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Cross-sectional study
exposed gr. diseased gr.
Non-exposed gr.
Nondiseased gr.
2013/7/27
Department of Medical Research, Chimei Medical Center
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Cross-Sectional StudyAdvantage
OR (Odds Ratio)

0<=OR<∞ 0<=OR<1, protection factor OR=1, no effect OR>1, risk factor
2013/7/27
Department of Medical Research, Chimei Medical Center
6
The association between O.C. use and MI - overestimation
Oral contraceptive use
+
O.C. users smoke more heavily than non users
Myocardial infarction
+ Smokers, irrespective of O.C. use, have a higher infarction than nonsmokers
2013/7/27
Department of Medical Research, Chimei Medical Center
12
RR(Relative Risk, Rate Ratio)
MI O.C. O.C. a c a+c MI b d a+b c+d MI MI
O.C.
O.C.
60
44
40 100
2013/7/27
Department of Medical Research, Chimei Medical Center
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Clinical Trial
RCT(Randomized controlled trial)

Parallel design Cross-Over design
2013/7/27
56 100
b+d a+b+ c+d =1.36
104 96 200 RR=(60/100) / (44/100)
RR=(a/(a+b)) / (c/(c+d))
2013/7/27
Department of Medical Research, Chimei Medical Center
13
RR(Relative Risk, Rate Ratio)
2
提出假說 演繹 歸納
推論出小前提
估計或檢定分析結 果得到研究摘要
研究設計並 進行測量
流行病學方法論，p 11。第三版。王榮德著 2013/7/27 Department of Medical Research, Chimei Medical Center
3
吸煙導致肺癌 演繹 歸納
台灣的男子吸煙者 比不吸煙者易得肺 癌

要有整個族群的資料 找符合條件裡頭最接近病例的人 Cases是陸續收案時

Individual matching


先考慮age, gender, race，避免 overmatching
Department of Medical Research, Chimei Medical Center

0<=RR<∞ 0<=RR<1, protection factor RR=1, no effect RR>1, risk factor
2013/7/27
Department of Medical Research, Chimei Medical Center
14
Case-control st 較快得到結果，較便宜 保留探討多種致病因子的可能性
2013/7/27
Department of Medical Research, Chimei Medical Center
17
Matching- 控制干擾因子的一種方法

Frequency matching
吸煙者之肺癌死亡率為 不吸煙者之10倍
研究設計 測量的台灣男 子中，吸煙者 與不吸煙者的 肺癌死亡率
流行病學方法論，p 11。第三版。王榮德著 2013/7/27 Department of Medical Research, Chimei Medical Center
4
因果關係的判定標準

必要條件—時序性 次要條件—
smoking
Mark Elwood. Critical Appraisal of Epidemiological Studies and Clinical Trails. 2nd Edition.
2013/7/27 Department of Medical Research, Chimei Medical Center

Cases:

一或多個醫院中就醫的所有病例 整個社區或團體族群的所有病例 整個社區 醫院其他病人 病人親屬 病人的同學、同事、鄰居
Department of Medical Research, Chimei Medical Center

Control:



2013/7/27
16
Case-Control Study-Advantage
7
The association between O.C. use and MI - underestimation
Oral contraceptive use
—
O.C. users are less obese than non-users
Myocardial infarction
+ Obesity increases the risk of myocardial infarction
obesity
Mark Elwood. Critical Appraisal of Epidemiological Studies and Clinical Trails. 2nd Edition.
2013/7/27 Department of Medical Research, Chimei Medical Center
Department of Medical Research, Chimei Medical Center
25
RCT
Parallel Design
Treatment A Recruited samples Outcome 1
Randomization
Treatment B
Outcome 2
2013/7/27
2013/7/27
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Case-Control Study-disadvantage



Exposure status需要靠過去的紀錄或回 憶 bias：recall bias, selection bias 不容易研究多重疾病事件，且疾病事件 的時序性不易建立 Control group不好選 Confounding effect
8
常見的研究設計法

觀察性研究法



Case series study 世代研究法(cohort study) 病例對照研究(case control study) 斷代研究法(cross-sectional study)

試驗性研究法


社區試驗法 臨床試驗法
Department of Medical Research, Chimei Medical Center
200 230
350 365 550 595
b+d a+b+ c+d
OR=30× 350 / 200× 15 =3.5
Department of Medical Research, Chimei Medical Center
Odds Ratio=odds1/odds2=ad/bc
2013/7/27
20
10
Department of Medical Research, Chimei Medical Center
Cohort study - advantages




適於研究rare exposure 可直接觀察exposed 和non-exposed group的疾病發生率 可觀察多重健康事件事件發生的時序性、 先後次序 Eligibility criteria和outcome assessments可以標準化 比RCT的行政作業簡單、便宜
Department of Medical Research, Chimei Medical Center
2013/7/27
19
OR (Odds Ratio)
MI Smk smk a c a+c odds1=a/b odds2=c/d MI b d a+b c+d MI MI
smk
smk
30
15 45
Department of Medical Research, Chimei Medical Center
2013/7/27
11
Cohort Study - disadvantage


前瞻性研究，費時、昂貴 不適於研究稀有或潛伏期夠長的疾病 若是retrospective cohort study，需要有 過去exposure status的紀錄 Loss of follow up可能影響效度