Introduction: There are numerous correlations between hypertension and the metabolic syndrome, although this is not always the case. The objective of this study was to compare the prevalence of the metabolic syndrome and its different phenotypes among hypertensive and normotensive subjects. Materials and Methods: This cross-sectional study was performed on a representative sample of adults living in 3 cities in Iran. Among the 12,514 subjects selected by multi-stage random sampling, 1736 (13.9%) were hypertensive. The prevalence of the metabolic syndrome [according to the Adult Treatment Panel (ATP) III criteria] was significantly higher in hypertensive than normotensive subjects (51.6% versus 12.9%, respectively; OR, 7.15; 95% CI, 6.4 to 7.9). The metabolic syndrome was more prevalent in normotensive and hypertensive subjects living in urban areas than those living in rural areas (14.2% and 53.9% versus 9.5% and 45.6%, respectively, P <0.05). The mean age of hypertensive subjects, with or without the metabolic syndrome, was not significantly different (55.7 ± 12 years versus 55.4 ± 15.5 years, P = 0.6). Hypertension with the metabolic syndrome was more prevalent in women than men (72% versus 28% respectively, P <0.000), and in subjects living in urban areas than those in rural areas (75.1% versus 24.9%, respectively, P = 0.002). Conclusion: The findings of this study indicate the need for metabolic screening in all hypertensive patients, and emphasise the importance of promoting primary and secondary prevention of high blood pressure and associated modifiable risk factors in order to counter the upcoming epidemic of non-communicable disease in developing countries.
The metabolic syndrome (MS) is characterised by a clustering of metabolic risk factors and an insulin-resistant state.1 Its prevalence is high in Western, as well as Asian, populations.2-4 There are numerous correlations between the MS and hypertension, although this is not always the case.5 Resistance to insulin-mediated glucose disposal and compensatory hyperinsulinaemia are common in patients with hypertension. However, not all hypertensive patients have insulin resistance. Several mechanisms appear to be involved in the link between hypertension and insulin resistance, involving the sympathetic nervous system,6,7 renal handling of sodium,8 and vasoconstrictor hormones.9,10As Reaven et al11 concluded in their review, the accumulated findings support the possibility that metabolic changes play a part in the regulation of blood pressure, although some contradictions remain. Some epidemiologic studies have shown a direct association between blood pressure and insulin resistance,12-14 but the findings of other studies do not confirm this.15-17 Some studies have shown that hypertension is associated with the MS in 50% of patients.11 Different studies have shown ethnic differences in the relationship between hypertension and insulin resistance syndrome.18-22 Some studies have found different associations between blood pressure and insulin in the same ethnic group living in different areas.13,14,23
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