Biology

Questions 5 - 7 refer to the information below about the British Doctors’ Study. The British Doctors’ Study was an epidemiological cohort study which started in 1951 and ran until 2001. It set out to establish whether, as strongly suspected, there was a link between smoking and health outcomes. It was the first study to prove the link between smoking and lung cancer and was hugely influential in informing government moves to reduce smoking. A very large number of male doctors were sent health surveys at regular intervals. These asked questions about any health issues they might have as well as about lifestyle factors such as alcohol consumption, diet and smoking habits. The simplified graph below illustrates one of their findings.

What percentage of smokers survived to age 70?
(A) 35%
(B) 45%
(C) 55%
(D) 65%

Questions 5 - 7 refer to the information below about the British Doctors’ Study. The British Doctors’ Study was an epidemiological cohort study which started in 1951 and ran until 2001. It set out to establish whether, as strongly suspected, there was a link between smoking and health outcomes. It was the first study to prove the link between smoking and lung cancer and was hugely influential in informing government moves to reduce smoking. A very large number of male doctors were sent health surveys at regular intervals. These asked questions about any health issues they might have as well as about lifestyle factors such as alcohol consumption, diet and smoking habits. The simplified graph below illustrates one of their findings.

Which one of the following statements about giving up smoking is best supported by this graph?
(A) If you give up smoking early enough, you have virtually the same life expectancy as a non-smoker.
(B) More people give up smoking before the age of 40 than do afterwards.
(C) It is smoking early in life which causes most of the damage to health.
(D) Giving up smoking gives you a better life expectancy than a smoker, but not as good as someone who has never smoked

Questions 5 - 7 refer to the information below about the British Doctors’ Study. The British Doctors’ Study was an epidemiological cohort study which started in 1951 and ran until 2001. It set out to establish whether, as strongly suspected, there was a link between smoking and health outcomes. It was the first study to prove the link between smoking and lung cancer and was hugely influential in informing government moves to reduce smoking. A very large number of male doctors were sent health surveys at regular intervals. These asked questions about any health issues they might have as well as about lifestyle factors such as alcohol consumption, diet and smoking habits. The simplified graph below illustrates one of their findings.

What was the independent variable in this study?
(A) age
(B) smoking habits
(C) gender
(D) cancer rate

E-cigarette operate by vaporising a nicotine containing liquid into an aerosol, which is then inhaled by the user. Since their first introduction to broad global markets in 2007, use has become increasingly common, particularly among youth. They were initially introduced as an alternative to traditional tobacco smoking, with the idea that it could potentially be less harmful due to the absence of tar and combustion products found in tobacco smoke. However, concerns have arisen about the safety and health risks associated with vaping.
Describe and justify an epidemiological study that could be carried out to investigate whether vaping using e-cigarettes causes lung disease.

The incidence of cervical cancer in the Australian population is shown in the graph from 1985−2015. Public health campaigns commenced during this period to reduce the incidence of cervical cancer. This included a national screening program to detect pre-cancerous cells and a vaccination program against human papillomavirus (HPV) which causes most cervical cancers.

Evaluate the success of these campaigns in reducing the incidence of cervical cancer in Australian women. Include reference to the data in your answer.

Rubella is an infectious disease caused by Rubivirus rubella. The disease is frequently mild, with a characteristic rash often appearing two weeks after exposure and lasting for three days. Other symptoms include fever, sore throat and fatigue, with joint pain common in adults. Up to half of infected cases are asymptomatic. Rubella is usually spread from one person to the next through the air via coughs of people who are infected. People are infectious during the week before and after the appearance of the rash. Only humans are infected. Once recovered, people are immune to future infections. In the early 1940s, Australian ophthalmologist Norman Gregg noticed a high incidence of congenital cataracts in babies whose mothers had suffered from rubella during pregnancy. It was then statistically shown that infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). The main defects result almost exclusively from rubella infection occurring in the first 16 weeks of gestation and include deafness due to cochlea malformation, eye and cardiovascular defects and central nervous system damage leading to mental retardation. Rubella is preventable with a single dose of the rubella vaccine being more than 95% effective. When rubella vaccination became feasible around 1971, both the United States and the United Kingdom embarked on vaccination programs. In the United States, the strategy was to vaccinate infants, so that eventually the reservoir in childhood would be abolished. In contrast, the United Kingdom decided on a program of vaccinating adolescent girls. Both strategies were partial successes, in that CRS incidence began to decrease.

Evaluate the importance of validity in biological research. In your response, refer to:
• the study that you have described in part (f),
• ONE other named epidemiological study that you have investigated as part of your course
• ONE first-hand investigation that you have carried out as part of your course
• ONE second-hand investigation that you have carried out as part of your course

Rubella is an infectious disease caused by Rubivirus rubella. The disease is frequently mild, with a characteristic rash often appearing two weeks after exposure and lasting for three days. Other symptoms include fever, sore throat and fatigue, with joint pain common in adults. Up to half of infected cases are asymptomatic. Rubella is usually spread from one person to the next through the air via coughs of people who are infected. People are infectious during the week before and after the appearance of the rash. Only humans are infected. Once recovered, people are immune to future infections. In the early 1940s, Australian ophthalmologist Norman Gregg noticed a high incidence of congenital cataracts in babies whose mothers had suffered from rubella during pregnancy. It was then statistically shown that infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). The main defects result almost exclusively from rubella infection occurring in the first 16 weeks of gestation and include deafness due to cochlea malformation, eye and cardiovascular defects and central nervous system damage leading to mental retardation. Rubella is preventable with a single dose of the rubella vaccine being more than 95% effective. When rubella vaccination became feasible around 1971, both the United States and the United Kingdom embarked on vaccination programs. In the United States, the strategy was to vaccinate infants, so that eventually the reservoir in childhood would be abolished. In contrast, the United Kingdom decided on a program of vaccinating adolescent girls. Both strategies were partial successes, in that CRS incidence began to decrease.

An alternative hypothesis for the mechanism is that some of the symptoms of CRS are due to maternal infection causing malfunction of the mother’s liver resulting in excessively high (toxic) levels of Vitamin A in the blood of both the mother and the developing embryo. Vitamin A is stored in the liver and is also found in the diet in cheese, dairy, liver and meat.
A group of unvaccinated pregnant women in a developing region has just been exposed to rubella virus.
Outline an epidemiological study that could be carried out ethically to test the Vitamin A hypothesis outlined above.

Exposure to arsenic in drinking water has been associated with the onset of many diseases. The World Health Organisation recommends arsenic levels in drinking water should be below 10 µg L–1.
An epidemiological study involving 58 406 young adults was conducted over an 11-year period in one country to investigate young-adult mortality due to chronic exposure to arsenic in local drinking water. Each individual’s average exposure and cumulative exposure to arsenic over the time of the study were calculated. Age, sex, education and socioeconomic status were taken into account during the analysis of the results.
The graphs show survival rates for males and females over the 11-year period associated with different average levels of exposure to arsenic in drinking water.

Identify TWO features of the method used that contributed to the validity of this study.

Exposure to arsenic in drinking water has been associated with the onset of many diseases. The World Health Organisation recommends arsenic levels in drinking water should be below 10 µg L–1.
An epidemiological study involving 58 406 young adults was conducted over an 11-year period in one country to investigate young-adult mortality due to chronic exposure to arsenic in local drinking water. Each individual’s average exposure and cumulative exposure to arsenic over the time of the study were calculated. Age, sex, education and socioeconomic status were taken into account during the analysis of the results.
The graphs show survival rates for males and females over the 11-year period associated with different average levels of exposure to arsenic in drinking water.
The hypothesis put forward was that exposure to arsenic in drinking water increases mortality in young adults.
Discuss the data presented in the graphs in relation to this hypothesis.

Explain the impact that genetic technologies have had on the management of both infectious and non-infectious diseases.

A large epidemiological study was conducted. It used historical data to investigate the association between Herpes simplex virus (HSV) infection and dementia. Dementia is caused by a variety of brain illnesses. Alzheimer’s disease is the most common cause of dementia.
The study used the records of 8362 patients with HSV infection and 25 086 randomly selected sex- and age-matched control patients without HSV infection. Some of the patients with HSV had been treated with antiviral medication.
The graph below shows some results of the study.

Describe the trends shown in the data.