The Sultanate of Oman is a high-income oil-producing country located on the southeast corner of the Arabian Peninsula. Rapid socioeconomic development has resulted in dramatic demographic and epidemiological transitions. Urgent public health action is required to address the alarming increase in the prevalence of type 2 diabetes, cardiovascular disease, obesity, and their risk factors in Oman and neighboring countries.1,2 Promoting physical activity and better quality dietary intake are key interventions being promoted by public health experts to address this growing concern.3−5

Sedentary behaviors, defined as any waking behavior characterized by an energy expenditure ≤ 1.5 metabolic equivalents (METs) while in a sitting or reclining posture must be addressed.6,7 High levels of sedentary behavior are associated with all-cause mortality and in premature mortality due to cardiovascular disease and risk of diabetes, obesity, and some cancers.8,9 Mortality risk increases significantly when total daily sitting time exceeds seven hours.10,11 High level of moderate physical activity appears to attenuate, but not eliminate, the risk of high sitting time.12 Reducing sedentary behavior is now identified as an additional strategy to address these diseases.13,14

Country-specific evidence on sedentary behavior is needed to identify target groups and develop interventions.8 This need is especially the case for countries of the Arabian Peninsula.15 Limited evidence is available on sedentary behavior in the region.

A recent review identified only one study reporting the prevalence of prolonged sitting among the adult population from the Arabian Peninsula; a sub-national study in Oman reported that half of the adult population sit ≥ 3 hours/day.16 It also reported a significant association of sitting time with the metabolic syndrome.16

We report a descriptive epidemiological analysis of high sitting time from a large population-based survey of Omani adults, reporting sociodemographic and other correlates that may help to identify higher-risk subgroups.

Methods

The Oman World Health Survey is a cross-sectional household survey of adults living in Oman conducted in 2008. It followed the World Health Organization (WHO) World Health Survey methodology.17 The Arabic version of the instrument was adapted using the local Arabic dialect. A multistage sampling design was used where a random sample of 1 700 houses was selected from 191 census clusters in Oman, and an individual was randomly selected in each selected household from all eligible household members. A high proportion of those selected completed the household interview (4 717 nationals and non-nationals, response rate 86.3%).18 Omani participants with complete data for all key variables were included in the present analyses.

The findings of the Oman World Health Survey 2008 were published by the Ministry of Health in 2012. Data preparation and analyses for this study was conducted in 2016 after ethical approval to carry out secondary analysis was granted by the Ministry of Health Research Committee.

The adapted Arabic version of the World Health Survey instrument was used to collect data for demographic variables (gender, age, education, work status, marital status, place of residence, and wealth). Physical activity behavior and sitting time were measured using the Global Physical Activity Questionnaire (GPAQ), a validated tool developed by the WHO to estimate physical activity levels in diverse countries around the world.19−21 Although not validated for Arab populations, both the long and short form have been used in numerous studies conducted in the Arabian Gulf.15 Demographic and behavioral data were collected using face-to-face household and individual interviews. Questionnaires were reviewed for quality prior to data entry into the SPSS statistical software (SPSS Statistics Inc., Chicago, USA) version 9.0.

The independent variables included gender, age (18–40 and > 40 years), educational attainment (illiterate, less than secondary education, and secondary and above), marital status (married, not married), work status (employed, unemployed), wealth (quintiles), and place of residence (urban, rural). Principle components analysis based on household assets was carried out to classify participants into wealth quintiles.18 Place of residence followed the government definition; participants living in an area with a population of at least 2 500 with access to basic services such as public education and electricity/telephone networks were classified
as urban.22

Physical activity and sitting time were scored as per the GPAQ protocol.23 Physically active individuals were those who engaged in at least 150 minutes of moderate physical activity per week. Inclusion and categorization of variables were based on bivariate and regression analysis to ensure that there was sufficient power for the regression models and adequate numbers in all categories.

The dependent variable was total sitting time based on the single item in the GPAQ instrument: ‘Over the past 7 days, how much time did you spend sitting or reclining on a typical day?’. Responses reported as hours and/or minutes per day. The distribution of sitting time as well as the natural logarithm were non-normal, therefore, a categorical variable (< 7 hours/day vs. ≥ 7 hours/day) was developed guided by the recent evidence of increased risk > 7 hours/day of sitting time.10,11

Data were analysed using the STATA 11 software (StataCorp. 2009. Stata Statistical Software: Release 11. College Station, TX: StataCorp LP.). Bivariate analysis and logistic regression using the sociodemographic variables and physical activity were carried out to examine the prevalence of prolonged sitting in Oman and to determine the independent associations of correlates with sitting time.

All models were weighted to the Omani population in 2008. Models (without weighting) were tested for gender and age interactions. Due to multiple interactions, regression analysis was carried out segregated by gender and age. Goodness of fit tests were carried out to determine how well data fitted the models. Results were reported as odds ratios (OR) with 95% confidence intervals (CI) and statistically significant at p ≤ 0.050.

Results

Participants who had complete information on sociodemographic variables, physical activity, and sitting time (n = 2 977, 49.9% women) were included in this study. The interquartile range (IQR) for daily sitting time was similar between men and women (men: 120, 300; women: 120, 360 minutes/day). Those who were older, married, less educated, unemployed, and not physically active had higher mean sitting times than their counterparts [Table 1]. One in five adults was found sitting for ≥ 7 hours/day (men: 17.4%, women: 20.0%). The proportion sitting for ≥ 7 hours/day was significantly higher in men and women age ≥ 40 years compared to
< 40 years, men: 22.0% and 14.6%, respectively
(p < 0.001), and women: 26.9% and 15.2%, respectively (p < 0.001).

Logistic regression analyses using variables identified as significant in bivariate analysis were carried out. The models for men included education, wealth status, work status, and physical activity levels. Women’s models included marital status, education, work status, and physical activity levels. Due to numerous gender and age interactions, analyses were conducted for men and women in two age groups (< 40 years, ≥ 40 years).

The p-values for the Hosmer−Lemeshow tests indicated that the models were all good fit (p-values ranged between 0.647 to 0.991). For men, working status was significantly associated with ≥ 7 hours/day of sitting time [Table 2]. The OR for prolonged sitting was half for men who were unemployed compared to those who were employed; 0.59 (95% CI 0.36–0.97, p = 0.038) for men < 40 years old and 0.47 (95% CI 0.25–0.90,
p = 0.022) for men ≥ 40 years. The OR was more than double for active men age ≥ 40 years compared to inactive; 2.31 (95% CI 1.25–4.26, p = 0.007); an association not seen in men age < 40 years. Education, marital status, and physical activity were significantly associated with sitting ≥ 7 hours/day in the women’s models but differed by age cohorts.

For women < 40 years old, the OR for sitting ≥ 7 hours/day was nearly a third for educated women compared to least educated, 0.35 (95% CI 0.13–0.93, p = 0.035). For women age ≥ 40 years, the OR for prolonged sitting was more than double for married women compared to the unmarried 2.59 (95% CI 1.52–4.40, p < 0.001). In addition, the OR was more than double for physically active older women compared to their inactive counterparts 2.12 (95% CI 1.23–3.66, p = 0.007).

Discussion

This is the first descriptive epidemiological study of sedentary behavior for a national population not only for Oman but for any of the oil-producing countries of the Arabian Peninsula. The prevalence of prolonged sitting time (≥ 7 hours/day) was significantly higher in men and women age ≥ 40 years compared to their younger cohorts. Education, marital status, working status, and physical activity levels were associated with prolonged sitting time but varied by gender and age.

Higher daily sitting times are associated with greater risk of all-cause mortality.10,11 A threshold of ≥ 7 hours/day has been proposed as a basis for public health recommendations.10 However, few studies used this cut-point making comparisons difficult. In this study, one in five Omani adults reported high sitting times. Similar proportions were seen in some parts of southern Europe (i.e., Hungary, Portugal, and Romania), the lowest in the continent; prevalences were much higher (≥ 30%) in countries in north western Europe.24

Although this study does not identify domain-specific sitting, it establishes a basis for monitoring sitting time trends in the region. Further research using objective measurements (such as accelerometers) and tools that assess sitting time across domains (e.g. occupational, transport, and leisure-time) are warranted.25,26 Given the changing trends in occupational, leisure activity, and motorization, research should focus on prolonged occupational sitting, sitting in cars, and screen use (TV, smart phones, and computers) during leisure.15

Higher prevalence of more-prolonged sitting among older adults contrasts with findings from Sur, a city 150 km from the national capital (Muscat), which reported age having a negative association among women.27 Similar to the findings for gender, this trend is not consistently reported globally.24,28−30 The variations by age and gender for sitting time in Oman could be due to various factors including occupational patterns, leisure time activities as well as cultural characteristics.28,29,31 It is possible, for example, that men and women of different age groups living in agricultural areas of the northern coast and southern tip of the country have differing activity patterns compared to the maritime communities of eastern Oman, the more nomadic communities of the desert region and the modernized parts of the capital city. Further research is required to better understand the age and gender relationships. Given the higher levels of inactivity among women and the differing associations of activity with the correlates according to gender, public health interventions should be targeted specifically to men and women.15,32,33

The higher odds of sitting time for men who are employed compared to unemployed indicates the importance of understanding the labor market. A multi-county review reported a similar finding with overall leisure sitting time,30 a common measure of sedentary behavior. Due to the high dependency on non-nationals, particularly in the unskilled labor market, it is likely Omani men are increasingly being employed in sedentary occupations. Thus, the Omani working population is a key group that
could be targeted for the reduction of sedentary behavior. Further research to examine occupational sitting would be useful for the development of appropriate interventions.

Among the other sociodemographic correlates examined, only higher educational attainment showed a significant association with prolonged sitting in younger women. Globally, results are mixed; the Eurobarometer study reported a positive association24 as seen among men in Sur, Oman.27 The International Prevalence Study reported broadly similar findings for 15 of the 20 countries.30 Further examination of the relationships of educational attainment and other indicators of socioeconomic position with domain-specific sedentary behavior would better identify possible high risk groups for targeting interventions.

Numerous studies have explored the association of sedentary behavior with physical activity. Many report higher sedentary behavior being associated with less physical activity,24,28,30 however, others detect no association or a positive association, higher sedentary behavior associated with higher physical activity.30 The positive association seen among older adults in this study warrants further examination. Domain-specific studies for both physical activity and sedentary behavior would help better assess
their relationship.

This study was a population-based national survey of Omani adults that followed a standard protocol and the data was weighted to the Omani population. However, four key limitations were identified. First, although the instrument is widely used in the region, it has not been validated for an Arab population. Second, given the error associated with self-reported measures and the one-item sitting time measure, it is possible that the reported sitting time is over- or underestimated. Objective measures would be useful to better understand sedentary behavior in this population. Third, dividing educational attainment into only two categories may have resulted in potentially biased findings. It is possible that more educated adults have better health literacy than their less educated counterparts. A larger sample would have been helpful to ensure adequate numbers in all categories to allow a more thorough exploration of the associations of education and behavior. Finally, the associations reported do not denote causality owing to the cross-sectional nature of the study.

Conclusions

Prolonged time spent in sedentary behavior is an emerging public health concern, particularly since the rates of type 2 diabetes, cardiovascular disease, and obesity are escalating in the countries of the Arabian Peninsula. These findings provide the first national-level evidence on the prevalence and correlates of this behavior in Omani adults. One in five Omani adults sit for seven or more hours every day, and preventive approaches focusing on older adults and working men may have public health benefit. However, further research is needed to understand domain-specific sitting time and to further identify high risk groups, in order to guide decision-makers in developing the most relevant preventive approaches.

Disclosure

The authors declared no conflicts of interest. No funding was received for this study.

Acknowledgements

The authors acknowledge the support by the Ministry of Health, Oman for providing the raw data. The views expressed in this paper are those of the authors and do not necessarily reflect those of the WHO.

references

1. 1. Rahim HF, Sibai A, Khader Y, Hwalla N, Fadhil I, Alsiyabi H, et al. Non-communicable diseases in the Arab world. Lancet 2014 Jan;383(9914):356-367.
2. 2. Ng SW, Zaghloul S, Ali HI, Harrison G, Popkin BM. The prevalence and trends of overweight, obesity and nutrition-related non-communicable diseases in the Arabian Gulf States. Obes Rev 2011 Jan;12(1):1-13.
3. 3. Ministry of Health. National policy on the prevention and control of noncommunicable diseases. 2016; Oman.
4. 4. Al-Mawali A. Non-Communicable Diseases: Shining a Light on Cardiovascular Disease, Oman’s Biggest Killer. Oman Med J 2015 Jul;30(4):227-228.
5. 5. Khan MU. Lifestyle modification in the prevention of type II diabetes mellitus. Oman Med J 2012 Mar;27(2):170-171.
6. 6. Gibbs BB, Hergenroeder AL, Katzmarzyk PT, Lee IM, Jakicic JM. Definition, measurement, and health risks associated with sedentary behavior. Med Sci Sports Exerc 2015 Jun;47(6):1295-1300.
7. 7. Pate RR, O’Neill JR, Lobelo F. The evolving definition of “sedentary”. Exerc Sport Sci Rev 2008 Oct;36(4):173-178.
8. 8. Owen N, Healy GN, Matthews CE, Dunstan DW. Too much sitting: the population health science of sedentary behavior. Exerc Sport Sci Rev 2010 Jul;38(3):105-113.
9. 9. de Rezende LF, Rodrigues Lopes M, Rey-López JP, Matsudo VK, Luiz OdoC. Sedentary behavior and health outcomes: an overview of systematic reviews. PLoS One 2014 Aug;9(8):e105620.
10. 10. Chau JY, Grunseit AC, Chey T, Stamatakis E, Brown WJ, Matthews CE, et al. Daily sitting time and all-cause mortality: a meta-analysis. PLoS One 2013 Nov;8(11):e80000.
11. 11. Matthews CE, George SM, Moore SC, Bowles HR, Blair A, Park Y, et al. Amount of time spent in sedentary behaviors and cause-specific mortality in US adults. Am J Clin Nutr 2012 Feb;95(2):437-445.
12. 12. Ekelund U, Steene-Johannessen J, Brown WJ, Fagerland MW, Owen N, Powell KE, et al; Lancet Physical Activity Series 2 Executive Committe; Lancet Sedentary Behaviour Working Group. Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet 2016 Sep;388(10051):1302-1310.
13. 13. Hamilton MT, Healy GN, Dunstan DW, Zderic TW, Owen N. Too little exercise and too much sitting: Inactivity physiology and the need for new recommendations on sedentary behavior. Curr Cardiovasc Risk Rep 2008 Jul;2(4):292-298.
14. 14. Wilmot EG, Edwardson CL, Achana FA, Davies MJ, Gorely T, Gray LJ, et al. Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis. Diabetologia 2012 Nov;55(11):2895-2905.
15. 15. Mabry R, Koohsari MJ, Bull F, Owen N. A systematic review of physical activity and sedentary behaviour research in the oil-producing countries of the Arabian Peninsula. BMC Public Health 2016 Sep;16:1003.
16. 16. Mabry RM, Winkler EA, Reeves MM, Eakin EG, Owen N. Associations of physical activity and sitting time with the metabolic syndrome among Omani adults. Obesity (Silver Spring) 2012 Nov;20(11):2290-2295.
17. 17. World Health Organization. World Health Survey, To Strengthen national capacity to monitor critical health outcomes and health systems [cited 16 November 2013]. Available from: http://apps.who.int/healthinfo/systems/surveydata/index.php/catalog/whs/about.
18. 18. Al Riyami A, Elaty MA, Morsi M, Al Kharusi H, Al Shukaily W, Jaju S. Oman world health survey: part 1 - methodology, sociodemographic profile and epidemiology of non-communicable diseases in oman. Oman Med J 2012 Sep;27(5):425-443.
19. 19. Bull FC, Maslin TS, Armstrong T. Global physical activity questionnaire (GPAQ): nine country reliability and validity study. J Phys Act Health 2009 Nov;6(6):790-804.
20. 20. Trinh OT, Nguyen ND, van der Ploeg HP, Dibley MJ, Bauman A. Test-retest repeatability and relative validity of the Global Physical Activity Questionnaire in a developing country context. J Phys Act Health 2009;6(Suppl 1):S46-S53.
21. 21. Armstrong T, Bull F. Development of the World Health Organization Global Physical Activity Questionnaire (GPAQ). J Public Health (Bangkok) 2006;14(2):66-70.
22. 22. Mokhtar B. Urban system and primate city in Oman. British Journal of Arts and Social Sciences 2013;13(1):84-95.
23. 23. World Health Organization. Global Physical Activity Questionnaire (GPAQ) Analysis Guide. Geneva, Switzerland; 2005.
24. 24. Bennie JA, Chau JY, van der Ploeg HP, Stamatakis E, Do A, Bauman A. The prevalence and correlates of sitting in European adults - a comparison of 32 Eurobarometer-participating countries. Int J Behav Nutr Phys Act 2013 Sep;10(11):107.
25. 25. Healy GN, Clark BK, Winkler EA, Gardiner PA, Brown WJ, Matthews CE. Measurement of adults’ sedentary time in population-based studies. Am J Prev Med 2011 Aug;41(2):216-227.
26. 26. Clark BK, Sugiyama T, Healy GN, Salmon J, Dunstan DW, Owen N. Validity and reliability of measures of television viewing time and other non-occupational sedentary behaviour of adults: a review. Obes Rev 2009 Jan;10(1):7-16.
27. 27. Mabry RM, Winkler EA, Reeves MM, Eakin EG, Owen N. Correlates of Omani adults’ physical inactivity and sitting time. Public Health Nutr 2013 Jan;16(1):65-72.
28. 28. Wallmann-Sperlich B, Bucksch J, Hansen S, Schantz P, Froboese I. Sitting time in Germany: an analysis of socio-demographic and environmental correlates. BMC Public Health 2013 Mar;13:196.
29. 29. Bauman A, Ainsworth BE, Sallis JF, Hagströmer M, Craig CL, Bull FC, et al; IPS Group. The descriptive epidemiology of sitting. A 20-country comparison using the International Physical Activity Questionnaire (IPAQ). Am J Prev Med 2011 Aug;41(2):228-235.
30. 30. O’Donoghue G, Perchoux C, Mensah K, Lakerveld J, van der Ploeg H, Bernaards C, et al; DEDIPAC Consortium. A systematic review of correlates of sedentary behaviour in adults aged 18-65 years: a socio-ecological approach. BMC Public Health 2016 Feb;16(1):163.
31. 31. Mabry RM, Al-Busaidi ZQ, Reeves MM, Owen N, Eakin EG. Addressing physical inactivity in Omani adults: perceptions of public health managers. Public Health Nutr 2013 Jan;17(3):674-681.
32. 32. Mabry RM, Reeves MM, Eakin EG, Owen N. Evidence of physical activity participation among men and women in the countries of the Gulf Cooperation Council: a review. Obes Rev 2010 June; 11(6):457-464.
33. 33. Hassanzadeh J, Moradi N, Esmailnasab N, Rezaeian S, Bagheri P, Armanmehr V. The correlation between gender inequalities and their health related factors in world countries: a global cross-sectional study. Epidemiology Research International, 2014 Nov; 2014, Article ID 521569.