Topic 10: Ageing

Question 1

What are the five leading causes of death in Australia based on findings from 2015?

Answer 1

• ischaemic heart disease
• dementia
• cerebrovascular disease
• trachea, bronchus, and lung cancer
• chronic lower respiratory diseases

Question 2

What is aging defined as?

Answer 2

regression of physiological function accompanied by the advancement of age

Question 3

Explain the changes in the CNS for aging

Answer 3

• neurons lose their capacity to divide after cell differentiation (changing from one cell type to another), while glial cells (non-neuronal) continue to divide.
• in the elderly there is an increase in the incidence of brain disorders such as Parkinson’s disease and dementia.

Question 4

Explain the changes in the endocrine system for ageing

Answer 4

• Essentially changes result from structural and metabolic changes in endocrine-related target tissues.
• For example, reduction in lean body mass is thought to be the basis for age-related decline in thyroxin levels. Changes in the synthesis of carrier proteins also influence blood levels and rates of conversion to active forms. Altered endocrine function may contribute to an impaired ability to adapt to changes in nutrient intake.

Question 5

Explain the changes in the cardiovascular system for ageing

Answer 5

• In healthy older men and women, heart weight does not decrease in relation to body size, but modest increases in the thickness of the left ventricular wall occur even in normotensive individuals.
• In the major arteries, changes related to ageing occur independent of atherosclerotic disease. The aorta increases in diameter and length and the arterial walls stiffen and lose elasticity due to structural changes in elastin and collagen and the deposition of calcium.

Question 6

Explain the changes to renal function for aging

Answer 6

• Kidney function can decrease with age due to loss of nephrons and changes in blood flow. Kidney mass may decrease by as much as 30% by 90 years. Structural changes contribute to the age-related decline in the glomerular filtration rate (GFR) of around 1 mL per minute per year after the age of 30 years.
• In older people, kidneys are less able to increase the rate of urine flow and urine osmolality. This limits the capacity to excrete waste products and may become critical in older individuals with low fluid intakes and high intakes of protein and electrolytes.

Question 7

What have trends in disability rates by age and sex in Australia revealed?

Answer 7

While the proportion of people in Australia aged 65 years and over continues to increase, the prevalence of disability amongst older people has decreased.

Question 8

Explain the changes to the pulmonary system with aging

Answer 8

• reduced ventilation of the alveoli (where the lungs and blood exchange oxygen)
• air sacs become larger with the collapse of some small airways
• due to the chest walls stiffening and not expanding as easily, this increases the work of breathing.

Question 9

Explain the changes to gastrointestinal function with aging

Answer 9

• most gastrointestinal functions are well preserved in older people
• decreased taste threshold
• decreased liver blood flow and size

Question 10

In the elderly, the decreased production and secretion of stomach acid results in a reduction in the production of…?

Answer 10

Intrinsic factor

Question 11

What are the physiological changes associated with aging that affect energy balance?

Answer 11

Lower:

• BMR
• Energy intake
• LBM
• Appetite and satiety
• gastric emptying
• taste and smell

Question 12

What is a consequence of the maintenance of body weight as aging progresses?

Answer 12

A consequence of the maintenance of body weight is that aging is also accompanied by an increase in the proportion of body fat and a decrease in lean mass and the percentage of body water, 60% in adults compared to 50% in the elderly

Question 13

What are the concerns for body composition with aging?

Answer 13

• An increased proportion of body fat predisposes individuals to developing glucose intolerance and to higher blood insulin levels and an increased risk of diabetes at older ages. Decreases in body water increases the susceptibility of older people to dehydration.
• The distribution of body fat also changes with age and more adipose tissue tends to accumulate in the abdominal region, increasing the adverse metabolic effects associated with obesity.

Question 14

What are the two groups of elderly populations?

Answer 14

‘Young’ elderly i.e. 55–70 years.

‘Old’ elderly i.e. 70+ years.

Question 15

What are the classifications for the elderly?

Answer 15

• Well fit elderly.
• Disabled elderly.
• Frail elderly.
• Elderly living at home.
• Elderly living in residential care.

Question 16

What is the EAR for Vitamin B6?

Answer 16

For older adults, the estimated average requirement (EAR) for vitamin B6 appears to be higher, and there is a gender difference with higher requirements in men. The increase due to age and gender appears to be in the order of 0.2 to 0.3 mg of food vitamin B6 a day.

Question 17

What is the clinical definition for constipation?

Answer 17

• straining when passing a stool on 25% or more occasions
• < 3 stools/week
• feeling of incomplete evacuation more than 25% of the time
• hard stools more than 25% of the time.
• Constipation can be also defined by an individual’s self-perception of the problem. Other factors contributing to constipation include medications and inadequate physical activity.

Question 18

Why do the elderly report a decreased appetite?

Answer 18

• Changes in sensory perception may be partly responsible. Taste acuity is diminished and the thresholds for detection of odors may be ten times higher than in younger adults.
• Changes in hormonal responses can also reduce food intake. For example, satiety may be induced earlier, as the production of cholecystokinin, a gut hormone released in response to eating, is raised with age.
• Changes in the muscular structure of the intestinal wall which reduces the motility of the gut may also influence feelings of satiety.
• Psychological factors such as bereavement, confusion, and depression, and physical and social factors such as immobility and social isolation can all reduce appetite in the elderly.

Question 19

List and explain the drug-nutrient interactions in the elderly

Answer 19

• Physicochemical interactions are characterized by binding with metal ions (chelation) to form chelation complexes and by changes in the stability of nutrients.
• Physiological interactions include drug-induced changes in appetite, digestion, gastric emptying, biotransformation and renal clearance.
• Pathophysiological interactions occur when a drug impairs nutrient absorption or inhibits nutrient-related metabolic processes.