Microorganisms - are single celled organisms including bacteria, viruses and fungi. Some are beneficial and some are pathogens.
Disease - is a change in the body or mind with adverse effects on health. Has physical, mental and social aspects.
Infection - when a disease leads to symptoms.
- For a microorganism to be a pathogen it must:
- Gain entry.
- Colonise tissues.
- Resist defences.
- Damage tissues.
- They gain entry by:
- Penetrating an interface with the environment e.g cut, gas exchange system (thin, moist) or digestive system (food carries them in).
- They cause disease by damaging host tissue or producing toxins.
Data and Disease.
Correlation - occurs when a change in 1 or 2 variables is reflected by a change in another variable, i.e. the realtionship between 2 variables.
Causal link - change in 1 variable results from or is caused by a change in another.
Looking Critically at Data
- Right factor measured.
- Correct questions asked and any unanswered.
- How data was gathered, with reliable method and right apparatus.
- If researcher had vested interets.
- Repeated by others.
- Sample size and age of data.
- Any other factors to explain causal link.
Lifestyle and Health.
Lifestyle - way of life including patterns of behaviour and personal choices affecting health risk.
Risk - a measure of probability damage to health will occur as a result of a given hazard. It has 2 elements: probability that the hazardous event will occur and consequences of that event.
- Health risks need a timescale.
- Statistics can be misleading.
- Risk is often relative - risk measured by comparing likelihood of harm occurring in those exposed to a hazard compared to those who aren't.
- Risk factors and cancer:
- Carcinogenic factors risk contracting cancer e.g. smoking, diet, obesity, exercise and sunlight.
- Risk factors and CHD:
- Some factors beyond control e.g. genes and age.
- Lifestyle factors e.g. smoking, high blood pressure, cholesterol, BMI higher than 25, salt and fatty acids in diet and lack of exercise.
- Reduce risk by having less alcohol and more antioxidants.