Title Health, Cardiovascular Disease and Their Determinants in the Kazakh Population
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Title Health, cardiovascular disease and their determinants in the Kazakh population Adil Supiyev Thesis submitted for the degree of Doctor of Philosophy Research Department of Epidemiology and Public Health Institute of Epidemiology and Health Care University College London London 2018 1 2 Declaration Declaration I, Adil Supiyev, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated and properly referenced in the thesis. Date: 26.11.2018 Signature: Name: Adil Supiyev 3 Abstract Abstract Background: The high and fluctuating mortality and rising health inequalities in post-Soviet countries have attracted considerable attention, but there are very few individual-level data on distribution of health outcomes in Central Asian countries of the former Soviet Union, including Kazakhstan. The main causes of death driving the low life expectancy (some 12 years shorter than in Western Europe) are chronic non-communicable diseases, particularly cardiovascular diseases (CVD). Aim: The main aim of the thesis was to investigate the levels and distribution of risk factors of CVD and the associations between a range of risk factors and CVD in Kazakhstan. Methods: This thesis describes a population-based cross-sectional survey and a case-control study of acute coronary syndrome (ACS) and stroke in the Astana (Kazakhstan capital city) region. The cross-sectional survey examined 977 men and women aged 50-74 years (493 in Astana city and 484 in a rural area) randomly selected from primary care registers. Subjects in the cross- sectional survey served as controls for 348 cases of acute coronary syndrome (ACS) and 235 cases of stroke hospitalised during the study period in two hospitals covering over 80% of acute admissions for these two conditions in the Astana region. The examination of both sets of cases followed identical protocol, including a structured questionnaire, objective examination and collection of blood samples. Results: The cross-sectional survey found high prevalence of cardio- metabolic risk factors and differences in the prevalence of risk factors by socioeconomic and demographic characteristics, including less favourable pattern in urban vs. rural residents. The case-control study identified 4 Abstract associations between ACS and stroke and cardio-metabolic risk factors, health behaviours and socioeconomic factors. A consistent finding was a less favourable risk profile in the Russian vs. Kazakh ethnicity. Conclusions: The prevalence of cardio-metabolic risk factors in the Kazakh population is high compared to Western Europe. The associations of ACS and stroke with risk factors were as expected, and there were some specific associations with socio-demographic characteristics. The pronounced socio- demographic differences in prevalence of cardio-metabolic risk factors suggest that preventive strategies may target population groups at higher risk of CVD. 5 Impact statement Impact Statement The most important impact of this research is that it provides the first individual-level evidence on cardiovascular diseases (CVD) in Central Asia obtained using internationally comparable methodology. CVD are the main cause of persistently low life expectancy in the region and investigation of the rates and causes of CVD in the region is of a paramount importance, and this is the first step in the consideration of effective prevention strategy. So far, data on CVD and other non-communicable diseases available from international agencies were based on routine data, and information on risk factors was derived from uncertain sources or external extrapolation. The information presented in this thesis will be important for governmental officials and policy makers. The second implication is on the general perception of CVD diseases within Central Asian countries. At present, CVD are deemed to be the domain of clinicians while public health professionals have not been involved in CVD control. The thesis presents convincing evidence that socio-demographic factors play a major role as determinants of CVD risk and need to be taken into account. With the emergence of evidence-based medicine and evidence- based public health, these locally specific data from Kazakhstan will provide a major impetus at the country and regional level to consider evidence in clinical and preventive deliberations. The third implication is related to the fact that in the present study many participants were unaware of their CVD risk status. Therefore all types of screening programs, including opportunistic screening, are likely to be 6 Impact statement effective in identifying CVD risk factors, such as raised blood pressure, abnormal blood lipids and blood glucose. In such cases, timely and sustained lifestyle interventions are likely to reduce the risk of CVD events, such as ACS and stroke, and hence will significantly reduce premature morbidity, mortality and disability. The CVD risk (and risk factors) can also improve clinical decisions related to the preventive interventions, such as improving coverage of statin therapy among adults with high risk of future CVD event. Therefore, comprehensive strategies that consider a full range of CVD determinants both at population-level and high-risk individual levels would be the most effective. Finally, this research will have an impact on academia and research. Epidemiology of non-communicable diseases has not been well developed in Kazakhstan and Central Asia. Traditionally, has epidemiology focused on communicable diseases and public health was concerned with industrial hygiene. As a result, non-communicable diseases in the region have been largely neglected. This population-based study provides an example that it is possible and affordable to conduct a high quality epidemiological study of a non-communicable disease in Central Asian settings. It is expected that this will provide a motivation to improve academic teaching and training in research methods, introduce modern methods in teaching and training curricula, and eventually lead to an expansion of academic research into non- communicable diseases in Kazakhstan and in the wider region. 7 Acknowledgements Acknowledgements Firstly, I would like to express my sincere gratitude to my primary supervisor, Professor Martin Bobak and co-supervisors, Dr Anne Peasey and Professor Zhaxybay Zhumadilov. I was very lucky to meet and work with such extraordinary scientists, who have generously shared their knowledge and experience with me all these years and who were extremely patient and supportive in all my undertakings. I would like specifically thank Professor Richard Suzman and Professor Michael Marmot, who helped me at the very beginning of my research aspirations and acquainted me with Professor Martin Bobak. I am very grateful to my UCL colleagues Dr Denes Stefler and Dr Milagros Ruiz for their support. I am especially thankful to the researchers of the Centre for life sciences, National Laboratory Astana at Nazarbayev University, specifically Dr. Alibek Kossumov and Professor Talgat Nurgozhin, who have been very supportive during the Astana Health Study implementation. I would also like to thank administrative, medical and laboratory staff of Republican diagnostic centre, Astana hospital #1 and #2, Polyclinic of Tselinograd region, located in Akmol village, who have contributed their time and energy to the data collection. I would like to acknowledge Talap scholarship awarded to me by the Nazarbayev University to pursuit my PhD programme at University College London. To my father, my mother and my sister – thank you very much for your love, constant support and guidance throughout my life. Finally, my beloved wife, Anara, your patience and encouragement that led me to the completion of the PhD programme. 8 Thesis output Thesis outputs Published articles 1) Supiyev A, Kossumov A, Utepova L, Nurgozhin T, Zhumadilov Z, Bobak M: Prevalence, awareness, treatment and control of arterial hypertension in Astana, Kazakhstan. A cross-sectional study. Public Health 2015, 129(7):948- 953. 2) Supiyev A, Kossumov A, Kassenova A, Nurgozhin T, Zhumadilov Z, Peasey A, Bobak M: Diabetes prevalence, awareness and treatment and their correlates in older persons in urban and rural population in the Astana region, Kazakhstan. Diabetes Research and Clinical Practice 2016, 112:6-12. 3) Supiyev A, Nurgozhin T, Zhumadilov Z, Peasey A, Hubacek JA, Bobak M: Prevalence, awareness, treatment and control of dyslipidemia in older persons in urban and rural population in the Astana region, Kazakhstan. BMC Public Health 2017, 17. Supplementary articles 1) Supiyev A, Nurgozhin T, Zhumadilov Z, Sharman A, Marmot M, Bobak M: Levels and distribution of self-rated health in the Kazakh population: results from the Kazakhstan household health survey 2012. BMC Public Health 2014, 14. 2) Hubacek JA, Stanek V, Gebauerova M, Adamkova V, Lesauskaite V, Zaliaduonyte-Peksiene D, Tamosiunas A, Supiyev A, Kossumov A, Zhumadilova A et al: Traditional Risk Factors of Acute Coronary Syndrome in Four Different Male Populations - Total Cholesterol Value Does Not Seem To Be Relevant Risk Factor. Physiological Research 2017, 66:S121-S128. 9 Table of contents Table of contents page TITLE ..................................................................................................................... 1 DECLARATION .................................................................................................... 3 ABSTRACT ..........................................................................................................