risk factors

what are risk factors?

factors that can be linked to an increased risk of a disease

what seven factors increase the risk of CVD?

genetics, diet, age, gender, high blood pressure, smoking and inactivity

how do genetics increase the risk of CVD?

individuals can inherit alleles making them more prone to high blood pressure/cholesterol

how does diet increase the risk of CVD?

a diet high in saturated fat increases blood cholesterol levels → thrombosis
a diet high in salt increases blood pressure

how does age increase the risk of CVD?

risk of CVD increases with age as blood vessels become more fragile and plaque building up over time

how does gender increase the risk of CVD?

men are x3 more likely than women (up until menopause) to suffer from CVD
oestrogen increases HDL levels so women have lower total blood cholesterol on average

how does high blood pressure increase the risk of CVD?

increased risk of damage to artery walls → atheroma → thrombosis

how does smoking increase the risk of CVD?

CO combines with haemoglobin in RBCs, reducing its oxygen carrying capacity
this decreases respiration in cells of brain and heart → stroke + heart attack
nicotine increases risk of thrombosis by increasing agglutination of platelets
decreases levels of antioxidants in blood → increases risk of damage to cells lining arteries → atheroma → thrombosis

how does inactivity increase risk of CVD?

inactivity → CVD system less exercised → decreased strength and efficiency of heart and arteries
higher workload on heart + increased blood pressure → plaque build up

what is the difference between correlation and causation?

correlation is when a change in one variable is accompanied by a change in the other
causation is when a change in one variable is responsible for a change in the other

what does conflicting evidence in a study show?

shows a different pattern to evidence gained elsewhere
often a sign other variables are involved

how can the risk of conflicting evidence in studies be reduced?

carrying out studies similar in design to be analysed together (meta-analysis) where similar conclusions are drawn
more research is needed to show which pattern is correct when conflicting evidence arises

what are six factors that need to be considered when evaluating the design of a study?

sample, variables, data, controls, repetition, reproducible

how is sample size evaluated when looking at the design of a study?

sample size should be representative of the population involved; larger samples are more likely to be representative
randomly selecting participants removes bias and increases the likelihood of a representative sample

how are variables evaluated when looking at the design of a study?

the more variables controlled, the more reliable (data can be reproduced) and valid (only tested one independent variable) the data

how is data evaluated when looking at the design of a study?

no bias involved in collection or analysis of data e.g. selecting a random sample + not manipulating data

how are controls evaluated when looking at the design of a study?

use of an experimental controls provides a point of comparison and ensures results are due to independent variable

how is repetition evaluated when looking at the design of a study?

repeats of data need to be taken within a study, and similar results should be collected to show that the study is reliable

how is reproducibility evaluated when looking at the design of a study?

it should be possible to reproduce a set of findings by repeating an entire investigation

what are two types of studies?

cohort and case-control

what are cohort studies?

group of people who are exposed/not exposed to risk factors are followed over time to see who develops the disease

what are case-control studies?

group of people with a disease are compared with a control group of people who do not have the disease

what are two ways risk can be perceived by individuals?

overestimated or underestimated

what are four reasons why risk can be overestimated?

misleading information in media, personal experience of associated risk, unfamiliarity with the event, even causing severe harm

what are four reasons why risk can be underestimated?

lack of information, lack of personal experience of associated risk, unfamiliarity with event, harm being non-immediate