smc-3660-11-Environmental/Nutritional

BIOLOGY, M8 2025 HSC 32

A population lives across three regions, \(A,\ B\) and \(C\).

People in community \(B\) developed an environmental disease. An epidemiological study was carried out to determine the risk of developing the disease due to age at exposure. The results of this study are shown in the graph.

Design an epidemiological study that could be used to produce the results shown in the graph. Justify the features of your design. (7 marks)

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Study Type: A prospective cohort study would be used. This is justified because it follows participants over extended time periods (up to 60 years) to observe disease development naturally.

Participants: Recruit individuals from community B across three age groups: 10-year-olds, 20-year-olds and 30-year-olds at the time of exposure to the environmental factor. This is justified because the graph displays separate curves for exposure at these three ages.

Baseline Data: Record each participant’s exact age at first exposure. This is justified because age at exposure is the independent variable being tested.

Longitudinal Follow-up: Monitor all participants annually for disease development over 60 years. This is justified because the graph tracks disease risk across this timeframe and shows when risk peaks and declines.

Data Collection: Document whether each participant develops the disease and calculate the percentage of each age cohort affected at yearly intervals. This is justified because the y-axis shows risk as a percentage.

Control Variables: Ensure all participants experience similar levels of environmental exposure in community B. This is justified because the study isolates age at exposure as the only variable affecting disease risk.

Statistical Analysis: Calculate risk percentages for each time point after exposure for each age group. This is justified because it produces the three distinct curves showing risk declining differently based on initial exposure age.

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Study Type: A prospective cohort study would be used. This is justified because it follows participants over extended time periods (up to 60 years) to observe disease development naturally.

Baseline Data: Record each participant’s exact age at first exposure. This is justified because age at exposure is the independent variable being tested.

BIOLOGY, M8 EQ-Bank 1

Outline the cause of a non-infectious nutritional disease in humans. In your answer, describe any possible effects that may be experienced by the a person living with the disease. (3 marks)

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Example Solution 1

Iron deficiency anaemia:

Iron deficiency anaemia develops when there is insufficient dietary iron intake or absorption from food sources.
Without adequate iron, the body cannot produce enough haemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body.
This results in symptoms such as chronic fatigue, weakness, shortness of breath and pale skin due to reduced oxygen transport capacity in the blood.

Example Solution 2

Vitamin D deficiency:

Vitamin D deficiency develops primarily due to insufficient sunlight exposure to the skin and inadequate dietary intake from foods like fatty fish or fortified products.
Without adequate Vitamin D, the body cannot properly absorb and regulate calcium in the intestines and maintain calcium homeostasis in the blood.
This results in soft bones, muscle weakness, and increased risk of fractures due to compromised bone mineralization.

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Example Solution 1

Iron deficiency anaemia:

Iron deficiency anaemia develops when there is insufficient dietary iron intake or absorption from food sources.
Without adequate iron, the body cannot produce enough haemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body.
This results in symptoms such as chronic fatigue, weakness, shortness of breath and pale skin due to reduced oxygen transport capacity in the blood.

Example Solution 2

Vitamin D deficiency:

Vitamin D deficiency develops primarily due to insufficient sunlight exposure to the skin and inadequate dietary intake from foods like fatty fish or fortified products.
Without adequate Vitamin D, the body cannot properly absorb and regulate calcium in the intestines and maintain calcium homeostasis in the blood.
This results in soft bones, muscle weakness, and increased risk of fractures due to compromised bone mineralization.

BIOLOGY, M8 2024 HSC 29

An epidemiological study was conducted to help model how many people will be affected by Type 2 diabetes globally in the future. Continuous data were collected from 1990 to 2020. From that data, the following data points were chosen to demonstrate the trend.

\begin{array} {|c|c|}
\hline
\rule{0pt}{2.5ex} \textit{Year} \rule[-1ex]{0pt}{0pt} & \textit{Percentage of population affected} \\
\rule{0pt}{2.5ex} \textit{} \rule[-1ex]{0pt}{0pt} & \textit{by Type 2 diabetes (%)} \\
\hline
\rule{0pt}{2.5ex} \text{1990} \rule[-1ex]{0pt}{0pt} & \text{3.1} \\
\hline
\rule{0pt}{2.5ex} \text{2000} \rule[-1ex]{0pt}{0pt} & \text{3.7} \\
\hline
\rule{0pt}{2.5ex} \text{2010} \rule[-1ex]{0pt}{0pt} & \text{4.3} \\
\hline
\rule{0pt}{2.5ex} \text{2010} \rule[-1ex]{0pt}{0pt} & \text{5.6} \\
\hline
\end{array}

Plot the data on the grid provided and include the line of best fit. (2 marks)

A prediction of the global population numbers suggests there will be about 9 billion \((9\ 000\ 000\ 000)\) people on the planet by 2040.

Predict the number of people that will be affected by diabetes in 2040. Show working on your graph on the previous page and your calculations. (3 marks)

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b. 630 000 000 (630 million)

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♦ Mean mark (a) 56%.

b. Using the LOBF on the graph:

Population (%) with diabetes in 2040 = 7%

People with diabetes in 2040 = \(\dfrac{7}{100} \times 9\ 000\ 000\ 000 = 630\ 000\ 000\)

BIOLOGY, M8 2024 HSC 24

Outline the cause of a disease due to environmental exposure. (2 marks)

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Explain how an educational program or campaign can be used to decrease the incidence of a disease caused by environmental exposure. (3 marks)

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a. Answers could include one of the following:

Lung cancer can be caused by exposure to inhalation of smoke from cigarettes.
Environmental exposure to asbestos can result in some microscopic fibres becoming lodged in the lining of a person’s lungs and cause mesothelioma (cancer).

b. Educational program on the dangers of UV radiation:

An educational program in schools could teach students about the link between UV exposure and skin cancer, emphasising protection through hats and sunscreen.
This preventative approach helps students understand the risks and increases the chances of them modifying their behaviour to be more sun safe.
Overall, the program should contribute to less DNA damage in cells of participants and a reduction in their chances of developing skin cancer.

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a. Answers could include one of the following:

Lung cancer can be caused by exposure to inhalation of smoke from cigarettes.
Environmental exposure to asbestos can result in some microscopic fibres becoming lodged in the lining of a person’s lungs and cause mesothelioma (cancer).

b. Educational program on the dangers of UV radiation:

An educational program in schools could teach students about the link between UV exposure and skin cancer, emphasising protection through hats and sunscreen.
This preventative approach helps students understand the risks and increases the chances of them modifying their behaviour to be more sun safe.
Overall, the program should contribute to less DNA damage in cells of participants and a reduction in their chances of developing skin cancer.

BIOLOGY, M8 2023 HSC 14 MC

Minamata Disease is caused by regular consumption of contaminated fish and shellfish. The symptoms include numbness in the hands and feet, muscle weakness, and damage to vision, hearing and speech.

Pellagra is a disease which causes delusions or mental confusion, diarrhoea, weakness and loss of appetite caused by insufficient levels of iron and niacin.

Wildervanck Syndrome is a condition that affects the bones in the neck, the eyes and the ears, and occurs primarily in females.

Given the information above, which row in the table correctly identifies the classification of these diseases?

	Minamata Disease	Pellagra	Wildervanck Syndrome
A.	Genetic	Nutritional	Environmental
B.	Genetic	Environmental	Nutritional
C.	Environmental	Genetic	Nutritional
D.	Environmental	Nutritional	Genetic

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\(D\)

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By Elimination:

Minamata is caused by consumption of contaminated seafood and is therefore environmental, not genetic (Eliminate A and B).
Pellagra is caused by insufficient iron and niacin levels, which are a mineral and a vitamin respectively. It is therefore a nutritional disease and not genetic (Eliminate C).
As Wildervanck Syndrome occurs primarily in females, there cannot be 100% certainty it is genetic. However, with all other options eliminated, it can be assumed to be the case here.

\(\Rightarrow D\)

BIOLOGY, M8 EQ-Bank 1 MC

What is the main focus of the study of epidemiology?

Skin diseases
Changes in the characteristics of a species
Factors involved in the occurrence, prevalence and spread of disease
How the body maintains its functions in response to variations in the environment

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`C`

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→ The nature of an epidemiological study reveals evidence for factors involved in disease incidence and mortality.

`=>C`

BIOLOGY, M7 2014 HSC 22b

Drinking water contaminated with dissolved lead (a heavy metal) can cause a serious disease.

Classify this disease as either infectious or non-infectious. Justify your answer. (2 marks)

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This disease is non-infectious as it is not caused by a pathogen and therefore cannot be transferred from host to host.
It can only be obtained through digestion of lead.

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This disease is non-infectious as it is not caused by a pathogen and therefore cannot be transferred from host to host.
It can only be obtained through digestion of lead.

BIOLOGY, M7 2017 HSC 22a

For each type of disease in the following table, name a specific disease and its cause. (2 marks)

\begin{array} {|l|c|}
\hline
\rule{0pt}{2.5ex} \text{Type of disease} \rule[-1ex]{0pt}{0pt} & \quad \quad\text{Name of disease} \quad\quad &\quad \quad\text{Cause of disease}\quad\quad\\
\hline
\rule{0pt}{2.5ex} \text{Infectious disease} \rule[-1ex]{0pt}{0pt} & \text{} &\text{}\\
\rule{0pt}{2.5ex} \text{} \rule[-1ex]{0pt}{0pt} & \text{} \text{}\\
\rule{0pt}{2.5ex} \text{} \rule[-1ex]{0pt}{0pt} & \text{} \text{}\\
\hline
\rule{0pt}{2.5ex} \text{Non-infectious} \rule[-1ex]{0pt}{0pt} & \text{} \text{}\\
\text{disease} \rule[-1ex]{0pt}{0pt} & \text{} \text{}\\
\rule{0pt}{2.5ex} \text{} \rule[-1ex]{0pt}{0pt} & \text{} \text{}\\
\hline
\end{array}

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Answers could include one example of the two given:

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Answers could include one example of the two given:

BIOLOGY, M8 2020 HSC 27

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 `mu`g 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. (2 marks)

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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. (4 marks)

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a. Successful answers should include two of the following:

The identification of the age and sex of participants
Socioeconomic status
Arsenic exposure
Large sample size
The length of the study period

b. Consider the less than 90 `mu`g L^-1 group:

The survival rate for both males and females was highest in this “control” group. This is despite the group being exposed to more arsenic than recommended by WHO.
In both males and females, increased exposure to arsenic led to lower survival rates.
This gradual survival decrease is best seen in males.
In females, all doses over 90 `mu`g L^-1 lead to similar survival decrease, suggesting other factors, such as a gene or diet, are interacting with the dosage of arsenic.
Over the 11 year period, survival progressively declined, supporting the hypothesis.
It is important to note, however, that despite the large sample size and time period the study was conducted, survival only dropped by 0.1%.

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a. Successful answers should include two of the following:

The identification of the age and sex of participants
Socioeconomic status
Arsenic exposure
Large sample size
The length of the study period

b. Consider the less than 90 `mu`g L^-1 group:

The survival rate for both males and females was highest in this “control” group. This is despite the group being exposed to more arsenic than recommended by WHO.
In both males and females, increased exposure to arsenic led to lower survival rates.
This gradual survival decrease is best seen in males.
In females, all doses over 90 `mu`g L^-1 lead to similar survival decrease, suggesting other factors, such as a gene or diet, are interacting with the dosage of arsenic.
Over the 11 year period, survival progressively declined, supporting the hypothesis.
It is important to note, however, that despite the large sample size and time period the study was conducted, survival only dropped by 0.1%.

BIOLOGY, M8 2021 HSC 1 MC

A patient felt tired, weak and had a swollen neck. After following the doctor's advice to eat more foods containing iodised salt, her symptoms disappeared.

What was the most likely cause of the patient's symptoms?

Cancer
Genetic disorder
Nutritional deficiency
Environmental exposure

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`C`

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Since iodised salt made symptoms disappear, the patient most likely had a deficiency of iodine.

`=>C`