BACKGROUND: Prehypertension has been shown to be an early risk factor of cardiovascular disease (CVD). We investigated the prevalence and pattern of cardiometabolic risk factors in prehypertension in three ethnic Asian populations in Singapore.
METHODS: We examined data from Chinese (n=1177), Malay (n=774), and Indian (n=985) adults aged 40-80 years who participated in three independent population based studies conducted from 2004-2011 in Singapore who were free of diabetes, hypertension and previous CVD. Prehypertension was defined as systolic blood pressure (BP) 120-139 mm Hg or diastolic BP 80-89 mm Hg. Random blood glucose, glycated haemoglobin (HbA1c), body mass index (BMI), triglycerides, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol were examined as indicators of adverse cardiometabolic profile. The association between metabolic variables and prehypertension was examined using logistic regression models adjusting for potential confounders.
RESULTS: The prevalence of prehypertension was 59.8% (Chinese), 68.9% (Malays) and 57.7% Indians. Higher levels of blood glucose, HbA1c and BMI were significantly associated with prehypertension in all three ethnic groups, odds ratio (95% confidence interval) of prehypertension in Chinese, Malays and Indians were: 1.42 (1.10, 1.83), 1.53 (1.05, 2.24), 1.49 (1.13, 1.98) for high-glucose; 3.50 (1.01, 12.18), 3.72 (1.29, 10.75), 2.79 (1.31, 5.94) for high-HbA1c; 1.86 (1.34, 2.56), 2.96 (2.10, 4.18), 1.68 (1.28, 2.20) for high-BMI. In addition, higher levels of LDL cholesterol in Chinese and higher levels of triglycerides were significantly associated with prehypertension. These associations persisted when metabolic variables were analysed as continuous variables.
CONCLUSIONS: Higher levels of blood glucose, HbA1c and BMI were associated with prehypertension in all three ethnic groups in Singapore. Screening for prehypertension and lifestyle modifications could potentially reduce the burden of CVD in otherwise healthy Asian adults living in Singapore.
Few previous studies in Western populations have reported an association between C-reactive protein (CRP) and prehypertension. However, no previous study has examined this association in Asians. We examined individuals who were free of hypertension from two independent population-based studies in Singapore: the Singapore Prospective Study Programme (SP2, n=2843 Chinese, Malay and Indians aged 24 years) and the Singapore Malay Eye Study (SiMES, n=957 Malays, aged 40-80 years). Prehypertension was defined as systolic blood pressure (BP) 120-139 mm Hg or diastolic BP 80-89 mm Hg. CRP was analyzed as categories (<1, 1-3, >3 mg l(-1)). The prevalence of prehypertension increased with increasing categories of CRP in both cohorts (P for trend <0.05 in both cohorts). After adjusting for potential confounders including body mass index (BMI), smoking and diabetes, persons with higher levels of CRP were more likely to have prehypertension in both SP2 (compared with CRP <1 mg l(-1), odds ratio (OR) 1.23, 95% confidence interval (CI) 1.03-1.48 for CRP 1-3 and OR 1.67, 95% CI 1.32-2.10 for >3 mg l(-1)) and SiMES (OR 1.45, 95% CI 1.04-2.01 and OR 1.56, 95% CI 1.07-2.27) respectively. In conclusion, data from two population-based Asian cohorts suggest that elevated serum CRP levels are associated with prehypertension.