wilfried karmaus department of epidemiology, msu [email protected] epi 824 reproductive epidemiology...
TRANSCRIPT
Wilfried Karmaus
Department of Epidemiology, MSU
EPI 824Reproductive Epidemiology
Fall 2002
Objectives (1)Objectives (1)
• Level 6: Evaluation (critique, appraise, Level 6: Evaluation (critique, appraise,
judge)judge)
• Level 5: Synthesize (integrate, Level 5: Synthesize (integrate,
collaborate)collaborate)
• Level 4: Analyze (hypothesis, structure)Level 4: Analyze (hypothesis, structure)
• Level 3: Application (utilize, produce)Level 3: Application (utilize, produce)
• Level 2: Comprehension (translate, Level 2: Comprehension (translate,
discuss)discuss)
• Level 1: Knowledge (define, enumerate, Level 1: Knowledge (define, enumerate,
recall) recall)
Problem Solving Cycle in Public Problem Solving Cycle in Public HealthHealth
Definition of the problem
Goals and priority setting
Studying the effects
Application and steering of the
measures
Strategies forproblem solving
Operational plan
Epidemiology: (Stallones 1980, Ann Rev Public Health 1:69-82)
Axiom: Disease does not distribute randomly
in human populations.Corollary 1: Aggregations of human diseases
are manifested along axes of:• time• space• individual / group characteristics.
Corollary 2: Variations in the frequency of
human disease occur in response to:• variation in exposure• variation in susceptibility.
Outcomes of human reproduction
Reproductive health Sex ratio
Predictors OutcomesGeneral etiologic model:
X1 X2
X3
Y1
problem: collinearity
Y2
Y3
(atopic eczema)
(increased cholesterol)
(bronchial hyperreactivity)
Latent factor for these three outcomes?
Predictors Outcomes
X1 X2
X3
Y1
problem: collinearity
Y2
Y3
(infertility)
(fetal loss)
(birth defect)
conditional interdependence(selective survival)
Etiologic model for reproductive epidemiology:
=
=
Frequency of reproductive outcomes in Frequency of reproductive outcomes in humanshumans
Infertility/Subfecundity » 14-20% of all couples at risk
Spontaneous abortions recognized: » 15% of all conceptions not recognized: » 20%
malformations » 2-5% of all live births
childhood cancer » 0.18% of all children
Initiation of the etiologic process (onset of the first cause)
Initiation of the patholo-gic process (disease starts)
Clinical detection of the disease (onset of sign and symptoms)
Outcome of the disease(subsequent change in health status or death)
Latency Duration
Primary Prevention Secondary Prevention Tertiary Prevention
Low birth weight and exposure to wood preservatives (PCP, PCDD/F)
Source: Karmaus et. al. 1995
% without conception
exposed at starting time (n=86)
not exposed at starting time (n=1001)
0.0
0.2
0.4
0.6
0.8
1.0
months
0 6 12 18 24 30 36 42 48 54 60
Living on a contaminated waste site and time to pregnancy
Study design in reproductive epidemiology golden standard = prospective study
time
starting time of unprotected intercourse
detected/ recognized conception
birth, miscarriage, stillbirth
starting time end of unprotec-ted intercourse
time to pregancy
period of unprotected intercourse
gestational age
Changes in sex ratioProportion of female newborns and mother’sresidence in the Bille-settlement before conception(Küppers et al. 1997)
born between
1950-1960
(F1-Genertation)
born between
1960-1970
(F1-generation)
born
after 1970
(F2-generation)
notexposed
exposed notexposed
exposed notexposed
exposed
n=83 n=44 n=67 n=48 n=101 n=81
47.0 47.7 53.7 50.0 44.6 29.6
Reproductive epidemiology includes a wide variety of outcomes with:
• different ways of measurements• different markers within physiologic and
pathologic processes• different statistical approaches
In the course you will learn- how to define reproductive outcomes- to review one outcomes and its etiology- to discuss empirical methods and - to apply some statistical methods.