专业课课件-流行病描述性研究

描述性研究Descriptive

Study哈尔滨医

学流行病学教研室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概述现况研究现况研究实例生态学研究OutlineCross-sectional

studyA

case

ofcross-sectionalstudyEcological

studyOutline7第一节概述

Outline8ConceptType

and

characteristicsUses概念种类与特点用途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.描述性研究通过描述疾病或健康状况的三间分布情况，获得因素与疾病或健康状况间关系的线索，提出病因假设。描述性研究的概念Concept9现况研究病例报告病例系列分析个案研究历史(常规）资料分析随访研究生态学研究Cross-sectional

studyCasereportCase

series

ysisCasestudyysis

of

historical（routine）dataFollow-up

studyEcological

study描述性研究的种类Type10在某一特定时间，某一定范围的人群中，对某种疾病或健康状况及相关因素的一种方法。A

method

to

survey

thedisease

or

health

status

andrelatedfactors

of

in

a

certainpopulation

at

a

single

pointin

time

or

during

a

specifictimeinterval.现况研究Cross-sectional

Study11是对临

某种罕见病的单个病例或少数病例的详细介绍;包括:人口学特征、症状、体征、、治疗、和随访等。A

detailed

report

of

anunusual

or

noveloccurrence

of

patients

inclinical;including:demographic

profile,symptoms,

signs,diagnosis,

treatment,and

follow-up

et

al.病例报告Case

Report12病例报告Case

Report定性研究的范畴无须描述事物的集中趋势或离散程度为研究者提供分析和决策的线索Quality

StudyNeed

not

describethecentralized

tend

dispersiondegreeProvide

the

clue

forysis

and

decisionmaking1314N

Engl

J

Med

2005;352:2508-14一组相同疾病的临床资料进行整理、统计、分析、总结并得出结论.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一般用来分析某种疾病的临床表现特征，评价预防、治疗措施的效果显示某些病变的自然进程的规律性用来确定开始流行或流行的存在方法为进一步研究提供线索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个案研究（个案）

Case

Study定义：是在发病现场对新发病例的接触史、家属及周围人病及健康状况、及其与发病可能有关的周围环境所进行的。Definition：

in

the

fieldintensively

investigate

thecontacting

history

of

thecases，the

health

anddisease

status

of

the

relativesand s,

and

relatedsurrounding

environment.19目的：探索发病原因和条件病因提供线索为控制疾病提供基础控制

扩散消灭疫源地防止再发生类似疾病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历史（常规）资料分析是登记报告系统或者疾病监测系统，收集既往或当前的疾病或健康状态资料进行分析，描述疾病和健康状态的分布以及变动趋势。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随访研究Follow-up

Study也称纵向研究通过定期随访，观察疾病、健康状况或某卫生事件在一个固定人群中随着时间推移的动态变化情况与现况研究的区别Longitudinal

studyObserve

the

change

ofincidence

of

disease,health

situation

withtime

in

a

fix

populationby

regularly

follow

upDifference

with

cross-sectional

study24随访间隔和方式根据具体的研究内容有所不同可用于疾病自然史的研究，为该疾病的病因研究提供线索还可用于提出或检验某些病因学假设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生态学研究：以群体为基本研究单位收集和描述疾病或健康状态与某些因素的关系。Unit

of

observation

and ysis

isa

population

tocollect

and

descript

disease

or

health

situationand

therelationship

between

them

and

factorsin

differentpopulation.25以观察为主，不对研究对象采取任何干预措施Mainly

depends

on

observation,

no

intervention

to

subjects其

因素的分配不是随机的The

location

of

exposures

are

not

random研究开始时一般不设立对照组No

controlis

set

up特点Features26与结局关系的因果推断无法确定The

causal

relationship

because

exposure

andis

often

impossible

to

work

out为后续研究提供线索Provide

clues

for

further

researche特点

Features27描述性研究的主要用途

Main

uses描述疾病或健康状况的分布及发生发展的规律Describe

the

distribution

and

development

of

disease

and

health获得病因线索，提出病因假设Obtain

the

clues

of

cause

of

disease

and

generate

hypothesis确定高危人群，为卫生政策、防制措施制定提供基础资料Identifyhigh

risk

population，to

provide

basic

data

forformulating

health

strategy

and

measurement28第二节现况研究Cross-sectional

Study概述设计与实施常见偏倚及其控制OutlineDesign

and

implementCommon

bias

and

control29基本概念特点类型与应用Basic

conceptCharacteristicsType

and

applications概述Outline30一、基本概念Conception又称横断面研究也称患病率研究研究特定时点或期间和特定范围内人群中的有关变量(因素)与疾病或健康状况的关系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开始时一般不设对照组特定时间或时期确定因果联系时受到限制对不会发生改变的

因素，可以可以作因果推断二、特点CharacteristicsNo

control

groupParticular

point

of

timeLimit

to

ensure

the

causalrelationshipTo

inference

causalrelationship

for

the

exposuresthat

won’t

be

changed34用现在的

（特征）来替代或估计过去情况是有条件的It

need some

conditions

to

use

current

exposures

(features)to

replace

or

estimate

the

exposure

situation

in

past定期重复进行可获得

资料Incidence

data

may

been

obtain

by

regularlyrepeatcross-sectional

studies二、特点Characteristics3536研究类型普查抽样三、类型与应用

Types

andUsesTypeCensusSample

survey普查的定义Definition

of

census普查的目的Purpose

of

census普查的优缺点Advantage

and

limitation

of

census普

查

Census37普查的定义Definition

of

census指为了了解某病的患病率或健康状况，在特定时间或时期内，对特定范围的人群中每一成员进行的Survey

ea或检查。ember

in

a

givenpopulationin

a

given

timeor

timeperiod

in

order

toknow

the

prevalence

or

health

status.38很短：甚至是某一时点，一般为1～2天、1～2周或1～2个月，最长不宜超过3个月。Very

short

time

period：even

in

asnapshot,1-3days

ingeneral,

1～2

weeks

or

1～2months,

nolonger

than

3

months.特定时间

Specify

time特定范围

Specify

range范围：指某一地区或具有某一特征的人群例如：儿童（≤14岁）的体格普查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早期发现疾病并及时给予治疗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长发育情况等Understandthe

health

level

of

population

or

the

growthand

development,4142普查的目的Purpose

of

census建立某些生理指标正常值：如血脂等；Set

up

the

cutoff

value

of

some

physiology在疾病爆发或流行时，可借助于普查来搜寻全部病例，也可用于了解该病流行的全貌。Find

the

total

cases

for

outbreak

or

epidemicofdisease

and

understandthe

whole

epidemic

situation43普查的优点和局限性Advantage

and

limitation优点Advantage研究对象易于确定

Easy

to

decidestudy

subjects能发现普查人群中的全部病例并给予及时的治疗Can

find

all

the

cases

in

the

population

and

providetreatment优点Advantage能提供疾病分布情况和流行因素或病因线索Can

describe

the

distribution

of

diseases,factorsorclues

related

epidemic能普及医学卫生知识。Can

spread

the

knowledge

of

Health一次

可观察多个因素和疾病的关系，May

investigation

the

association

between

more

factorsand

a

disease44局限性limitations所获资料比较粗，准确性较差Datais

crude

and

lowaccuracy不适于患病率低和检查方法复杂的疾病Notsuitable

for

disease

with

low

prevalenceandneedcomplex

method

to

exam人群范围比较大，

时费时、费人力、费用大Huge

population,

time,

labor

andmoney

consuming45局限性limitations对象多、时限短，难免漏诊、误诊，且无应答率较高May

existed

miss

diagnosis

andmisdiagnosis

andlowresponse

rate due

to

large

number

of

subjects普查的质量不易控制Difficult

to

control

the

quality一次普查只能获得现患率，不能得到Ca ly

obtain

prevalence

but

not

incidence

for

once

census46抽样

的定义Definition抽样

的优点和局限性Advantage

and

limitation抽样Sample

Survey47抽样Sample

survey对特定时间、特定范围内人群的一

性样本的

，以样本人群的

结果来推论其所在总体的情况。Survey

on

a

representative

sample

of

a

definedpopulation

in

a

specified

time,

use

the

results

ofsample

to

infer

the

situation

to

total

population.48抽样

的优点和局限性Advantage

and

limitation优点Advantage1.样本小，

省时、省力、成本低；2.Small

sample，

time，labor

and

costsaving工作易做得精细Accurate

and

details

ofresults3.因而质量易得到保证，获得结果快，而且应答率较高。Quality

insure，quick

result

and

high

responserate49局限性Limitations研究不适用于那些

过低疾病的Not

suitable

for

low

incidence

disease不适用于那些变异过大的资料的Not

suitablefor

dataof

high

variant设计、实施比较复杂，资料分析也有一定难Complexdesign

and

difficult

indata

ysis5051局限性Limitations存在抽样误差和偏倚Sampling

error

and

bias重复和遗漏不容易发现Not

easy

to

find

the

repeated

and

missed

subjects该方法不能满足普查普治的工作要求Could

not

satisfied

the

requirement

of

census

and

treatmentfor

all现况

的应用

Uses用于描述疾病或与健康有关事件的分布Describe

the

distribution

of

disease

and

health

related

events可用于研究影响疾病与健康的相关因素Study

the

factorsthat

effect

the

diseases

andhealth制订医疗、预防措施提供科学依据

Provide

basisforFormulate

measures

of

medicine

and

prevention考核、评价预防措施的效果Evaluate

the

effect

of

medicine

and

prevention

measurement52衡量一个国家或地区医疗卫生水平及健康状况Measure

the

level

health

work

and

heathsituation用于卫生标准的检验Test

the

health

criteria用于检查和衡量信息、资料的质量Check

the

quality

of

information

andd

ensus）现况

的应用

Uses53The

census

of

the

lifetime

alcohol

drinking

statusin

America

population54明确

目的和类型确定研究对象确定研究内容确定样本量和抽样方法现况研究的设计与实施Design

and

implementation

of

cross-sectionalstudyClarify

the

objective

andtype

ofstudySelection

of

study

subjectsDetermine

contents

of

studySamplesize

and

samplingmethod56现况研究的设计与实施Design

and

implementation

of

cross-sectional

study资料的收集资料的整理与分析常见偏倚及其控制研究的优点与局限性★

D★

Dataollectionyze★

Bias

and

control★

Advantage

and

limitation57一、明确 目的和类型Clarify

the

objective

and

type

of

study问题，根据研究明确

目的根据具体研究目的确定是普查还是抽样Clarify

theobjective

of

studybasedontheissued

problemSelect

the

survey

methodreferenceto

the

aim,

census

orsampling

survey.二、确定研究对象Selection

of

study

subjects其中一部分某些特殊群体普查

Census某个区域内的全体居民或Entire

or

part

of

theresidence

in

a

regionCertain

special

groups

ofpeople58二、确定研究对象抽样明确抽样研究总体保证样本代表性Clarify

total

populationof

sampling

studyEnsure

therepresentative

of

sampleSelection

ofStudySubjectsSample

survey59三、确定研究内容

Contents研究内容和指标依据

目的而定The

contents

and

indicators

of

studyisbased

on

the

objectives.60主要内容包括：Main

contents

included研究的疾病（或某些特征）--

标准disease（characteristics）—diagnosis

criteria(

）--定义Exposure

（risk

factor）--

definition影响

与疾病关系的因素（混杂因素），如人口学因素等Confounders

suchas

demography

factors61表Questionnaire定义是记录研究（）内容的原始表格，是收集问题答案的工具（形式）。Definition

An

original

table

for

recording

the

studycontents,

an

instrument

(form)

to

collect

answers

toquestions.62表的一般结构The

Construction

of

Questionnaire标题说明部分填表说明对象的一般情况的主要内容编码者TitleDemonstrationGeneral

situation

ofsubjectsMaincontentsCodeInvestigator63四、确定样本量和抽样方法Determine

the

sample

size

and

sampling

method确定样本量预期现患率(P)允许误差（d）显著性水平（α）Determine

the

sample

sizeExpected

prevalence(

P

)Allowable

error（d）Significance

level（α）计数资料（现患率）样本大小估计公式Formulasfor

categorical

data

（prevalence）P

预期的现患率Expected

prevalence，q=1-p，d

容许误差Allowable

error，z

显著性检验的统计量Parameter

for

Significance

level，n

样本量Sample

size。65计量资料样本大小估计公式Formulas

for

Numericaldata66d

2t

2

s2n

n

样本量Sample

size，d

容许误差

Allowable

error，S

总体标准差的估计值

Estimated

of

total

standard

deviation抽样方法Sampling

Method非随机抽样-randomsampling随机抽样Random

sampling67非随机抽样-random

sampling因素，使总体中每选择样本时，加入人个 被抽取的机会是不均等的-randomsamples

areselected

by

any

kind

ofprocedure

that

does

not

give

allcases

in

the

population

equalchances

to

fall

into

the

sample.随机抽样

Randomsampling总体中每一个对象都有同等机会被选入作为研究对象Every(andin

the population

has

thesameknown-zero)

chance

ofbeing

included

in

the

survey69随机抽样

Randomsampling单纯随机抽样系统抽样整群抽样分层抽样多级抽样Simple

randomsamplingSystematic

samplingClustering

samplingStratified

samplingMultistagesampling70单纯随机抽样(简单随机抽样)最简单、最基本的抽样方法从总体N个对象中，利用抽签或其他随机方法抽取n个总体中每个对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系统抽样(机械抽样)Systematic

Sampling将总体各个单位按某种标志排列、连续编号根据总体数N和确定的样本数n，计算抽样距离（N/n）Rank

every

units

by

acharacter

and

numberthem

sequenceDefine

the

size

of

thesample

and

calculatesampling

interval(k

=

N/n)75系统抽样(机械抽样)Systematic

sampling用单纯随机方法在第一组中确定一个起始号从此起始点开始，每隔K（K=N/n）个单位抽取一个作为研究对象Draw

a

random

number(

k)

for

startingDraw

every

k

units

fromunit图3－2 系统抽样示意图Fig

3－2 Diagram

of

systematic

sampling76N=100，需抽取n=20N/n=100/20=5从1-5中随机抽取一个号选中4从第4号开始，每隔4个，抽选一个样本7778整群抽样Cluster

SamplingThe

entire

populationofinterest

is

divided

intogroups,

or

clusters,

and

arandom

sample

oftheseclusters

is

selected.单纯整群抽样（Simplecluster

sampling）二阶段抽样（Two

stages

sampling）将总体分成若干群组，抽取其中部分群组作为观察单位组成样本Section

4Section

5Section

3Section

2Section

1Example:

Cluster

sampling图3－3 整群抽样示意图Fig

3－3

Diagram

of

cluster

sampling分层抽样Stratified

Sampling,

stratify

thepopulationinto

several

strata

bycharacter

of

areas,

ages,

etc.then

select

objects

usingrandom

sampling

ineachstrata.将总体单位按某种特征如年龄等分为若干次级（层）然后从每一层内单纯随机抽样组成一个样本。80分层抽样Stratified

Sampling按比例分配（Proportionalallocation）最优分配（Optimum

allocation)8182Example:

Stratified

Sampling图3－4 分层抽样示意图Fig

3－3

Diagramof

stratifiedsampling多级抽样Multistage

sampling将抽样过程分阶段进行，每个阶段使用的抽样方法往往不同，即将以上抽样方法结合使用，在大型流行病学中常用。Multi-stage

sampling

is

a

kind

of

complex

sampledesign

inwhich

two

or

more

levels

of

units

areimbedded

one

inthe

other.83……84一级抽样单位Primary

units二级抽样单位Secondary

units……多级抽样Multistage

sampling五、资料收集D

ollection收集内容（研究内容）收集方法员培训ContentsMethodTraining

of

investigator85资料收集方法Method

ofdollection测定或检查

Lab

detect

or

testInvestigate

subjects（questionnaire）Use

routine

data对研究对象（

表）利用常规资料86员培训Training

of

investigator掌握

方法收

料方法和标准一致性保证资料准确性Grasp

method

ofinvestigationAccordance

of

method

andcriteriaof

d

ollectInsurance

the

accuracy

ofdata87资料整理检查完整性和准确性按标准归类、核实六、资料的整理与分析Data

sort

and

ysisdata

sortCheck

the integrity

andaccuracyof

dataClassify

and

check

data

bystandard88资料分析

dataysis计算各种率；定量资料可计算平均数计算标化率分析三间分布与疾病关系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与疾病关系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常见的偏倚偏倚的控制七、偏倚及其控制Bias

and

controlCommon

type

of

biasControl

of

bias定义Definition从研究设计、实施、到数据处理和分析的各个环节中产生的系统误差，以及结果解释、推论中的片面性，导致研究结果与真实值之间出现倾向性的差异，从而错误地描述暴露与疾病之间的联系，称之为偏倚。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.第二节现况研究的设计与实施偏倚

Bias102选择研究对象Selection

subjects

subjectively任意变换抽样方法Change

sampling

method

arbitrary对象不合作或因种种原因 参加Subjects

are

not

compliance

or

refuse

to

participate产生原因Reason

for

Result

in

Bias103者到的对象均为幸存者，无法Subjects

are

survival

not

including

death回答 确或回忆不清Not

answer

exactly

recall

clearly偏倚Investigation

bias测量误差

Measurement

error104确保随机化原则提高研究对象的依从性和受检率正确选择测量工具和检测方法培训

员偏倚的控制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做好资料的复查、复核工作正确选择统计方法，辨析混杂因素Review，check

anddouble

check

dataSelect

statistics

methodcorrectly

and

yzeconfounding

factors106常用抽样 ，结果有较强推广意义有来自同一群体的自然形成的同期对照组，结果具有可比性可同时观察多种因素八、研究的优点和局限性Advantage

and

Limitation优点AdvantageCommon

sampling

surveywith

strong

extension

resultsWith

a

control

group

fromthe

same

group

over

thesame

period

formednaturallyCan

observe

a

variety

offactors

simultaneously107难以确定先因

的时相关系不能获得难以资料病例、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第三节研究实例Example目的和研究方法

Purpose

and

method研究对象、样本量和抽样方法Study

subject,sample

size

and

sampling

method研究内容和资料收集方法ysisStudyContentsand

of

d

ollection资料整理与分析Data

sorting

and结论conclusion110中国居民2002年营养与健康状况调查A

descriptio the

Chinese

nationalnutritionand

health

survey

in

2002，等中华流行病学杂志2005年7月第26卷第7期目的掌握我国城乡及不同地区居民营养与健康状况分析影响我国居民营养及健康状况的主要因素研究方法现况一、目的和研究方法111研究对象城乡居民样本量约25万人抽样方法多阶段分层整群随机抽样二、确定研究对象、样本量和抽样方法112具体方案我国分成6个不同经济类型地区每个地区的样本点为22个总样本点位132个113二、研究对象、样本量和抽样方法第一阶段：从每一类地区系统抽样，抽取22个县/区第二阶段：从样本县/区随机抽样，抽取3各乡/街道第三阶段：从样本乡/街道随机抽样，抽取2个村/居委会第四阶段：从样本乡/街道整群抽样，抽取90户家庭，家庭所有成员二、确定研究对象、样本量和抽样方法114收集方法询问医学体检检测膳食三、研究内容和资料的收集方法115及检测项目（内容）医学体检：询问

：

家庭及成员基本情况慢

患病史，

行为

等血压，身高、体重等检测：血红蛋白，胆固醇，甘油三酯等膳食

：24小时回顾法，事务频率法和称进行膳食116四、资料整理与分析主要结果：2002年中国居民能量食物来源构成（%）合计城市农村能量的食物来源谷类57.948.561.4薯类2.01.42.2豆类2.62.72.6动物性食物12.717.610.8纯热能食物17.219.316.4能量的营养素来源脂肪29.635.027.5蛋白质的食物来源动物性食物25.335.821.31172002年群超重率与肥胖率的地区、分布%）肥胖率（%）（岁）城市农村＜73.63.43.47～8.53.24.518～26.620.822.6845～37.425.829.015.160～37.219.524.316.06.合计22.615.617.68.24.62002年中国≥18岁人群患病率的地区、

分布组（岁）城市患病率（%）农村合计18～2.01.01.345～7.83.04.360～13.14.46.8合计4.51.82.6118我国人群营养和健康水平正逐渐发生变化肥胖，

等慢性疾病流行城市及农村人口营养及健康水平存在差异五、 结论119概

念研究目的

研究类型

优点与局限研究实例第四节生态学研究Ecological

StudyDefinitionPurposeCategoryAdvantage

and

limitationA

case

study121以群体为观察和分析单位描述不同人群中某因素的

状况与疾病的频率，分析该因素与疾病的关系一、概念

DefinitionUnit

of

observation

andysisis

a

populationrather

than

an

individual.Descript

the

frequency

ofexposure

and

disease

toyze

the

relationshipbetween

them

in

differentpopulation.提供病因线索，产生病因假设评估人群干预措施的效果二、研究目的

Purpose

of

StudyTo

provide

etiological

cluesand

generate

hypotheses

foryticstudiesEvaluate

the

effectofinterventions

amongpopulation生态比较研究生态趋势研究123三、研究类型Ecological

comparison

studyEcological

time

trends

studyTypes

of

study观察不同人群或地区某种疾病的分布，根据疾病分布的差异，提出病因假设生态比较研究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饮食脂肪摄入与发病126生态趋势研究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.连续观察不同人群中某因素平均水平的改变和(或)某种疾病、率变化的关系，了解变动趋势，比较水平变化前后疾病频率的变化情况，判断某因素与某疾病的联系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经济，出结果快提供病因未明疾病的病因线索对剂量无法测量的情况，是唯一可供选择的方法优点四、优点与局限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适用于研究因素变异范围小，较难测量暴露与疾病的关系人群干预措施的评价及估计疾病发展趋势优点四、优点与局限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出现生态学谬误难以控制混杂因素存在多重共线性问题难以确定因果联系局限性Ecological

fallacyDifficult

to

controlconfoundingMulticollinearity

problemsDifficult

to

determinecausal

relationshipLimitations131生态学谬误