Original Article

Obesity Prevalence Among Older People in Tabriz, Iran: Data from Health Status of Aged People in Tabriz (HSA-T) Study

Introduction

Aging and obesity are two growing public health challenges worldwide in the present century.^1,2 Parallel to the population aging, the prevalence of obesity among older people is also increasing. It has increased over the past decade and reached epidemic proportions in European countries.³ Obesity is defined as “an unhealthy excess of body fat, which increases the risk of morbidity and premature mortality among young and middle-aged adults”.⁴ In older adults, obesity is associated with mobility disability and exacerbates the onset of chronic morbidities, leading to premature mortality.^2,5-7 Furthermore, compared to non-obese status, obesity amongst older adults is a known metabolic phenotype associated with higher risks of cardiometabolic diseases, including type 2 diabetes and cardiovascular diseases (CVDs).⁸

Obesity and aging are topics that raised much discussion in the research literature and clinical practice, particularly in relation to effective treatment and management strategies.⁹ As such, it is valuable to track the obesity prevalence in older people.^10,11 An increased prevalence of overweight and obesity has previously been reported among all age groups, which is a major health concern across the lifespan in both developing and developed countries,^5,12,13 and it has reached epidemic proportions globally.¹⁴ However, the prevalence of obesity varies among countries and across different age groups. Even though the population is aging, previous data has mostly focused on younger and middle-aged individuals.^15,16 In Iran, as a developing country, there has been no published study to assess the prevalence of obesity amongst older community dwellers using a representative sample.^15,16 Therefore, this study aimed to estimate the obesity prevalence in a representative sample of community-dwelling older adults in Tabriz, Iran.

Methods

The current study was embedded within the Health Status of Aged People in Tabriz (HSA-T) study, as a representative sample of noninstitutionalized people aged ≥ 60 years living in Tabriz, Iran.

Study Setting

This study was conducted in Tabriz, the metropolitan region in northwest Iran in 2015. According to the last national census data, the total population aged ≥ 60 years is about 180 000 which is equivalent to 10.5% of the total population of the city.¹⁷

Study Population

The statistical population included all of the community-dwelling older people ≥ 60 years living in Tabriz, Iran.

Sample Size and Sampling Method

In brief, a random representative sample of 1071 older adults was selected using the probability proportional to size sampling method. In the first stage, 107 blocks were randomly selected out of 8531 urban blocks in Tabriz. In the next stage, 10 eligible older adults were randomly selected from each city block. Then, anthropometric measures were conducted among 1041 subjects (506 males and 535 females) out of the total 1071 participants in the HSA-T study. Details on the sampling method have been described elsewhere.¹⁸

Data Collection Tools

Data were collected by trained interviewers. Socio-demographic information was obtained using a structured questionnaire from the HSA-T study. Anthropometric measurements were then used to collect the specific data for the study as described below:

Anthropometric Measurements

Various anthropometric measures/indices were collected, including body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHpR). BMI was used to define obesity, whereas WC and WHpR were used to assess central adiposity and body fat distribution.^19-22 BMI and WHpR were calculated by dividing the values of weight (kg) by the square of height (m²) and dividing the WC by hip circumference (HC), respectively.^19,23 Participants were weighed while wearing light clothes and without footwear. Measures of WC and HC were performed at the point recommended by World Health Organization (WHO).²² All measures were performed by trained nutrition experts. To evaluate obesity and analyze the data, cut-off points recommended by WHO for BMI, WC, and WHpR were applied.²² According to the WHO cutoff criteria, we considered BMI as a categorical variable containing underweight, normal weight, overweight, and obese. Furthermore, BMI of 30-34.99, 35-39.99, and ≥ 40 were considered as grade-I obesity, grade-II obesity, and grade-III obesity, respectively.^19,23 Abdominal adiposity was defined as a WHpR of ≥ 0.90 for males and ≥ 0.85 for females.²⁴ In the European population, the cut-off points for WC have been recommended as ≥ 102 cm for males and ≥ 88 cm for females.^20,25 However, given that different populations have different desirable cut-off points for the assessment of cardiometabolic risk,²⁶ the Iranian Ministerial Committee has declared that the anthropometric cut-off points derived from the European population should not be applied to an Iranian population²⁰ and suggested a criterion cut-off of ≥ 90 cm for both genders. Furthermore, individuals (males and females) with WC ≥ 95 cm are at substantial risk of CVD and need immediate preventive interventions.²⁰ For analyzing the data related to WC, in addition to WHO cut-off points, the standards recommended specifically for Iranians were used. In the present study, data analysis was performed in terms of gender and age groups.

Statistical Methods

Descriptive data were presented as frequency (and percentages) and means ± standard deviations for continuous variables, including weight, BMI, HC, WC, WHpR, and age, respectively. The independent samples t-test and the analysis of variance (ANOVA) tests were used to compare the means of the two independent sub-groups and more than two independent sub-groups, respectively. The statistical analyses were performed using the SPSS version 23, and the level of significance was set at P< 0.05.

Results

A total of 1041 participants (506 males and 535 females with mean age of 70.1 ± 8.2) were included in the final analyses. Findings related to anthropometric indices, including BMI, HC, WC, and WHpR by gender and age group showed that mean BMI and WC are lower in males than in females and significantly decreased with increasing age (Table 1). In contrast, WHpR was lower in females but did not significantly change with increasing age.

Table 2 reports the prevalence of overweight and obesity, according to BMI classifications. Almost two-thirds of the studied cohort were overweight or obese (37.43% overweight and 34.25% obese), with a greater prevalence of obesity in females compared with males (females: 46.64%; males: 21.15%).

Table 3 presents categories of BMI according to age groups. Both overweight and obesity, as well as mean BMI (reported in Table 1), decreased significantly with increasing age. Similarly, As Table 4 illustrates, WC significantly decreased with increasing age. In contrast, this trend was not observed for WHpR, as depicted in Table 5. Lastly, Pearson correlation coefficients further revealed that weight (r = -0.255; P < 0.001), BMI (r = -0.212; P < 0.001), WC (r = -0.153; P < 0.001), and HC (r = -0.221; P < 0.001) were all inversely associated with age (Table 6).

Discussion

The present study found a high prevalence of overweight and obesity in community-dwelling Iranian older people, particularly among older women. Several important physiological changes are associated with aging, including reductions in lean body mass and a simultaneous accumulation of fat mass. However, changes in fat distribution from subcutaneous adipose tissue to the abdominal visceral adipose tissue are of great concern,²⁷ since this increases the risk for cardiometabolic disorders. Moreover, a reduction in physical activity is also a strong contributing factor to obesity with advanced age.²⁸ In addition, most studies reported a lack of physical activity in females to be greater than in males^28-30. In the following sections, the findings of the anthropometric indicators (BMI, WC, and WHpR) are discussed separately.

Based on BMI classifications, the present study indicated that more than one-third of the cohort were obese, with most being identified as grade-I obesity. In comparison, in a study conducted in Hamadan, 39.9% of older people were identified as overweight (BMI: 25-29.9), and 14.9% were obese (BMI ≥ 30).³¹ Furthermore, a study conducted in Tehran showed that the average BMI of older adults was 24.9 ± 4.68 kg/m². ³² Similar results have also been reported in older people living in Urmia,³³ Birjand,³⁴ and the Razavi-Khorasan province.³⁵ Comparing the results of previous studies with the current study, a greater BMI was observed amongst community-dwelling older adults in the current study.

In the present study, the average BMI in females was significantly higher than that in males P < 0.001). Specifically, the prevalence of obesity among females was twice that of males. In a study of older adults living in Tehran, 45.36% of males were overweight or obese, with 51.41% of females being overweight or obese.³² Reports of significant gender disparities in the prevalence of overweight and obesity have also been found in Birjand,³⁴ Hamadan,³¹ and the Razavi-Khorasan province³⁵ with a greater prevalence of overweight and obesity amongst females, akin to the present study.

The average BMI amongst older adults significantly reduced with increasing age in the present study. The prevalence of both overweight and obesity had a decreasing trend by increasing the age group from 60-69.9 to 80 years or older. In Europe, the United States, and the majority of the developed countries, BMI increased with increasing age and reached its peak at the age of 60, before gradually reducing with age.^19,36-38 In fact, this trend was also observed in the present study. In contrast to obesity and overweight, the prevalence of underweight increased with increasing age.

Although obesity is a well-documented risk factor for chronic disease and premature mortality in adults,^39,40 using the BMI in isolation for the assessment of obesity is limited by the fact that the BMI is not a measure of body composition and provides an indirect estimation of adiposity.⁴¹ Therefore, the present study used WC, a useful proxy measure for abdominal or central distribution of fat^21,22,42 as well as total body fat,²² for the assessment of abdominal adiposity.⁴¹

In the present study, the average WC of participants was higher than the criterion cut-off points determined for Iranians (≥ 102 cm for males and ≥ 88 cm for females).^20,25 Specifically, the mean WC was greater than 90 cm in four-fifths of the studied population, and over two-thirds of older people had central obesity based on the criterion cut-off points for Iranians (WC of 95 cm or above).

Furthermore, females’ average WC was higher than males (P = 0.003). Based on the criterion cut-off points for Iranians, two-thirds of males and more than two-thirds of females had abdominal obesity. Regarding WHO standards, most females (84.5%) and about half of all males were identified with central obesity (WC ≥ 88 in females and WC ≥ 102 in males).

In the present study, the average WC among the studied population decreased with increasing age. Similar to the BMI, WC significantly decreased by increasing the age group from 60-69.9 to 80 years or older. Moreover, the percentage of central obese older adults (based on criterion cut-offs for Iranians) decreased by increasing the age group from 60-69.9 to 80 years or above.

The central obesity indices, compared to BMI, are more appropriate measures for application to determine or estimate risk factors of CVDs.^20,42 It has been reported that WHpR is a more efficient predictor of overall mortality amongst older people; furthermore, it is a better predictor of CVD compared to WC or BMI alone.²¹ This index is used more frequently than other indices in population-based studies as a proxy measure for abdominal adiposity.²⁶ On this basis, in addition to WC, the WHpR index was used in this study to assess abdominal adiposity in the studied cohort.⁴¹

In the current study, the average WHpR of older adults was higher than the criterion cut-off points for abdominal adiposity. The study of older people in Birjand showed that 63.5% of older adult population had abdominal adiposity (WHpR of above 0.9 for males and above 0.85 for females)³⁴; however, in the present study, the prevalence of abdominal adiposity was much higher than such values.

Among females, the average WHpR was lower compared with males, which is likely attributable to the greater adiposity (higher HC) in females relative to males. Over three-quarters of the male cohort and nearly all females (94.30%) had a WHpR of more than the related criterion cut-off points. In a study conducted in Isfahan, the prevalence of abdominal adiposity (based on WHpR) among females was much higher than in males.⁴³ In the study of older people in Birjand, the prevalence of abdominal adiposity among women was also significantly higher than among men,³⁴ both of which are consistent with results presented in the current study. Further, in the present study, the average WHpR did not change significantly by increasing age in both genders.

Conclusions

Overweight, obesity, and abdominal adiposity have a high prevalence among Iranian community-dwelling older people. This study found that the prevalence of obesity and abdominal adiposity decreased with increasing age, and both were higher among female participants compared with males. Therefore, regarding the status of the prevalence of overweight and obesity and considering the complications of obesity as a known risk factor for non-communicable and lifestyle-related diseases, the following suggestions are presented. (1) It is necessary to study the complications and effects of such status on older people’s health in longitudinal studies. (2) As some epidemiological findings are in favor of a beneficial or neutral effect of a high BMI on survival in old age, it is valuable to track more comprehensive and robust studies to better understand the consequences and complications of overweight and obesity in aged people. (3) It seems necessary to implement proper interventions for older adults to improve their lifestyle and prevent overweight and obesity among this population.

Acknowledgments

Funding for this study was provided by the Health Services Management Research Center, Tabriz University of Medical Sciences. We would like to express our thanks for the financial support of this study. In addition, the authors would like to acknowledge the participation and cooperation of all individuals in the study

Funding

Funding for this study was provided by the Health Services Management Research Center, Tabriz University of Medical Sciences.

Data availability statement

The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.

Ethical approval

This study was reviewed and approved by the Deputy of the Research Ethics Committee at the Tabriz University of Medical Sciences (Ethical ID: IR.TBZMED.REC.1392.243). Moreover, informed consent was obtained from all participants, and they were assured of the confidentiality of the information.

Consent for publication

Not applicable.

Conflict of interests

The authors declare that they have no conflict of interests.

References

1. Chen C, Xu X, Yan Y. Estimated global overweight and obesity burden in pregnant women based on panel data model. PLoS One 2018; 13(8):e0202183. doi: 10.1371/journal.pone.0202183 [Crossref] [ Google Scholar]
2. Tan YH, Lim JP, Lim WS, Gao F, Teo LLY, Ewe SH. Obesity in older adults and associations with cardiovascular structure and function. Obes Facts 2022; 15(3):336-43. doi: 10.1159/000521729 [Crossref] [ Google Scholar]
3. Peralta M, Ramos M, Lipert A, Martins J, Marques A. Prevalence and trends of overweight and obesity in older adults from 10 European countries from 2005 to 2013. Scand J Public Health 2018; 46(5):522-9. doi: 10.1177/1403494818764810 [Crossref] [ Google Scholar]
4. World Health Organization (WHO). Obesity: Preventing and Managing the Global Epidemic: Report of a WHO Consultation on Obesity, Geneva, 3-5 June 1997. Geneva: WHO; 1998.
5. Donini LM, Chumlea WC, Vellas B, del Balzo V, Cannella C. In preparation for the international symposium on ‘obesity in the elderly’. Aging Health 2006; 2(1):47-51. doi: 10.2217/1745509x.2.1.47 [Crossref] [ Google Scholar]
6. Kenchaiah S, Evans JC, Levy D, Wilson PW, Benjamin EJ, Larson MG. Obesity and the risk of heart failure. N Engl J Med 2002; 347(5):305-13. doi: 10.1056/NEJMoa020245 [Crossref] [ Google Scholar]
7. Adams KF, Schatzkin A, Harris TB, Kipnis V, Mouw T, Ballard-Barbash R. Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old. N Engl J Med 2006; 355(8):763-78. doi: 10.1056/NEJMoa055643 [Crossref] [ Google Scholar]
8. Gutierrez-Mariscal FM, García-Ríos A, Gómez-Luna P, Fernández-Gandara C, Cardelo MP, de la Cruz-Ares S. Age-dependent effect of metabolic phenotypes on carotid atherosclerotic disease in coronary heart disease patients (CORDIOPREV study). BMC Geriatr 2020; 20(1):151. doi: 10.1186/s12877-020-01544-5 [Crossref] [ Google Scholar]
9. Villani A. Lifestyle strategies for the management of obesity in older adults: from controversies to alternative interventions. Healthcare 2022; 10(10):2107. doi: 10.3390/healthcare10102107 [Crossref] [ Google Scholar]
10. Lakdawalla DN, Goldman DP, Shang B. The health and cost consequences of obesity among the future elderly. Health Aff (Millwood) 2005; 24 Suppl 2:W5R30-41. doi: 10.1377/hlthaff.w5.r30 [Crossref] [ Google Scholar]
11. Decaria JE, Sharp C, Petrella RJ. Scoping review report: obesity in older adults. Int J Obes (Lond) 2012; 36(9):1141-50. doi: 10.1038/ijo.2012.29 [Crossref] [ Google Scholar]
12. Barreto SM, Passos VM, Lima-Costa MF. Obesity and underweight among Brazilian elderly: the Bambuí Health and Aging Study. Cad Saude Publica 2003; 19(2):605-12. [ Google Scholar]
13. Vellas BJ, Hunt WC, Romero LJ, Koehler KM, Baumgartner RN, Garry PJ. Changes in nutritional status and patterns of morbidity among free-living elderly persons: a 10-year longitudinal study. Nutrition 1997; 13(6):515-9. doi: 10.1016/s0899-9007(97)00029-4 [Crossref] [ Google Scholar]
14. World Health Organization (WHO). Overweight and Obesity Fact Sheet. WHO; 2012.
15. Eftekhar-Ardebili H, Lashkarboloki F, Jazayeri SA, Aryaei M, Minaei M. Nutritional status of elderly people. Journal of School of Public Health and Institute of Public Health Research 2014;12(2):59-68. [Persian].
16. Lashkarboloki F, Aryaei M, Jazayeri SA, Eftekhar-Ardebili H, Minaei M. Association of demographic, socio-economic features and some health problems with nutritional status in elderly. Iran J Nutr Sci Food Technol 2015;9(4):27-34. [Persian].
17. Statistical Center of Iran. Detailed results of the General Population and Housing Census; 2016. 2017.
18. Ghaffari S, Pourafkari L, Tajlil A, Sahebihagh MH, Mohammadpoorasl A, Tabrizi JS. The prevalence, awareness and control rate of hypertension among elderly in northwest of Iran. J Cardiovasc Thorac Res 2016; 8(4):176-82. doi: 10.15171/jcvtr.2016.35 [Crossref] [ Google Scholar]
19. Babiarczyk B, Turbiarz A. Body mass index in elderly people - do the reference ranges matter?. Prog Health Sci 2012; 2(1):58-67. [ Google Scholar]
20. Azizi F, Khalili D, Aghajani H, Esteghamati A, Hosseinpanah F, Delavari A. Appropriate waist circumference cut-off points among Iranian adults: the first report of the Iranian National Committee of Obesity. Arch Iran Med 2010; 13(3):243-4. [ Google Scholar]
21. Mahmoud AH, Taha HM. Study of the relationship between abdominal obesity and micro-albuminuria in elderly. Journal of Obesity and Overweight 2015; 1(2):202. doi: 10.15744/2455-7633.1.202 [Crossref] [ Google Scholar]
22. dos Santos DM, Sichieri R. [Body mass index and measures of adiposity among elderly adults]. Rev Saude Publica 2005; 39(2):163-8. doi: 10.1590/s0034-89102005000200004.[Portuguese] [Crossref] [ Google Scholar]
23. Swami HM, Bhatia V, Gupta AK, Bhatia SP. An epidemiological study of obesity among elderly in Chandigarh. Indian J Community Med 2005; 30(1):11. [ Google Scholar]
24. World Health Organization (WHO). Waist Circumference and Waist-Hip Ratio. Geneva: WHO; 2011. p. 39.
25. Zamboni M, Mazzali G, Zoico E, Harris TB, Meigs JB, Di Francesco V. Health consequences of obesity in the elderly: a review of four unresolved questions. Int J Obes (Lond) 2005; 29(9):1011-29. doi: 10.1038/sj.ijo.0803005 [Crossref] [ Google Scholar]
26. Esmaillzadeh A, Mirmiran P, Azizi F. Waist-to-hip ratio is a better screening measure for cardiovascular risk factors than other anthropometric indicators in Tehranian adult men. Int J Obes Relat Metab Disord 2004; 28(10):1325-32. doi: 10.1038/sj.ijo.0802757 [Crossref] [ Google Scholar]
27. Jura M, Kozak LP. Obesity and related consequences to ageing. Age (Dordr) 2016; 38(1):23. doi: 10.1007/s11357-016-9884-3 [Crossref] [ Google Scholar]
28. Vaisi-Raygani A, Mohammadi M, Jalali R, Ghobadi A, Salari N. The prevalence of obesity in older adults in Iran: a systematic review and meta-analysis. BMC Geriatr 2019; 19(1):371. doi: 10.1186/s12877-019-1396-4 [Crossref] [ Google Scholar]
29. Cassou AC, Fermino R, Rodriguez Añez CR, Santos MS, Domingues MR, Reis RS. Barriers to physical activity among Brazilian elderly women from different socioeconomic status: a focus-group study. J Phys Act Health 2011; 8(1):126-32. doi: 10.1123/jpah.8.1.126 [Crossref] [ Google Scholar]
30. Banz WJ, Maher MA, Thompson WG, Bassett DR, Moore W, Ashraf M. Effects of resistance versus aerobic training on coronary artery disease risk factors. Exp Biol Med (Maywood) 2003; 228(4):434-40. doi: 10.1177/153537020322800414 [Crossref] [ Google Scholar]
31. Jamshidi L, Seif A. Comparison of cardiovascular diseases risk factors in male and female older adults of Hamadan city, 2014. J Gerontol 2016; 1(1):1-10. doi: 10.18869/acadpub.joge.1.1.17.[Persian] [Crossref] [ Google Scholar]
32. Shamsi A, Ebadi A. Risk factors of cardiovascular diseases in elderly people. Iran J Crit Care Nurs 2011;3(4):189-94. [Persian].
33. Asefi M, Asadi Shorkand A, Tizfah Ghavi T. Survey of prevalence of obesity in over 60 years old elderly in Urmia city. In: Asefi M, ed. Iranian’s 5th National Congress on Prevention and Treatment of Obesity; 2015; Tehran.
34. Tyuri A, Yari E, Beheshti D, Khodabakhshi H, Sharifzade G. prevalence of overweight, obesity and abdominal obesity in elderly in Birjand city in 2014. In: Tyuri A, ed. Iranian’s 5th National Congress on Prevention and Treatment of Obesity; 2015; Tehran.
35. Aliabadi M, Kimiagar M, Ghayour-Mobarhan M, Shakeri MT, Nematy M, Ilaty AA. Prevalence of malnutrition in free living elderly people in Iran: a cross-sectional study. Asia Pac J Clin Nutr 2008; 17(2):285-9. [ Google Scholar]
36. Mathus-Vliegen EM. Obesity and the elderly. J Clin Gastroenterol 2012; 46(7):533-44. doi: 10.1097/MCG.0b013e31825692ce [Crossref] [ Google Scholar]
37. Mathus-Vliegen EM. Prevalence, pathophysiology, health consequences and treatment options of obesity in the elderly: a guideline. Obes Facts 2012; 5(3):460-83. doi: 10.1159/000341193 [Crossref] [ Google Scholar]
38. Villareal DT, Apovian CM, Kushner RF, Klein S. Obesity in older adults: technical review and position statement of the American Society for Nutrition and NAASO, The Obesity Society. Am J Clin Nutr 2005; 82(5):923-34. doi: 10.1093/ajcn/82.5.923 [Crossref] [ Google Scholar]
39. Faeh D, Braun J, Tarnutzer S, Bopp M. Obesity but not overweight is associated with increased mortality risk. Eur J Epidemiol 2011; 26(8):647-55. doi: 10.1007/s10654-011-9593-2 [Crossref] [ Google Scholar]
40. Aune D, Sen A, Prasad M, Norat T, Janszky I, Tonstad S. BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 374 million deaths among 303 million participants. BMJ 2016; 353:i2156. doi: 10.1136/bmj.i2156 [Crossref] [ Google Scholar]
41. Kvamme JM, Holmen J, Wilsgaard T, Florholmen J, Midthjell K, Jacobsen BK. Body mass index and mortality in elderly men and women: the Tromso and HUNT studies. J Epidemiol Community Health 2012; 66(7):611-7. doi: 10.1136/jech.2010.123232 [Crossref] [ Google Scholar]
42. Abolfotouh MA, Daffallah AA, Khan MY, Khattab MS, Abdulmoneim I. Central obesity in elderly individuals in south-western Saudi Arabia: prevalence and associated morbidity. East Mediterr Health J 2001; 7(4-5):716-24. [ Google Scholar]
43. Alavi Naeini AM, Dorosty Motlagh AR, Aghdak P. Survey of obesity, underweight and associated factors in elderly people, using some of anthropometric indices in Isfahan city, 2004. J Mazandaran Univ Med Sci 2006;16(52):117-25. [Persian].