Cross Sectional Studies

Question 1

what are features of a cross sectional study

Answer 1

takes place at a single point in time
does not involve manipulating variables
considers several characteristics at once
analyses prevailing characteristic in given population

Question 2

what is a cross sectional study used to estimate

Answer 2

prevalence of a specified outcome in a defined population
e.g for public health planning

Question 3

what individual characteristics is collected data based on

Answer 3

exposure to risk factors
outcome information

Question 4

why do we do a cross sectional study

Answer 4

used when the study purpose is descriptive,
often uses survey
often there is no prior hypothesis

Question 5

what is the aim of cross sectional studies

Answer 5

describe population or subgroup with regards to outcome and set of risk factors
and to determine prevalence of specified outcome for population/subgroups at particular point in time

Question 6

why are cross sectional studies limited

Answer 6

because only carried out at one point in time
give no indication of sequence of events so not possible to determine CAUSALITY

Question 7

what does a repeated cross sectional study give

Answer 7

a pseudo-longitudinal study

Question 8

where are the individuals chosen from

Answer 8

same sampling frame or a different one

Question 9

what is an example of a cross-sectional study

Answer 9

british association for the study of community dentistry survey
5 y/o children examined annually, prevalence of dental caries recorded and monitored over time

Question 10

what do the sample frame and response rate determine

Answer 10

how well results can be generalised to whole population

Question 11

how can the selected sample be representative of the population

Answer 11

if it is selected using a random method

Question 12

what are some techniques used to minimise non-response

Answer 12

telephone and mail prompting
second and third mailing surveys
letters stressing importance of replying
incentives - money?

Question 13

how can a response become biased

Answer 13

a person could be more likely to respond if they have particular characteristics and this is biased if the characteristic is related to the probability of having the outcome

Question 14

what is an example of how response rate and sampling can be biased

Answer 14

door to door interviews - response rate highest in elderly and unemployed
this is because these people are most likely to be at home and more likely to experience higher levels of disease
leads to biased results

Question 15

is loss to follow up an issue in cross sectional studies

Answer 15

no

Question 16

what is a cross sectional study good for

Answer 16

broad knowledge of subjects who do or do not have specified outcome
but important to have optimum response levels

Question 17

what are advantages of cross sectional studies

Answer 17

inexpensive
done in short time span
can estimate prevalence of specified outcome - as the sample is taken from whole population
many outcomes and risk factors can be studied
useful for public health planning, understanding disease aetiology and generation of hypotheses

Question 18

what are disadvantages of cross sectional study

Answer 18

not easy to infer causal associations
only presents situation at one point in time - may change
prevalence-incidence bias - for long-standing diseases risk factors associated with death will be under-represented

Question 19

outline coronary heart disease as an example of cross sectional study

Answer 19

objective - compare coronary risk factors and prevalence in Indians, Pakistani,Bangladeshi + Europeans in Newcastle
age 27-74 years

Question 20

what were the results of the coronary heart disease study

Answer 20

differences in SES, lifestyles and anthropometric measures and disease
poorest groups - bangladesh and pakistani
bangladeshi men had most risk factors
smoking common
south asians disadvantaged in wide range of factors
high proportion had diabetes

Question 21

what were the conclusions about the coronary heart disease study

Answer 21

coronary artery risk if not uniform among south asians
previously thought south asians had lower levels of Coronary risk factors than europeans, this study showed this is incorrect

Question 22

why may have those conclusions been made about the coronary heart disease study

Answer 22

from combining ethnic subgroups and studying a narrow range of risk factors

Question 23

outline the risk taking behaviours study

Answer 23

being involved in military combat role has negative effect on risk taking behaviour - smoking drinking
self-report questionnaire to assess hazardous behaviour
1700 participants

Question 24

what were the results of the risk taking behaviour study

Answer 24

deployment significantly associated with risky driving, smoking and physical violence

Question 25

what were limitations of the risk taking behaviour study

Answer 25

risk taking behaviours were examined at a single time point - direction of causality cannot be determined
confounding effects cannot be taken into account - sociodemographic
self reported behaviours - social desirability bias

Question 26

outline the HPV cross-sectional study

Answer 26

aim to examine young womens perception and acceptability of HPV vaccination in china
117 female undergraduates surveyed

Question 27

what were the results of the HPV study

Answer 27

only 44% of participants willing to be vaccinated
low awareness about HPV and cervical cancer
intention to receive future vaccination associated with high level of knowledge about risk factors for cervical cancer

Question 28

what conclusions were made from the HPV study

Answer 28

low awareness and knowledge among young chinese women about HPV vaccine
social and cultural factors may influence womens intentions regarding future vaccination

Question 29

what is the summary about cross sectional studies

Answer 29

cheap
not time consuming
very applicable to wide range of things
but cant be used for causal inference