Objective:

Hypertension covers a large portion of burden of diseases, especially in the developing countries. The unequal distribution of hypertension in the population may affect ‘health for all’ goal. This study aimed to investigate the socioeconomic inequality of hypertension in Iran and to identify its influencing factors.

Methods:

We used data from Iran's surveillance system for risk factors of noncommunicable diseases which was conducted on 89 400 individuals aged 15–64 years in 2005. To determine the socioeconomic status of participants, a new variable was created using a principal component analysis. We examined hypertension at different levels of this new variable and calculated slop index of inequality (SII) and concentration index (C) for hypertension. We then applied Oaxaca–Blinder decomposition analysis to determine the causes of inequality.

Results:

The SII and C for hypertension were −32.3 and −0.170, respectively. The concentration indices varied widely between different provinces in Iran and was lower (more unequal) in women than in men. There was significant socioeconomic inequality in hypertension. The results of decomposition indicated that 40.5% of the low-socioeconomic group (n = 18190) and 16.4% of the high-socioeconomic group (n = 16335) had hypertension. Age, education level, sex and residency location were the main associated factors of the difference among groups.

Conclusion:

According to our results, there was an inequality in hypertension in Iran, so that individuals with low socioeconomic status had a higher prevalence of hypertension. Age was the most contributed factor in this inequality and women in low-socioeconomic group were the most vulnerable people for hypertension.