B7 - Non-communicable diseases

• Non-communicable disease


  A disease that cannot be passed from one individual to another
• Only three of the top 10 killer diseases in the world in 2012 were communicable
• Top 10 killer diseases globally in 2012

  • Coronary heart disease
  • Stroke
  • COPD
  • Lower respiratory infections
  • Trachea bronchus, lung infections
  • HIV/AIDS
  • Diarrhoeal diseases
  • Diabetes mellitus
  • Road injury
  • Hypertensive
• Non-communicable diseases (blue bars) contribute to more deaths than communicable diseases (pink bars)
• Risk factors for disease

  • Genes inherited from parents
  • Age
  • Aspects of lifestyle (smoking, lack of exercise, overeating)
  • Substances present in the environment or body (ionising radiation, UV light, second-hand tobacco smoke)
• Risk factors for non-communicable diseases vary from one disease to another and some may affect more than one disease
• Examples of risk factors for non-communicable diseases

  • Diet
  • Obesity
  • Fitness levels
  • Smoking
  • Drinking alcohol
  • Exposure to carcinogens in the environment (ionising radiation)
• Correlation


  A link or relationship between two things
• Causal mechanism


  An explanation of how one factor influences another through a biological process
• A correlation does not prove that one thing is the cause of another
• Non-communicable diseases affect far more people than communicable diseases, so they have the greatest effect at both human and economic levels
• Diseases cost nations huge sums of money both in the expense of treating ill people and in the loss of money earned when large numbers of the population are ill
• The global economy suffers too, especially when diseases affect younger, working-age populations
• Tumour


  A mass of abnormally growing cells
• Benign tumour


  A growth of abnormal cells contained in one place, usually within a membrane, that does not invade other parts of the body
• Malignant tumour


  A tumour that can spread around the body, invading neighbouring healthy tissues
• Malignant tumours are often referred to as cancer
• Cancer cells not only divide more rapidly than normal cells, they also live longer
• Causes of cancer


  • Genetic risk factors
  • Mutations caused by chemicals (asbestos, tar in tobacco smoke)
  • Ionising radiation (UV light, X-rays)
  • Virus infections (HPV)
• About 15% of human cancers are caused by virus infections
• Main ways to treat cancer

  • Radiotherapy
  • Chemotherapy
• Smoking is big business, with around 1.1 billion smokers worldwide smoking around 6000 billion cigarettes each year
• At least 150 of the 4000 different chemicals in tobacco smoke are linked to disease
• Nicotine


  The addictive but relatively harmless drug found in tobacco smoke
• Carbon monoxide


  A poisonous gas found in tobacco smoke that takes up some of the oxygen-carrying capacity of the blood
• Smoking a cigarette


  Up to 10% of the blood will be carrying carbon monoxide rather than oxygen
• Oxygen shortage is a particular problem in pregnant women who smoke, as the fetus may not get enough oxygen to grow properly
• The cilia in the trachea and bronchi that move mucus, bacteria, and dirt away from the lungs are anaesthetised by some of the chemicals in tobacco smoke
• Tar is a sticky, black chemical in tobacco smoke that accumulates in the lungs, turning them from pink to grey
• The build-up of tar in the delicate lung tissue can lead to a breakdown in the structure of the alveoli, causing chronic obstructive pulmonary disease (COPD)
• Tar is also a carcinogen that acts on the delicate cells of the lungs and greatly increases the risk of lung cancer developing
• The chemicals in tobacco smoke also affect the heart and blood vessels, making smokers more likely to develop cardiovascular disease
• Components of tobacco smoke

  • Mucus
  • Tar
• Tar


  A sticky, black chemical that accumulates in the lungs, turning them from pink to grey
• Tar in tobacco smoke

  Makes smokers much more likely to develop bronchitis
• Build-up of tar in the delicate lung tissue

  Can lead to a breakdown in the structure of the alveoli, causing chronic obstructive pulmonary disease (COPD)
• Tar


  Is a carcinogen that acts on the delicate cells of the lungs and greatly increases the risk of lung cancer developing
• Tar


  Causes other cancers of the breathing system, for example, the throat, larynx, and trachea
• Smoking narrows the blood vessels in your skin, ageing it
• Nicotine makes the heart rate increase whilst other chemicals damage the lining of the arteries