NUT506/NUT814 Research Methods and Biostatistics for Food and Nutrition

Please complete all 3 parts of this assignment. Notes:

Do not copy and paste outputs directly from SPSS.

Format tables as appropriate for publication and include the statistical tests used in the footnotes along with other relevant information.

PART 1

Coeliac disease is an autoimmune condition caused by gluten intolerance in those individuals who are genetically susceptible. Coeliac disease affects approximately 1% of the European population and results in damage to the lining of the gut. Symptoms of coeliac disease include diarrhoea, weight loss, pain and vomiting. If a gluten-free diet is not strictly followed, nutrient deficiencies can occur. On a standard gluten- free diet, approximately 80% of overweight coeliac patients will gain weight and 30% of normal weight coeliac patients will become overweight.

A study was carried out to assess the effect of a strict gluten-free diet on nutritional status of coeliac patients and healthy controls. Fifteen coeliac patients and fifteen healthy controls were recruited and followed a 6-month gluten-free diet. Blood samples were taken at baseline (before the diet) and 6-months later (after the diet) and used to assess iron, folate and vitamin B12 status. Body mass index (BMI) was also recorded before and after the diet intervention.

BMI and nutritional status measures of iron, folate and vitamin B12 before and after the diet intervention are given in DATA Assignment 1.0.sav for both the coeliac patients and healthy controls.

• State the aim of the study and give the null and alternate hypotheses (2%)
• Using SPSS, assess and comment on the normality of the BMI and nutritional status data (3%)
• Produce a summary table of the baseline BMI and nutritional status data for the coeliac patients and controls, showing any statistical differences between the groups using appropriate statistical tests (assume all data are normally distributed) (15%)
• Carry out statistical tests to analyse the differences between baseline and post intervention BMI and nutritional status measures and present these data in an appropriate table (assume all data are normally distributed) (15%)
• Give an overall summary of your results and critically evaluate your findings using at least 2 appropriate pieces of published literature (cited correctly) to justify your answer. (15%)

PART 2

Antibiotics are powerful medicines that fight bacterial infections. In treating a patient, a doctor must know which antibiotics are most effective in either killing the organism or at least inhibiting or retarding its further growth. A study was carried out in which 500 patients admitted to hospital with bacterial infections were given a specific antibiotic and the response to the treatment recorded. The effectiveness of the antibiotic in the 500 patients is presented in the table below.

Use the data from the table above to answer the following questions:

(Ensure all working out is shown and results are presented to one d.p; probability and proportion answers are acceptable as either a fraction or %)

• What proportion of those who were not cured is male? (2%)
• What is the probability of selecting a person, from the sample of 500 subjects, who is female and was partially cured? (2%)
• The data in the table above were analysed using the chi-square The results from SPSS are shown below. What can you conclude from the results of the test? (5%)

PART 3

A study was carried out to assess maternal factors during pregnancy which influence birth outcomes. A total of 90 pregnant women were recruited at 12 weeks gestation and blood samples and anthropometric measurements were taken. The type of delivery, gestational age at delivery and anthropometric measurements of the baby were recorded at birth.

Using dataset labelled DATA Assignment 3.0.sav, complete the following questions.

• State the aim of the study and give the null and alternate hypotheses (2%)
• Produce a summary table of the age, height, weight and BMI data for the pregnant women according to ‘Type of Delivery’, showing any statistical differences between the ‘type of delivery’ groups using appropriate statistical tests (assume all data are normally distributed) (15%)
• If the data were not normally distributed, what summary statistics would you produce within a table and what statistical tests would you carry out to assess differences between ‘type of delivery’ groups? (5%)
• Give an overall summary of your results and critically evaluate your findings using at least 3 appropriate pieces of published literature (cited correctly) to justify your conclusion. Within your answer, state any further analysis which could be carried out to further address your research (20%)