SAN DIEGO STATE UNIVERSITY
Graduate School of Public Health
Division of Epidemiology and Biostatistics
PH 826 Analysis of Case-Control Studies
Section
1
Day
Thursday
Instructor: John Alcaraz, Ph.D.
E-mail: jalcaraz@mail.sdsu.edu
Time
9:30am – 12:10pm
3 units
Fall 2013
Location
HH 128
Schedule No.
22346
Office location: Hardy Tower 231
Office hours: Mon Wed 11:30am – 1:30pm
Thursday 1:00pm – 3:00pm
Course Description:
Statistical methods and applications for analyzing case-control studies. Use of conditional and
unconditional logistic regression and approaches for incorporating confounding and interaction in
models. Computer applications included.
Prerequisites:
– PH 623: Epidemiologic Methods
– PH 627: Advanced Statistical Methods in Public Health
– Ability to independently carry out SAS programs based on examples discussed in class.
Students who took the SAS lab as part of PH 627 should have the requisite knowledge.
– Recommended: PH 823: Case-control studies
Grading System:
Homework:
20%
Take-home exam:
40%
Class presentation of analysis of case-control study: 40%
Homework/Exam Schedule (subject to change):
Assigned
Homework 1
Sept 5
2
Sept 12
3
Sept 19
4
Sept 26
5
Oct 3
6
Oct 10
7
Oct 17
Take-home exam
Oct 31
Presentation
Oct 3
93 – 100 = A
90 – 93 = A–
87 – 90 = B+
83 – 87 = B
80 – 83 = B–
77 – 80 = C+
73 – 77 = C
70 – 73 = C–
67 – 70 = D+
63 – 67 = D
60 – 63 = D–
0 – 60 = F
Due
Sept 12
Sept 19
Sept 26
Oct 3
Oct 10
Oct 17
Oct 24
Nov 14
Dec 5
All coursework must be printed, computer-written documents. Handwritten submissions are not
acceptable. Most coursework will require the use of SAS. Do not submit any SAS output.
The exam will consist of two problems. The first is similar to the homework in that it requires
analyzing a data set. The second involves writing a critical review of a published paper.
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For the class presentation, you must prepare overheads or a PowerPoint slideshow to accompany
the talk. Printouts of these materials must be given to the instructor as part of the grading process.
You are graded on the basis of the quality of the materials you have prepared as well as the
quality of the oral presentation. Particular focus should be on the appropriate development of
tables for presentation to represent both descriptive and analytical results. More details about the
presentation will be posted on Blackboard on October 3. The presentations are scheduled to take
place on December 5.
Required Texts:
– Woodward M. Epidemiology: Study Design and Data Analysis, 2nd Ed. New York: CRC Press,
2005.
– Hosmer DW and Lemeshow S. Applied Logistic Regression, 2nd Ed. New York: Wiley and
Sons, 2000.
– Slymen D. Annotated SAS Output for Public Health 826: Analysis of Case-Control Studies.
[Available under my name at bookstore]
– Thompson WD. Statistical analysis of case-control studies. Epidemiologic Reviews, 1994, v. 16,
no. 1, pp. 33-50. [On Blackboard]
– Lecture notes. [On Blackboard]
Other Resources:
– Schlesselman JJ. Case-Control Studies: Design, Conduct, Analysis. New York: Oxford
University Press, 1982. [Chapters 7 and 8 are pertinent to this course. But some material is out of
date.]
– Breslow NE and Day NE. Statistical Methods in Cancer Research: Volume 1 – The Analysis of
Case-Control Studies. Lyon: International Agency for Research on Cancer, 1980. [Notation is
difficult to follow, but a classic.]
– Kleinbaum DG, Kupper LL, Nizam A, Muller KE. Applied Regression Analysis and Other
Multivariable Methods, 4th Ed. New York: Duxbury Press, 2007. [Your PH 627 text. Chapter 23
as a review of logistic regression.]
Course Objectives:
1. Acquire knowledge on the appropriate use of statistical methods to analyze case-control
studies.
2. Gain proficiency in the use of statistical software to carry out analyses of case-control studies.
3. Practice the written and oral transmission of results from analyses appropriate for case-control
studies.
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Specific Objectives:
1. Gain in-depth knowledge of epidemiologic principles associated with case-control studies:
a) Evaluate how measures of association such as the odds ratio and attributable risk apply to
case-control studies.
b) Relate how bias minimization and increasing precision may be implemented through study
design and analytical approaches.
2. Demonstrate knowledge in data management:
a) Build upon existing knowledge using the SAS statistical package to reorganize a data set
appropriate for analyses of unmatched and matched case-control studies.
b) Examine strategies for handling missing data problems.
3. Demonstrate advanced knowledge in the data analysis and interpretation of results from casecontrol studies:
a) Use appropriate measures of association and confidence intervals for unmatched and
matched studies with and without adjusting for covariates.
b) Explain and implement the use of unconditional and conditional likelihood with logistic
regression.
c) Apply concepts of confounding and interaction as they relate to case-control studies in the
analysis of data sets.
d) Be able to carry out statistical analyses using SAS software and correctly interpret results
from the output of this software.
4. Gain communication skills:
a) Construct a set of tables appropriate for reporting of results from a case-control study.
b) Practice communicating clearly and concisely written and oral results from a case-control
study.
Attendance:
Attendance is required at all class meetings. If because of severe circumstances (such as illness,
injury, death in the family) you are absent on a day when an assignment (homework or exam) is
due, you must submit it to me via email no later than one week after the due date, along with
documentation explaining your absence. Students for whom a due date (homework or exam) falls
on a date of planned absence (e.g., religious observance) must submit their assignment to me via
email by 9:30am on the due date or earlier. Email submissions must be in Word or PDF format.
If you are absent for any reason on the date of the presentations, then you must make an
appointment with me to give your oral presentation in my office.
Student Conduct and Grievances:
SDSU is committed to maintaining a safe and healthy living and learning environment for
students, faculty and staff. Section 41301, Standards for Student Conduct (at
http://csrr.sdsu.edu/conduct1.html ), and Sections 41302-41304 of the University Policies
regarding student conduct should be reviewed.
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If a student believes that a professor’s treatment is grossly unfair or that a professor’s behavior is
clearly unprofessional, the student may bring the complaint to the proper university authorities
and official reviewing bodies. See University Policies on Student Grievances.
Academic Ethics:
SDSU has a strict code of ethical conduct which students are expected to follow. See
http://csrr.sdsu.edu/conduct1.html for details. In particular, cheating on the exam will not be
tolerated. You may not work together on the exam, may not copy answers from other students,
and may not allow other students to copy your answers. Anyone caught cheating will face
disciplinary action.
Nondiscrimination Policy:
SDSU complies with the requirements of Title VI and Title VII of the Civil Rights Act of 1964,
as well as other applicable federal and state laws prohibiting discrimination. No person shall, on
the basis of race, color, or national origin be excluded from participation in, be denied the
benefits of, or be otherwise subjected to discrimination in any program of the California State
University.
SDSU does not discriminate on the basis of sex, gender, or sexual orientation in the educational
programs or activities it conducts.
SDSU does not discriminate on the basis of disability in admission or access to, or treatment or
employment in, its programs and activities. Students should direct inquiries concerning SDSU’s
compliance with all relevant disability laws to the Director of Student Disability Services (SDS),
Calpulli Center, Suite 3101, or call 619-594-6473 (TDD: 619-594-2929).
More details on SDSU’s Nondiscrimination Policy can be found in the SDSU General Catalog,
University Policies.
Students with Disabilities:
Students with disabilities should discuss with me privately any specific accommodations for
which they have received authorization. Authorization may be obtained by contacting Student
Disability Services at 619-594-6473 (Calpulli Center, Suite 3101). Please obtain authorization
before making an appointment to see me. More information can be found at
http://www.sa.sdsu.edu/sds/.
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Course Outline for PH 826
Basic design concepts and issues
Unmatched Studies
Binary exposure, no adjustment
Odds ratio, attributable risk
Confidence intervals
Chi-square tests
Binary exposure with categorical adjustment
Stratification and Mantel Haenszel
Test for heterogeneity
Maximum likelihood and logistic regression
Binary exposure with continuous (and possibly categorical) covariates
Logistic regression
Multiple levels of exposure (nominal and ordinal)
Dose response and test for trend
Continuous exposure, no adjustment
Dose response and test for trend
Categorizing a continuous variable
Continuous exposure with adjustment
Multiple exposure variables
Identifying confounders
Assessing interactions
Missing data problems
Goodness of fit
Matched studies
Pair matching
1:1 – binary exposure, no adjustment
– adjustment with stratification
– continuous exposure with adjustment
1:c matching, 1:variable matching
Conditional logistic regression
Three or more groups: polychotomous logistic regression
Other designs
Nested case-control
Case-crossover
Case-cohort
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