroidism is not unusual. However, it may go unrecognized for a variety of reasons including mistaking the non-specific signs and symptoms as a part of the "normal aging" process or other medical conditions that may exist in the elderly. This article will discuss normal thyroid physiology, changes to the thyroid as a result of the aging process, etiology of hypothyroidism as well as diagnosis, management and screening for hypothyroidism.

Physiology of the Thyroid
A review of the physiology of the normal feedback loop of the hypothalamic-pituitary-thyroid axis is quite useful in aiding clinicians in interpreting thyroid function tests and subsequently diagnosing thyroid dysfunction (see figures 1 and 2). Thyrotropin-releasing hormone (TRH) is produced by the hypothalamus. This hormone stimulates thyrotroph cells in the anterior pituitary to secrete thyrotropin (TSH). This hormone then stimulates the thyroid follicular cells to release tri-iodothyronine (T3) and thyroxine (T4). The release of T3 and T4 suppress the release of TSH and TRH; this completes the feedback loop. Although T3 differs from T4 by one iodide molecule (see figure 1 on page 18), this difference results in a significant increase in receptor affinity and activation.

Margaret C Gibson, PhD, CPsych
Psychologist
Veterans Care Program
Parkwood Hospital Site
St. Joseph's Health Centre
London, Ontario

Sexual health is defined by the World Health Organization as the integration of the physical, emotional, intellectual and social aspects of sexual being in ways that are positively enriching and that enhance personality, communication and love.¹ Sexual health includes elements that are sensory, cognitive, emotional, physical, spiritual, functional, relational, social, cultural and historical. It reflects our basic concepts of ourselves as male, female, man, woman, child, mother, father, partner, lover and friend. Sexual health includes overt sexual behaviours, but is about much more than behaviours alone. It is about who we are, about our connections to others with whom we share both basic evolutionary drives and the capacity for profound interpersonal bonds. Sexual health involves having a sense of comfort with the life course of one's own sexuality. It is an integral part of overall psychological well-being and quality of life.

Eleanor Brownridge

Until recently, many general practitioners have been hesitant to diagnose Alzheimer's Disease (AD), especially at the mild and moderate stages. They believe that patients and their families don't want to hear this bad news and therefore don't push the issue.

"We have to work hard to change the attitudes of physicians," says Dr. Ron Keren, geriatric psychiatrist with the University Health Network, Toronto General Hospital. "We have to move away from stigmatizing Alzheimer's and start approaching it as any other serious disease. We need to talk frankly, openly and honestly with our patients." Research from the United States has shown that 80 percent of seniors want to know if they have dementia. Dr. Keren, who also practices at the Toronto Rehabilitation Institute and the Whitby Health Centre, says that in over seven years he has never had a patient who didn't want to know the state of his disease. "If you can't talk about it, how can you treat it?"

With the recent decisions of Ontario and Manitoba to reimburse donepezil (Aricept) in those provinces, physicians now have a treatment for mild to moderate dementia of the Alzheimer's type that can bring hope to all patients and their families, not just those who can afford it.

Donepezil inhibits the activity of acetylcholinesterase, thereby increasing levels of acetylcholine in the brain.

No More Splitting Pills! Study Calls for Low Dose Pills for Seniors

An Ontario study is calling for pharmaceutical companies to make low dose tablets of commonly prescribed drugs for seniors.

The population-based study, conducted by Baycrest Centre for Geriatric Care, was published in the August issue of the Journal of the American Geriatrics Society. It is the first comprehensive look at low dose prescribing in a large population of seniors.

Using the Ontario Drug Benefit Plan database, investigators at Baycrest identified over 133,000 adults aged 65 and older who were prescribed either thiazide diuretics or beta blockers over a one-year period from 1995 to 1996.

The study found that of the 120,000 seniors in Ontario who were repeat users of thiazide diuretics, more than a quarter (26%) were dispensed a dose lower than the standard pills produced by pharmaceutical companies.

The "mismatch" between dosage prescribing and dosage formulations means doctors rely on patients and pharmacists to split standard dose tablets. Splitting pills, particularly when done by older patients who may have impaired vision or motor skills, may increase drug error or lead to frustration and non-compliance.