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Read the methods and the worked example, then answer the questions.
Calculating a mean:
Calculating a percentage change:
Worked example – the percentage change in skin-cancer deaths from 766 (in 2014) to 861 (in 2016):
Task: complete the table by working out the mean number of deaths and the percentage change for each cancer.
| Type of cancer | Deaths 2014 | Deaths 2015 | Deaths 2016 | Mean | % change |
|---|---|---|---|---|---|
| Lung cancer | 12 700 | 10 300 | 13 000 | 12 000 | +2.4% |
| Prostate cancer | 6 478 | 7 220 | 8 001 | 7 233 | +23.5% |
| Leukaemia | 14 300 | 14 678 | 11 000 | 13 326 | −23.1% |
| Bowel cancer | 3 678 | 3 789 | 4 352 | 3 939.7 | +18.3% |
| Breast cancer | 9 000 | 8 423 | 8 421 | 8 614.7 | −6.4% |
| Skin cancer | 766 | 798 | 861 | 787 | 12.4% |
Read about the four main chart types, then answer the questions.
Scientists use graphs to analyse patterns of data related to disease. The main types are:
Read the rules for drawing a good graph, then answer the questions.
The independent variable (what you changed) goes on the x axis; the dependent variable (what you measured) goes on the y axis.
Key rules for drawing a good graph:
| Year | 2004 | 2005 | 2006 | 2007 | 2008 |
|---|---|---|---|---|---|
| Number infected | 3499 | 3553 | 3767 | 3809 | 4131 |
| Student | A | B | C | D | E | F | G | H |
|---|---|---|---|---|---|---|---|---|
| Water fleas per 1000 cm³ | 66 | 37 | 51 | 102 | 40 | 122 | 75 | 19 |
| Year | Confirmed cases of measles |
|---|---|
| 2012 | 2030 |
| 2013 | 1843 |
| 2014 | 121 |
| 2015 | 91 |
| Time in minutes | Person R (bpm) | Person S (bpm) |
|---|---|---|
| 0 (at rest) | 60 | 78 |
| 1 | 76 | 100 |
| 2 | 85 | 110 |
| 3 | 91 | 119 |
| 4 | 99 | 129 |
| 5 | 99 | 132 |
| Year | London | South East | South West |
|---|---|---|---|
| 2000 | 37 | 5 | 3 |
| 2001 | 36 | 6 | 4 |
| 2002 | 42 | 6 | 6 |
| 2003 | 42 | 7 | 4 |
| 2004 | 42 | 7 | 5 |
| 2005 | 49 | 8 | 5 |
| 2006 | 44 | 8 | 3 |
| 2007 | 43 | 8 | 5 |
| 2008 | 44 | 8 | 5 |
| 2009 | 44 | 9 | 6 |
| 2010 | 42 | 9 | 5 |
| 2011 | 45 | 10 | 5 |
Read the passage and use the table, then answer the questions.
Health is defined as a state of complete physical, mental and social wellbeing. Things that can damage a person's health include disease, diet and stress.
Diseases are a cause of illness or ill health. They can be classed as communicable or non-communicable:
| Communicable diseases | Non-communicable diseases |
|---|---|
| Can spread from person to person, or between people and animals (also called infectious or contagious). | Cannot spread between people or between animals and people. |
| Caused by microorganisms called pathogens (e.g. bacteria and viruses); they spread fast and make people sick quickly. | Lifestyle choices such as diet, alcohol and smoking can increase the risk; they last a long time and get worse slowly. |
| Examples: measles, malaria, influenza. | Examples: asthma, cancer, coronary heart disease. |
Read the passage about disease interactions, then answer the questions.
Diseases can interact to create unexpected consequences. Some examples are:
Read the passage and use the table, then answer the questions.
A risk factor is something that can increase the chance of a consequence occurring. For disease, risk factors increase the chance of a person developing a certain disease in their lifetime – they do not guarantee it. They are often aspects of lifestyle, e.g. diet, exercise and drug use. Some risk factors directly cause some diseases.
| Risk factor | Disease it has been shown to cause |
|---|---|
| Smoking | Heart disease, lung disease, lung cancer |
| Obesity (being overweight) | Type 2 diabetes, heart disease |
| Drinking too much alcohol | Liver disease, damage to nerve cells in the brain |
| Exposure to ionising radiation | Cancer |
Some risk factors have not been shown to directly cause disease but are related to another risk factor that can, e.g. a lack of exercise and a high-fat diet can cause high blood pressure and high cholesterol, both of which are risk factors for heart disease.
| Country | CHD deaths per 100 000 per year | % who smoke | % who drink heavily | Fruit & veg (kg/person/year) |
|---|---|---|---|---|
| A | 285 | 36 | 19 | 180 |
| B | 251 | 63 | 34 | 404 |
| C | 186 | 47 | 36 | 251 |
| D | 149 | 23 | 34 | 218 |
| E | 128 | 27 | 12 | 222 |
Read the passage about cancer, then answer the questions.
Cancer is a non-communicable disease caused by uncontrollable cell division. Once cells have divided enough to repair or replace a piece of tissue they stop. Uncontrollable cell division causes the cells to keep on dividing and they layer on top of each other forming a tumour – a mass of cells. Tumours that can spread and invade surrounding tissues are called cancers.
Read the passage and look at the diagram, then answer the questions.
| Benign tumour | Malignant tumour |
|---|---|
| Non-cancerous | Cancerous |
| Slow growing | Fast growing |
| Do not spread, but can put pressure on organs or cause blockages | Cells can break off and spread around the body in the bloodstream, invading other tissues |
| Cells have a normal shape | Cells may have an abnormal shape |
Cancer treatments include:
Survival rates have improved due to improved treatments/drugs, earlier diagnosis, more screening, and better knowledge of risk factors.
Read the passage about cancer risk factors, then answer the questions.
Anyone can develop cancer but risk factors can increase your chances. Mutations are changes to DNA; these can be caused by ionising radiation (e.g. UV or X-rays) or carcinogenic chemicals such as those in cigarette smoke. Risk factors include:
Read the passage and look at the graph, then answer the questions.
While causation and correlation can exist at the same time, correlation does not imply causation. Causation applies to cases where action A causes outcome B. Correlation is simply a relationship: action A relates to action B, but one does not necessarily cause the other.
Correlation and causation are often confused because two variables can appear closely associated as if one depends on the other.
Scientists have established causes for risk factors. For smoking and lung cancer: as the number of cigarettes smoked has increased over the years, the cases of lung cancer have also increased – a clear correlation. Scientists then found evidence of a causal link: analyses of cigarette smoke showed that at least 70 of the chemicals present cause cancer in laboratory animals.
Read the passage and use the tables, then answer the questions.
Nicotine in cigarettes is a drug that makes them addictive. Smoking, especially long term, can directly cause diseases:
| Disease caused by smoking | How smoking is a risk factor |
|---|---|
| Cardiovascular disease | Damages the artery lining (fatty build-up); carbon monoxide reduces oxygen in the blood; nicotine increases heart rate; increased blood clotting – can lead to heart attack or stroke. |
| Lung disease (COPD) | Cilia stop working so mucus and bacteria build up; airways become inflamed and blocked; less oxygen reaches the blood. The damage is permanent. |
| Lung cancer | Carcinogens in the tar and smoke mutate cells. Almost all cases of lung cancer are caused by smoking. |
Drinking lots of alcohol can also damage the body:
| Organ affected | Effect |
|---|---|
| Liver | The liver breaks down alcohol; excess alcohol damages it, causing fatty liver disease, alcoholic hepatitis and cirrhosis (scarring). |
| Brain | If the liver is damaged, alcohol travels to the brain, causing brain shrinkage, memory problems and mental-health problems. |
Read the passage about pregnancy, then answer the questions.
Smoking and alcohol are risk factors that can harm a foetus during pregnancy, so pregnant women are advised not to drink alcohol or smoke.
Alcohol can pass from the mother's blood to the foetus through the placenta. Heavy alcohol consumption can cause foetal alcohol syndrome (FAS), which leads to:
Chemicals from cigarette smoke, including nicotine and carbon monoxide, pass through the placenta to the foetus. This can:
As a result, smoking during pregnancy increases the risk of:
Non-communicable diseases caused by obesity, smoking and drinking have a large financial impact on the NHS, so the NHS runs campaigns to encourage healthier living.
| Category | Birth mass in g |
|---|---|
| Above normal birth mass | > 4500 |
| Normal birth mass | 2500-4500 |
| Low birth mass | 1500-2499 |
| Very low birth mass | 1000-1499 |
| Extremely low birth mass | < 1000 |
