Determinants of urban–rural differences in cardiovascular risk factors in middle-aged women in India: A cross-sectional study

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Abstract

Objectives

Cardiovascular diseases (CVD) are the most important cause of death amongst middle-aged Indian women. To determine prevalence of CVD risk factors and their determinants we performed a nationwide study.

Methods

Population based studies amongst women 35–70 years were performed in four urban and five rural locations in India. Location based stratified sampling was performed and we enrolled 4624 (rural 2616, urban 2008) of eligible 8000 women (58%). Demographic details, medical history, diet, physical activity and anthropometry were recorded using standardised techniques. Blood haemoglobin, glucose and total cholesterol were determined. Risk factors were diagnosed using current guidelines. Descriptive statistics are reported. Stepwise multivariate logistic regression was performed to identify determinants of urban–rural differences.

Results

In urban women mean body mass index (BMI), waist circumference, waist–hip ratio (WHR), systolic BP, haemoglobin, fasting glucose and cholesterol were significantly greater (p < 0.01). Age-adjusted prevalence of risk factors (%) in urban vs rural was of obesity BMI  25 kg/m2 (45.6 vs 22.5), truncal obesity WHR > 0.9 (44.3 vs 13.0), hypertension (37.5 vs 29.3), hypercholesterolemia  200 mg/dl (27.7 vs 13.5), and diabetes (15.1 vs 4.3) greater whilst any tobacco use (19.6 vs 41.6) or smoking lower. Significant determinants of urban–rural differences were greater income and literacy, dietary fats, low physical activity, obesity and truncal obesity (p < 0.01).

Conclusions

Greater prevalence of CVD risk factors in urban middle-aged women is explained by greater income and literacy, dietary fat, low physical activity and obesity.

Introduction

Cardiovascular diseases (CVD) are the number one cause of death in women in economically developed countries and coronary heart disease (CHD) is the most important [1], [2]. This is due to high prevalence of multiple cardiovascular risk factors — smoking, diabetes, hypertension and dyslipidemia [3]. Million Death Study in India reported that CVD is the most important cause of death in women [4]. In an analysis of causes of death in about 1.1 million homes and 113,000 subjects in all regions of the country using a validated verbal autopsy instrument it was reported that 16.9% of all deaths in women resulted from cardiovascular diseases. In the middle age (25–69 years) proportionate mortality from CVD was 22.5% in women as compared to 26.3% in men. This would translate into more than a million women dying prematurely from CVD in India. The reasons for high cardiovascular disease in women are similar to men and include standard risk factors — hypertension, diabetes, dyslipidemias and smoking [3], [5]. The INTERHEART study reported that major risk factors – smoking, lipid abnormalities, hypertension, diabetes, obesity, low physical activity, low fruit and vegetable intake and psychosocial stresses – explained more than 90% of incident myocardial infarctions in South Asians [6]. These risk factors were equally important in women [7].

In India, no prospective study has determined cardiovascular risk factor and incident disease association. The prevalence of CVD risk factors in the whole country has not been studied using a common protocol. Large national health surveys in India (e.g., National Family Health Surveys 2 and 3) [8], [9] have not focused on cardiovascular risk factors. Regional CVD risk factor epidemiological studies amongst men and women have reported lower prevalence of CVD risk factors in rural as compared to urban populations [5], [10]. Highly variable prevalence rates of CVD risk factors in different regions of the country have been reported [11], [12], [13], [14]. Most of these studies have reported similar male–female prevalence of hypertension [11], diabetes [12], and dyslipidemias [13]. Smoking prevalence is lower in women [14]whilst metabolic syndrome is more [15]. Determinants of these risk factors have not been adequately studied as sample size of women in these studies was small [10], [16]. To determine prevalence of multiple cardiovascular risk factors amongst middle-aged women in India and to identify regional differences and to assess socioeconomic and lifestyle determinants we performed a multisite epidemiological study.

Section snippets

Methods

A multisite study was initiated by investigators from different regions of the country and funding obtained from the Science and Society Division, Department of Science and Technology, Government of India, New Delhi. A central institutional review board approved the study and ethical clearance was obtained from each study site. Sites participating in the study included institutions in northern (Haryana), central (Jaipur), western (Pune), eastern (Kolkata), and southern (Kochi, Gandhigram)

Results

A total of 4624 women aged 35–70 years were evaluated at different sites, more from rural areas (n = 2616) than urban (n = 2008) of the targeted 8000 (response 57.8%). The age-adjusted mean values of various anthropometric, dietary and biochemical variables in urban and rural women and the overall population are shown in Table 1. All the physical variables (height, weight, waist, hip, MUAC, calf), BMI and WHR are more in urban women as compared to the rural (p < 0.001). Dietary calorie intake is more

Discussion

This study shows high prevalence of multiple cardiovascular risk factors in middle-aged women in India. The prevalence of obesity, truncal obesity, hypertension, hypercholesterolemia, impaired fasting glucose and diabetes is significantly greater in urban women as compared to the rural. This is associated with greater income and literacy, greater consumption of fats and lower physical activity in urban women. Worldwide women are known to have high prevalence of CVD and metabolic CVD risk

Acknowledgement

This work was supported by ad-hoc research grants from Science and Society Division, Department of Science and Technology, Government of India, New Delhi to all the participating centres. The contribution of study coordinators and research workers in data collection and management is gratefully acknowledged.

The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology.

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    Authors' contributions: RMP conceptualised and designed the study, obtained funding, trained the investigators, supervised data collection and management, performed the statistical analyses, and provided critical comments to the manuscript. RG was involved in study conceptualisation, funding, data collection and statistical analyses and wrote the first draft of the manuscript. AM was involved in study conceptualisation, funding, statistical analyses and jointly wrote the first draft of the manuscript. PM was involved in study conceptualisation, funding, data collection and management and provided critical inputs for manuscript. VS was involved in training of investigators, supervision of the study and data collection. SJ, SR, VUM, NK, KPVD and KR were all involved in study design, obtaining funding, supervision of data collection and management, and provided critical comments to the manuscript. AA was involved in the data collection, data management, performed the initial statistical analyses and provided critical comments to the manuscript. VS was involved in study conceptualisation, funding and study supervision. The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology.

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