Hypertension is the most important and prevalent chronic disorders which still remains a major health concern despite medical progresses. Given prevalence of this disease and its serious subsequent complications, the current study aimed to investigate known factors as risk factors for hypertension and the way of their association in study population of the Cohort in south of Iran at 2019.
Number of adults with hypertension in Iran reaches 9 million and 700 thousands individuals at 2015, which more than 5 million and 200 thousands were man and more than 4 million and 500 thousands were woman. Number of individuals with HTN in Iran has been reached more than 9.7 million at 2015 from 4 million individuals (2 million and 100 thousands men and one million and 900 thousands women), which the majority of this increase is a result of increase in population of Iran and increase in life expectancy an aging of the Iranian society.
Prevalence of HTN varies in various studies, which in part could be attributed to time difference of studies and regional and ethnical differences. However, very different numbers can also be result of mistake or bias. As an example, in the sugar and lipid study of Tehran, prevalence of HTN in old ages was reported about 47% , and or in the study by Sharifi, it was reported as 60% .
However, there are studies which estimates this amount as 25% , this value in The current study is 42% based on JNC-8. Results of the cohort studies as our study commonly respond better and more accurate for prevalence studies, since they are not affected by bias.
Regarding factors effective in blood pressure, the most association was observed with blood pressure in univariate associations, BMI, BUN, diabetes, cigarette use, and breastfeeding duration.
The study by Rao et al (2012) in India showed that prevalence of elevated blood pressure in Bambaei is about 43%, and the most important factors associated the HTN in their study was odl ages over 40 years, male gender, being diabetic, BMI greater than 25, and a family history of HTN .
The study by Fawokan et al (2018) which investigated factors effective on blood pressure in pediatrics as a systematic review, factors such as gender, being overweight, economic and social status, educational level of parents, being stable, using tobacco and alcohol, and finally dietary regimen were among the factors effective in increase of susceptibility to HTN .
The study by Anteneh et al (2015) investigated factors effective in HTN in Ethiopia. In this study, prevalence rate was reported as 25.1%, and age, tobacco use, physical activity, diabetes history, salt intake and BMI were introduced as the most important factors related to HTN .
The study by Patra & Bhise (2018) also investigated factors related to HTN in India population and reported general prevalence of HTN about 25%. This study reports factors associated with the disease as age, gender, marital status, habitat, Socioeconomic status, unhealthy behaviors such as tobacco and alcohol and higher BMI [21–22]. Results of our study investigated more variables comparing to most studies which were done in the environment similar to the region we performed the study.
Numerous biochemical and nutritional indices were entered in the study, and for the first time comparing to similar studies, all the medications related to HTN which might affect blood pressure status were investigated (potency of decrease and increase of blood pressure as the side effect) and were entered in the multi-variate analysis to attenuate their effects on blood pressure. Regarding analysis of blood pressure, in order to achieve more accurate results and in order to control the effect of high and low pressure on the results in some groups, regression analysis was used, and as the results show, some of the findings are fully consistent with findings of similar studies. For example, BMI and/or waist circumference which are indices of obesity, almost played critical role in most gender and blood pressure groups, and were considered as significant risk factor for blood pressure.
Of course it should not be neglected that waist circumference in previous similar studies was not used, and index of abdominal obesity which waist circumference is a representative of it was neglected in other studies, while in our study, for SBP and DBP in women, after modification for many known variables, waist circumference showed strong association with HTN. As stated in the other studies that diabetes is considered as a risk factor for HTN, blood sugar showed a strong association with HTN in our study.
Alkaline phosphatase (ALP) considered as an index of hepatic function showed a considerable association with HTN specially SBP which is also pointed in a few studies to date. Regarding variables related to dietary regimen, as expected, and almost all the studies had consensus on it, sodium is associated with HTN, however, interesting point in our study was weak association of it rather than other variables.
While opposite to our expectation, calcium and potassium pointed as anti-HTN factors in many studies, and considered as the components of DASH diet (Dietary Approaches to Stop Hypertension) [23–24], were blood pressure elevator in our study which there is a need to more investigation to better clarify the underlying reason another component of DASH diet.
Another component of DASH diet which is considered as a decreasing factor of HTN is magnesium which in our study showed to be preventive factor which is fully consistent with the findings of other studies [25–26].
Another considerable point in our study was breastfeeding duration in women which is a risk factor for susceptibility to HTN, approximately opposite to other studies which introduce breastfeeding as a preventive factor for HTN . Our study our study showed that breastfeeding duration can increase risk of HTN.
However, the study by Struebe et al (2011) pointed to this tip but they explained the underlying cause so that in 12% of mothers who reported this increase in blood pressure, breastfeeding duration was lesser than the expected one, and they recommended that thorough breastfeeding might prevent this elevation in blood pressure .
This is the point should be considered in further studies, however, average breastfeeding duration in our study was considerable comparing to other studies 86.4 ± 58.8 months, which the reason for this considerable and different finding might be due to the long duration of breastfeeding, which we know that it can cause considerable health risks for mother due to mother’s reservoir loss.