Epidemiology is the study of how often diseases occur in different groups of people and why. Cancer epidemiology is therefore the study of how often cancer occurs in different groups and why. Part of the work on examining why is to measure the effect of factors which may put a patient at high risk of getting the type of cancer in question.

Pressure ulcers (PU) may cause intolerable suffering to the patient. Not only do they affect patients but they also increase nursing workload. In Finnish studies, PU prevalence was 5.4–22% depending on the type of institution caring for the patient. The same level of prevalence is reported from other European countries. In 2000, it was reported that PUs, as the main diagnosis, were responsible for over 20000 bed days in Finnish long-term care hospitals, at a cost of approximately 3 million EUROs a year. In England, it was estimated that a 600-bed general hospital spends 600000 to 3 million GB£/year to care for PUs. Some US statistics estimate that nearly 2 million American patients acquire a PU during the course of their care, and the cost to treat one wound is from 2000 US$ to 70000 US$. Prevention is therefore not only beneficial for the patient but obviously cost-effective for the health care system.

Coronary atherosclerosis is a nearly universal finding in people over 75 years old living in developed countries, but is often sub-clinical. Broadly speaking, symptomatic patients manifest coronary artery disease in two distinct ways: chronic stable angina or an acute coronary syndrome. Stable angina produces symptoms of exertional chest pain due to fixed atherosclerotic narrowing of the coronary artery, and requires chronic therapy. In contrast, the acute coronary syndromes, namely acute myocardial infarction (MI) and unstable angina, occur as a result of plaque rupture or erosion leading to acute coronary arterial thrombosis and occlusion that requires emergency hospitalization and treatment.

Benign enlargement of the prostate gland does not always cause symptoms or obstruction to the flow of urine. Old terminology, for example, ‘prostatism’ can therefore be misleading, and the British Association of Urological Surgeons (BAUS), the International consultation on BPH and the International Continence Society accept the definitions given below:

Benign prostatic hyperplasia (BPH) is a histological diagnosis. The first pathological signs appear under the age of 40 years, followed by a rapid increase in prevalence with age; 80% of 80-year-olds have evidence of BPH. The onset of BPH is dependent on the presence of functioning testes and increasing age. It is characterized by a combination of atrophy and proliferation in both glandular and stromal tissue. Although BPH is detectable in most elderly men, it does not always cause enlargement of the prostate, symptoms, or obstruction to the flow of urine.

Continence is a basic function that should be maintained in healthy elderly people, regardless of age. Loss of continence should be interpreted as a dysfunction of either the lower urinary tract or bowel, or of some other system that participates in the maintenance of continence, especially the nervous system.

A stroke typically results in a variety of impairments that are primarily unilateral, with the severity of symptoms and resultant disabilities dependent on the site and extent of the insult. While the overall goal of rehabilitation after a stroke is to maximize the individual's functional independence at home and in the community, improved walking function is the treatment goal most often stated by patients following a stroke.

The issue of not taking medicines as prescribed by medical practitioners has a history as long as the medical profession itself. The World Health Organization recently described the problem of patients diagnosed with chronic illnesses not taking their medication as prescribed as ‘a worldwide problem of striking magnitude’. Not taking medicines as prescribed has consequences not only for the individual in terms of therapeutic failure, but also for the wider society. For the individual, failure to take medication as prescribed may result in ill health, poorer quality of life, and reduced life expectancy. For the wider society, consequences include avoidable health care expenditure and the development of drug resistance.

The search for the most appropriate, effective and efficient ways to care for vulnerable older people is an enduring one. Hence, the importance of research which seeks to explore how best to meet the needs of frail older people at the margins of care, whose care needs can therefore be appropriately met in more than one setting. The theme of balance of care has been a recurrent theme in the literature of long-term care and relates to ideas of optimality and efficiency in resource use and has been primarily, but not exclusively, applied to the care of older people. Interestingly, it is not a new concept but rather one which is implicit in policy relating to the care of vulnerable older people since the 1970s, although periodically it has risen to become more explicit. In this context it almost always relates to the relative priority accorded to services provided in the community compared to those provided in long-term care settings, such as care homes or hospital.