Secular trends in cholesterol lipoproteins and triglycerides and prevalence of dyslipidemias in an urban Indian population

BACKGROUND: Coronary heart disease is increasing in urban Indian subjects and lipid abnormalities are important risk factors. To determine secular trends in prevalence of various lipid abnormalities we performed studies in an urban Indian population. METHODS: Successive epidemiological Jaipur Heart Watch (JHW) studies were performed in Western India in urban locations. The studies evaluated adults ≥ 20 years for multiple coronary risk factors using standardized methodology (JHW-1, 1993–94, n = 2212; JHW-2, 1999–2001, n = 1123; JHW-3, 2002–03, n = 458, and JHW-4 2004–2005, n = 1127). For the present analyses data of subjects 20–59 years (n = 4136, men 2341, women 1795) have been included. In successive studies, fasting measurements for cholesterol lipoproteins (total cholesterol, LDL cholesterol, HDL cholesterol) and triglycerides were performed in 193, 454, 179 and 252 men (n = 1078) and 83, 472, 195, 248 women (n = 998) respectively (total 2076). Age-group specific levels of various cholesterol lipoproteins, triglycerides and their ratios were determined. Prevalence of various dyslipidemias (total cholesterol ≥ 200 mg/dl, LDL cholesterol ≥ 130 mg/dl, non-HDL cholesterol ≥ 160 mg/dl, triglycerides ≥ 150 mg/dl, low HDL cholesterol <40 mg/dl, high cholesterol remnants ≥ 25 mg/dl, and high total:HDL cholesterol ratio ≥ 5.0, and ≥ 4.0 were also determined. Significance of secular trends in prevalence of dyslipidemias was determined using linear-curve estimation regression. Association of changing trends in prevalence of dyslipidemias with trends in educational status, obesity and truncal obesity (high waist:hip ratio) were determined using two-line regression analysis. RESULTS: Mean levels of various lipoproteins increased sharply from JHW-1 to JHW-2 and then gradually in JHW-3 and JHW-4. Age-adjusted mean values (mg/dl) in JHW-1, JHW-2, JHW-3 and JHW-4 studies respectively showed a significant increase in total cholesterol (174.9 ± 45, 196.0 ± 42, 187.5 ± 38, 193.5 ± 39, 2-stage least-squares regression R = 0.11, p < 0.001), LDL cholesterol (106.2 ± 40, 127.6 ± 39, 122.6 ± 44, 119.2 ± 31, R = 0.11, p < 0.001), non-HDL cholesterol (131.3 ± 43, 156.4 ± 43, 150.1 ± 41, 150.9 ± 32, R = 0.12, p < 0.001), remnant cholesterol (25.1 ± 11, 28.9 ± 14, 26.0 ± 11, 31.7 ± 14, R = 0.06, p = 0.001), total:HDL cholesterol ratio (4.26 ± 1.3, 5.18 ± 1.7, 5.21 ± 1.7, 4.69 ± 1.2, R = 0.10, p < 0.001) and triglycerides (125.6 ± 53, 144.5 ± 71, 130.1 ± 57, 158.7 ± 72, R = 0.06, p = 0.001) and decrease in HDL cholesterol (43.6 ± 14, 39.7 ± 8, 37.3 ± 6, 42.5 ± 6, R = 0.04, p = 0.027). Trends in age-adjusted prevalence (%) of dyslipidemias in JHW-1, JHW-2, JHW-3 and JHW-4 studies respectively showed insignificant changes in high total cholesterol (26.3, 35.1, 25.6, 26.0, linear curve-estimation coefficient multiple R = 0.034), high LDL cholesterol ≥ 130 mg/dl (24.2, 36.2, 31.0, 22.2, R = 0.062), and high low HDL cholesterol < 40 mg/dl (46.2, 53.3, 55.4, 33.7, R = 0.136). Increase was observed in prevalence of high non-HDL cholesterol (23.0, 33.5, 27.4, 26.6, R = 0.026), high remnant cholesterol (40.1, 40.3, 30.1, 60.6, R = 0.143), high total:HDL cholesterol ratio ≥ 5.0 (22.2, 47.6, 53.2, 26.3, R = 0.031) and ≥ 4.0 (58.6, 72.5, 70.1, 62.0, R = 0.006), and high triglycerides (25.7, 28.2, 17.5, 34.2, R = 0.047). Greater correlation of increasing non-HDL cholesterol, remnant cholesterol, triglycerides and total:HDL cholesterol ratio was observed with increasing truncal obesity than generalized obesity (two-line regression analysis p < 0.05). Greater educational level, as marker of socioeconomic status, correlated significantly with increasing obesity (r(2 )men 0.98, women 0.99), and truncal obesity (r(2 )men 0.71, women 0.90). CONCLUSION: In an urban Indian population, trends reveal increase in mean total-, non-HDL-, remnant-, and total:HDL cholesterol, and triglycerides and decline in HDL cholesterol levels. Prevalence of subjects with high total cholesterol did not change significantly while those with high non-HDL cholesterol, cholesterol remnants, triglycerides and total-HDL cholesterol ratio increased. Increasing dyslipidemias correlate significantly with increasing truncal obesity and obesity.