ORIGINAL RESEARCH

Health-promoting behaviour among women with abdominal obesity: a conceptual link to social support and perceived stress Jeong Hyun Cho, Sae Young Jae, IL Han Choo & Jina Choo Accepted for publication 5 October 2013

Correspondence to J. Choo: e-mail: [email protected] Jeong Hyun Cho PhD RN Researcher College of Nursing, Korea University, Seoul, South Korea Sae Young Jae PhD Associate Professor Department of Sports and Informatics, College of Arts and Physical Education, University of Seoul, South Korea IL Han Choo MD PhD Assistant Professor Department of Neuropsychiatry, School of Medicine, Chosun University, Gwangju, South Korea Jina Choo PhD DrPH RN Associate Professor College of Nursing, Korea University, Seoul, South Korea

C H O J . H . , J A E S . Y . , C H O O I . H . & C H O O J . ( 2 0 1 4 ) Health-promoting behaviour among women with abdominal obesity: a conceptual link to social support and perceived stress. Journal of Advanced Nursing 70(6), 1381–1390. doi: 10.1111/jan.12300

Abstract Aim. To identify a conceptual link among health-promoting behaviour, interpersonal support and perceived stress and to examine whether the link between interpersonal support and health-promoting behaviour would be mediated by perceived stress among women with abdominal obesity. Background. Abdominal obesity is a strong risk factor for cardiovascular disease in women and its reduction can be achieved by weight loss. Adopting healthpromoting behaviour may be critical for successful weight loss. Design. A cross-sectional, correlational study design. Method. Study participants were 126 women with abdominal obesity, who comprised a baseline sample in the Community-based, Heart and Weight Management Trial. The Data were collected between September 2010–November 2011. A multiple regression analysis and Sobel’s test were performed. Findings. Higher levels of interpersonal support and lower levels of perceived stress were significantly associated with higher levels of health-promoting behaviour, after controlling for age, obesity-related comorbidity, postmenopausal status and current smoking in the regression models. The association between interpersonal support and health-promoting behaviour was significantly mediated by perceived stress in the Sobel’s test; the magnitude of the association between interpersonal support and health-promoting behaviour decreased when adding perceived stress to the predictor variables in the regression model. Conclusion. Our findings indicate the practical significance of identifying the levels of interpersonal support and perceived stress among women seeking weight management interventions. Nurses need to develop effective strategies for enhancing social support and stress management skills in weight management interventions for facilitating health-promoting behaviour. Keywords: abdominal obesity, health behaviour, health promotion, nursing, psychological stress, social support, women

© 2013 John Wiley & Sons Ltd

1381

J. H. Cho et al.

Why is this research or review needed? • Abdominal obesity is a strong risk factor for cardiovascular disease in women and its reduction can be achieved by weight loss. • Adopting health-promoting behaviour may be critical for successful weight loss. • Identifying factors conceptually linked with health-promoting behaviour is necessary for providing the theoretical basis required to develop effective nursing strategies to facilitate health-promoting behaviour for successful weight loss.

What are the key findings? • Factors conceptually linked with health-promoting behaviour were interpersonal social support and perceived stress among women with abdominal obesity. • The conceptual link between interpersonal social support and health-promoting behaviour was mediated by perceived stress.

How should the findings be used to influence policy/ practice/research/education? • Our key findings indicate the practical significance of assessing the levels of social support and perceived stress among women seeking weight management interventions. • Based on our key findings, nurses should develop effective strategies for enhancing social support and stress management skills in weight management interventions for facilitating health-promoting behaviour.

Introduction Obesity is now recognized as one of the most prevalent public health problems, even in low- and middle-income countries. The World Health Organization has already declared obesity a global epidemic that constitutes one of the greatest current health problems (World Health Organization 2000). Being obese is associated with numerous health problems, including hypertension, type 2 diabetes mellitus and cardiovascular disease (Mokdad et al. 2003, Lavie et al. 2009). Growing evidence has shown that abdominal obesity is strongly associated with insulin resistance, dyslipidaemia and systematic inflammation, which play essential roles in the pathogenesis of cardiovascular disease (Zhu et al. 2002, Wang et al. 2005, Zhang et al. 2008). More evidence exists regarding the risk for cardiovascular disease associated with abdominal obesity among women compared with men (Rexrode et al. 1998, Zhang et al. 2008). The Nurses’ 1382

Health Study reported that abdominal obesity was strongly and positively associated with cardiovascular mortality and cancer mortality among women (Zhang et al. 2008). Weight loss is crucial for the reduction of abdominal obesity, which may result primarily from adopting healthpromoting behaviours. It has been reported that the levels of health-promoting behaviours among obese women were lower than among non-obese women (Nies et al. 1998). Thus, factors associated with health-promoting behaviours need to be identified to develop effective nursing strategies for facilitating health-promoting behaviours required for successful weight loss among obese women. Previous literature has demonstrated that social support and perceived stress may be associated with health-promoting behaviours (Stark & Brinkley 2007, Peker & Bermek 2011). The Health Promotion Model (HPM) shows that interpersonal influences have a direct effect on desired health-promoting behaviours (Pender et al. 2006). However, no previous studies have reported a specific pathway through which such social support and perceived stress would influence health-promoting behaviour and, at the same time, perceived stress would play a role as a mediator in the association between social support and healthpromoting behaviour among obese women. Therefore, the theoretical basis for perceived stress as a mediator needs to be addressed, in light of earlier research studies that have provided theoretical and empirical evidence for an association between social support and health-promoting behaviour and between perceived stress and health-promoting behaviour. We have proposed four hypotheses in the present study: (1) Interpersonal support would be positively associated with health-promoting behaviour in women with abdominal obesity; (2) interpersonal support would be negatively associated with perceived stress in women with abdominal obesity; (3) perceived stress would be negatively associated with health-promoting behaviour in women with abdominal obesity; and (4) perceived stress would mediate the association between interpersonal support and health-promoting behaviour in women with abdominal obesity.

Background Recent studies have reported that health-promoting behaviours may be a prerequisite for preventing chronic diseases such as diabetes and cardiovascular diseases (Beaglehole et al. 2011) and for improving general well-being (Ko 2006, Pender et al. 2006, Zahran et al. 2007). According to the Health Promotion Model, health-promoting behaviour is a comprehensive pattern of actions and cognitions © 2013 John Wiley & Sons Ltd

JAN: ORIGINAL RESEARCH

that aim to augment the level of wellness, self-actualization and fulfilment of an individual (Pender 1996). The Health Promotion Model that was first formulated by Pender in 1982 and then revised in 1996 is an explanatory model of health behaviour that emphasizes the role of expectations in shaping behaviour (Pender 1996, Pender et al. 2006). Obesity, social support and health-promoting behaviour Obesity and social support may be closely interrelated. Obese persons have significantly lower levels of support in their family and peer relationships (Carr & Friedman 2006, Fletcher et al. 2011) and studies have reported that those who are obese are highly stigmatized and socially isolated (Puhl & Brownell 2001, Puhl & Heuer 2009). These factors may then affect their self-esteem and mood (Schmalz 2010), which, in turn, are associated with poorer interpersonal relationships (Carr & Friedman 2006). The lack of social networks and social support may affect the poor levels of health behaviours, which may lead to poor health outcomes (House et al. 1988, Melchior et al. 2003, Cohen & Lemay 2007). The marriage and friendship ties were associated with preventive health behaviour such as physical activity, smoking cessation, less drinking and healthy eating in adults (Seeman 2000). Conversely, Cohen and Lemay (2007) reported that those with diverse social networks smoked less and drank less than those with low social interactions. However, little evidence has been found for such an association between social support and health-promoting behaviour among women, especially obese women. Obesity, perceived stress and health-promoting behaviour Obesity may be associated with perceived stress (Roberts et al. 2007, Wardle et al. 2011). Physiologically, stressinduced cortisol reactivity may play an important role in eating behaviour and food intake, resulting in subsequent weight changes during periods of prolonged stress (Adam & Epel 2007, Torres & Nowson 2007). As a result, psychosocial stress may induce weight gain, especially among overweight and obese women (Epel et al. 2001, Block et al. 2009). Additionally, individuals’ means of coping with psychological stress have often been associated with body weight regulation through their impact on behaviours (Krueger & Chang 2008). Social support and perceived stress Social support may be associated with a reduction in perceived stress. Specifically, interpersonal relationships may protect one from the potentially pathogenic effects of a stressful event (Cohen & Wills 1985). Supportive relation© 2013 John Wiley & Sons Ltd

Health-promoting behaviour in women with abdominal obesity

ships may help individuals manage their weight and may help buffer against the distress associated with weight-based discrimination and health problems (House et al. 1988, Carr & Friedman 2005). We thus posited that health-promoting behaviour would be conceptually linked to social support and perceived stress and specifically tested whether perceived stress plays a role as a mediator in the association between interpersonal support and health-promoting behaviour among women with abdominal obesity.

The study Aim The purpose of the study was to identify a conceptual link among interpersonal support, perceived stress and healthpromoting behaviour and to examine whether the link between social support and health-promoting behaviour would be mediated by perceived stress among women with abdominal obesity.

Design A cross-sectional, correlational study design was used in this analysis, using data from a parent study, the Community-based Heart and Weight Management Study. The parent study is an ongoing, single-centre, randomized controlled trial, testing the differential effects of a weight management intervention by exercise mode on subclinical atherosclerosis as a primary outcome among women with abdominal obesity. Participants who satisfied the eligibility criteria of the parent study (n = 110) were randomized to an aerobic exercise group (n = 50), a resistance exercise group (n = 30) and a combination group (n = 30) and then followed up for 12 months. The eligibility criteria were as follows: (1) age between 18 and 65 years; (2) waist circumference of 85 cm or greater, the criteria for abdominal obesity as defined by the Korean Society for the Study of Obesity (Stark & Brinkley 2007); (3) willingness to be randomly assigned to one of three different exercise modes; (4) no current medical conditions such as cardiovascular diseases, diabetes, or cancers requiring physician supervision; and (5) no physical limitation restricting exercise ability.

Participants Study participants for this analysis were 126 women who visited the baseline enrolment session of the parent study and completed self-administered questionnaires. The mini1383

J. H. Cho et al.

mum sample size of the present study was 97 subjects, with the desired statistical power level at 0
80, an anticipated effect size of 0
15 for predictor variables on the outcome variable, a type I error rate of 0
05 and six predictors (Table 5) (Cohen et al. 2003, Soper 2013). Between September 2010 and November 2011, the participants were recruited into two cohorts spaced 7 months apart, from a community in Seoul, South Korea. Methods of recruitment included the use of posters and leaflets; a database of persons seeking weight-loss treatment at a community health centre; and telephone and mailing announcements to staff, students and faculty at Korea University.

Measures The following instruments were used to collect the data. Health Promoting Lifestyle Profile-II The Health Promoting Lifestyle Profile-II (HPLP-II) was used to measure participants’ levels of health-promoting behaviours (Walker & Hill-Polerecky 1996). This scale contains 52 items, asking participants to indicate the frequency with which they engaged in each behaviour on a 4-point Likert scale (1 = never - 4 = routinely). This scale contains six subgroups: self-actualization, health responsibility, physical activity, nutrition, interpersonal relations and stress management. High scores on the scales indicated higher levels of health-promoting behaviours, ranging from 1–4 points. The English version of the HPLP-II was translated into Korean separately by three Korean nursing scholars and the three Korean versions were discussed, confirmed and consolidated into a single Korean version. Then the Korean version was back-translated by a native English speaker. The back-translated English version was again confirmed by the nursing scholars who translated it into Korean. Cronbach alpha coefficients for the total score were 0
94 in the original study (Walker & Hill-Polerecky 1996) and 0
88–0
90 in a community-based sample of women (Nies et al. 1998). In the present study, the Cronbach’s alpha was 0
91. Interpersonal Support Evaluation List The Interpersonal Support Evaluation List (ISEL) was used to measure the perceived availability of social support resources. This scale consists of four 10-item subscales reflecting appraisal (availability of people to whom one can talk about personal problems), belonging (availability of someone with whom one can do things), tangible (instrumental aid) and self-esteem (perception of a positive comparison when comparing oneself with others) (Cohen 1384

et al. 1985). Responses range from definitely false to definitely true (from 0–3) on a 4-point Likert scale. Higher scores indicated a better perception of social support availability, ranging from 0–120 points for the total score and 0–30 points for each subscale score. The English version of the ISEL instrument was translated and back-translated in the same manner as the HPLP-II instrument. Cronbach’s alpha coefficients for the total ISEL scores ranged from 0
88–0
90 in previous studies (Cohen et al. 1985). In the present study, the Cronbach’s alpha was 0
94. Perceived Stress Scale The Korean version of the Perceived Stress Scale (PSS) was used to assess perceptions of how unpredictable, unmanageable and stressful life had been during the past month. This scale contains 10 items, asking participants to indicate their response to each item on a 5-point Likert scale (0 = never – 4 = very often). High scores on the scale indicated higher levels of perceived stress. The PSS has demonstrated good reliability and validity, with Cronbach’s alphas ranging from 0
78–0
91 (Cohen et al. 1983, Cohen & Williamson 1988). In the present study, the Cronbach’s alpha was 0
85.

Ethical considerations Participants were given an explanation regarding the purpose of the study and they provided written informed consent. Participants were asked to complete questionnaire packages of the community-based Heart and Weight Management Study, including sociodemographic, health-related and psychosocial variables. The study was approved by the Institutional Review Board at Korea University (KU-IRB11-10-A-2) and all procedures were followed in accordance with the ethical standards of this board.

Data analysis Data were analysed using SPSS 18.0 (SPSS Inc., Chicago,IL, USA). A P-value less than 0
05 was considered significant. The frequencies, percentages, means and standard deviations (SD) of the study variables are presented in Tables 1 and 2. To identify correlates of health-promoting behaviour with participants’ characteristics (i.e. sociodemographic and health-related variables), a Student’s t-test and a Pearson’s correlation analysis were performed on the continuous variables and dichotomous variables, respectively (Table 3). Additionally, to identify correlates of health-promoting behaviour with the main study variables (i.e. ISEL and PSS), a Pearson correlation analysis was performed (Table 4). © 2013 John Wiley & Sons Ltd

JAN: ORIGINAL RESEARCH

Health-promoting behaviour in women with abdominal obesity

Table 1 Participants’

characteristics: health-related variables (N = 126) Characteristics

Age Marital status Married Single/separated/widowed/ divorced Education Some college or more High school degree or less Monthly income (won)* 4,000,000 Religion, yes Employment, yes Body weight (kg) Body mass index (kg/m2) Waist circumference (cm) Obesity-related comorbid conditions† Postmenopause Current smoking Alcohol drinking (2 or more/week)

Sociodemographic

and

pants’ characteristics (N = 126)

n (%)

t (P†)

Mean (SD)

Characteristics

42
6 (9
5)

Age Married College educated or higher* Monthly income (>4,000,000 won)* Religion (yes)* Employment (yes)* Body weight (kg) Body mass index (kg/m2) Waist circumference (cm) Obesity-related comorbid conditions (yes)* Postmenopause (yes)* Current smoking (yes)* Alcohol drinking (2 or more/week)*

100 (79
4) 26 (20
6)

76 (60
3) 50 (39
7) 57 69 81 50

Table 3 Correlates of health-promoting behaviour with partici-

(45
2) (54
8) (64
3) (39
7) 72
2 (10
3) 28
4 (3
8) 94
9 (7
7)

33 (26
2)

r (P‡) 0
20 (0
027)

1
06 (0
292) 0
05 (0
964) 0
75 (0
453) 1
29 (0
200) 0
42 (0
678) 0
00 (0
963) 0
06 (0
534) 0
04 (0
660) 1
56 (0
121) 1
68 (0
095) 2
28 (0
024) 0
81 (0
420)

*Dichotomous variables. † Significance obtained by Student’s t-test. ‡ Significance obtained by Pearson’s correlation analysis. SD, standard deviation.

34 (27
0) 8 (6
3) 12 (9
5)

Table 4 Correlates of health-promoting behaviour with main *For monthly income, participants were asked to report their income in won, which is the South Korean currency; a million won is approximately equal to 889 U. S. dollars (The World’s Favorite Currency Site’s 2012). † Obesity-related comorbid conditions include hypertension and hyperlipidaemia. SD, standard deviation.

Table 2 Means, standard deviations and range of scores for main study variables (N = 126) Variables HPLP-II Total score Health responsibility Physical activity Nutrition Spiritual growth Interpersonal relations Stress management ISEL Total score Appraisal Tangible Self-esteem Belonging PSS

Mean (SD)

2
1 1
8 1
5 2
4 2
4 2
5 2
1

(0
3) (0
5) (0
5) (0
5) (0
6) (0
4) (0
5)

82
2 22
2 20
5 19
0 20
6 17
2

(15
5) (4
5) (4
7) (3
7) (4
7) (5
6)

r (P*) Variables ISEL PSS HPLP-II

ISEL 1
00 0
47 (