General

Question 1

How much physical activity and of what intensity should adults be performing per week to achieve greater health benefits?

Answer 1

300 min mod. activity or 150 min vigorous activity a week

or a combination of both

Question 2

Which method is the gold standard in measuring total energy expenditure (TEE) during free-living conditions?

What accuracy and precision figures has it provided?

Answer 2

The doubly-labeled water (DLW) method

When applied correctly, the DLW method can produce estimates of TEE with an accuracy of 1–3% and a precision of 2–8%.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6359212/#:~:text=The%20doubly%2Dlabeled%20water%20(DLW)%20method%20is%20the%20gold,–8%25%20%5B9%5D.

Question 3

What can a forest plot show?

Answer 3

It provides a simple visual representation of the amount of variation between the results of the studies, as well as an estimate of the overall result of all the studies together.

Question 4

Advantages of prevalance/cross-sectional studies

(Type of observational study)

Answer 4

Comparatively quick + cheap

Fairly simple to carry out + analyse

Useful for healthcare planning + investigating trends over time.

Question 5

Disadvantages of prevalance/cross-sectional studies

(Type of observational study)

Answer 5

Not useful for conditions which have short duration

Not a 1st choice for investigating causality.

Sampling + data collection need great care.

Question 6

Advantages of cohort/longitudinal studies

(Type of observational study)

Answer 6

Allows outcomes to be explored over time.

Inicidence of disease in both exposed + non-exposed groups can be measured.

Used for rare exposures.

Can examine the effects of more than one exposure/risk factor.

Question 7

Disadvantages to Cohort/longitudinal studies

(Type of observational study)

Answer 7

Can take a long time + be expensive.

Diseases with long latent periods may need many years of follow up.

Not so useful for rare diseases.

Carefull follow up of all subjects is vital.

Question 8

How is prevalance of disease calculated?

Answer 8

Total number with disease / total sample

Question 9

How is prevalence of risk factor calculated?

Answer 9

Total number with risk factor / total sample

Question 10

How is risk factor calculated

Answer 10

Number that did get disease / (Number that didnt get disease + number that did get disease)

Question 11

How is risk ratio (a.k.a relative risk) calculated

Answer 11

risk in the exposed group / risk in the unexposed group

Question 12

How is odds ratio calculated

Answer 12

Odds in exposed group / odds in unexposed group

Question 13

What are the types of systematic reviews?

Answer 13

Those with a qualitative synthesis and those with a quantative synthesis.

Question 14

What 3 modern trends are expected to increase the prevalance of cardiovascular diseease in the 21st century?

Answer 14

Epidemic of obesity

Physical inactivity in children

Increasing age of the population

Question 15

Define PA

Answer 15

Any bodily movement produced by contraction of skeletal muscle that substantially increases energy expenditure.

Question 16

Define exercise

Answer 16

A sub-cateorgy of leisure-time PA in which planned, structured and repetitive bodily movements are performed to improve or maintain 1 or more component of physical fitness.

Question 17

Define epidemiology

Answer 17

The study of the distribution and determinants of health-related states or events in specified populations and the application of this study to control health problems - WHO.

Question 18

What are the 2 main types of epidemiological study?

Answer 18

Observational

Experimental

Question 19

What can come under observational epidemiological studies

Answer 19

Descriptive studies (i.e case reports)

Analytical studies (i.e correlational, cross-sectional surveys, case-control studies, cohort studies)

Question 20

What is knowing prevalence helpful for?

Answer 20

For assessing the need for health care or preventative strategies.

Question 21

Define risk difference (a.k.a excess risk)

Answer 21

Its the absolute difference in rates of occurence between groups of ind who have and have not been exposed to the factor of interest.

Question 22

Define relative risk (a.k.a risk ratio)

Answer 22

The ratio of the risk of occurence among exposed people to that amont the unexposed.

Question 23

What does relative risk (a.k.a risk ratio) measure?

Answer 23

The strength of an association

i.e if the incidence of stroke is 17.7 per 100,000 person-years among non-smokers and 49.6 per 100,000 person-years among smokers… the relative risk of stroke in smokers vs non-smokers will be 2.8 (49.6/17.7).

= Smokers are 2.8 times more likely to have a stroke than non-smokers.

Question 24

What is meant by the population-attribbutable risk?

Answer 24

It reflects the strength of the risk associated with an exposure and its prevalance.

It can help to determine which exposures have the most relevance to the health of a community. i.e the relative risk of developing lung cancer in smokers is high (14 in a classic study of British doctors). But if only 1% of the population smoke, then the population-attributable risk is low.

HOWEVER, if 30% of people smoke, then the population-attribbutable risk is high + this behaviour represents a considerable publich health burden thaty justifies investiment in strategies to reduce its prevalance.

Question 25

What is random error due to?

Answer 25

Chance

It can derive from sources such as individual biological variation, sampling error and measurement error.

– These errors can’t be eliminated but they can be reduced by making ind measurements as precise as porrible + by increasing the sample size.

Question 26

What can random error lead to?

Answer 26

Imprecision in measurement

Question 27

How is precision achieved in the laboratory?

Answer 27

By calibrating instruments

By making careful measurements

Increasing the no. of measurements

Question 28

How can selection bias arise?

Answer 28

When the characterstics of people selected to participate in the study differ systematically from this of the people who are not in the study.

Question 29

What may selection bias influence in a laboratory study?

Answer 29

It may infuence the subsequent generalisability of findings, but not its validity.

Question 30

How may selection bias influence epidemiology?

Answer 30

If theres associations between a putative risk factor and a health outcome, selection bias will threaten the validity of the study.

Question 31

What is the best way to control the problem of confounding factors?

Answer 31

Randomisation

Question 32

What is the major advantage of studying physical fitness and mortality risk over PA and mortality risk?

Answer 32

Physical fitness can be measured more objectively than self-reports of PA.