Background: Urban middle-socioeconomic status (SES) subjects have high burden of cardiovascular risk factors in low-income countries. To determine secular trends in risk factors among this population and to correlate risks with educational status we performed epidemiological studies in India.
Methods: Five cross-sectional studies were performed in middle-SES urban locations in Jaipur, India from years 1992 to 2010. Cluster sampling was performed. Subjects (men, women) aged 20-59 years evaluated were 712 (459, 253) in 1992-94, 558 (286, 272) in 1999-2001, 374 (179, 195) in 2002-03, 887 (414, 473) in 2004-05, and 530 (324, 206) in 2009-10. Data were obtained by history, anthropometry, and fasting blood glucose and lipids estimation. Response rates varied from 55 to 75%. Mean values and risk factor prevalence were determined. Secular trends were identified using quadratic and log-linear regression and chi-squared for trend.
Results: Across the studies, there was high prevalence of overweight, hypertension, and lipid abnormalities. Age- and sex-adjusted trends showed significant increases in mean body mass index (BMI), fasting glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides (quadratic and log-linear regression, p < 0.001). Systolic blood pressure (BP) decreased while insignificant changes were observed for waist-hip ratio and low-density lipoprotein (LDL) cholesterol. Categorical trends showed increase in overweight and decrease in smoking (p < 0.05); insignificant changes were observed in truncal obesity, hypertension, hypercholesterolaemia, and diabetes. Adjustment for educational status attenuated linear trends in BMI and total and LDL cholesterol and accentuated trends in systolic BP, glucose, and HDL cholesterol. There was significant association of an increase in education with decline in smoking and an increase in overweight (two-line regression p < 0.05).
Conclusion: In Indian urban middle-SES subjects there is high prevalence of cardiovascular risk factors. Over a 20-year period BMI and overweight increased, smoking and systolic BP decreased, and truncal obesity, hypercholesterolaemia, and diabetes remained stable. Increasing educational status attenuated trends for systolic BP, glucose and HDL cholesterol, and BMI.