Part 1: Observational Study Design Identification For each of the descriptions b
ID: 3181783 • Letter: P
Question
Part 1: Observational Study Design Identification
For each of the descriptions below, first name the unit of analysis (1 point each). Then identify the study design (2 points each). Choose only one study design per description: ecologic, cross-sectional, case-control, historical cohort or prospective cohort study
Examples:
The 1996-1998 cause-specific and age-specific mortality rates from trauma, in children from birth to 14 years old, were compared among continental United States counties, some of which had pediatric intensive care facilities and some of which did not.
Unit of Analysis: the county
Study Design: Ecologic
A survey was taken to ascertain the prevalence of depressive symptoms in South Korean adults after the financial crisis of 1997.
Unit of Analysis: the individual adult
Study Design: Cross-Sectional
In a small pilot study, 12 women with endometrial cancer (cancer of the uterus) and 12 women with no apparent disease were contacted and asked whether they ever used estrogen.
In 2002 the computer records of 1,099 children from an urban pediatric practice in New Orleans born between April 1, 1998 and June 1, 1999 were examined. It was found that 568 had been vaccinated against rotavirus infection, while 513 had not. Hospital records were also reviewed to determine rates of hospitalization for rotavirus infections in this group of children between October 1998 and June 2001. The attack rate (incidence) of rotavirus hospitalization was 0.34 per 100 child-years for the entire sample. It was 0.52 for unvaccinated (no doses) children, 0.20 for partially vaccinated (one or two doses) children and 0 for fully vaccinated (three doses) children.
A study was undertaken to correlate the iron content of community water supplies with the average hematocrit of the children in those communities.
A group of non-caffeine consuming Mormons were compared to another group who were of similar age, race, gender and education, but of different Judeo-Christian faiths, which allowed caffeine consumption. They were followed forward in time to determine relative mortality rates from cardiovascular diseases. Mormons proved less likely to die from these causes than their caffeine consuming counterparts in other religious faiths.
Measurements of height, weight, consumption of alcohol, and blood pressure were taken in a sample of men and women aged 30-59 in order to determine the distribution of these characteristics.
Incidence rates of early stage prostate cancer in the United States were compared in every consecutive year from 2005 through 2012. It was discovered that incidence rates had decreased along with PSA testing, following the 2008 US Preventive Services Task Force recommendation against PSA screening for average risk older men.
Thirty-two thousand six hundred and fifty Swedish women, aged 40-74 years at the start of the study, were asked about their caffeine consumption, and then followed forward in time for 5 years (165,896 person-years of follow up) to determine if coffee consumption increased the risk of myocardial infarction. Contrary to expectations, it did not.
A study was done to determine if the amount of intra-abdominal fat was associated with fasting circulating levels of insulin in a sample of patients with Type II Diabetes.
Fifty patients recently diagnosed with hepatitis A were selected along with another 50 patients without hepatitis A, from among those attending a local clinic. The participants in the two groups were then interviewed to determine if they had obtained any new body piercings within the last two months.
To study the presumed inverse (protective) relationship between black tea consumption and cardiovascular disease, investigators randomly selected a sample of 13,500 participants, 50-64 years of age, and queried them about tea consumption and cardiovascular disease. No significant association was found between drinking black tea and having cardiovascular disease.
In 1996 a study was designed to test the hypothesis that alcohol consumption may increase the risk of certain types of cancer. In a 1965 survey, a group of 3,000 adults without cancer in Baltimore had been asked about alcohol consumption. This dataset was later linked to a cancer registry, which contained records of the occurrence of new cases of cancer between 1981 and 1995.
Incidences rates of gonorrhea and rates of premature death before age 65 were correlated with a high percentage of boarded up houses in 107 U.S. cities.
One hundred incident cases of infectious hepatitis and 100 healthy neighbor controls were asked about their history of eating raw clams and oysters over the preceding year.
Data were obtained from 4,763 American Indians and Alaskan Natives, aged 45 and older, to determine the prevalence of functional limitations in walking, climbing stairs, reaching, lifting or carrying.
The incidence and mortality rates from breast and prostate cancer were compared among 100 major cities around the world. Cities located at relatively low latitudes had low incidence and mortality rates of these cancers, while cities at higher latitudes had higher rates.
Two hundred newly homeless men and women were compared to 200 men and women with no history of homelessness. The homeless were less likely to have a high school diploma, and had less income, including from their families, than the never homeless.
The average per capita intake of vitamin A for each island was correlated with the prevalence of blindness among the islands of Indonesia.
The prevalence of type 2 diabetes was determined from a randomly selected sample of 3,000 adults over 50 years of age in a large city in the Southwest. Based on clinical examinations and testing, the prevalence of diabetes was found to be 7.5% in men and 6.2% in women.
A large Australian study enrolled 7,223 infants at birth and followed up at 3-5 days, 6 months, 5 years, 14 years and 21 years. Among females, it was discovered that low birth weight was a risk factor for depression at age 21.
One thousand five hundred thirty-six Canadian women who had delivered a small for gestational age baby were compared with 4,441 Canadian women who had delivered an infant of normal weight during the same time period. Both groups were questioned on the telephone. Irregular or shift work, and combinations of night hours, standing, lifting loads, noise, high psychological demands and low social support at work all appeared associated with giving birth to a small for gestational age infant.
Explanation / Answer
a) In a small pilot study, 12 women with endometrial cancer (cancer of the uterus) and 12 women with no apparent disease were contacted and asked whether they ever used estrogen.
Unit of Analysis:Is the individual
Study Deisgn:Case Control Study
In this,exposure precedes outcome.
b) In 2002 the computer records of 1,099 children from an urban pediatric practice in New Orleans born between April 1, 1998 and June 1, 1999 were examined. It was found that 568 had been vaccinated against rotavirus infection, while 513 had not. Hospital records were also reviewed to determine rates of hospitalization for rotavirus infections in this group of children between October 1998 and June 2001. The attack rate (incidence) of rotavirus hospitalization was 0.34 per 100 child-years for the entire sample. It was 0.52 for unvaccinated (no doses) children, 0.20 for partially vaccinated (one or two doses) children and 0 for fully vaccinated (three doses) children.
Unit of Analysis:It is the individual
Study Design:Retrospectie(Historic) Cohort Study
It involves the study of group of individuals who share common factors.It is called historic cohort study.
c)A study was undertaken to correlate the iron content of community water supplies with the average hematocrit of the children in those communities.
Unit of Analysis:Group
Study Design:Ecological Study
It is due to the fact there we are finding the correlation between the iron content of community water supplies with the average hematocrit of the children in those communities.It is also called correlation study.
d) A group of non-caffeine consuming Mormons were compared to another group who were of similar age, race, gender and education, but of different Judeo-Christian faiths, which allowed caffeine consumption. They were followed forward in time to determine relative mortality rates from cardiovascular diseases. Mormons proved less likely to die from these causes than their caffeine consuming counterparts in other religious faiths.
Unit of Analysis:It is the individual.
Study Design:Prospective Study.
Follow up proceeds from study initiative forward in time.Also called follow up study.