Abstract
Objectives
The main aim of this study is to determine the central obesity trends during the period from 2006 to 2010 among 15-65 years old people in Northern Iran.
Methods
This was a population-based cross-sectional study conducted on 6466 subjects who had been chosen by a multi stage cluster random sampling within five steps. The subjects were randomly chosen from 325 clusters and each cluster included 20 cases. Central obesity was defined as waist circumference ³102 cm and ³88 cm in men and women, respectively.
Results
Compared to 2010, the mean waist circumference in 2006 changed from 87.2 cm to 88.1 cm in men (p=0.237), and from 90.3 cm to 88.6 cm in women (p=0.045). The comparison between 2006 and 2010 revealed that the prevalence of central obesity slightly decreased, 6.8% and 2.4% in urban women and men, respectively. Generally, the mean of waist circumference significantly decreased in urban women (by 0.069 cm in each year; p=0.020); however, the decrease of waist circumference in urban men was not significant (0.006 cm decrease each year; p=0.915).
Conclusion
The prevalence of central obesity declined among both males and females in the urban area; however, there was an attenuated increasing trend in the rural area. The disparity of trends between the two regions should be considered for further study.
Keywords: Central obesity, Waist circumference, Trend, Adult, Iran
Introduction
Obesity, general and abdominal, is one of the greatest public health challenges for the current century with particularly alarming trends in several parts of the world.1 In 2005, the estimated total number of worldwide obese and overweight adults were 396 million and 937 million, respectively.1 The numbers have doubled from 20 years ago.2 There are various risk factors which cause weight gain and obesity in humans. The metabolic factors such as leptin, and lifestyle such as low physical activity, have a significant effect on overweight and obesity.3 The World Health Organization (WHO) reported that obesity is increasing in the world,4 and it is also an established health problem in Iran5
The prevalence of overweight and obesity in Iran was common among 42.8% of men and in 57% of women in 2005,6 and these figures are predicted to reach 54% and 74% by 2015, respectively.7 Studies have shown that abdominal obesity is prevalent between 9.7-12.9% and 54.5-63.7% in Iranian men and women, respectively,6,8 and it is a major health problem in northern Iran.9,10 Using waist circumference (WC) for central obesity classification,11,12 WC has been known to be a risk factor for cardiovascular disease, stroke and type 2 diabetes.13,14 This study was conducted in the Golestan province (northern Iran and south east of Caspian the Sea), where agriculture is the main occupation in the rural area, which is home to 1,600,000 people.15
Central obesity is a major health problem in Iran, yet no study has been performed to examine its trends in northern Iran. Thereby, the present study was conducted over five years (2006-2010) to assess the trends of central obesity in northern Iran.
Methods
This was a population-based cross-sectional study conducted on 6,466 subjects aged between 15 and 65 years, who were chosen by a multi stage random cluster sampling within five steps (2006 = 2471; 2007 = 999; 2008 = 1000; 2009 = 997; and 2010 = 999 cases), from 11 districts of the Golestan province (northern Iran). The subjects were randomly chosen from 325 clusters and each cluster included 20 cases. Family code of primary health center in rural areas and postal code in urban areas were used for classification, with equal proportion of age and sex. A trained group completed the questionnaires containing demographic factors and measured the waist circumferences.
SPSS 16.0 software was used for statistical data analysis. One-way analysis of variance (ANOVA) and Cochran’s test were used to compare the groups and statistical significance was defined as p<0.05. Waist circumference was measured to the nearest 0.5 cm at the superior border of the iliac crest, and central obesity was defined based on WHO criteria: waist circumference ³102 cm and ³88 cm in men and women, respectively.16
Results
For the most part, the mean and standard deviation of age was 39.2±14.6 years. In this study, 50.3% of the study participants were males and 47.9% were females. While, 41.7% of the study participants lived in urban areas and 58.3% lived in rural areas, (Table 1). In the urban area; the mean WC significantly decreased by 0.069 cm each year amongst the urban females (p=0.020); however, there was no significant decrease in WC amongst males (0.006 cm decrease each year; p=0.915). On the other hand; in the rural areas, WC increased by 0.036 cm each year in males (p=0.075), but there was a decrease in WC by 0.034 cm each year in females (p=0.190). However, the change in WC in the rural area was not significant.
Table 1. Distribution of baseline characteristics of gender and location in the five years study. N(%).
| Year | Men | Women | ||||
|---|---|---|---|---|---|---|
| No. | Urban | Rural | No. | Urban | Rural | |
| 2006 | 1250 | 582(46.6) | 668(53.4) | 1221 | 567(46.4) | 654(53.6) |
| 2007 | 500 | 230(46.0) | 270(54.0) | 499 | 230(46.1) | 269(53.9) |
| 2008 | 500 | 180(36.0) | 320(64.0) | 500 | 181(36.2) | 319(63.8) |
| 2009 | 499 | 187(37.5) | 312(62.5) | 496 | 192(38.7) | 304(61.3) |
| 2010 | 501 | 184(36.7) | 317(63.3) | 498 | 161(32.3) | 337(67.7) |
| Total | 3250 | 1363(42.9) | 1887(58.1) | 3214 | 1331(41.4) | 1883(58.6) |
The means and standard deviation of WC based on gender and location during the five years study are presented in Table 2. In comparison of 2006 with 2010, the mean WC in males changed from 87.2 cm to 88.1 cm in rural areas (p=0.237), and from 90.3 cm to 88.6 cm (p=0.045) among females. While, in urban areas; WC changed from 90.7 cm to 89.5 cm (p=0.197) in males and from 87.0 cm to 87.8 cm in females (p=0.295).
Table 2. Mean waist circumference among adults in northern Iran.
| Year | No. | Men | No. | Women | ||||
|---|---|---|---|---|---|---|---|---|
| Urban | Rural | Total | Urban | Rural | Total | |||
| 2006 | 1250 | 89.8(14.2) | 84.8(12.9) | 87.2(13.7) | 1221 | 91.5(16.1) | 89.2(15.4) | 90.3(15.8) |
| 2007 | 500 | 89.9(14.0) | 86.4(12.2) | 88.0(13.1) | 499 | 90.1(16.0) | 90.5(15.4) | 90.3(15.7) |
| 2008 | 500 | 88.5(12.6) | 86.4(13.0) | 87.1(12.9) | 500 | 89.4(15.0) | 90.2(15.2) | 89.9(15.1) |
| 2009 | 500 | 90.4(15.4) | 84.8(14.7) | 86.9(15.1) | 497 | 88.9(15.9) | 88.0(17.0) | 88.3(16.6) |
| 2010 | 501 | 89.7(14.9) | 87.1(14.6) | 88.1(14.8) | 498 | 89.2(14.9) | 88.4(15.1) | 88.6(15.0) |
| Total | 3251 | 89.718(14.2) | 85.704(13.4) | 87.4(13.9) | 3215 | 90.303(15.8) | 89.225(15.6) | 89.7(15.7) |
| p value | 0.915 | 0.075 | 0.507 | 0.020 * | 0.190 | 0.072 | ||
* Statistically significant. Overall, t test was significant between gender, (p=0.001).
Table 3 presents the prevalence of central obesity based on gender and location during the five-year study. The results showed that central obesity was prevalent in 35.4% of adults, and it was more prevalent in urban areas than rural areas (38.9% vs. 32.9%). The findings also conveyed that central obesity was more prevalent in females than males (55.7% vs.15.4%). The Chi-square test was significant between gender (p=0.001), and between location (p=0.001). Additionally, in the rural area; central obesity was prevalent in 11.7% and 54.3% of men and women, respectively.
Table 3. Comparison of central obesity prevalence among adults in the five-year study.
| Year | No. | Men | No. | Women | ||||
|---|---|---|---|---|---|---|---|---|
| Urban | Rural | Total | Urban | Rural | Total | |||
| 2006 | 1250 | 128(22) | 69(10.3) | 197(15.8) | 1221 | 342(60.2) | 352(53.8) | 694(56.8) |
| 2007 | 500 | 46(20) | 32(11.9) | 78(15.6) | 499 | 131 (57) | 142(52.8) | 273(54.7) |
| 2008 | 500 | 23(12.8) | 43(13.4) | 66(13.2) | 500 | 100(55.2) | 183(57.4) | 283(56.6) |
| 2009 | 499 | 46(24.6) | 31(9.9) | 77(15.4) | 496 | 109(56.8) | 166(54.6) | 275(55.4) |
| 2010 | 501 | 36(19.6) | 45(14.2) | 81(16.2) | 498 | 86(53.4) | 179(53.1) | 265(53.2) |
| Total | 3250 | 279(20.5) | 220(11.7) | 499(15.4) | 3214 | 768(57.7) | 1022(54.3) | 1790(55.7) |
| p value | 0.576 | 0.183 | 0.926 | 0.095 | 0.925 | 0.245 | ||
Five-year trends in urban areas decreased and increased in rural areas, but there was no statistical significance based on Cochran’s test.
The comparison of 2006 with 2010 indicated that the prevalence of central obesity decreased slightly in men (6.8%) and women (2.4%) in the urban area; however, the prevalence of central obesity increased in the rural area, in the same order.
Discussion
This is the first study to investigate the prevalence of central obesity longitudinally in northern Iran. The findings showed that the mean WC decreased in both males and females in the urban areas, but WC only increased amongst males in the rural areas. Consistent with many other studies, trends in central obesity increased especially amongst males in rural areas, but declined in urban areas. Increasing trends of central obesity have been reported in some studies, but the decreasing trend observed in the current study has not been reported in other studies; therefore, it is a considerable finding.
Trends in central obesity among adults in Tehran increased during 1998-1999 and 2001-2002.17 In Finland, WC significantly increased from 1987 to 1997 in both males and females.18 However, during five years in Germany (1989/90-1994/95), the increase in WC was not significant both in males and females.19 Yet, the mean of waist to hip ratio, subscupular and triceps skin fold thickness increased substantially in Swedish women.20
From 1988 to 1994; the prevalence of central obesity in U.S. significantly increased among all age groups except men aged 30-59 years and women aged 40-59 years.21 While in another study, an increased abdominal obesity was reported in adults after a period of 15 years.22 Furthermore, it was reported in a 6-year period in the U.S. that body weight increased in children, adolescents and men, while it remained unchanged in women.23
Iran is considered to be a country in a nutrition transition phase, since lifestyle and food behavior have been changing in recent years.24 Most of the rural people are farmers and the new agricultural technology has resulted into low physical activity amongst them. Besides, several studies are in agreement that women make more of an effort and take better care of their health compared to men.25-27 Consequently, these factors probably relate to the increasing trends of central obesity in men compared to women in the rural areas of the current study.
In this study, central obesity was common in 35.4% of the study participants and it was more prevalent in females and urban areas. The prevalence of central obesity in Gorgan (northern Iran) was 39.1%,28 and 21.2% in Ahvaz (south of Iran),29 while it was reported to be 9.7% in the whole of Iran.30 In another study conducted in Iran, central obesity was reported among 12.9% and 54.5% of adult men and women, respectively.6 The prevalence of central obesity was reported to be 39.2% in Rio de Janeiro31; 24.1% in Egypt32; 30.5% in Australian adults33; 2% in Croatia34; and it was also reported to be 31.5% and 64.4% among Omani males and females, respectively.35 Similarly in this study; central obesity was especially common in females in northern Iran.
Conclusion
In summary, central obesity has been recognized as a major health problem in northern Iran, and the recent trend based on the study findings show a decline of central obesity in urban areas, but an increase was observed in rural areas, particularly amongst males. It is therefore necessary to plan health programs to control and manage this health problem. Also, we advocate that the issue of increasing trends of central obesity among males in rural areas be studied further.
Acknowledgments
The researchers would like to thank the medical and administrative staff in Primary Health Care Centers of Golestan University of Medical Sciences for their valuable assistance during the field work. This study was created from provincial incommunicable data study and was supported by the Health Office of Golestan University of Medical Sciences. Furthermore, based on 416183 official documents, the study was justified for publication.
References
- 1.Kelly T, Yang W, Chen CS, Reynolds K, He J. Global burden of obesity in 2005 and projections to 2030. Int J Obes (Lond) 2008. Sep;32(9):1431-1437 10.1038/ijo.2008.102 [DOI] [PubMed] [Google Scholar]
- 2.James PT, Rigby N, Leach R, International Obesity Task Force The obesity epidemic, metabolic syndrome and future prevention strategies. Eur J Cardiovasc Prev Rehabil 2004. Feb;11(1):3-8 10.1097/01.hjr.0000114707.27531.48 [DOI] [PubMed] [Google Scholar]
- 3.Auwerx J, Staels B. Leptin. Lancet 1998. Mar;351(9104):737-742 10.1016/S0140-6736(97)06348-4 [DOI] [PubMed] [Google Scholar]
- 4.World Health Organization. Obesity: Preventing and managing the global epidemic. World Health Organization.1998; Geneva. [PubMed] [Google Scholar]
- 5.Rashidi A, Mohammadpour-Ahranjani B, Vafa MR, Karandish M. Prevalence of obesity in Iran. Obes Rev 2005. Aug;6(3):191-192 10.1111/j.1467-789X.2005.00174.x [DOI] [PubMed] [Google Scholar]
- 6.Janghorbani M, Amini M, Willett WC, Mehdi Gouya M, Delavari A, Alikhani S, et al. First nationwide survey of prevalence of overweight, underweight, and abdominal obesity in Iranian adults. Obesity (Silver Spring) 2007. Nov;15(11):2797-2808 10.1038/oby.2007.332 [DOI] [PubMed] [Google Scholar]
- 7.World Health Organization: Chronic deaseases are the major cause of death and disability worldwide. [http://www.who.int/ chp/chronic_disease_report/media/Factsheet1.pdf]. [Cited 2008 Aug 12].
- 8.Kelishadi R, Alikhani S, Delavari A, Alaedini F, Safaie A, Hojatzadeh E. Obesity and associated lifestyle behaviours in Iran: findings from the First National Non-communicable Disease Risk Factor Surveillance Survey. Public Health Nutr 2008. Mar;11(3):246-251 10.1017/S1368980007000262 [DOI] [PubMed] [Google Scholar]
- 9.Veghari G, Sedaghat M, Joshaghani H, Hoseini A, Niknajad F, Angizeh A, et al. The Prevalence and Associated Factors of Central obesity in Northern Iran. Iranian Cardiovascular Research Journal. 2010;4(4):164-168 [Google Scholar]
- 10.Veghari G, Joshaghani H, Niknezhad F, Sedaghat M, Hoseini A, Angizeh A, et al. Obesity in the north of Iran (south east of Caspian Sea). Bangladesh Med Res Counc Bull 2010. Dec;36(3):100-101 [DOI] [PubMed] [Google Scholar]
- 11.Licata G, Argano C, Di Chiara T, Parrinello G, Scaglione R. Obesity: a main factor of metabolic syndrome? Panminerva Med 2006. Jun;48(2):77-85 [PubMed] [Google Scholar]
- 12.Ito H, Nakasuga K, Ohshima A, Maruyama T, Kaji Y, Harada M, et al. Detection of cardiovascular risk factors by indices of obesity obtained from anthropometry and dual-energy X-ray absorptiometry in Japanese individuals. Int J Obes Relat Metab Disord 2003. Feb;27(2):232-237 10.1038/sj.ijo.802226 [DOI] [PubMed] [Google Scholar]
- 13.Rexrode KM, Carey VJ, Hennekens CH, Walters EE, Colditz GA, Stampfer MJ, et al. Abdominal adiposity and coronary heart disease in women. JAMA 1998. Dec;280(21):1843-1848 10.1001/jama.280.21.1843 [DOI] [PubMed] [Google Scholar]
- 14.Folsom AR, Stevens J, Schreiner PJ, McGovern PG, Atherosclerosis Risk in Communities Study Investigators Body mass index, waist/hip ratio, and coronary heart disease incidence in African Americans and whites. Am J Epidemiol 1998. Dec;148(12):1187-1194 [DOI] [PubMed] [Google Scholar]
- 15.Statistical Center of Iran. Population and Housing Census.2006; Available from:URL http://www.sci.org.ir
- 16.World Health Organization. Obesity: Prevention and Managing the Global Epidemic. WHO Obesity Technical Reports Series 894. WHO, 2000.Geneva, Switzerland. [PubMed] [Google Scholar]
- 17.Azizi F, Azadbakht L, Mirmiran P. Trends in overweight, obesity and central fat accumulation among Tehranian adults between 1998-1999 and 2001-2002: Tehran lipid and glucose study. Ann Nutr Metab 2005. Jan-Feb;49(1):3-8 10.1159/000084171 [DOI] [PubMed] [Google Scholar]
- 18.Lahti-Koski M, Pietinen P, Männistö S, Vartiainen E. Trends in waist-to-hip ratio and its determinants in adults in Finland from 1987 to 1997. Am J Clin Nutr 2000. Dec;72(6):1436-1444 [DOI] [PubMed] [Google Scholar]
- 19.Liese AD, Döring A, Hense HW, Keil U. Five year changes in waist circumference, body mass index and obesity in Augsburg, Germany. Eur J Nutr 2001. Dec;40(6):282-288 10.1007/s394-001-8357-0 [DOI] [PubMed] [Google Scholar]
- 20.Lissner L, Björkelund C, Heitmann BL, Lapidus L, Björntorp P, Bengtsson C. Secular increases in waist-hip ratio among Swedish women. Int J Obes Relat Metab Disord 1998. Nov;22(11):1116-1120 10.1038/sj.ijo.0800760 [DOI] [PubMed] [Google Scholar]
- 21.Ford ES, Mokdad AH, Giles WH. Trends in waist circumference among U.S. adults. Obes Res 2003. Oct;11(10):1223-1231 10.1038/oby.2003.168 [DOI] [PubMed] [Google Scholar]
- 22.Li C, Ford ES, McGuire LC, Mokdad AH. Increasing trends in waist circumference and abdominal obesity among US adults. Obesity (Silver Spring) 2007. Jan;15(1):216-224 10.1038/oby.2007.505 [DOI] [PubMed] [Google Scholar]
- 23.Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM. Prevalence of overweight and obesity in the United States, 1999-2004. JAMA 2006. Apr;295(13):1549-1555 10.1001/jama.295.13.1549 [DOI] [PubMed] [Google Scholar]
- 24.Ghassemi H, Harrison G, Mohammad K. An accelerated nutrition transition in Iran. Public Health Nutr 2002. Feb;5(1A):149-155 10.1079/PHN2001287 [DOI] [PubMed] [Google Scholar]
- 25.Heo S, Moser DK, Lennie TA, Riegel B, Chung ML. Gender differences in and factors related to self-care behaviors: a cross-sectional, correlational study of patients with heart failure. Int J Nurs Stud 2008. Dec;45(12):1807-1815 Published online 31 Jul 2008. 10.1016/j.ijnurstu.2008.05.008 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Frayne SM, Yu W, Yano EM, Ananth L, Iqbal S, Thrailkill A, et al. Gender and use of care: planning for tomorrow’s Veterans Health Administration. J Womens Health (Larchmt) 2007. Oct;16(8):1188-1199 10.1089/jwh.2006.0205 [DOI] [PubMed] [Google Scholar]
- 27.Poulain M, Pes G, Salaris L. A population where men live as long as women:villagrande strisaili, sardinia. J Aging Res.2011:153756. Epub 2011 Oct 25. [DOI] [PMC free article] [PubMed]
- 28.Veghari GR, Mansourian AR. Obesity among Mothers in Rural Golestan-Iran (south east of Caspian sea). Iran J Public Health 2007;36(3):71-76 [Google Scholar]
- 29.Amani R. Comparison between bioelectrical impedance analysis and body mass index methods in determination of obesity prevalence in Ahvazi women. Eur J Clin Nutr 2007. Apr;61(4):478-482 [DOI] [PubMed] [Google Scholar]
- 30.Kelishadi R, Alikhani S, Delavari A, Alaedini F, Safaie A, Hojatzadeh E. Obesity and associated lifestyle behaviours in Iran: findings from the First National Non-communicable Disease Risk Factor Surveillance Survey. Public Health Nutr 2008. Mar;11(3):246-251 10.1017/S1368980007000262 [DOI] [PubMed] [Google Scholar]
- 31.Ramos de Marins VM, Varnier Almeida RM, Pereira RA, Barros MB. Factors associated with overweight and central body fat in the city of Rio de Janeiro: results of a two-stage random sampling survey. Public Health 2001. May;115(3):236-242 10.1016/S0033-3506(01)00450-4 [DOI] [PubMed] [Google Scholar]
- 32.Abolfotouh MA, Soliman LA, Mansour E, Farghaly M, El-Dawaiaty AA. Central obesity among adults in Egypt: prevalence and associated morbidity. East Mediterr Health J 2008. Jan-Feb;14(1):57-68 [PubMed] [Google Scholar]
- 33.Dalton M, Cameron AJ, Zimmet PZ, Shaw JE, Jolley D, Dunstan DW, et al. AusDiab Steering Committee Waist circumference, waist-hip ratio and body mass index and their correlation with cardiovascular disease risk factors in Australian adults. J Intern Med 2003. Dec;254(6):555-563 10.1111/j.1365-2796.2003.01229.x [DOI] [PubMed] [Google Scholar]
- 34.Tucak-Zorić S, Curcić IB, Mihalj H, Dumancić I, Zelić Z, Cetina NM, et al. Prevalence of metabolic syndrome in the interior of Croatia: the Baranja region. Coll Antropol 2008. Sep;32(3):659-665 [PubMed] [Google Scholar]
- 35.Al-Riyami AA, Afifi MM. Prevalence and correlates of obesity and central obesity among Omani adults. Saudi Med J 2003. Jun;24(6):641-646 [PubMed] [Google Scholar]