專業(yè)課課件-流行病描述性研究

描述性研究Descriptive

Study哈爾濱醫(yī)

學流行病學教研室Department

of

epidemiology

，Harbin

Medical

UniversityEpidemiology

is

the

study

ofthe

distribution

anddeterminants

of

disease

and

health

related

status

in

aspecify

population

and

the

application

of

this

study

to2control

of

health

problems.A

Dictionary

of

Epidemiology,

2nded.by

Last,J.M1988The

distribution

ofDisease

considersWho

is

getting

disease?Where

is

disease

occurring?When

is

disease

occurring?3Methods

ofstudyObservationalDescriptive

studyExperimentalTheoreticalyticstudyCross-sectional

study

Ecological

studyCase-control

studyCohort

studyClinical

trial

Field

trialCommunityinterventionthree

types

of basic

methods4PlaceTimeCases051015160040020000-4

'5-14

'15-44Age

GrouDescriptive

EpidemiologyWho?Where?When?5Descriptive

studies

often

representthe

scientific

toe

in

the

waterin

new

areas

of

inquiryDavid

A

GrimesLancet

2002;

359:145–496概述現(xiàn)況研究現(xiàn)況研究實例生態(tài)學研究OutlineCross-sectional

studyA

case

ofcross-sectionalstudyEcological

studyOutline7第一節(jié)概述

Outline8ConceptType

and

characteristicsUses概念種類與特點用途Descriptive

study

describe

thedistribution

of

disease

or

heathstatus

in

relation

to

variables

suchas ,

place

and

time,

toprompt

the

clue

ofrelationshipbetween

risk

factors

and

diseaseor

health,

to

formulate

hypothesis.描述性研究通過描述疾病或健康狀況的三間分布情況，獲得因素與疾病或健康狀況間關系的線索，提出病因假設。描述性研究的概念Concept9現(xiàn)況研究病例報告病例系列分析個案研究歷史(常規(guī)）資料分析隨訪研究生態(tài)學研究Cross-sectional

studyCasereportCase

series

ysisCasestudyysis

of

historical（routine）dataFollow-up

studyEcological

study描述性研究的種類Type10在某一特定時間，某一定范圍的人群中，對某種疾病或健康狀況及相關因素的一種方法。A

method

to

survey

thedisease

or

health

status

andrelatedfactors

of

in

a

certainpopulation

at

a

single

pointin

time

or

during

a

specifictimeinterval.現(xiàn)況研究Cross-sectional

Study11是對臨

某種罕見病的單個病例或少數(shù)病例的詳細介紹;包括:人口學特征、癥狀、體征、、治療、和隨訪等。A

detailed

report

of

anunusual

or

noveloccurrence

of

patients

inclinical;including:demographic

profile,symptoms,

signs,diagnosis,

treatment,and

follow-up

et

al.病例報告Case

Report12病例報告Case

Report定性研究的范疇無須描述事物的集中趨勢或離散程度為研究者提供分析和決策的線索Quality

StudyNeed

not

describethecentralized

tend

dispersiondegreeProvide

the

clue

forysis

and

decisionmaking1314N

Engl

J

Med

2005;352:2508-14一組相同疾病的臨床資料進行整理、統(tǒng)計、分析、總結并得出結論.病例系列分析Case

SeriesysisA

series

of

similarpatients

with

an e

ofinterest,

in

which

tosort,statistics, ysis

andsummarize

and

derive

aconclusion.15病例系列分析Case

Seriesysis一般用來分析某種疾病的臨床表現(xiàn)特征，評價預防、治療措施的效果顯示某些病變的自然進程的規(guī)律性用來確定開始流行或流行的存在方法為進一步研究提供線索To ysis

the

clinicalmanifestation

of

thedisease,to

evaluation

the

effective

ofprevention

and

treatmentTo

display

the

naturalhistory

of

some

diseaseAs

a

method

to

identify

thebeginning

or

presence

of

anepidemicTo

provide

clue

for

furtherstudy161718Case

report

and

case

series

areimportant

interface

between

ClinicalMedicine

&

Epidemiology個案研究（個案）

Case

Study定義：是在發(fā)病現(xiàn)場對新發(fā)病例的接觸史、家屬及周圍人病及健康狀況、及其與發(fā)病可能有關的周圍環(huán)境所進行的。Definition：

in

the

fieldintensively

investigate

thecontacting

history

of

thecases，the

health

anddisease

status

of

the

relativesand s,

and

relatedsurrounding

environment.19目的：探索發(fā)病原因和條件病因提供線索為控制疾病提供基礎控制

擴散消滅疫源地防止再發(fā)生類似疾病Purpose：Explore

the

causes

andcondition

for

disease

occurringProvide

clue

of

causesProvide

basis

for

preventionand

control

disease

Control

the

spread

of

theepidemicEradicate

focus

of

infectionPrevent

re-emerging

thedisease20歷史（常規(guī)）資料分析是登記報告系統(tǒng)或者疾病監(jiān)測系統(tǒng)，收集既往或當前的疾病或健康狀態(tài)資料進行分析，描述疾病和健康狀態(tài)的分布以及變動趨勢。用ys已is

有of的H疾ist病orical

oUrsRe

tohueteinxiestDedadtaiseaseregister

or

surveillancesystematic，collect

andyze

the

disease

andhealth

at

present

or

in

thepast，describe

thedistribution

and

changeofdisease

and

healthstatus2123隨訪研究Follow-up

Study也稱縱向研究通過定期隨訪，觀察疾病、健康狀況或某衛(wèi)生事件在一個固定人群中隨著時間推移的動態(tài)變化情況與現(xiàn)況研究的區(qū)別Longitudinal

studyObserve

the

change

ofincidence

of

disease,health

situation

withtime

in

a

fix

populationby

regularly

follow

upDifference

with

cross-sectional

study24隨訪間隔和方式根據(jù)具體的研究內容有所不同可用于疾病自然史的研究，為該疾病的病因研究提供線索還可用于提出或檢驗某些病因學假設The

interval

and

way

offollow

up

depends

on

thecontents

of

studyMay

study

the

history

ofdisease,

provide

the

clueof

etiology

study

May

suggest

or

testsome

hypothesis生態(tài)學研究：以群體為基本研究單位收集和描述疾病或健康狀態(tài)與某些因素的關系。Unit

of

observation

and ysis

isa

population

tocollect

and

descript

disease

or

health

situationand

therelationship

between

them

and

factorsin

differentpopulation.25以觀察為主，不對研究對象采取任何干預措施Mainly

depends

on

observation,

no

intervention

to

subjects其

因素的分配不是隨機的The

location

of

exposures

are

not

random研究開始時一般不設立對照組No

controlis

set

up特點Features26與結局關系的因果推斷無法確定The

causal

relationship

because

exposure

andis

often

impossible

to

work

out為后續(xù)研究提供線索Provide

clues

for

further

researche特點

Features27描述性研究的主要用途

Main

uses描述疾病或健康狀況的分布及發(fā)生發(fā)展的規(guī)律Describe

the

distribution

and

development

of

disease

and

health獲得病因線索，提出病因假設Obtain

the

clues

of

cause

of

disease

and

generate

hypothesis確定高危人群，為衛(wèi)生政策、防制措施制定提供基礎資料Identifyhigh

risk

population，to

provide

basic

data

forformulating

health

strategy

and

measurement28第二節(jié)現(xiàn)況研究Cross-sectional

Study概述設計與實施常見偏倚及其控制OutlineDesign

and

implementCommon

bias

and

control29基本概念特點類型與應用Basic

conceptCharacteristicsType

and

applications概述Outline30一、基本概念Conception又稱橫斷面研究也稱患病率研究研究特定時點或期間和特定范圍內人群中的有關變量(因素)與疾病或健康狀況的關系Cross-sectional

study

orprevalence

studyStudy

the

relationshipbetweenvariables

(factors)and

diseaseor

health

in

apopulation

at

a

particularpoint

of

timeor

period31TimeSchematic

diagram

of

Cross-sectional

StudyT1T2T332TimeDZDZEE-33開始時一般不設對照組特定時間或時期確定因果聯(lián)系時受到限制對不會發(fā)生改變的

因素，可以可以作因果推斷二、特點CharacteristicsNo

control

groupParticular

point

of

timeLimit

to

ensure

the

causalrelationshipTo

inference

causalrelationship

for

the

exposuresthat

won’t

be

changed34用現(xiàn)在的

（特征）來替代或估計過去情況是有條件的It

need some

conditions

to

use

current

exposures

(features)to

replace

or

estimate

the

exposure

situation

in

past定期重復進行可獲得

資料Incidence

data

may

been

obtain

by

regularlyrepeatcross-sectional

studies二、特點Characteristics3536研究類型普查抽樣三、類型與應用

Types

andUsesTypeCensusSample

survey普查的定義Definition

of

census普查的目的Purpose

of

census普查的優(yōu)缺點Advantage

and

limitation

of

census普

查

Census37普查的定義Definition

of

census指為了了解某病的患病率或健康狀況，在特定時間或時期內，對特定范圍的人群中每一成員進行的Survey

ea或檢查。ember

in

a

givenpopulationin

a

given

timeor

timeperiod

in

order

toknow

the

prevalence

or

health

status.38很短：甚至是某一時點，一般為1～2天、1～2周或1～2個月，最長不宜超過3個月。Very

short

time

period：even

in

asnapshot,1-3days

ingeneral,

1～2

weeks

or

1～2months,

nolonger

than

3

months.特定時間

Specify

time特定范圍

Specify

range范圍：指某一地區(qū)或具有某一特征的人群例如：兒童（≤14歲）的體格普查Range：refers

a

population

in

a

area

orwithsome

characteristicSuch

as

the

physical

examination

ofchildren

(≤14years

old)40普查的目的Purpose

of

census早期發(fā)現(xiàn)疾病并及時給予治療Early

diagnosis

and

treatment

on

time了解疾病的

和分布Describe

the

epidemicsituation

anddistribution了解人群的健康水平或生長發(fā)育情況等Understandthe

health

level

of

population

or

the

growthand

development,4142普查的目的Purpose

of

census建立某些生理指標正常值：如血脂等；Set

up

the

cutoff

value

of

some

physiology在疾病爆發(fā)或流行時，可借助于普查來搜尋全部病例，也可用于了解該病流行的全貌。Find

the

total

cases

for

outbreak

or

epidemicofdisease

and

understandthe

whole

epidemic

situation43普查的優(yōu)點和局限性Advantage

and

limitation優(yōu)點Advantage研究對象易于確定

Easy

to

decidestudy

subjects能發(fā)現(xiàn)普查人群中的全部病例并給予及時的治療Can

find

all

the

cases

in

the

population

and

providetreatment優(yōu)點Advantage能提供疾病分布情況和流行因素或病因線索Can

describe

the

distribution

of

diseases,factorsorclues

related

epidemic能普及醫(yī)學衛(wèi)生知識。Can

spread

the

knowledge

of

Health一次

可觀察多個因素和疾病的關系，May

investigation

the

association

between

more

factorsand

a

disease44局限性limitations所獲資料比較粗，準確性較差Datais

crude

and

lowaccuracy不適于患病率低和檢查方法復雜的疾病Notsuitable

for

disease

with

low

prevalenceandneedcomplex

method

to

exam人群范圍比較大，

時費時、費人力、費用大Huge

population,

time,

labor

andmoney

consuming45局限性limitations對象多、時限短，難免漏診、誤診，且無應答率較高May

existed

miss

diagnosis

andmisdiagnosis

andlowresponse

rate due

to

large

number

of

subjects普查的質量不易控制Difficult

to

control

the

quality一次普查只能獲得現(xiàn)患率，不能得到Ca ly

obtain

prevalence

but

not

incidence

for

once

census46抽樣

的定義Definition抽樣

的優(yōu)點和局限性Advantage

and

limitation抽樣Sample

Survey47抽樣Sample

survey對特定時間、特定范圍內人群的一

性樣本的

，以樣本人群的

結果來推論其所在總體的情況。Survey

on

a

representative

sample

of

a

definedpopulation

in

a

specified

time,

use

the

results

ofsample

to

infer

the

situation

to

total

population.48抽樣

的優(yōu)點和局限性Advantage

and

limitation優(yōu)點Advantage1.樣本小，

省時、省力、成本低；2.Small

sample，

time，labor

and

costsaving工作易做得精細Accurate

and

details

ofresults3.因而質量易得到保證，獲得結果快，而且應答率較高。Quality

insure，quick

result

and

high

responserate49局限性Limitations研究不適用于那些

過低疾病的Not

suitable

for

low

incidence

disease不適用于那些變異過大的資料的Not

suitablefor

dataof

high

variant設計、實施比較復雜，資料分析也有一定難Complexdesign

and

difficult

indata

ysis5051局限性Limitations存在抽樣誤差和偏倚Sampling

error

and

bias重復和遺漏不容易發(fā)現(xiàn)Not

easy

to

find

the

repeated

and

missed

subjects該方法不能滿足普查普治的工作要求Could

not

satisfied

the

requirement

of

census

and

treatmentfor

all現(xiàn)況

的應用

Uses用于描述疾病或與健康有關事件的分布Describe

the

distribution

of

disease

and

health

related

events可用于研究影響疾病與健康的相關因素Study

the

factorsthat

effect

the

diseases

andhealth制訂醫(yī)療、預防措施提供科學依據(jù)

Provide

basisforFormulate

measures

of

medicine

and

prevention考核、評價預防措施的效果Evaluate

the

effect

of

medicine

and

prevention

measurement52衡量一個國家或地區(qū)醫(yī)療衛(wèi)生水平及健康狀況Measure

the

level

health

work

and

heathsituation用于衛(wèi)生標準的檢驗Test

the

health

criteria用于檢查和衡量信息、資料的質量Check

the

quality

of

information

andd

ensus）現(xiàn)況

的應用

Uses53The

census

of

the

lifetime

alcohol

drinking

statusin

America

population54明確

目的和類型確定研究對象確定研究內容確定樣本量和抽樣方法現(xiàn)況研究的設計與實施Design

and

implementation

of

cross-sectionalstudyClarify

the

objective

andtype

ofstudySelection

of

study

subjectsDetermine

contents

of

studySamplesize

and

samplingmethod56現(xiàn)況研究的設計與實施Design

and

implementation

of

cross-sectional

study資料的收集資料的整理與分析常見偏倚及其控制研究的優(yōu)點與局限性★

D★

Dataollectionyze★

Bias

and

control★

Advantage

and

limitation57一、明確 目的和類型Clarify

the

objective

and

type

of

study問題，根據(jù)研究明確

目的根據(jù)具體研究目的確定是普查還是抽樣Clarify

theobjective

of

studybasedontheissued

problemSelect

the

survey

methodreferenceto

the

aim,

census

orsampling

survey.二、確定研究對象Selection

of

study

subjects其中一部分某些特殊群體普查

Census某個區(qū)域內的全體居民或Entire

or

part

of

theresidence

in

a

regionCertain

special

groups

ofpeople58二、確定研究對象抽樣明確抽樣研究總體保證樣本代表性Clarify

total

populationof

sampling

studyEnsure

therepresentative

of

sampleSelection

ofStudySubjectsSample

survey59三、確定研究內容

Contents研究內容和指標依據(jù)

目的而定The

contents

and

indicators

of

studyisbased

on

the

objectives.60主要內容包括：Main

contents

included研究的疾?。ɑ蚰承┨卣鳎?-

標準disease（characteristics）—diagnosis

criteria(

）--定義Exposure

（risk

factor）--

definition影響

與疾病關系的因素（混雜因素），如人口學因素等Confounders

suchas

demography

factors61表Questionnaire定義是記錄研究（）內容的原始表格，是收集問題答案的工具（形式）。Definition

An

original

table

for

recording

the

studycontents,

an

instrument

(form)

to

collect

answers

toquestions.62表的一般結構The

Construction

of

Questionnaire標題說明部分填表說明對象的一般情況的主要內容編碼者TitleDemonstrationGeneral

situation

ofsubjectsMaincontentsCodeInvestigator63四、確定樣本量和抽樣方法Determine

the

sample

size

and

sampling

method確定樣本量預期現(xiàn)患率(P)允許誤差（d）顯著性水平（α）Determine

the

sample

sizeExpected

prevalence(

P

)Allowable

error（d）Significance

level（α）計數(shù)資料（現(xiàn)患率）樣本大小估計公式Formulasfor

categorical

data

（prevalence）P

預期的現(xiàn)患率Expected

prevalence，q=1-p，d

容許誤差Allowable

error，z

顯著性檢驗的統(tǒng)計量Parameter

for

Significance

level，n

樣本量Sample

size。65計量資料樣本大小估計公式Formulas

for

Numericaldata66d

2t

2

s2n

n

樣本量Sample

size，d

容許誤差

Allowable

error，S

總體標準差的估計值

Estimated

of

total

standard

deviation抽樣方法Sampling

Method非隨機抽樣-randomsampling隨機抽樣Random

sampling67非隨機抽樣-random

sampling因素，使總體中每選擇樣本時，加入人個 被抽取的機會是不均等的-randomsamples

areselected

by

any

kind

ofprocedure

that

does

not

give

allcases

in

the

population

equalchances

to

fall

into

the

sample.隨機抽樣

Randomsampling總體中每一個對象都有同等機會被選入作為研究對象Every(andin

the population

has

thesameknown-zero)

chance

ofbeing

included

in

the

survey69隨機抽樣

Randomsampling單純隨機抽樣系統(tǒng)抽樣整群抽樣分層抽樣多級抽樣Simple

randomsamplingSystematic

samplingClustering

samplingStratified

samplingMultistagesampling70單純隨機抽樣(簡單隨機抽樣)最簡單、最基本的抽樣方法從總體N個對象中，利用抽簽或其他隨機方法抽取n個總體中每個對象被抽到的概率相等Simple

random

samplingSimplest

and

basic

methodSelect

n

subjects

by

drawing

lotor

byusing

a

table

of

randomnumber

from

population

with

NunitsSame

chance

for

each

subject

inthe

population7174系統(tǒng)抽樣(機械抽樣)Systematic

Sampling將總體各個單位按某種標志排列、連續(xù)編號根據(jù)總體數(shù)N和確定的樣本數(shù)n，計算抽樣距離（N/n）Rank

every

units

by

acharacter

and

numberthem

sequenceDefine

the

size

of

thesample

and

calculatesampling

interval(k

=

N/n)75系統(tǒng)抽樣(機械抽樣)Systematic

sampling用單純隨機方法在第一組中確定一個起始號從此起始點開始，每隔K（K=N/n）個單位抽取一個作為研究對象Draw

a

random

number(

k)

for

startingDraw

every

k

units

fromunit圖3－2 系統(tǒng)抽樣示意圖Fig

3－2 Diagram

of

systematic

sampling76N=100，需抽取n=20N/n=100/20=5從1-5中隨機抽取一個號選中4從第4號開始，每隔4個，抽選一個樣本7778整群抽樣Cluster

SamplingThe

entire

populationofinterest

is

divided

intogroups,

or

clusters,

and

arandom

sample

oftheseclusters

is

selected.單純整群抽樣（Simplecluster

sampling）二階段抽樣（Two

stages

sampling）將總體分成若干群組，抽取其中部分群組作為觀察單位組成樣本Section

4Section

5Section

3Section

2Section

1Example:

Cluster

sampling圖3－3 整群抽樣示意圖Fig

3－3

Diagram

of

cluster

sampling分層抽樣Stratified

Sampling,

stratify

thepopulationinto

several

strata

bycharacter

of

areas,

ages,

etc.then

select

objects

usingrandom

sampling

ineachstrata.將總體單位按某種特征如年齡等分為若干次級（層）然后從每一層內單純隨機抽樣組成一個樣本。80分層抽樣Stratified

Sampling按比例分配（Proportionalallocation）最優(yōu)分配（Optimum

allocation)8182Example:

Stratified

Sampling圖3－4 分層抽樣示意圖Fig

3－3

Diagramof

stratifiedsampling多級抽樣Multistage

sampling將抽樣過程分階段進行，每個階段使用的抽樣方法往往不同，即將以上抽樣方法結合使用，在大型流行病學中常用。Multi-stage

sampling

is

a

kind

of

complex

sampledesign

inwhich

two

or

more

levels

of

units

areimbedded

one

inthe

other.83……84一級抽樣單位Primary

units二級抽樣單位Secondary

units……多級抽樣Multistage

sampling五、資料收集D

ollection收集內容（研究內容）收集方法員培訓ContentsMethodTraining

of

investigator85資料收集方法Method

ofdollection測定或檢查

Lab

detect

or

testInvestigate

subjects（questionnaire）Use

routine

data對研究對象（

表）利用常規(guī)資料86員培訓Training

of

investigator掌握

方法收

料方法和標準一致性保證資料準確性Grasp

method

ofinvestigationAccordance

of

method

andcriteriaof

d

ollectInsurance

the

accuracy

ofdata87資料整理檢查完整性和準確性按標準歸類、核實六、資料的整理與分析Data

sort

and

ysisdata

sortCheck

the integrity

andaccuracyof

dataClassify

and

check

data

bystandard88資料分析

dataysis計算各種率；定量資料可計算平均數(shù)計算標化率分析三間分布與疾病關系Calculate

prevalence，average

for tative

dataCalculate

standardizedprevalenceysis

3

dimensiondistributionAssociation

betweenexposure

and

disease89PlaceTimeCases051015160040020000-4

'5-14

'15-44Age

GrouDescriptive

EpidemiologyWho?Where?When?90605040%

302010050-5455-59

60-64

65-69Male

FemaleCork

and

Kerry

Diabetes

&

Heart

Disease

Study,

199891Prevalence

of

hypertension

by

age

and

sex2DiseaseAndExposure-diseaseandExposure-diseaseand-exposureDiseaseand-exposure與疾病關系Association

between

exposure

and

diseasePopulation

or

Sampling

FrameCensus

or

SamplingSurveySample9394Example:Job

A

(hazardous)100

Workers80

Healthy20

Respiratorysymptoms80

well10

wellJob

B

(hazardous)100

Workers95

Healthy5Respiratorysymptoms95

well15

wellPointX20%(20/100)Point

Y11%(10/90)14%(15/110)Prevalence

rate

of

respiratorysymptoms

in

Job

APrevalence

rate

of

respiratorysymptoms

in

Job

BRatio

of

prevalence

rates,

Job

A/Job

B:5%(5/100)4.00.896Example

of

Cross-Sectional

StudyHypothesis:Obesity

is

a

risk

factor

for

knee

osteoarthritisSample:100

retirees

living

at

“University

Village”97Medical

exam

+

X-rays

to

diagnose

osteoarthritisof

the

kneeOsteoarthritis+-40102030+-Obesity5050Prevalence

of

osteoarthritis

among

obese

subjects:40/50

=

0.8Prevalence

of

osteoarthritis

amongsubjects:20/50

=

0.4Prevalence

ratio

=

0.8/0.4

=

2.0-obese98Obese

subjects

are

two

timesmorelikely

to

have

osteoarthritisof

the

knee

than -obesesubjects.99Cross-Sectional

StudyChicken

or

egg

dilemma

?What

came

ly?

Obesity

or

Osteoarthritis？100常見的偏倚偏倚的控制七、偏倚及其控制Bias

and

controlCommon

type

of

biasControl

of

bias定義Definition從研究設計、實施、到數(shù)據(jù)處理和分析的各個環(huán)節(jié)中產生的系統(tǒng)誤差，以及結果解釋、推論中的片面性，導致研究結果與真實值之間出現(xiàn)傾向性的差異，從而錯誤地描述暴露與疾病之間的聯(lián)系，稱之為偏倚。Bias,is

a

system error

in

design，execution

to

dataysis

of

a

study,

also

including

the

one-sidedness

inexplain

and

inference，which

produces

results

thatareconsistently

distorted

i e

direction

because

ofrandomfactors.第二節(jié)現(xiàn)況研究的設計與實施偏倚

Bias102選擇研究對象Selection

subjects

subjectively任意變換抽樣方法Change

sampling

method

arbitrary對象不合作或因種種原因 參加Subjects

are

not

compliance

or

refuse

to

participate產生原因Reason

for

Result

in

Bias103者到的對象均為幸存者，無法Subjects

are

survival

not

including

death回答 確或回憶不清Not

answer

exactly

recall

clearly偏倚Investigation

bias測量誤差

Measurement

error104確保隨機化原則提高研究對象的依從性和受檢率正確選擇測量工具和檢測方法培訓

員偏倚的控制Control

of

BiasPrinciple

of

randomizationImprove

the

compliance

ofsubjects

and

detect

rateSelect

proper

measuretools

and

test

methodsTraining

investigators105偏倚的控制Control

of

bias做好資料的復查、復核工作正確選擇統(tǒng)計方法，辨析混雜因素Review，check

anddouble

check

dataSelect

statistics

methodcorrectly

and

yzeconfounding

factors106常用抽樣 ，結果有較強推廣意義有來自同一群體的自然形成的同期對照組，結果具有可比性可同時觀察多種因素八、研究的優(yōu)點和局限性Advantage

and

Limitation優(yōu)點AdvantageCommon

sampling

surveywith

strong

extension

resultsWith

a

control

group

fromthe

same

group

over

thesame

period

formednaturallyCan

observe

a

variety

offactors

simultaneously107難以確定先因

的時相關系不能獲得難以資料病例、病、已痊愈的病例局

限性

LimitationDo

not

establishthe

truetemporal

sequence

of

events.Does

not

yield

incidence

ortrue

relative

risk.They

are

not

feasible

forthe

cases

of

death,

recoveryand

short

course.109第三節(jié)研究實例Example目的和研究方法

Purpose

and

method研究對象、樣本量和抽樣方法Study

subject,sample

size

and

sampling

method研究內容和資料收集方法ysisStudyContentsand

of

d

ollection資料整理與分析Data

sorting

and結論conclusion110中國居民2002年營養(yǎng)與健康狀況調查A

descriptio the

Chinese

nationalnutritionand

health

survey

in

2002，等中華流行病學雜志2005年7月第26卷第7期目的掌握我國城鄉(xiāng)及不同地區(qū)居民營養(yǎng)與健康狀況分析影響我國居民營養(yǎng)及健康狀況的主要因素研究方法現(xiàn)況一、目的和研究方法111研究對象城鄉(xiāng)居民樣本量約25萬人抽樣方法多階段分層整群隨機抽樣二、確定研究對象、樣本量和抽樣方法112具體方案我國分成6個不同經濟類型地區(qū)每個地區(qū)的樣本點為22個總樣本點位132個113二、研究對象、樣本量和抽樣方法第一階段：從每一類地區(qū)系統(tǒng)抽樣，抽取22個縣/區(qū)第二階段：從樣本縣/區(qū)隨機抽樣，抽取3各鄉(xiāng)/街道第三階段：從樣本鄉(xiāng)/街道隨機抽樣，抽取2個村/居委會第四階段：從樣本鄉(xiāng)/街道整群抽樣，抽取90戶家庭，家庭所有成員二、確定研究對象、樣本量和抽樣方法114收集方法詢問醫(yī)學體檢檢測膳食三、研究內容和資料的收集方法115及檢測項目（內容）醫(yī)學體檢：詢問

：

家庭及成員基本情況慢

患病史，

行為

等血壓，身高、體重等檢測：血紅蛋白，膽固醇，甘油三酯等膳食

：24小時回顧法，事務頻率法和稱進行膳食116四、資料整理與分析主要結果：2002年中國居民能量食物來源構成（%）合計城市農村能量的食物來源谷類57.948.561.4薯類2.01.42.2豆類2.62.72.6動物性食物12.717.610.8純熱能食物17.219.316.4能量的營養(yǎng)素來源脂肪29.635.027.5蛋白質的食物來源動物性食物25.335.821.31172002年群超重率與肥胖率的地區(qū)、分布%）肥胖率（%）（歲）城市農村＜73.63.43.47～8.53.24.518～26.620.822.6845～37.425.829.015.160～37.219.524.316.06.合計22.615.617.68.24.62002年中國≥18歲人群患病率的地區(qū)、

分布組（歲）城市患病率（%）農村合計18～2.01.01.345～7.83.04.360～13.14.46.8合計4.51.82.6118我國人群營養(yǎng)和健康水平正逐漸發(fā)生變化肥胖，

等慢性疾病流行城市及農村人口營養(yǎng)及健康水平存在差異五、 結論119概

念研究目的

研究類型

優(yōu)點與局限研究實例第四節(jié)生態(tài)學研究Ecological

StudyDefinitionPurposeCategoryAdvantage

and

limitationA

case

study121以群體為觀察和分析單位描述不同人群中某因素的

狀況與疾病的頻率，分析該因素與疾病的關系一、概念

DefinitionUnit

of

observation

andysisis

a

populationrather

than

an

individual.Descript

the

frequency

ofexposure

and

disease

toyze

the

relationshipbetween

them

in

differentpopulation.提供病因線索，產生病因假設評估人群干預措施的效果二、研究目的

Purpose

of

StudyTo

provide

etiological

cluesand

generate

hypotheses

foryticstudiesEvaluate

the

effectofinterventions

amongpopulation生態(tài)比較研究生態(tài)趨勢研究123三、研究類型Ecological

comparison

studyEcological

time

trends

studyTypes

of

study觀察不同人群或地區(qū)某種疾病的分布，根據(jù)疾病分布的差異，提出病因假設生態(tài)比較研究Ecological

comparison

studyTo

observe

the

differencebetween

the

distributions

ofgroupsor

regions,

to

generatedthe

hypothesis

accordingto

the

distribution.12425250200150100500016001400120080

10000600JapanDenmarkFed.

Repub.OfGermanyCanadaIsraelSwitzerlandUSAAustraliaYugoslaviaRomaniaNew

ZealandNorwayFinlandSpainPolandHungaryItalyUKSweden

FranceIncidenceRatio

per

100,000

WomenPer

Capita

Supply

of

Fat

Calories飲食脂肪攝入與發(fā)病126生態(tài)趨勢研究Ecological

trend

studyTo

investigate

the

temporalrelationship

between

the

exposureand

disease

by

observing

andcomparing

the

fluctuations

ofaverage

exposure

level

andfrequency

changes

of

disease

in

apopulation，finding

thefluctuationstrend.連續(xù)觀察不同人群中某因素平均水平的改變和(或)某種疾病、率變化的關系，了解變動趨勢，比較水平變化前后疾病頻率的變化情況，判斷某因素與某疾病的聯(lián)系127Tobacco

Use

in

the

US,

1900-19991000500015002500200045004000350030005000

100Year*Age-adjusted

to

2000

US

standard

population.Source:

Death

rates:

US

Mortality

Public

Use

Tapes,

1960-1999,

US

Mortality

Volumes,1930-1959,

National

Center

for

Health

Statistics,

Centers

for

Disease

Control

andPrevention,

2001.

Cigarette

consumption:

Us

Department

of

Agriculture,

1900-1999.Per

Capita

Cigarette

Consumption2010030504090807060Age-Adjusted

Lung

Cancer

DeathRates*Per

capita

cigarette

consumptionMale

lung

cancer

death

rateFemale

lung

cancer

death

rate經濟，出結果快提供病因未明疾病的病因線索對劑量無法測量的情況，是唯一可供選擇的方法優(yōu)點四、優(yōu)點與局限Quick,

inexpensive,

does

notrequire

time

consuming

datacollectionCan

help

in

formulatinghypothesis

for

the

disease

ofunknown

etiologyThe

only

way

to

theCircumstances

of

individual

dosescan

not

be

measuredStrengths

and

limitationsStrengths適用于研究因素變異范圍小，較難測量暴露與疾病的關系人群干預措施的評價及估計疾病發(fā)展趨勢優(yōu)點四、優(yōu)點與局限Strengths

and

limitationsStrengthsApplies

to

study

the

exposureswith

narrow

range

of

variation,hard

to

measure

the

relationshipbetween

exposure

and

diseaseApplies

to

evaluate

the

effect

ofinterventions

in

population

andestimate

the

disease

trends出現(xiàn)生態(tài)學謬誤難以控制混雜因素存在多重共線性問題難以確定因果聯(lián)系局限性Ecological

fallacyDifficult

to

controlconfoundingMulticollinearity

problemsDifficult

to

determinecausal

relationshipLimitations131生態(tài)學謬誤