NUTR 331 CORE MAIN EXAMS QUESTIONS AND
ANSWERS SURE A+
✔✔How to reduce random chance - ✔✔1) test groups must be large enough to reduce
the effect of random chance influences (usually 30 or more subjects per group); 2) to
help prevent bias, subjects are randomly placed into the groups; and 3) the two groups
are compared at the start to make sure that they are similar with respect to factors
relevant to the study
✔✔What are 5 characteristics of a well-designed intervention study? - ✔✔Double blind
study, to overcome the bias of investigators. Large test groups, groups are as similar as
possible, groups are randomized, and placebo is similar to the active treatment.
✔✔Errors of Uncontrolled study - ✔✔many conditions clear up without treatment.
Another source of error is in the assessment of subjects
✔✔Advantages of Intervention studies - ✔✔can be carried out on healthy subjects with
the aim of preventing disease or on sick people to test a treatment (clinical study).
Shows CAUSE AND EFFECT RELATIONSHIP btw nutrition variable and disease
✔✔Anecdotal evidence - ✔✔both the simplest and the least reliable avenue for studying
the role of diet in disease. The investigator makes inferences from the experiences of
one or more individuals case studies. Can lead to a reliable conclusion where there are
many similar reports describing an unusual condition.
✔✔Advantages of anecdotal evidence - ✔✔Completely new and previously
unsuspected relationships can be discovered. Side effects from new drugs, for example,
are often uncovered when many reports based on individual patients are collated and a
distinctive pattern emerges
✔✔Disadvantage of anecdotal evidence - ✔✔inherent unreliability, all types of errors
can occur. First, there is chance. Second, there is bias in the observation. As a result of
the power of suggestion, people are often unreliable in describing their symptoms
, ✔✔Epidemiology - ✔✔the study of the incidence and distribution of diseases, and of
their control and prevention. Researchers simply observe what people do and whether
they develop diseases. The four types are population, historical, case-control, and
cohort studies.
✔✔population studies and limitations - ✔✔Population studies compare disease patterns
with various factors, including food consumption, on a country-wide basis. First, there
could be errors in the data. The second is the presence of confounding variables that
occur with the factor under study and may mask the real cause of the disease. Because
many factors tend to appear together in a diet or a lifestyle, it is quite easy for some
confounding variable to be the culprit instead of the identified factor.
✔✔Historical studies - ✔✔useful when there are accurate records available of the
number of people who have died from or have a specific health problem. Historical
studies are best compared with population studies. Historical studies have the
advantage of being based on large populations, and they often involve large or even
massive changes in disease incidence. However, disease statistics collected 60 or more
years ago can often be unreliable. A more important disadvantage is that confounding
variables often give rise to spurious relationships.
✔✔case-control - ✔✔recruitment of subjects and data collection are done after the
disease has developed. Two groups of subjects are recruited, one consisting of
individuals suffering from the disease of interest, and the other (the control group) free
of the disease. As the data are collected after the disease has developed, case control
studies are sometimes known as retrospective studies.
✔✔Cohort - ✔✔a large number of healthy subjects are recruited. They are questioned
or examined to determine each person's exposure to the particular factors under study
(24 hr recall or food frequency). The investigators then keep track of the subjects over
time until enough of them have developed the disease of interest. The investigators
then compare those who developed the disease to those who did not, particularly with
respect to exposure to the possible disease-causing factors.
✔✔Advantages of case control and cohort studies - ✔✔Case control are cost effective
and cohort studies allow you to examine multiple outcomes for a single exposure.
✔✔Disadvantages of case control and cohort studies - ✔✔They both are prone to recall
bias with the use of 24 hour recall and food frequency questions
✔✔Animal Experiments - ✔✔Helps with investigating the causes of disease.
researchers will investigate the effects of different treatments on disease occurrence or
on some other parameter relevant to health. The researcher will divide the animals into
groups. Each group will receive a different treatment. A control group will receive no
ANSWERS SURE A+
✔✔How to reduce random chance - ✔✔1) test groups must be large enough to reduce
the effect of random chance influences (usually 30 or more subjects per group); 2) to
help prevent bias, subjects are randomly placed into the groups; and 3) the two groups
are compared at the start to make sure that they are similar with respect to factors
relevant to the study
✔✔What are 5 characteristics of a well-designed intervention study? - ✔✔Double blind
study, to overcome the bias of investigators. Large test groups, groups are as similar as
possible, groups are randomized, and placebo is similar to the active treatment.
✔✔Errors of Uncontrolled study - ✔✔many conditions clear up without treatment.
Another source of error is in the assessment of subjects
✔✔Advantages of Intervention studies - ✔✔can be carried out on healthy subjects with
the aim of preventing disease or on sick people to test a treatment (clinical study).
Shows CAUSE AND EFFECT RELATIONSHIP btw nutrition variable and disease
✔✔Anecdotal evidence - ✔✔both the simplest and the least reliable avenue for studying
the role of diet in disease. The investigator makes inferences from the experiences of
one or more individuals case studies. Can lead to a reliable conclusion where there are
many similar reports describing an unusual condition.
✔✔Advantages of anecdotal evidence - ✔✔Completely new and previously
unsuspected relationships can be discovered. Side effects from new drugs, for example,
are often uncovered when many reports based on individual patients are collated and a
distinctive pattern emerges
✔✔Disadvantage of anecdotal evidence - ✔✔inherent unreliability, all types of errors
can occur. First, there is chance. Second, there is bias in the observation. As a result of
the power of suggestion, people are often unreliable in describing their symptoms
, ✔✔Epidemiology - ✔✔the study of the incidence and distribution of diseases, and of
their control and prevention. Researchers simply observe what people do and whether
they develop diseases. The four types are population, historical, case-control, and
cohort studies.
✔✔population studies and limitations - ✔✔Population studies compare disease patterns
with various factors, including food consumption, on a country-wide basis. First, there
could be errors in the data. The second is the presence of confounding variables that
occur with the factor under study and may mask the real cause of the disease. Because
many factors tend to appear together in a diet or a lifestyle, it is quite easy for some
confounding variable to be the culprit instead of the identified factor.
✔✔Historical studies - ✔✔useful when there are accurate records available of the
number of people who have died from or have a specific health problem. Historical
studies are best compared with population studies. Historical studies have the
advantage of being based on large populations, and they often involve large or even
massive changes in disease incidence. However, disease statistics collected 60 or more
years ago can often be unreliable. A more important disadvantage is that confounding
variables often give rise to spurious relationships.
✔✔case-control - ✔✔recruitment of subjects and data collection are done after the
disease has developed. Two groups of subjects are recruited, one consisting of
individuals suffering from the disease of interest, and the other (the control group) free
of the disease. As the data are collected after the disease has developed, case control
studies are sometimes known as retrospective studies.
✔✔Cohort - ✔✔a large number of healthy subjects are recruited. They are questioned
or examined to determine each person's exposure to the particular factors under study
(24 hr recall or food frequency). The investigators then keep track of the subjects over
time until enough of them have developed the disease of interest. The investigators
then compare those who developed the disease to those who did not, particularly with
respect to exposure to the possible disease-causing factors.
✔✔Advantages of case control and cohort studies - ✔✔Case control are cost effective
and cohort studies allow you to examine multiple outcomes for a single exposure.
✔✔Disadvantages of case control and cohort studies - ✔✔They both are prone to recall
bias with the use of 24 hour recall and food frequency questions
✔✔Animal Experiments - ✔✔Helps with investigating the causes of disease.
researchers will investigate the effects of different treatments on disease occurrence or
on some other parameter relevant to health. The researcher will divide the animals into
groups. Each group will receive a different treatment. A control group will receive no
