Risk Factors in Health and Disease


1. What are risk factors?

Ageing populations and longer life expectancy have led to an increase in long-term (chronic), expensive-to-treat diseases and disabilities. However, there are not enough healthcare resources to cope with this rising demand. This puts the healthcare sector under increasing budget pressure. It is important that we, as a society and users of healthcare systems, understand the causes and risk factors behind these diseases so that we can actively take part in cost effective prevention and treatment programmes. 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 a characteristic, condition, or behaviour that increases the possibility of getting a disease or injury. Risk factors are often presented individually, however in practice they do not occur alone. They often co-exist and interact with one another. 

For example, physical inactivity will, over time, cause weight gain, high blood pressure and high cholesterol levels.  These significantly increase the chance of developing chronic heart diseases and other health related problems.

In general, risk factors can be categorised into the following groups:

  • Behavioural
  • Physiological
  • Demographic
  • Environmental
  • Genetic.

These are described in more detail below.

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
  • poor diet and nutrition
  • physical inactivity
  • spending too much time in the sun
  • not having certain vaccinations
  • unsafe sex

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 broad factors. Examples include:

  • being overweight or obese
  • high blood pressure
  • high blood cholesterol
  • high blood sugar (glucose).

 Demographic risk factors are those that relate to the overall population. Examples include:

  • age
  • population subgroups such as occupation, religion or income.

Environmental risk factors cover a wide range of topics such as social, economic, cultural and political factors as well as physical, chemical and biological factors. Examples include:

  • access to clean water and sanitation
  • risks in the workplace
  • air pollution
  • social relationships.

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.