Michelle Durkin, BSc

How to determine when people suffering from Alzheimer's disease and other dementias should stop operating a motor vehicle is a complex and controversial issue. The decision can affect the patient (by impairing independence and mobility), his or her family, and the safety of the general public. As a greater percentage of the population ages, the number of functionally impaired drivers only increases, further complicating the issue.

The Canadian Medical Association's Guide for Physicians in Determining Fitness to Drive (5th edition) states that physicians should monitor the driving competence of a patient with dementia. Until now this has been difficult because an appropriate and accurate evaluation tool has not been available. Physicians relied solely on their own judgement. Now, however, the research of Dr. Allen Dobbs of the University of Alberta may provide this needed, effective evaluation tool with the development of a computer-based test called the Competence Screen.

In an interview, Dr.

Shari Tyson, BSc, MSc

Contrary to popular belief, osteoporosis (OP) is not just an aging woman's ailment. About 8% of men can also expect to develop this disease. In fact, hip fractures in elderly men account for approximately one third of all hip fractures sustained due to OP. In addition, one third of those who have suffered such a fracture will not survive beyond a year. Yet despite the large numbers of men affected, and the millions of health care dollars allocated to the care of individuals with this disease, osteoporosis in men remains under-diagnosed, infrequently reported, and inadequately studied.

OP affects women to a greater extent than men. However, for several key reasons, men develop this disease at a much later age than women. For the first thirty years of life, the rate of bone formation exceeds the rate of resorption resulting in general bone growth and thickening. After peaking at age 30 for both sexes, the opposite is true; there is an increased rate of bone resorption and a general loss of bone mass. This rate is further accelerated in women when a dramatic decrease in estrogen production occurs at menopause.

Both estrogen and testosterone have been shown to play key roles in preventing the resorption process. The exact manner in which testosterone performs this function has yet to be discerned.

D'Arcy L. Little, MD
Chief Resident, Family Medicine, Sunnybrook Health Science Centre, North York, Ontario

Background

Angiotensin Converting Enzyme inhibitors (ACE inhibitors) interact with the body's renin-angiotensin-aldosterone axis. Angiotensinogen (alpha-2 globulin) is converted to angiotensin I or AG-I (inactive) by renin released by the kidney in response to renal ischemia, hypotension, hypovolemia or depletion of sodium ions. ACE inhibitors block the conversion of AG-I to AG-II. AG-II is a powerful vasoconstrictor, as well as a releaser of aldosterone (an adrenal cortical hormone that leads to sodium retention in the kidney), see Figure 1.

 

FIGURE 1

Despite the fact that elderly patients have lower levels of plasma renin than their younger counterparts, ACE inhibitors have been evolving as important agents in the treatment of several cardiovascular diseases in both younger and older patients.

Jocalyn P. Clark, MSc

A recent article published in a special issue of the Canadian Medical Association Journal on Diversity and Women's Health described poor inclusion and representation of women in clinical drug trials for treatment of myocardial infarction (MI). Despite heart disease being a leading cause of disability and death among North American women, especially older women, less than one-quarter of the patients included in the studies were women and the average age of participants was only 62 years. The work of Rochon and colleagues at the University of Toronto extends earlier findings of Gurwitz et al. at the University of Massachusetts who reviewed the literature for a 30 year period up to 1991 and found that women represented only 20% of MI drug trial participants. Most of these trials excluded patients over the age of 75 years. Traditionally, older people have been poorly represented in clinical trials because they are more difficult to study: they tend to have coexisting illnesses, they use other medications that may interact with study drugs, and the elderly are more vulnerable to adverse drug effects. Additional reasons for explaining women's exclusion include fear of harming a fetus, hormonal fluctuations that may complicate responses to medication, and the use of estrogens which may be protective for some diseases.

Shechar Dworski, BSc

Osteopenia literally means "poverty of bone," while osteoporosis (OP) means "porous bone." The underlying cause of both conditions is a difference in the rate of bone formation and bone loss. Normally, both processes take place at equal rates resulting in a dynamic equilibrium. Bone density peaks during the second or third decade of life and then gradually declines with age, when bone loss exceeds bone formation. Bone is formed in response to physical stresses imposed on it, so excessive loss may occur as a result of immobility. Other causes of excessive loss include hormonal changes, either after menopause, or with excess parathyroid or corticosteroid hormones, or insufficient vitamin D or calcium intake.

In radiological terms, osteopenia refers to an increased radiolucency of bone. The most common cause of this is OP, although there are other causes for osteopenia, such as osteomalacia (so-called "renal rickets", Vitamin D deficiency-related problems), hyperparathyroidism, and some renal diseases. Renal osteodystrophy (or uremic bone disease) is the term for a complex group of bone disorders that occur in patients with chronic renal failure (CRF). Specific radiographic clues for other causes of osteopenia include: looser zones found in osteomalacia, subperiosteal resorption present in hyperparathyroidism, and focal lytic lesions (as seen in disseminated multiple myeloma).

Michele Kohli, BSc, MSc

The Osteoporosis Society of Canada estimates that 1.4 million Canadians have osteoporosis (OP). As discussed in the Clinical Practice Guidelines for the diagnosis and management of osteoporosis,¹ the Society recommends several treatments to improve bone mineral density (BMD) and decrease an individual's risk of fracture.¹ Since BMD loss occurs in all people as they age, the challenge is to decide which individuals have a low enough BMD to warrant preventive treatment. The Osteoporosis Society of Canada endorses using the World Health Organization definition of OP to decide whether or not BMD loss is significant enough to increase the risk of fracture. This definition utilizes the spectrum, or distribution, of BMDs found in young adults. Any individual whose BMD is at least 2.5 standard deviations below the mean for this distribution is said to have OP.¹

Several risk factors for OP and OP-related fractures have been identified, including: older age, female gender, low body weight, cigarette smoking, family history of fracture, history of fragility fractures, loss in height, hyperthyroidism, immobility/ inactivity, calcium or vitamin D deficiency, use of certain pharmaceutical agents (benzodiazepines, anticonvulsants, corticosteroids, heparin) and alcoholism. These risk factors only account for about one third of the risk of having an OP-related fracture.

Rhonda Witte, BSc

Our body's framework is subjected to continual use throughout our daily rituals. Whether we are walking, lifting, exercising or even rolling over in bed while we sleep, we depend on our skeletal system to function adequately. Amazingly, it handles a lot of use and is incredibly reliable. With age, however, our framework becomes less capable of withstanding the "wear and tear" of every day life. Research provides insight into the mechanisms behind the "normal" aging of the skeletal system. With this knowledge, we are gradually learning ways to counteract the effects of aging bone.

Lawrence Papoff

Warfarin is an important tool in the prevention of thromboembolisms. Prescribing the drug to the elderly, and monitoring their progress while on the drug, however, are becoming increasingly complex matters, requiring careful attention to patient's blood levels, as measured by International Normalized Ratios (INRs) and in-depth knowledge of the patient.

Michele Kohli, BSc

Congestive heart failure (CHF), a clinical syndrome caused by failure of the left or right ventricle, is a leading cause of chronic illness in older persons. In the United States, CHF is the most common cause of hospitalization among those aged 65 years and above. Each year, approximately 400,000 Americans are diagnosed with CHF. Few statistics regarding CHF in Canada have been compiled, but the Heart and Stroke Foundation estimates that 200,000 to 300,000 Canadians have the syndrome. The incidence of CHF appears to be increasing in both Canada and the United States.

An individual's risk of developing CHF increases exponentially as a person ages (See Figure 1), due to age-related changes in the heart structure and function. Physiological and pathological alterations affecting heart rate, preload, afterload and contractile states of the heart reduce cardiac output (See More Fat, Less Specialized Cells in Old Heart). Concurrent changes in the kidney, respiratory and nervous systems may further impair the function of the heart. Congestive heart failure is a syndrome with multiple etiologies.

Early diagnosis of CHF greatly improves the success of treatment.

Sonya Lytwynec, RegN, BScN
Nurse Clinician, Southwestern Ontario Regional Geriatric Program: Continence Outreach

Stress urinary incontinence (SUI) is one of five types of incontinence.¹ The assessment and therapeutic interventions associated with stress incontinence will be reviewed in this second article of a five-part series on Urinary Incontinence.

SUI is defined as urine loss coincident with an increase in intra-abdominal pressure in the absence of a detrusor muscle contraction or an over-distended bladder.² SUI is a term used in reference to symptoms, physical findings or conditions. Coughing, sneezing, laughing, lifting, or bending over along with simultaneous urine loss often indicates SUI. However, in complex or unresolved cases, urodynamic testing may be beneficial to differentiate between SUI and other types such as urge incontinence.

Prevalence studies report variable results according to definition and design. Subjective reports of SUI in community-dwelling elderly women (65 years of age or older) ranged between 12% and 17%, while urodynamic studies at a urological clinic estimated prevalence rates of SUI at 16% for females and 2% for males.³

SUI in males is commonly the result of intrinsic sphincter deficiency (ISD) post prostatectomy.