2. Acknowledgement
• This presentation has been prepared with the help of many books
and presentations on the topic.
• The presenter pays his sincere gratitude to all authors, professors
and experts for their efforts and contributions.
• There is no claim for IPR.
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3. Concept of Risk
• The term "risk" generally means "dangerousness“,
• More strictly, the term is used to refer to
• "the magnitude of the influence of damage"
• "the possibility of any damage (likelihood)”
• or the both - "the combination of the magnitude and the likelihood”
• The focus is
• not on actual existence of damage -"whether or not there are any risks“,
• but on "to what extent or by how many times risks exist or increase"
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4. Concept of Risk
• Do not forget !
• "having risks" is not equal to "(surely) being subject to damage."
• Risk –
• the chance/likelihood/probability of (negative) outcome such as developing
disease.
• When considering health effects of smoking,
• the term "risk" is used in the sense of "the probability (of suffering from
stroke)”
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5. What is Risk (in epidemiology) ?
• Therefore, Risk –
• the probability that a specific action or exposure will give rise to a
negative health outcome.
• For example, having sex without a condom may lead to risk of becoming
pregnant or acquiring a sexually transmitted infection.
• In epidemiology, our prime interest is in the interaction between the risk, and
those environmental, individual, and social characteristics which influence the
risk.
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6. Why it is important to know about risks ?
Quantitative estimate of risk helps us provide the evidence to make an
appropriate public health choices –
• to decide course of actions to address the health problems.
• to allocate scarce resources – time, money and manpower for effective and
efficient outputs.
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7. Characteristics of Risks
• Risk is not certain.
• Not everyone who is exposed to a risk condition will have an adverse outcome.
• Risk is not a neutral concept.
• It involves determining what are acceptable or unacceptable factors.
• Risk is a relative term.
• It exists from comparison between two groups of people, or in the same group of
people over time.
• Longer the exposure to the risk conditions, the greater the likelihood of health
problems to occur.
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8. Unpacking “risk”
In public health, the word risk is used in many ways:
• Risk behaviours:
• Behaviours that increase the likelihood of a negative health outcome such as diseases,
disability or death, now or in the future—for example, excessive alcohol use.
• Risk conditions:
• Conditions such as overweight/obesity, which are not behaviours but that nonetheless
contribute to health outcomes.
• Risk conditions may be linked to risk behaviours (for example, overweight/obesity is linked
to diet and exercise) and to factors in the host’s environment (for example, gender norms
and food security influence the occurrence of anaemia).
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9. Unpacking “risk”…
• Risk exposures:
• Things that happen to an adolescent that may have negative impacts on health and are
outside of his/her control—physical or psychological abuse,
• for example, developing respiratory disease as a result of indoor air pollution or becoming
infected with typhoid from contact with contaminated water.
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10. Unpacking “risk”… At risk
• Population described as “at risk” are
• those who live, learn and develop in conditions that contribute or predispose to poor
health (for example, poverty and discrimination),
• or those who engage in behaviours that increase the likelihood of negative health
outcomes (for example, injecting drugs using unclean needles and syringes).
• Population at risk refers to group of persons who are exposed to risk and are vulnerable of
suffering from disease (in question).
• susceptible people who might get the disease of interest, but do not have it yet,
• Provides the denominator to compute the risk of occurrence of the disease under study,
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11. Population at risk in a study of carcinoma of the
cervix
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12. Unpacking “risk”… Risk factors
• Health and wellbeing are affected by many factors – those linked to poor health, disability,
disease or death, are known as risk factors.
• A risk factor is any attribute, characteristic or exposure of an individual that increases the
likelihood of developing a disease or injury (WHO 2017).
• Risk factors are often presented individually, however in practice they do not occur alone.
• They often coexist and interact with one another.
• For example, physical inactivity will, over time, cause weight gain, high blood pressure and high
cholesterol levels. Together, these significantly increase the chance of developing chronic
heart diseases
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13. Types of Risk factors
Type of Risk
factors
Behavioural
risk factors
Environmental
risk factors
Physiological
risk factors
Demographic
risk factors
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14. Behavioural risk factors
• Behavioural risk factors usually relate to ‘actions’ that the individual has chosen to take.
• They can therefore be eliminated or reduced through lifestyle or behavioural choices.
• Examples include:
• smoking tobacco
• drinking too much alcohol
• nutritional choices
• physical inactivity
• unprotected sex
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15. Demographic risk factors
• Demographic risk factors are those that relate to the overall population.
• Examples include:
• age
• gender
• population subgroups, such as
• occupation,
• religion,
• income, etc
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16. Environmental risk factors
• The environmental factors can be defined as the identifiable element within the environment
that affects an organism’s survival, and growth.
• Environmental factors involve everything that changes the environment – visible/non-visible.
• By definition, the environmental factors affect everyday living.
• It includes factors like air, water, noise, temperature, climate, soil, natural vegetation, and
landforms, in addition to social, economic, cultural and political factors.
• Examples include:
• air pollution,
• working conditions, etc
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17. Genetic risk factors
• Genetic risk factors are based on an individual’s genes.
• Some diseases, such as cystic fibrosis and muscular dystrophy, come entirely
from an individual’s ‘genetic make-up’.
• Many other diseases, such as asthma or diabetes, reflect the interaction
between the genes of the individual and environmental factors.
• Other diseases, like sickle cell anaemia, are more prevalent in certain
population subgroups.
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18. Physiological risk factors
• Physiological risk factors are those relating to an individual’s body or biology.
• They may be influenced by a combination of genetic, lifestyle and other environmental
factors.
• Examples include:
• being overweight or obese
• high blood pressure
• high blood cholesterol
• high blood sugar (glucose)
• Short height (<150 cm)
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