The metabolic syndrome is an important risk factors for diabetes type 2 and cardiovascular diseases, thus the clinical implication of diagnosis of MS is identification of patients who needs aggressive life style modification [21–23].
The results of this study showed that the prevalence of metabolic syndrome is high in studied population and it increases with increment of age and BMI significantly. The prevalence of MS was 22.8% (15.9% in men 29.4% in women) with significant difference. Smoking, ethnicity, level of education, family history of diabetes, hypertension and obesity, marital status, and parity and history of GDM in women had no effects on prevalence of MS.
The prevalence of MS in this study is similar to studies in Zanjan 23%  and Zahedan 21%  but lower than some other studies in Iran. MS was detected in 32% of population in Yazd  and about 30% in Tehran [13, 14]. One reason for these differences may be heterogeneity of studied population. In this study, only about 31% of the population was in age group higher than 50 years, but in Yazd  study more than 50% of population was in this high risk age group. Given the increasing prevalence of metabolic syndrome with increasing age, this can be one reason for lower prevalence of MS in our study. Genetic factors, race, nutrition and physical activity can also have an impact on the prevalence of MS. Differences in prevalence of metabolic syndrome in communities are because of differences in prevalence of each component of MS. For example, diabetes prevalence in this study was 15.3% but it was 25.7% in Tehran  study.
Prevalence of low HDL in our study was 40.2%, but in Tehran study it was 63% , in Yazd  35% in men and 64% in women and in Zanjan  93% in women and 63% in men.
Genetic factors are important in the incidence of low HDL. Existence of specific genes in addition to nutrition and physical activity and smoking can have effect on the prevalence of low HDL [26–30]. The prevalence of MS has been reported in other parts of the world with different diagnostic criteria. In a study in USA 34.5% of people had MS based on ATPIII 2002 criteria .
In DECODE study that was conducted in 9 European countries, MS was detected in 32% of men and 28.5% of women . High prevalence of MS was reported in recent studies in Estonia 25.9% , Norway 25.9% , Turkey 28/8%  and luxamburg 24/7% .
In a recent study in Korea  MS was seen in 6.4% of adolescences and 22.3% of adults.
Many factors including: age, race, weight, menopause in women, smoking, low income economies, high carbohydrate intake, no alcohol consumption, low physical activity , consumption of soft drink , antipsychotic drugs , poor cardiovascular fitness  and Genetic factors may play a role in metabolic syndrome.
A parental history of metabolic syndrome increases the risk, and genetic factors may account for as much as 50% of the variable in level of metabolic syndrome traits in offspring [33–36]. In most studies (2, 8.12) increasing age was the key factor affecting the prevalence of metabolic syndrome and it also showed in our study. Increasing in BMI was correlate with increasing prevalence of MS in this study. This is in agreement with other studies . There is controversy about the relation between sex and MS in different studies. In this study, prevalence of metabolic syndrome was significantly higher in women than men. This is in agreement with other studies (2, 8, 14, 37). But in some studies, the prevalence of MS in men is more than women . That’s may be become of reduction of physical activity in Iranian women than may cause higher rate of abdominal obesity and low HDL. Genetic, cultural, physical activity and nutritional differences can be the cause of controversies. This association was seen in some other studies [39, 40]. In this study, smoking, ethnicity (Arabs and Persians) and marital status and education does not affect the rate of metabolic syndrome. Smoking more than 20 cigarettes per day has been associated with increased risk of metabolic syndrome in some studies [41, 42].
Strengths of this study are that it is a population based study in an urban population of Iran, extensive information of confounders and a relatively large sample size. One limitation was that, this study was cross sectional that does not allow us to draw any causal interference. Therefore in the future large prospective studies should be used to confirm the association between above mentioned factors and metabolic syndrome.