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PRABHAKARANTHE NATIONAL MEDICALet al. : CARDIOVASCULARJOURNAL OF INDIA RISK BURDEN VOL. 18, INNO AN. 2 INDIAN, 2005 INDUSTRY 59 Original Articles Cardiovascular risk factor prevalence among men in a large industry of northern India D. PRABHAKARAN, PANKAJ SHAH, VIVEK CHATURVEDI, LAKSHMY RAMAKRISHNAN, AJAY MANHAPRA, K. SRINATH REDDY ABSTRACT metabolic syndrome was present in 28%35% of the individu- Background. Industrial settings, with their intramural re- als depending on the diagnostic criteria used. The prevalence of sources and healthcare infrastructure, are ideal for initiating several risk factors and the metabolic syndrome was high with preventive activities to increase the awareness and control of increasing age, BMI and waist circumference. A third of those cardiovascular diseases (CVD). However, there are no reliable who had hypertension (31.5%) and diabetes (31%) were aware estimates of CVD and risk factor burden, nor of its awareness and of their status. Among those aware, adequate control of blood treatment status in urban Indian industrial settings. We aimed to pressure and blood glucose was present in only 38% of those evaluate the prevalence of CVD and its risk factors, and to assess with hypertension and 31% of those with diabetes, respectively. the status of awareness and control of CVD risk factors among Coronary heart disease was present in 7.3% of the individuals a large industrial population of northern India. while 0.3% had a history of stroke. Methods. We conducted a cross-sectional survey among all Conclusion. This study demonstrates the high prevalence of employees aged 2059 years of a large industry near Delhi CVD and its risk factors against a background of poor awareness (n=2935), to evaluate their cardiovascular risk profileby and control among a comparatively young male population in a employing a structured questionnaire and clinical and biochemi- north Indian industrial setting. cal estimations. The presence of coronary heart disease was Natl Med J India 2005;18:5965 ascertained by evidence of its treatment, Rose angina question- naire and Minnesota coded electrocardiograms. INTRODUCTION Results. The results for 2122 men, in whom complete The cardiovascular disease (CVD) burden of India is expected to information was available, are reported here. The mean age was double in the next two decades, making it the single largest cause 42 years and 90% of the men were below 50 years of age. The of death and the second largest cause of disability by the year prevalence of major CVD risk factors (95% CI) was: hyperten- 2020.1 This will be characterized by an enormous burden of CVD sion 30% (28%32%), diabetes 15% (14%17%), high among urban communities. Further, the prevalence of CVD in serum total cholesterol/HDL ratio (>4.5) 62% (60%64%) rural and semi-urban areas is expected to increase substantially.2,3 and current smoking 36% (34%38%). Forty-seven per cent While the exact aetiology of this predisposition to CVD in Indians of the respondents had at least two of these risk factors. Another is still debated, from a public health point of view it is clear that 44% (95% CI: 42%46%) had pre-hypertension (JNC VII the rapid transition in diet and lifestyles with urbanization has criteria) and 37% (95% CI: 35%39%) had evidence of either contributed to increasing levels of potentially reversible CVD risk impaired fasting glucose or impaired glucose tolerance. Thirty- factors.4 Data from several cross-sectional studies confirm the five per cent (95% CI: 33%37%) of the individuals were high prevalence of risk factors such as smoking, type 2 diabetes, 5–11 overweight (BMI >25 kg/m2) while 43% (95% CI: 40% high blood pressure, dyslipidaemia and obesity in urban Indi- 45%) had central obesity (waist circumference >90 cm). The ans. Despite this high burden, there is poor awareness among Indians, in addition to low detection and control rates.12–18 The Cardiothoracic Sciences Centre, All India Institute of Medical Sciences, reasons for this include low literacy, lack of access to healthcare Ansari Nagar, New Delhi 110029, India and competing priorities such as infectious and nutritional dis- D. PRABHAKARAN, LAKSHMY RAMAKRISHNAN, eases. Given this background and with the expected overall K. SRINATH REDDY Department of Cardiology improvement in literacy and socioeconomic status, it would be Department of Internal Medicine, Mayo Clinic, Rochester, USA useful to study the awareness of CVD risk factors and lifestyle PANKAJ SHAH Division of Endocrinology patterns in industrial settings, where the access to healthcare is Initiative for Cardiovascular Health Research in Developing Countries, usually better than that among the general community. New Delhi, India VIVEK CHATURVEDI Recent research has highlighted the importance of a continuum 19–23 Initiative for Cardiovascular Health Research in Developing Countries, of risk with variables such as blood pressure and glucose. New Delhi, India and Division of Hospital Medicine, Hackley Hospital, There is robust evidence of increased vascular risk even in the Muskegon, Michigan, USA presence of pre-hypertension (or high-normal blood pressure) and AJAY MANHAPRA pre-diabetes (impaired fasting glucose and impaired glucose Correspondence to K. SRINATH REDDY; [email protected] tolerance).24,25 These risk categories have a high rate of progres- © The National Medical Journal of India 2005 18-2oa-final.PMD 59 5/27/05, 10:23 AM 60 THE NATIONAL MEDICAL JOURNAL OF INDIA VOL. 18, NO. 2, 2005 sion to hypertension and type 2 diabetes. They are also compo- centre of these two points was marked. At this point the waist nents of the metabolic syndrome, which confers an almost 2-fold circumference was measured with a fibreglass tape after apply- risk for future diabetes, CVD mortality and morbidity.26,27 How- ing a tension of 600 g (done with the help of a spring balance). ever, detailed data regarding the burden of these risk factors in The measurement was made up to the nearest millimetre. Ad- India are limited. equate care was taken to ensure that the subject was breathing We report the findings of a survey done among the employees normally at the time the measurement was taken. Hip circumfer- of a large organized sector industry located close to Delhi. The ence was measured at the level of the greater trochanters with the main objectives of the study were (i) to study the risk factor and subject standing and breathing normally in a manner similar to treatment status in individuals with respect to CVD, (ii) to that during measurement of the waist circumference. All the estimate the prevalence of risk factors for coronary heart disease measurements were taken without intervening clothes, with the (CHD), both traditional and intermediary, and (iii) to estimate the subject wearing a loose-fitting surgical gown. prevalence of CHD using a history of previously diagnosed An ECG was obtained after the clinical measurements. All disease, Rose angina questionnaire and electrocardiogram (ECG). ECGs were read by a cardiologist and coded using the Minnesota coding system. Ten per cent of randomly selected ECGs were METHODS checked by two different cardiologists for agreement. There was Study design and setting complete agreement between the original and fresh coding. We did a cross-sectional survey of all employees in the 20–59 (Kappa was not estimated in view of the complete agreement.) years’ age group in an organized sector industry, during 1995–98. A total of 2935 employees (344 women and 2591 men) were Laboratory measurements eligible to participate. All potential participants received a letter Blood samples were drawn by trained personnel, centrifuged inviting them to participate in the study. Approval for conducting and stored for later analysis. Laboratory measurements included the study was obtained both from the management and the estimation of fasting blood glucose, 2-hour post-load blood employee representatives. Participation in the study was voluntary glucose (all post-load measurements were made 2 hours after a and all the measurements were carried out in the medical unit 75 g glucose solution was administered orally under supervi- located within the industry. Informed consent was obtained from sion), plasma insulin (both fasting and post-load), total blood each participant. cholesterol, high density lipoprotein (HDL) cholesterol (HDL- C), and triglycerides (both fasting and post-load). Glucose was Study questionnaire analysed by the glucose oxidase method (GOD-PAP), choles- We used a simple structured questionnaire which was adminis- terol by the CHOD-PAP method, and triglycerides were esti- tered by research assistants, who had received training in the mated by the GPOD-PAP method. The intra- and interassay methodology of field-based cardiovascular surveys. The question- coefficient of variation (CV) for glucose was 1.5% and 2%, naire was used to elicit information from each study participant for respectively; for cholesterol and triglycerides these were <2% the following variables: (i) demographic characteristics such as and <2.5%, respectively. HDL-C was estimated by the precipi- age, marital status, profession, education and socioeconomic tation method (phosphotungstate/Mg) and the inter- and intra- status; (ii) lifestyle-related factors such as dietary habits, physical assay CVs were <2.5%. Insulin concentrations were measured activity, tobacco and alcohol consumption; (iii) the health status by radioimmunoassay (Coat-a-Count insulin kit, Diagnostic of the individual and any history related to heart disease, stroke, Products). The intra- and interassay CVs were <5% and <7.5%, hypertension and diabetes. The presence of angina was assessed respectively. using the Rose angina questionnaire. If a person reported the presence of hypertension or diabetes or CVD (defined as the Definition of risk factors presence of CHD or stroke or angina), a detailed questionnaire The definitions used for the categorization of risk levels among the was administered to elicit information on control, awareness, participants are given in Box 1. treatment and limitations due to the illness.