Is prehypertension a risk factors for cardiovascular diseases among Iranian women?

Background: Numerous studies have reported prehypertension (pre-HTN) as a risk factor for the cardiovascular diseases as hypertension (HTN). Aim : The present study aimed to evaluate the effects of pre-HTN on cardiovascular incidences among the females of Isfahan cohort study (ICS). Materials and Methods: Healthy female at baseline were followed for a median of 6.7 years. They were divided into 3 groups of normal blood pressure, pre-HTN (120/80 < BP < 139/89 mmHg) and HTN (BP > 140/90 mmHg) based on their baseline measurements. The endpoints were ischemic heart disease (IHD), stroke, CVD (combination of IHD and stroke) and mortality. Results: Normal BP, pre-HTN and HTN were observed in 1073 (33%), 1185 (36%), and 994 (31%) participants, respectively. One hundred and ninety-eight subjects developed CVDs and 110 died. In the HTN group, the hazard ratio [HRs (95% confidence interval)] adjusted for age and other risk factors were 3.44 (1.95-6.09) for IHD (P value < 0.001), 1.28 (0.59-2.77) for stroke (P value = 0.536) 4.89 (1.37-17.45) for CVD mortality (P value < 0.001) and 1.70 (0.98-2.96) for all cause mortality (P value = 0.060). Although, pre-HTN significantly increased the risk of IHD incidence in the crude model (HR 2.21, 95% CI 1.23-3.97) and after adjustments for age (HR 1.85, 95% CI 1.02-3.33), (P value < 0.001) the association did not remain statistically significant after including other risk factors in the model. Conclusion: Hypertension ( HTN) to be a strong risk factor for CVD and IHD. However, in contrast to previous researches, pre-HTN was not found to be a risk factor for CVD, IHD or death independent to other risk factors in women.