The serum phosphate levels are measured in 1,000 patients with anorexia nervosa. The mean phosphate is 1.5 mmol/l with a standard deviation of 0.3 mmol/l. Which one of the following statements is correct?

A study is designed to test the effectiveness of Drug A vs placebo in hypertension. Volunteers are allocated via chance by a computer, to either the 'Drug' group or the 'placebo' group. The study observers do not know which volunteer has been allocated to which group. What type of study does this describe?

A study looks at the prevalence of breast cancer in the West Midlands population, between the years 2010 and 2011 in the UK What type of study does this describe?

An new test is developed to diagnose pancreatic cancer, Test A, when compared to the gold standard, Test B. Test A is able to diagnose pancreatic cancer much earlier than Test B. The researchers of test A state that this increases the lifespan of a patient with a new diagnosis of pancreatic cancer. What type of bias is this?

Which is the SINGLE MOST appropriate epidemiological measure to estimate the rate at which new cases of chlamydia occur among students on a university campus?

The table below shows data from a cross sectional study showing the prevalence of lung cancer in smokers, in the UK. What is the relative risk of having lung cancer, for those who smoke, compared to those who do not?

In the early 2000s, there was considerable news coverage arising from a claim that the measles, mumps and rubella (MMR) vaccine was related to and possibly caused autism in children (the originating claim was subsequently found to be based on fraudulent data and the publication was withdrawn) (Andrews 2002). Researchers found that parents of autistic children diagnosed after the article was published, tended to remember the start of autism as being soon after the MMR jab more often than parents of similar children who were diagnosed prior to the article being published. What type of bias is this?

A study looks at starting a new 1st line diabetic drug in comparison to just diet changes alone for newly diagnosed type 2 diabetics. 500 patients are selected for the study with 250 receiving the new diabetic drug and the remainder receiving just dietary advice. After 3 months, 75 patients who received the new drug had a signifcant drop in their HbA1c compared to 50 people who just received dietary advice. What is the number needed to treat?

By definition 'the proportion of patients with a condition who have a positive test result' fits which ONE of the following terms?

A cohort study evaluated the relationship between Vitamin D supplementation and hip fractures in post-menopausal women. 100 women took Vitamin D supplements and 100 women took placebo tablets. Over the 5 year period, five women had hip fractures in the Vitamin D group and ten women had hip fractures in the placebo group. The 95% confidence interval is 0.18 to 1.4. What is the RISK of a hip fracture in the TREATED group?

A study to determine the long-term effectiveness of influenza vaccines in elderly people is created. Groups of vaccinated elderly and unvaccinated elderly were studied. The results suggest that the elderly who are vaccinated have a reduced risk of hospitalization for pneumonia or influenza. What type of study does this describe?

Which one term listed below is defined as "the number of NEW CASES of a disease that occur over a period of time''?

A study analyzed 7 prospective cohort studies (52,092 patients). The results indicated that individuals who smoked had a 3.5 times higher risk of developing CVD than the controls (relative risk 1.14, 95% CI 1.074-1.213, P < .001) , indicating that both the prevalence and incidence of CVD are significantly increased in smoking and smoking may be a risk factor for CVD. What type of study does this describe?

A study looks at adding a new analgesic drug in addition to codeine for patients who've had a fracture. 2000 patients are selected for the study with 1000 receiving the new drug in addition to codeine and the remainder receiving just codeine. After 24 hours, 200 patients who received the new drug had no pain compared to 50 people who just received codeine. What is the number needed to treat?

What is the commonest outcome measure in a cohort study?

A study looks at how many people are cured from antibiotic A in comparison to antibiotic B, which is the Gold Standard for necrotising fasciitis. 50 patients are selected for the study with 10 receiving antibiotic A and the remainder receiving antibiotic B. After 7 days, 1 patient who received antibiotic A had been cured compared to 10 people who received antibiotic B. What is the number needed to treat?

By definition the 'proportion of patients without the condition who have a negative test result' fits which ONE of the following terms?

In a qualitative study on women who had overdosed, 7 subjects are recruited with the following ages, 30, 22, 38, 17, 35, 18, and 22. What is the the mean age of women in the study?

A study is designed to test the effectiveness of Drug A vs placebo in hypertension. Volunteers are allocated via chance by the study observers, to either the 'Drug' group or the 'placebo' group. What type of study does this describe?

A randomised controlled trial is done to look at a new drug to prevent strokes in diabetic patients. Cohort A consists of 1,000 patients who take the new drug whilst Cohort B contains 1,000 patients taking a placebo. The stroke rate in cohort A is 5% and in cohort B it is 10%. What is the number needed to treat?

A cohort study evaluated the relationship between Vitamin D supplementation and hip fractures in post-menopausal women. 100 women took Vitamin D supplements and 100 women took placebo tablets. Over the 5 year period, five women had hip fractures in the Vitamin D group and ten women had hip fractures in the placebo group. The 95% confidence interval is 0.18 to 1.4. What is the RISK ratio?

With regards to the normal distribution curve, what percentage of values lie within 2 standard deviations?

What is the most correct definition of incidence?

An new study is proposed to assess if night shift workers are more at risk of having a myocardial infarction than day shift workers. A flyer to is put up in the Doctors mess of a hospital to recruit volunteers. What type of bias is this?

500 smokers and 500 non-smokers are randomly selected and followed up for 5 years to assess their risk of developing lung cancer. What term best describes this study?

250 men with erectile dysfunction consent to participate in a study to test a new drug. 125 of the men are given the drug and 125 of the men are given a placebo. They are followed up for 6 weeks to assess their response and to report any side effects. What term best describes this study?

What is the commonest outcome measure in a case-control study?

A study is designed to look at the relation between risk of acute myocardial infarction and former smoking, type of tobacco, amount smoked, effect of smokeless tobacco, and exposure to secondhand smoke. What type of study does this describe?

What is the most appropriate term for the graphical representation of this data?

A study looks at how many people go into remission from antiviral A in comparison to antiviral B, which is the Gold Standard for HIV . 500 patients are selected for the study with 100 receiving antiviral A and the remainder receiving antiviral B. After 30 days, 50 patients who received antiviral A had gone into remission compared to 25 people who received antiviral B. What is the number needed to treat?

The table below shows data from a cross sectional study showing the prevalence of hay fever and eczema in 11 year old children. What is the relative risk of having hay fever, for children with eczema, compared to those who do not?

A study analyzed 34 other studies (randomized, double-blinded, and placebo controlled) that used bisoprolol to determine whether there is any benefit or harm in using bisoprolol to treat chronic heart failure when compared to placebo. The authors determined that bisoprolol provides “significant benefit in symptom control and physiologic outcomes” when used as an adjuvant treatment for chronic heart failure. What type of study does this describe?

Several studies have reported on the risk of lung cancer and exposure to tobacco smoke. Researchers now wish to reach a summary conclusion about the overall findings. Which is the SINGLE MOST appropriate study design?

A new blood test is developed to screen for the risk of oesophageal cancer. Following the blood test, CT imaging and a biopsy are done to confirm the diagnosis. Of the 250 patients that took part in the study, 32 patients, whose blood test results were initially positive, went on to have a negative CT and biopsy. What is the term best used to describe these results?

The following is an abstract taken from a 1981 Lancet article. "The clinical findings in eight young homosexual men in New York with Kaposi's sarcoma showed some unusual features. Unlike the form usually seen in North America and Europe, it affected younger men (4th decade rather than 7th decade); the skin lesions wee generalised rather than being predominantly in the lower limbs, and the disease was more aggressive (survival of less than 20 months rather 8-13 years). All eight had had a variety of sexually transmitted diseases. All those tested for cytomegalovirus antibodies and hepatitis B surface antigen of anti-hepatitis B antibody gave positive results. This unusual occurrence of Kaposi's sarcoma in a population much exposed to sexually transmissible diseases suggests that such exposure may play a role in its pathogenesis." What type of study does this describe?

What is the most correct definition of prevalance?

What is the most correct definition of morbidity?

A study is conducted to measure the blood pressure readings of patients as they leave the doctors surgery. The patients are notified of this before they enter the clinic. What bias may result here?

A double blind study was conducted to test 'Drug A' versus a placebo. 'Drug A' was given to 1000 patients and a placebo was given to another cohort of 1000 patients. Both groups were followed up for 6 months. Approximately 3 months into the study, 375 people in the placebo group dropped out versus only 7 in the 'Drug A' group. What is most likely reason for this to have occured?

What is the most correct definition of mortality rate?