The relationship between quality of life and perceived body weight ...

International Journal of Obesity (2001) 25, 1386–1392 ß 2001 Nature Publishing Group All rights reserved 0307–0565/01 $15.00 www.nature.com/ijo

PAPER The relationship between quality of life and perceived body weight and dieting history in Dutch men and women CM Burns1*, MAR Tijhuis1 and JC Seidell1 1 Department of Chronic Diseases Epidemiology, National Institute of Public Health and the Environment, Bilthoven, The Netherlands

OBJECTIVES: (1) To study the relationship between quality of life (QoL) and measured and perceived weight and dieting history in Dutch men and women; (2) to assess the effect of weight loss over a 5 y period on QoL. DESIGN: A cross-sectional study, in a sub-sample longitudinal over 5 y. SUBJECTS: A total of 2155 men and 2446 women, aged 20-59 and recruited from the general population from three towns in The Netherlands. MEASUREMENTS: Body weight, height, self-administered questionnaire including questions concerning demographic variables and weight loss practices as part of the Dutch Monitoring project on Risk Factors for Chronic Disease (MORGEN). The Rand-36 questionnaire was used as the QoL measure. RESULTS: In men, measured overweight (body mass index, BMI>25 kg=m2) was not associated with any dimension of QoL after adjustment for age, educational level and perceived overweight. Perceived overweight was related to reduced scores for general health and vitality. This relationship was independent of measured obesity. A history of repeated weight loss was associated with reduced scores for role functioning due to both physical and emotional problems. In women, measured overweight was significantly associated with lower scores for five out of eight QoL dimensions and perceived overweight with three: general health, vitality and physical functioning. A history of frequent weight loss was related to significantly reduced scores in six dimensions. However, only with history of frequent weight loss, and uniquely in women, was there a significant reduction in scores on mental health and limited emotional role functioning. Measured and perceived overweight and frequent weight loss were all related to reduced scores for physical functioning. Longitudinal data indicate that in older women weight gain of 10% body weight or more was associated with a significant deterioration in QoL. CONCLUSIONS: When looking at measures of QoL in relation to overweight it is important to separate the effects of perception of weight status and history of weight loss. We observed that the latter two factors were associated with reduced scores on several dimensions of QoL, particularly in women. These associations were observed to be independent of body weight. International Journal of Obesity (2001) 25, 1386 – 1392 Keywords: quality of life; body weight; perceived weight; dieting

Introduction Obesity is a wide-spread and increasing public health problem. It is associated with negative health impact and elevated mortality. The deleterious effects of extreme obesity on quality of life (QoL) and psychosocial functioning have

*Correspondence: CM Burns, School of Health Sciences, Deakin University, 221 Burwood Highway, Victoria, Australia 3125. E-mail: [email protected] Received 5 July 2000; revised 16 February 2001; accepted 1 March 2001

been well described.1 – 5 Massive weight loss in the obese population, usually induced by surgery, has been shown to improve both physical and mental aspects of QoL.5,6 There is some information on QoL and lesser degrees of overweight using QoL measures. Most studies have concentrated on impairment of physical functioning with overweight.7 – 9 Stafford10 showed that current body mass index (BMI) was monotonotically associated with poor physical functioning in women, with evidence of threshold effect of current BMI in men at 27 kg=m2.10 Han11 looked at a comprehensive range of QoL dimensions and demonstrated a direct association between adiposity and abdominal obesity and physical

Quality of life and perceived body weight CM Burns et al

1387 functioning with some evidence of impairment in other aspects of psychosocial functioning.11 Brown, et al12 showed some decreased vitality and poorer mental health in overweight and obese women. However, although it is known that excess body weight is detrimental to physical well-being and is associated with social stigma13 and some psychological distress,14 the effect of perceived weight status on QoL both physical and emotional has not been explored. The perception of body size can be defined as ‘the picture of our own body which we form in our own mind’.15 Men and women are known to be inaccurate in their perception of body size.16 Men have been shown to underestimate even frank obesity and women to overestimate relative adiposity.17 In men, this underestimation, if real, may lessen the likelihood of weight control action being taken.18 In women, distortion of body size perception can be associated with disordered eating.19 However, it is not known, whether perception of weight status, influences physical and mental aspects of QoL. In addition, dieting behaviour is ubiquitous13 and known to cause psychological harm20 and eating disorders in specific sub-populations.19 As a consequence of dieting many individuals experience cycles of weight gain and weight loss which may be both physically and psychologically harmful. It is therefore also of interest to quantify the effect of dieting and a history of repeated weight loss associated with an impairment in either physical or mental QoL in the general population. The aim of this study was: (1) to examine cross-sectionally the relative effect of measured and perceived body weight and history of past weight loss on QoL; (2) to assess the relationship between weight change over previous 5 y and current QoL.

Methods Subjects Subjects were selected from the Dutch Monitoring Project on Risk Factors for Chronic Diseases (MORGEN). The data used to investigate the cross-sectional research questions where collected in 1995. Randomised samples of men and women aged 20 – 59 y and stratified according to gender and 5 y age categories were selected from the municipal registry of Amsterdam and Maastricht. In Doetinchem, the study population consisted of individuals who had participated in 1989 in the previous Monitoring Project on Cardiovascular Disease Risk Factors. In 1995, these individuals were aged 26 – 65 y. In addition a random sample of those aged 20 – 25 y was taken. For the cross-sectional analyses presented here, we selected all respondents aged 20 – 59 y in 1995. For the analyses on longitudinal relationships we selected all respondents from the Doetinchem cohort, aged 26 – 59 y in 1995, for whom data were also collected in 1989. In 1995, a total of 4946 subjects agreed to participate in the study (mean response rate 44%). To assess the possible selection bias a continuous non-response survey was performed. Non-responders tended to be somewhat younger

compared to the study population. However, their education and smoking behaviour was comparable to that of the people who participated.17 The study population used in the cross-sectional analyses included 4601 subjects (2155 men and 2446 women). The number of respondents included in the longitudinal analyses on weight changes from 1989 to 1995 and QoL measured in 1995 is 1113 (534 men and 579 women). Those who were pregnant (n ¼ 30), those who had a history of cancer (n ¼ 133) and those who were of non-Dutch nationality (n ¼ 2) were excluded from analysis. In addition, subjects with a BMI < 18.5 kg=m2 (n ¼ 79) and subjects with missing data on education, height, weight (n ¼ 35) were excluded. Participants received two questionnaires to complete at home, a general and a dietary questionnaire, and were invited to attend a medical examination at the Municipal Health Service where blood samples were collected, blood pressure was measured, and anthropometric measurements were taken. The general questionnaire consisted of questions on demographic characteristics, on risk factors for chronic disease, and on QoL. A series of closed questions about perception of weight status, current weight control status, history of weight loss and dieting were included in 1995. These questions asked: ‘How would you describe your weight?’ ‘How frequently over your whole life have you lost more than 5 kg by dieting?’ ‘Are you trying to do something about your weight at the moment?’ Variables were categorised in: (1) self-perceived weight status — too fat, too thin, just right; (2) current weight control status — lose, gain, maintain, nothing; (3) weight loss diet in last year — never, once, 2 – 5 times, over 5 times; (4) weight losses >5 kg in a lifetime — never, 1 – 2 times, 3 – 5 times, over 5 times. To measure QoL we used the standardised RAND-36 questionnaire,21 which was adapted from the standardised SF-36 Health Survey. This questionnaire comprises measures of functioning — the ability to perform daily tasks and activities, and measures of well-being — subjective internal states including how people feel physically and emotionally and how they think and feel about their health. The eight dimensions are: physical functioning, role functioning limitations due to poor physical health, bodily pain, general health, vitality, social functioning, role functioning limitations due to poor emotional health and mental health. The 36 items of reported health were grouped to make up the eight dimensions and converted into standardised scores (Table 1).11,21 Education, a possible confounder, was used as a measure for socio-economic status (SES). It was categorised into: low (primary school, lower occupational education or less), medium (secondary level education), and high education (university, higher occupational or corresponding education). Age was categorised as 20 – 40 and 40 – 59 y. During the medical examination respondents were weighed wearing indoor clothing after they had taken off their shoes and emptied their pockets. Weight and height International Journal of Obesity


1388 Table 1 Basic characteristics, dieting behaviours and standardised quality of life scores of 2042 men and 2352 women Men

Women a

Age (y) 42.9 10.8 2 b BMI (kg=m ) 25.4 3.6 Perceived weight status (%) Too fat 39.3 Too thin 5.9 Just right 54.8 Current weight control status (%) Trying to lose weight 24.8 Trying to gain weight 3.8 Trying to maintain weight 20.0 Doing nothing 51.5 Number of times weight loss diet attempted in last year (%) Never 79.2 Once 13.4 2 – 5 times 6.8 >5 times 0.7 Number of weight losses>5 kg in a lifetime (%) Never 74.8 1 – 2 times 18.1 3 – 5 times 5.5 >5 times 1.7 b Physical functioning (score) 89.7 0.36 b Role functioning — physical (score) 84.4 0.66 Bodily pain (score) 83.2 0.47b General health (score) 70.6 0.39b Vitality (score) 68.0 0.39b b Social functioning (score) 86.7 0.46 b Role functioning — emotional (score) 85.2 0.67 b Mental health (score) 76.1 0.35 a b

41.5 11.1 b 24.5 4.2

a

45.1 3.1 51.8 35.3 2.2 28.0 34.6 62.8 20.2 14.3 2.8 59.2 26.2 11.1 3.5 b 87.0 0.36 b 79.6 0.71 79.4 0.46b 70.2 0.37b 63.0 0.37b b 83.1 0.46 b 80.3 0.73 b 71.8 0.34

Longitudinal analyses consisted of a comparison of mean scores of QoL dimensions over categories of weight change (ANOVA). Weight change between 1989 and 1995 was categorised as gained over 10%, gained 5 – 10%, gained or lost maximum 5%, lost 5 – 10%. For these analyses those subjects losing in excess of 10% of their body weight (n ¼ 17) were excluded on the basis of small numbers.

Results From Table 1 it is apparent that the population had mean BMI in upper range of ideal (men 25.4, women 24.5). The majority of men (55%) believed their weight to be ‘just right’. Most men had never lost >5 kg in their lifetimes or been on a diet in the last 12 months, and were doing nothing about their weight currently (51%). Women were equally divided between those describing themselves as too fat or just right, and between those who were trying to lose weight and doing nothing. In all, 63% of the women had not dieted in the last year and nearly 60% had never lost >5 kg in a lifetime. Men had better QoL (higher scores) than women on all dimensions except for general health. Women who perceived their weight was ‘just right’ had the highest scores over all QoL dimensions compared with those who described themselves as either too fat or too thin. These differences reached significance for all dimensions (Figure 1). For all dimensions those describing themselves

Standard deviation. Standard error of the mean.

were measured to the nearest 0.1 kg and 0.5 cm, respectively. In the data-analyses 1 kg was subtracted from the measured weight, to allow for the clothes. Body mass index (BMI) was calculated as weight divided by height squared (kg=m2) as a measure for relative weight. The cut-off for BMI was 25: 25 was termed overweight and < 25 considered ideal body weight.

Statistical analysis The SAS version 6.12 was used for statistical analyses. In all analyses P-values below 0.05 were considered to be statistically significant. Differences in QoL between the categories of weight perception and history of weight loss were analysed using ANOVA F-test and Scheffe’s test. Relative effect of BMI was determined using ANOVA with adjustment made for perceived weight, age and SES. Relative effects of measured weight, perceived weight, current weight control status and history of weight loss was determined using ANOVA with adjustment for BMI, age and SES. For the analysis on perceived weight and BMI obese individuals who felt they were too thin were excluded because of small number (n ¼ 18). For the same reason respondents with more than two weight losses >5 kg during lifetime were taken together. International Journal of Obesity

Figure 1 Quality of life dimension scores relative to self-perceived weight status in females. Quality of life dimensions designated as follows: physical functioning, role functioning physical, bodily pain, general health, vitality, social functioning, role functioning emotional, mental health. Self-described weight status — too fat, too thin or just right.


1389 as too thin scored lowest. It should be noted that for role functioning, emotional and mental health there was no difference in the scores between those perceiving themselves as just right and too fat. For vitality and social functioning most marked difference were between the too thin and just right categories. For men (results not shown) highest QoL across all dimensions was for the just right category (significant for physical functioning, bodily pain, general health, vitality, social function and mental health) and lowest scores for the too thin category (general health, vitality, social function and mental health). For women the relationship between QoL and weight loss >5 kg in a lifetime is given in Figure 2. There is a direct and positive relationship between history of weight loss and all QoL dimensions with lowest scores being for the women with the strongest history of weight loss. For men (results not shown) a similarly direct relationship was observed between weight loss history and QoL, but differences between weight loss categories were significant only for physical functioning, bodily pain, general health and vitality. BMI adjusted for weight perception, age and SES was not a significant determinant of any QoL dimension for men (Table 2). For women all QoL dimensions (with the exception of vitality, mental health and role-functioning emotional) differed between BMI categories after adjustment, with the overweight having lower mean scores. Perceived weight was associated with general health and vitality, independent of obesity in men. In women, differences between mean scores of perceived weight categories (adjusted for BMI) were significant for physical functioning, general health and vitality with highest mean scores for the just

Figure 2 Quality of life dimension scores relative to weight loss history in females. Quality of life dimensions designated as follows: physical functioning, role functioning physical, bodily pain, general health, vitality, social functioning, role functioning emotional, mental health. Weight loss history is report of frequency of loss >5 kg in lifetime — never, 1 – 2 times, 3 – 5 times, 6 times.

right category. For men, there was lower QoL in terms of physical functioning and role functioning (emotional) with

Table 2 The relationship between BMI, perceived weight status and weight losses and quality of life for men and women (mean quality of life scores standard error of the mean) BMI

a

Perceived weight status

b

Weight losses >5 kg in a lifetime

b

Not overweight

Overweight

Just right

Too fat

Never

1 – 2 times

3 times or more

Men Physical functioning Role functioning — physical Bodily pain General health Vitality Social functioning Role functioning — emotional Mental health

90.0 0.8 84.0 1.6 84.0 1.1 70.6 0.9 68.3 0.9 86.6 1.1 84.2 1.6 75.6 0.8

89.4 0.5 85.1 1.0 83.4 0.7 70.7 0.5 68.6 0.6 87.2 0.7 85.6 1.0 77.2 0.5

90.6 0.5 85.0 1.0 84.2 0.7 72.1 0.5* 70.0 0.5* 87.5 0.6 85.8 1.0 77.2 0.5

88.8 0.8 84.0 1.6 83.2 1.1 69.2 0.9 67.0 0.9 86.3 1.1 84.0 1.6 75.5 0.8

90.5 0.4 85.0 0.8 84.0 0.5 71.1 0.4 68.4 0.5 87.1 0.5 86.2 0.8 76.5 0.4

89.9 1.0 84.6 1.9 82. 1.3 70.1 1.1 69.2 1.1 86.9 1.3 87.0 1.9 76.8 1.0

85.6 1.9* 83.0 3.6 81.3 2.5 70.7 2.1 65.8 2.1 85.6 2.5 76.3 3.7* 73.7 1.9

Women Physical functioning Role functioning — physical Bodily pain General health Vitality Social functioning Role functioning — emotional Mental health

88.5 0.5 81.8 1.1 81.1 0.7 71.7 0.6 63.9 0.6 84.8 0.7 81.9 1.1 72.5 0.6

84.6 0.8* 76.2 1.6* 76.5 1.1* 68.3 0.8* 62.2 0.9 80.6 1.0* 78.1 1.7 70.7 0.8

87.7 0.7* 79.7 1.5 79.1 1.0 70.9 0.8* 64.4 0.8* 83.0 1.0 80.2 1.6 71.8 0.7

85.5 0.5 78.2 1.1 78.5 0.7 69.0 0.6 61.7 0.6 82.4 0.7 79.8 1.2 71.4 0.6

87.1 0.5 80.0 1.1 80.3 0.7 70.1 0.6 63.4 0.6 83.4 0.7 81.0 1.2 72.2 0.6

86.8 0.7 78.2 1.4 78.3 0.9 69.7 0.7 63.2 0.7 82.9 0.9 79.3 1.4 71.9 0.7

83.8 1.0* 75.2 2.1 75.8 1.3* 68.2 1.0 58.5 1.1* 79.5 1.3* 74.8 2.1* 69.1 1.0*

a

ANOVA, adjusted for age, SES and perceived weight status. ANOVA, adjusted for age, SES and BMI. Statistical significant difference in adjusted mean scores, *P < 0.05; **P < 0.01; ***P < 0.001.

b

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Figure 3 Quality of life dimension scores relative to weight change in 40 – 50 y old females. Quality of life dimensions designated as follows: physical functioning, role functioning physical, bodily pain, general health, vitality, social functioning, role functioning emotional, mental health. Weight change over 5 y given as percentage change of initial weight.

more frequent weight loss (after adjustment for BMI). Those women with a stronger history of weight loss had significantly lower scores for physical function, mental health, bodily pain, role functioning, emotional, social function and vitality. Longitudinal analysis showed that women with weight increase of greater than 10% had significant lower QoL scores in terms of physical health, general health and vitality (Figure 3). This was only apparent for females in the age range 40 – 60 y. Weight change over a period of 5 y was not related to QoL in men.

Discussion These results reflect findings in psycho-social literature and speculation on the part of many clinical and public health practitioners that the impact of obesity on well-being more often depend on subjective assessment by an individual of their weight rather then realistic appraisal relative to healthy standards.18 The present study shows that it is important to separate the effects of measured and perceived overweight because they both seem to be independently related to different dimensions of QoL. A history of repeated weight loss also contributes, independently of measured overweight, to reduced scores of emotional and mental dimensions of QoL, particularly in women. These data are International Journal of Obesity

important because they indicate that part of the lower QoL in overweight people is due to their dissatisfaction with their weight or their frustrations with repeated dieting attempts. Overweight per se may lead to reduced QoL especially in the domains of physical functioning, bodily pain and general health, as shown in this study in women, because of the mechanical consequences of carrying excess weight. This finding is consistent with previous reports both by ourselves and others.1 – 10 Perceived overweight, as also shown in the present study in men and women, may be associated with general health and vitality independent of body weight. Physical disability is a logical and well-reported consequence of obesity. Impairment of health and vitality from perceived overweight is more difficult to explain. We would posit that this has its origins in the social stigma attached to obesity and the so called ‘fat phobia’ that pervades our daily life. Previous reports have shown that this disquiet may not reflect an actual problem of overweight or obesity.17,18 The negative effects on mental well-being of perceived overweight have been reported in the psychological literature. Our findings mirror these data and add the dimension of impaired QoL to that of psychological harm. In our society drive for thinness has always had salience for women and now increasingly for men. Hence we observed an impairment in vitality and general health in both sexes and in physical functioning in women, associated with perceived overweight. It has been shown that unsuccessful dieting leads to diminished self-esteem and higher scores of depression.20 The effect observed in the current study between QoL and weight loss history is consistent with these findings. Although dieting is pervasive in our society, weight loss attempts meet with limited success.22 The futility of these attempts coupled with the constantly reinforced notion of weight management being synonymous with personal control ‘if I’m in control of my weight I’m in control of my life’23 may impair QoL. These data may go some way to explaining the increased morbidity shown with repeated cycles of intentional weight loss.24 This may have more relevance for the female psyche, hence the impairment of mental health and emotional well-being in women. Seidell et al25 have previously shown that, in women, dieting behaviour is related independently of overweight to subjective health complaints.25 The interpretation of the present and those earlier findings is not unambiguous. It may be that overweight women with poorer health are more likely to diet than those with better health status. Alternatively, and perhaps more likely, frequent dieting leads to lower QoL scores especially in the domains of emotional well-being and mental health. The results presented here have some limitations because they are observational and cross-sectional but they also may have advantages over other studies. The presented results were obtained in a population-based sample not in selected obese patients presenting for certain medical care such as surgical procedures. The present results may therefore be


1391 more representative. In addition, we know of no other studies that have tried to separate the effects of objectively and subjectively measured overweight and weight loss history. Our study found that in women overweight is more clearly associated with subjective health and QoL than in men. This is puzzling, as there is hardly any difference in the association between the degree of overweight and mortality and morbidity (eg coronary heart disease and diabetes mellitus). We observed earlier, however, that symptoms of chronic low back pain and respiratory symptoms were more strongly related to overweight in women than men.26 It may also be that overweight in women, more than in men, is related to subjective health not only because of somatic symptoms but more to their mental state which is not fully captured by a simple question on perceived weight status. Women may be more attuned or aware of their bodies and their health than men and so for women these perceptions may have more salience.27 We observed a reduction in QoL measures with weight gain but only with weight gain of the order of 10% and only in older women. There was no improvement in QoL with weight loss. A relative weight loss of 10% has been previously shown to be associated with an improvement in cardiovascular risk factors.27 Our finding of impairment of QoL with weight gain was consistent with the longitudinal data of Fine.28 Fine, however, did find an improvement in physical functioning, vitality and bodily pain with weight loss.29 Their study population were however older. The relationship between weight loss and QoL requires further study. QoL should continue to be used as an endpoint for weight control interventions in addition to health risk factors and tool for statistical modelling of benefits of weight control programmes.

Conclusions Though distortion of body image has been previously described in both men and women, the current study is the first to report on the effect of body perception on QoL. Our findings highlight the relative importance of objective and subjective assessments of health risk. This could have implications on an individual’s assessment of health needs and the likelihood of health care action. It has been previously reported that men are slow to take action about their health and somewhat reticent to discuss health issues.30 These results suggest that strategies towards weight management which focus on either weight loss or on weight acceptance may both influence QoL. The current data would suggest that if programmes for weight control are to be directed towards men they need to concentrate on physical benefits of weight loss. For women, the detrimental effect on emotional well-being of perceiving themselves to be too fat, independent of objective weight, is more important. Weight control programmes for women should be tailored to include components on body image and size acceptance.

Acknowledgements The authors would like to thank the MORGEN-project Steering Group and administrative staff as well as the field workers of the participating municipal health services in Doetinchem, Maastrict and Amsterdam for their contributions to the study. The study was made possible by contributions from the Ministry of Health, Sports and Welfare of The Netherlands, and an NHMRC Fellowship from the Commonwealth of Australia to Dr CM Burns. The authors would like to thank Dr Thang Han for his help in the analysis of the data and Professor Damien Jolley for his help with data presentation.

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