Different types of diseases
diseaseIllness affecting plants and animals. can be grouped into two types:
- non-communicable, which are not transferred between people or other organisms
- communicable, which can be transferred from one person to another, or from one organism to another, eg in humans, these include measles, food poisoning and malaria.
Non-communicable diseases include:
- cancerA disease caused by normal cells changing so that they grow and divide in an uncontrolled way. The uncontrolled growth causes a lump called a tumour to form.
- diabetesA serious disease in which the body is unable to regulate blood sugar.
- geneticTo do with inheritance because of genes. disorders and conditions
- heart diseaseA wide range of conditions that affect the heart.
- neurologicalTo do with the nervous system. disorders
Interactions between different types of diseases
Different types of disease may interact. This can mean that the presence of one disease can lead to a higher chance of developing another disease.
- Defects in the immune systemThe body's defence system against entry of any foreign body, including pathogens and agents such as pollen grains. The role of the immune system is to prevent disease. mean that an individual is more likely to suffer from infectious diseases. For instance, human immunodeficiency virus (HIV) infections, which lead to AIDS, affect the immune system and lead to an increase risk of developing other infectious diseases.
- virusAn ultramicroscopic infectious non-cellular organism that can replicate inside the cells of living hosts, with negative consequences. living in cells can be the trigger for cancers. For instance, the majority of cases of cancer of the cervixRing of muscle at the lower end of the uterus. are linked with a virus present in the female reproductive systemThe organs and tissues involved in producing offspring..
- The reaction of the immune system to pathogenMicroorganism that causes disease. and other foreign bodies can trigger allergic reactions that lead to skin rashes and asthmaA disease that affects the respiratory system.. For instance, severe respiratory infections in babies can lead to asthma in later childhood.
- Severe physical ill health can lead to depressionDepression is a condition which affects mental health and causes people to experience symptoms such as depressed mood, loss of interest or pleasure and feelings of guilt or low self-worth. and other types of mental illness.
Risk factors
Anything that increases a chance of developing a disease is called a risk factorSomething that increases a person's chances of developing a disease.. Risk factors can be caused by lifestyle factorsHabits which can be modified that impact positively or negatively upon physical and/or mental health. or substances in a person's body or their environment. Some diseases are caused by an interaction between risk factors.
Some risk factors have been proven to cause a disease. We know that smoking causes lung cancer. Other risk factors are linked but not proven.
Some diseases, their effects and their risk factors are shown in the table below.
| Disease | Risk factor | Effects |
| Type 2 diabetes | Obesity | Blood sugar levels cannot be regulated properly |
| Liver cirrhosis | Alcohol | Scar tissue is formed in the liver which stops it removing toxins |
| Lung cancer | Smoking | Smoking causes lung cancer and also the underdevelopment of unborn babies |
| Disease | Type 2 diabetes |
|---|---|
| Risk factor | Obesity |
| Effects | Blood sugar levels cannot be regulated properly |
| Disease | Liver cirrhosis |
|---|---|
| Risk factor | Alcohol |
| Effects | Scar tissue is formed in the liver which stops it removing toxins |
| Disease | Lung cancer |
|---|---|
| Risk factor | Smoking |
| Effects | Smoking causes lung cancer and also the underdevelopment of unborn babies |
Learn more about non-communicable diseases with Dr Alex Lathbridge.
Listen to the full series on BBC Sounds.
Learn all about risk factors for non-communicable diseases with Dr Alex Lathbridge.
