Incident hypertension and its predictors: the Isfahan Cohort Study

The present study aimed to investigate the incidence and predictors of hypertension in an Iranian adult population.

Isfahan Cohort Study was a longitudinal population-based study that was conducted on adults aged 35 years or older, living in urban and rural areas of three districts in central Iran. After 7 years of follow-up, 3283 participants were re-evaluated using a standard protocol similar to the baseline. At both measurements, participants underwent medical interview, physical examination, and fasting blood measurements. Participants (n = 833) with prevalent hypertension were excluded from the analysis, resulting in a sample size of 2450.

The participants' age was 47.3 ± 9.4 years (mean ± SD) and 50.7% were men. During the follow-up period, 542 (22.1%) individuals developed hypertension, 49.6% of whom were aware of their disease, 42.4% were treated, but only 24.9% were controlled. Incidence rates have shown no sex-specific difference across age and blood pressure (BP) categories. Multivariate-adjusted model controlled for all study covariates showed that age, male sex, general and central obesity, hypertriglyceridemia, impaired fasting glucose, diabetes mellitus, baseline BP at least 120/80  mmHg (nonoptimal BP), and parental history of hypertension independently contributed to the development of hypertension. Higher education level and more than 10% decrease in waist circumference over 7-year follow-up represented protective effects. In men, weight loss decreased and weight gain increased the risk of developing hypertension. Nonoptimal BP along with central obesity and hypertriglyceridemia together were responsible for 71% of the burden of hypertension.

Our findings imply that there are other factors in addition to nonoptimal BP that deserve integrating into the risk assessment criteria for developing hypertension.