Clustering of chronic non-communicable disease risk factors among selected Asian populations: levels and determinants Syed Masud Ahmed1*, Abdullahel Hadi1, Abdur Razzaque2, Ali Ashraf3, Sanjay Juvekar4, Nawi Ng5, Uraiwan Kanungsukkasem6, Kusol Soonthornthada6, Hoang Van Minh7 and Tran Huu Bich8 1WATCH Health and Demographic Surveillance System, Bangladesh 2Matlab Health and Demographic Surveillance System, Bangladesh 3AMK Health and Demographic Surveillance System, Bangladesh 4Vadu Health and Demographic Surveillance System, India 5Purworejo Health and Demographic Surveillance System, Indonesia 6Kanchanaburi Health and Demographic Surveillance System, Thailand 7Filabavi Health and Demographic Surveillance System, Vietnam 8Chililab Health and Demographic Surveillance System, Vietnam Background: The major chronic non-communicable diseases (NCDs) operate through a cluster of common risk factors, whose presence or absence determines not only the occurrence and severity of the disease, but also informs treatment approaches. Primary prevention based on mitigation of these common risk factors through population-based programmes is the most cost-effective approach to contain the emerging epidemic of chronic NCDs. Objectives: This study was conducted to explore the extent of risk factors clustering for the major chronic NCDs and its determinants in nine INDEPTH Health and Demographic Surveillance System (HDSS) sites of five Asian countries. Design: Data originated from a multi-site chronic NCD risk factor prevalence survey conducted in 2005. This cross-sectional survey used a standardised questionnaire developed by the WHO to collect core data on common risk factors such as tobacco use, intake of fruits and vegetables, physical inactivity, blood pressure levels, and body mass index. Respondents included randomly selected sample of adults (25 64 years) living in nine rural HDSS sites in Bangladesh, India, Indonesia, Thailand, and Vietnam. Results: Findings revealed a substantial proportion ( 70%) of these largely rural populations having three or more risk factors for chronic NCDs. Chronic NCD risk factors clustering was associated with increasing age, being male, and higher educational achievements. Differences were noted among the different sites, both between and within country. Conclusions: Since there is an extensive clustering of risk factors for the chronic NCDs in the populations studied, the interventions also need to be based on a comprehensive approach rather than on a single factor to forestall its cumulative effects which occur over time. This can work best if it is integrated within the primary health care system and the HDSS can be an invaluable epidemiological resource in this endeavor. Keywords: chronic NCDs risk factors surveillance clustering INDEPTH Asia WHO STEPS Received: 6 May 2009 Revised: 30 June 2009 Accepted: 16 July 2009 Published: 28 September 2009 Ccancer, hronic non-communicable diseases (NCDs) such as heart disease and stroke, diabetes mellitus, and chronic respiratory diseases account for approximately 60% of total mortality in the world, with around 80% of these deaths occurring in low and middle-income countries (1). According to a recent projection, seven out of every 10 deaths in low-income countries will be from chronic NCDs by 2020 (2), and ��SUPPLEMENTNCD Global Health Action 2009. # 2009 Syed Masud Ahmed et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 68 Citation: Global Health Action Supplement 1, 2009. DOI: 10.3402/gha.v2i0.1986

poses a serious challenge to the developing countries (3). WHO have been advocating policy makers to develop efficient strategies to halt ���tomorrow���s pandemic��� of the chronic NCDs (4, 5). The risk factors underlying the major chronic NCDs are well documented and are relatively few in number (6). These include tobacco and alcohol consumption, unhealthy diet (low in fruits and vegetables and high in salt, fat, and sugar), physical inactivity (sedentary life- style), and raised blood pressure (BP) which may explain 75% of these chronic NCD conditions (2, 7). Evidence shows that the major chronic NCDs operate through a cluster of common risk factors, whose presence or absence determines the occurrence and severity of the disease (8 10). The burden of NCDs is also increasing in South Asia. Almost half of all deaths in Asia are now attributable to NCDs, accounting for 47% of global burden of disease (11). In contrast to conventional wisdom, poverty has been found to be a predictor of chronic NCDs in ���low income��� countries (12, 13) like the ���high income��� countries (14, 15). Evidence is now emerging on linkage of low birth weight to incidence of chronic NCDs in later life (16), intrauterine origin of chronic NCDs (17), and under-nutrition in fetal life giving rise to the development of chronic NCDs in adult life (18). The increased prevalence of NCDs in these countries is linked to the rapid urbanisation and increasing globalisa- tion of the food, tobacco, and alcohol industries (10). There is lack of comprehensive data on NCD risk factors and its clustering in the Asian countries. Some small-scale studies have been done in India in industrial settings (19), in urban slums (20), and in urban, per- urban, and rural areas for specific disease and risk factors (21, 22). Similar studies on risk factors for specific disease/area have also been done in Vietnam (23), Indonesia (24), and Bangladesh (25, 26). However, these studies did not address the risk factors from a generic approach which is essential for designing a comprehensive preventive intervention. This paper aims to fill in this knowledge gap and explore the extent of risk factors clustering for the major chronic NCDs and its determinants in nine Health and Demographic Surveillance System (HDSS) sites of five Asian countries, which are members of the IN- DEPTH Network (please see below). This information will have important policy implications for identifying potential population groups at risk and designing tar- geted cost-effective interventions both at the popula- tion level and at the individual level, in order to reduce burden of chronic NCDs within the shortest possible time. Materials and methods Data source This cross-sectional study used pooled dataset from nine HDSS sites in five Asian countries namely Matlab, Mirsarai, Abhoynagar and WATCH (Bangladesh), Kan- chanaburi (Thailand), Filabavi and Chililab (Vietnam), Vadu (India), and Purworejo (Indonesia). The choice of these HDSS sites (and countries) happens to arise from their affiliation to the INDEPTH, a network of HDSS sites in developing countries (http://www.indepth-netwo rk.org). Its purpose is to monitor population dynamics and to test and evaluate various health interventions to influ- ence policy and practice, and improve population health. All these rural sites are conveniently located in particular geographical areas of the respective countries and as such is not representative of the entire country. However, these provide an indication of the current situation prevailing in these countries. These low (Bangladesh, Vietnam, India) and middle income (Thailand, Indonesia) countries are experiencing different stages of demographic, economic, and epidemiological transitions. Sampling and survey In each site, a sample was drawn following the WHO STEPS methodology (27), which included a minimum of 250 individuals in each 10 years age group (25 64 years) for each sex to a total of 1,000 males and 1,000 females. From the HDSS sampling frame, a stratified random sampling technique was used to draw samples in each age and sex group. In STEP 1, an assessment of chronic NCDs risk factors (such as tobacco and alcohol consumption, physical inactivity, fruit and vegetable intake) was undertaken by questionnaire. Data on core items of selected risk factors were collected through face-to-face interview during household visits by trained interviewers using a pre-tested local version of the WHO STEPS questionnaire. In addition, because of the wide- spread practice of chewing tobacco in most of the HDSS, expanded questions on this item were also included as an option. In STEP 2, weight, height, and BP measurements were taken using standardised instruments and protocols. To ensure uniform and standard method of data collection across sites, the principal investigators initially met and agreed on standard study protocol and data collection instruments and later, training was organised by them at the site levels. BP was measured using digital device (Omron M4-I, Omron Healthcare, Europe BV, Hoofddorp, the Netherlands). BP was measured at the right arm at heart level after a period of 10 minutes of rest. Out of three measurements, the average of the last two readings were used. Raised BP was defined as systolic BP (sbp)]140 mmHg and diastolic BP (dbp)]90 mmHg or under any anti-hypertensive drug medication. Clustering of risk factors in rural Asian INDEPTH HDSS 69