RISK FACTOR SURVEILLANCE FOR CORONARY HEART DISEASE IN SOFIA, BULGARIA Lidia Mladenova Georgieva Doctor of philosophy 2001 CONTENTS Declaration of originality and word length ……………………………………………14 Acknowledgements…………………………………………………………..…………..15 List of relevant publications and presentations…………………………………..…….16 Summary………………………………………………………………………………….18 SECTION I – INTRODUCTION AND METHODS 1. CHAPTER - INTRODUCTION...............................................................................19 1.1 EPIDEMIOLOGY OF CARDIOVASCULAR DISEASES ...................................................19 1.1.1 Definitions of terms..........................................................................................19 1.1.2 Brief history of epidemiological investigation of IHD and stroke risk factors21 1.1.3 Current stage of knowledge about risk factors for cardiovascular disease and measuring problems.....................................................................................................22 1.1.3.1 Blood pressure..........................................................................................22 1.1.3.2 Cholesterol ...............................................................................................27 1.1.3.3 Anthropometrical measurements .............................................................31 1.1.3.4 Smoking ...................................................................................................31 1.1.3.5 Alcohol.....................................................................................................34 1.1.3.6 Physical activity.......................................................................................38 1.1.3.7 Diet...........................................................................................................39 1.1.3.8 New and candidate risk factors for CVD.................................................43 1.2 THEORY AND PRACTICE OF RISK FACTOR SURVEILLANCE FOR VASCULAR DISEASES 43 1.2.1 International experience in risk factor surveillance........................................43 1.2.1.1 WHO MONICA.......................................................................................43 1.2.1.2 The Health Survey for England ...............................................................45 1.2.1.3 The Dietary and Nutritional Survey of British Adults.............................46 1.2.1.4 USA the first National Health and Nutrition Examination Survey..........47 1.2.1.5 Risk Factor Prevalence Study in Australia ..............................................47 1.3 VASCULAR DISEASES IN BULGARIA.......................................................................48 1.3.1 Background ......................................................................................................48 1.3.2 Demographic and mortality trends in Bulgaria...............................................49 1.3.3 Mortality trends for chronic diseases in Bulgaria...........................................54 1.3.4 Current knowledge about risk factors for cardiovascular diseases in Bulgaria 59 1.3.4.1 Primary data sources ................................................................................59 1.3.4.2 Summary of findings................................................................................64 1.3.5 Shortcomings in available risk factor evidence for Bulgaria ..........................68 1.3.5.1 Study populations.....................................................................................68 1.3.5.2 Data collection.........................................................................................68 1.3.5.3 Interpretation of results ............................................................................69 1.3.6 How Sofia differs from the rest of Bulgaria.....................................................69 1.4 NEED FOR CARDIOVASCULAR RISK FACTOR SURVEILLANCE IN BULGARIA ...........70 1.5 THE AIMS OF THE THESIS .......................................................................................73 2. CHAPTER - METHODS ..........................................................................................75 2.1 STUDY DESIGN AND IMPLEMENTATION: ISSUES AND CHOICES ...............................75 2.1.1 Origin, funding and organization of parent study ...........................................75 2.1.1.1 Original ideas planned .............................................................................75 2.1.1.2 Further refinement of proposal ................................................................76 2.1.1.3 Management structure of SHS .................................................................77 2.1.2 Statistical power and sample size ....................................................................78 2.1.3 Selection of target population..........................................................................79 2.1.3.1 Definition of target population.................................................................79 2.1.3.2 Selection of administrative districts (obstinae)........................................80 2.1.3.3 Sampling of subjects ................................................................................82 2.1.4 Ethical clearance .............................................................................................83 2.2 MANAGEMENT OF PRIMARY DATA COLLECTION....................................................83 2.2.1 Selection and staffing of survey centers...........................................................83 2.2.1.1 Training staff............................................................................................84 2.2.2 Recruitment ......................................................................................................85 2.2.2.1 Arranging appointments...........................................................................85 2.2.3 Subject flow within survey centers...................................................................86 2.3 MEASUREMENTS ...................................................................................................88 2.3.1 Height and weight measurements ....................................................................88 2.3.1.1 Height.......................................................................................................88 2.3.1.2 Weight......................................................................................................88 2.3.2 Measurement of waist and hip circumferences................................................88 2.3.2.1 Quality control of physical measurements...............................................89 2.3.3 Blood pressure measurements .........................................................................89 2.3.3.1 Quality control of blood pressure measurement ......................................90 2.3.4 Blood sample collection...................................................................................93 2.3.4.1 Quality control of blood analyses ............................................................94 2.4 QUESTIONNAIRE....................................................................................................98 2.4.1 Overall structure..............................................................................................98 2.4.2 The recording process......................................................................................98 2.4.3 The food frequency questionnaire....................................................................99 2.4.4 Alcohol ...........................................................................................................100 2.4.5 The smoking behavior questionnaire .............................................................100 2.4.6 Physical activity .............................................................................................100 2.4.7 Quality control of the interview .....................................................................101 2.5 DATA ANALYSES AND PRESENTATION .................................................................101 2.5.1 Data entry and editing ...................................................................................101 2.5.2 Data presentation...........................................................................................101 2.5.3 Standardisation ..............................................................................................102 2.5.4 Data analyses.................................................................................................103 2.5.4.1 Social-demographic variables................................................................103 2.5.4.2 Alcohol...................................................................................................104 2.5.4.3 Smoking .................................................................................................105 2.5.4.4 Physical activity.....................................................................................106 SECTION II – RESULTS 3. CHAPTER: STUDY POPULATION.....................................................................107 3.1 RECRUITMENT.....................................................................................................107 3.2 PARTICIPATION BY AGE AND SEX ........................................................................109 3.3 MARITAL STATUS................................................................................................109 3.4 SOCIO-ECONOMIC CHARACTERISTICS ..................................................................111