Prevalence of Overweight and Obesity and their Relation to Hypertension in Adult Male Population of Fars Province of Iran.
Background: The prevalence of overweight and obesity is increasing in Iran since the last decade. Both are associated with high mortality and morbidity, including cardiovascular disease, diabetes mellitus, degenerative joint disease, gallbladder disease, depression and cancer.
Objectives: To estimate the prevalence of overweight and obesity and their relation to hypertension in adult population of Fars Province.
Subjects and Methods: A total of 401 adult males were included in the study, out of which 372 underwent all required tests. Body weight and height were measured by a scale and a non-stretchable tape respectively. Body mass index was calculated according to World Health Organization (2002) definition. Waist circumference and waist hip ratio were measured in a standing position. Body fat % was measured by Bioelectrical Impedance Analysis. The partial correlation coefficient was used to quantify the association between all anthropometric indicators with hypertension. Linear regression analysis was used to assess the influence of all anthropometric indicators on the variance of systolic and diastolic blood pressure.
Results: The mean body mass index was 26.12kg/m2, waist hip ratio was 0.93.7, waist circumference was 90.10cm and fat percentage was 25.2%. The mean systolic blood pressure was 130.78mmHg and diastolic blood pressure was 79.56mmHg. Eighty seven subjects (23.4%) had systolic blood pressure higher than cut-off value and 39 subjects (10.5%) had diastolic blood pressure higher than cut-off value. Descriptive analysis showed that 30.1% population was overweight and 13.7% were obese. Partial correlation for all the anthropometric indicators (waist- hip ratio, body mass index and % body fat) showed a positive correlation with both systolic blood pressure and diastolic blood pressure. Waist circumference only correlated with systolic blood pressure.
Conclusions: Adult male population of Fars province had a high prevalence of hypertension, overweight and obesity which can be handled through healthy diet and physical exercises.
Key words: Overweight, obesity, adult male population, body mass index, fars province.
The prevalence of overweight and obesity has been on rise in both developed and developing countries in the last decade and Iran is no exception1-3. Both overweight and obesity are directly or indirectly associated with increased mortality and morbidity, including cardiovascular disease, diabetes mellitus, degenerative joint disease, gallbladder disease, depression and cancer4-6.
Body mass index is assigned by the World Health Organization (WHO) as the most useful epidemiological measure of obesity7. Blood pressure increases as body mass index increases and obese people have been found to have a higher prevalence of high blood pressure8,9.
Obesity and hypertension are closely linked, when obesity is central10,11. The evaluation of central adiposity by measuring waist to hip circumference ratio, waist circumference and body fat % is used in the assessment of cardiovascular disease risk factors especially hypertension in the West12.
In Iran during 1998-99, the body mass index values in men were 26.1+-4.1 which raised to 26.7+-4.1kg/m2 during 2001-2002 (p less than 0.001). The prevalence of overweight during the same periods were 42.4% and 46%, and that of obesity were 32.7% and 40.3% respectively. The highest trends in obesity and central fat accumulation were seen in age groups 30 to 40 and 20 to 30 years. Comparison of the 50th percentile of body mass index in all age groups showed a significant increase in 2001-2002 as compared to 1998-1999 (p less than 0.01)13-15.
Studies in Urban Iranian population also showed relationship between different anthropometric indicators and the extent of hypertension. However, there is substantially less information about such relationships among adult male population of Fars province particularly about the relationship between body fat % and hypertension.
This study was done to examine the prevalence of overweight and obesity and their relationship with the risk of hypertension among adult male population of Fars Province.
Subjects and Methods
The population of this study was 401 adult males aged 25 years or above belonging to Fars province. Only 372 completed all required tests and were therefore, included in the analysis. Written informed consent was obtained from all subjects prior to their participation in the study.
All anthropometrical measurements were done with the subjects wearing light underwear and without shoes. Body weight was measured to the nearest 0.5 kg; using digital scale (made in Germany) that was calibrated with a 50 Kg weight in the days that test was done. Height was measured to the nearest 0.5 cm against a wall mounted tape. Body mass index was calculated by dividing the weight in Kilograms by height in meters squared and was classified into four categories according to WHO16. The underweight was defined as a body mass index of fewer than 18.5, normal weight as body mass index of 18.5-24.9, overweight as body mass index of 25-29.9 and obesity as a body mass index [greater than or equal to] of 30.00 kg/m2.
Waist circumference was measured in centimeters at the midpoint between the iliac crest and the rib cage17. Hip circumference was measured at the largest width of the buttocks with the subject in standing position and both feet together18,19. All measurements were taken twice. Both measurements were rounded to the nearest 0.5 cm using a non- stretchable tape without compression of the skin. The mean of the two sets of values was recorded20. Central obesity was also calculated and defined on the basis of waist hip ratio. The cut-off value of central obesity was greater than0.9221. Waist circumference cut off was taken as greater than90. Body fat percent was measured using Bioelectrical Impedance Analysis (made in South Korea body composition analyzer in body 3.0). The cut off body fat percent was 25%14.
Blood pressure was measured on the right arm, using the standard mercury sphygmomanometer. The individual was made to rest in a comfortable seat for at least five minutes before the measurement was taken. Hypertension was defined as a systolic blood pressure greater than140mmHg and a diastolic blood pressure greater than 90mmHg20. BP measurements were done by a physician.
Data were analyzed using SPSS version 11.50. Descriptive statistics for anthropometric characteristics, systolic blood pressure and diastolic blood pressure are shown as mean+-SD. Partial correlation coefficient was used to quantify the association between independent variables (body mass index, waist circumference and waist hip ratio) and dependent variables (systolic blood pressure and diastolic blood pressure). Linear regression analysis was used to assess the influence of different anthropometric indicators on the systolic blood pressure and diastolic blood pressure. All tests for statistical significance were two tailed and the level of significance was selected at p-value less than 0.05.
The study population consisted of 372 adult males. Age distribution showed that 15 were 25-34 years old, 36% were 35-44 years old, 43% were 45-54 years of age, and 6% were 55 years and older.
Anthropometric and blood pressure characteristics of the subjects are shown in Table-1. Using definitions for overweight and obesity; 2.1% subjects were underweight, 54% had normal weight, 30.1% were overweight, and 13.7% were obese. Eighty six subjects (23%) had a higher waist hip ratio and 41 subjects (11%) had a higher waist circumference than the cut-off values. One hundred and two subjects (27.4%) had higher body fat % than the cut-off value. The mean values of body mass index was 26.1kg/m2, waist hip ratio 0.9, waist circumference 90.1cm and body fat % was 25.2%.
The mean systolic blood pressure was 130+-0.78mmHg and the diastolic blood pressure was 79+-0.56 mmHg. Eighty seven subjects (23.4%) had a systolic blood pressure higher than cut-off value and 39 subjects (10.5%) had diastolic blood pressure higher than cut-off value. Partial correlation for anthropometric indicators (waist hip ratio, body mass index and body fat %) showed a positive correlation with both systolic blood pressure and diastolic blood pressure. Positive correlations of waist hip ratio, body mass index, and body fat % with systolic blood pressure were (r=0.685, p less than 0.0001), (r=0.679, p less than 0.0001) and (r=0.699, p less than 0.0001), respectively, and the corresponding values for diastolic blood pressure were (r=0. 223 p less than 0.0001), (r=0. 202 p less than 0.0001) and (r=0. 251 p less than 0.0001) respectively. There was no significant correlation between waist circumference and diastolic blood pressure. However, there was a significant correlation between waist circumference and systolic blood pressure (r=0.621, p less than 0.0001).
The results of the multiple regression analysis showed that waist hip ratio, body fat % and body mass index were significant predictors for systolic and diastolic blood pressure (Table- 2).
Table 1: Baseline characteristics of study population.
H= Height,###W= Weight,###T-W= Target Weight###BMI= Body Mass Index,
WHR = Waist -Hip ratio,###WC = Waist circumference,###BF%= Body fat %###SBP= Systolic blood pressure
DBP=diastolic Blood Pressure
Table 2: Predictors for systolic blood pressure and diastolic blood pressure.
###Systolic Blood Pressure###Diastolic Blood Pressure
Predictor###Beta###SE###p value###Beta###SE###p value
Percent Body Fat###.37###.22###.05###.42###.12###.12
This study showed a high prevalence of overweight, obesity and hypertension in Iranian males with waist hip ratio, body fat %, and body mass index as significant predictors for systolic and diastolic blood pressure.
The importance of body mass index, waist hip ratio, Body fat % and waist circumference has been recognized for estimating cardiovascular disease risk factors, especially due to their positive association with hypertension4-6. According to our knowledge in Iran there is almost no data on the association of body fat % with hypertension.
Many researchers have reported significant positive correlation between body mass index, waist hip ratio, body fat % or waist circumference and the systolic and diastolic blood pressure19. In the present study, results of partial correlation coefficients controlled for all the anthropometric indicators (body mass index, waist hip ratio, body fat % and waist circumference) demonstrated a significant positive correlation with both systolic blood pressure and diastolic blood pressure. Waist circumference was only found as a significant predictor of systolic blood pressure. Results also showed that mean values of all anthropometric factors were significantly higher in hypertensive than in normal subjects. Our findings are similar to those reported by others10,11,22-25.
Other workers have also reported that overweight and obesity are increasing in Iranians due to the progressive increase of BP and overweight and or obesity with age13-15. Another reason is probably due to higher consumption of carbohydrates and fats by Iranians. Added to these is the increased interest of the community in a more westernized diet containing greasy, spicy, salty and low fiber content. Sedentary lifestyle due to a lack of adequate physical activity and infrequent walking coupled with environmental factors (Change in employment structure, transport systems and leisure and recreation activities) have also contributed to the emergence of overweight, obesity and high blood pressure in Iran.
An important finding of this study was that nearly all subjects had a higher body fat % at a lower body mass index indicative of a low muscle mass and a higher fat content due to the lack of adequate physical activity and tendency towards a sedentary lifestyle which, support the hypothesis that the adequate physical activity is negatively associated with body fat %, waist circumference, waist hip ratio, body mass index, and hypertension. It is recommended that healthy lifestyles including balanced diet and physical activity should be adopted to reduce cardiovascular risk factors.
The authors are grateful to Professor Mohmood Vessal for reading an earlier draft of this manuscript. We would like to thank all the subjects who participated in this study.
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Department of Physical Education, Science and Research Branch, Islamic Azad University1, Fars, Department of Physical Education and Sport, College of Education and Psychology, Shiraz University2, Shiraz, Iran., Corresponding Author: Eskandar Rahimi, Department of Physical Education Science and Research Branch, Islamic Azad University Fars, Iran., Email: email@example.com
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|Author:||Rahimi, Eskandar; Cheric, Majid Chahardah|
|Publication:||Pakistan Journal of Medical Research|
|Date:||Sep 30, 2012|
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