Depression and obesity: A meta-analysis of community-based studies☆
Introduction
In recent decades, a considerable number of population-based studies have examined the association between depression and obesity. According to the World Health Organization (WHO), depression is among the leading causes of disability (WHO, 2006), affecting about 121 million people globally at each moment in time. Obesity is an increasing major public health concern. In 2002, the prevalence in the US adult population was 32.2%, having doubled since 1980 (Ogden et al., 2006). Both depression and obesity are causing huge burden of disease and enormous economic costs, worldwide (Allison et al., 1999, Druss et al., 2000, WHO, 2006).
The high prevalence of both might be an indication of an association between depression and obesity (Stunkard et al., 2003). This could be expected from a psychiatric point of view, since increased food intake and decreased physical activity, are Diagnostic and Statistical Manual of Mental Disorders, fourth edition, (DSM-IV) symptoms of depression, and these symptoms are also responsible for weight gain. Furthermore, negative body image and stigmatisation of obese individuals could lead to low self esteem and psychological distress (Ross, 1994). However, this hypothesis has not yet been ascertained in community samples (Stunkard et al., 2003).
Current community studies show mixed results. Some researchers find a positive association (John et al., 2005, Baumeister and Härter, 2007, Ohayon, 2007), some a negative association (Crisp and McGuiness, 1975, Crisp et al., 1980, Palinkas et al., 1996) and there are studies that found no association at all (Kress et al., 2006, Ohayon and Hong, 2006). Hence, it seems clear that not all obese individuals in the general population suffer from mood disorders; accordingly, there could be specific factors protecting some individuals. Sociodemographic variables may be potential moderators and mediators in the association between depression and obesity and might explain the conflicting results (Friedman and Brownell, 1995).
Some researchers have investigated demographic variables as moderators that influence the association between depression and obesity. For instance, a few studies have examined gender as a possible moderator. The results are conflicting, with some studies indicating a significant association between depression and obesity in females but not in males (Istvan et al., 1992, Carpenter et al., 2000, Onyike et al., 2003, McIntyre et al., 2006, Scott et al., 2007), while other studies found no gender discrepancy (Haukkala and Uutela, 2000, Herva et al., 2006). This could possibly be explained by differences in study design. For example some used self-report questionnaires (Haukkala and Uutela, 2000, Herva et al., 2006), while others used DSM-IV criteria to establish a diagnosis (Carpenter et al., 2000, Onyike et al., 2003, McIntyre et al., 2006, Scott et al., 2007). Furthermore, there is evidence that socioeconomic status (SES) influences the association. A stronger association was found among those with higher SES (Moore et al., 1962, Ross, 1994, Scott et al., 2007), but there are studies reporting these findings only for females and not for males (Carpenter et al., 2000). In addition, there are incongruent results for age as a moderating factor, with some showing no age differential effects (Scott et al., 2007), others showing a lack of association in the oldest age group, and one longitudinal study showing an obesity–depression association that rose with increasing age (Hasler et al., 2005). So far, no differences have been found in the association between different ethnic groups (Franko et al., 2005).
Because the results of the studies in this area do not point in the same directions, a meta-analysis may be helpful in clarifying the association between depression and obesity. Until now, only one meta-analysis has been conducted. In this meta-analysis, published in 1995, no association was found between depression and obesity. The authors suggested that there should be more research to investigate the nature of the association between depression and obesity and variables influencing the association (Friedman and Brownell, 1995).
In order to clarify the nature of the association between depression and obesity, and discover which demographic variables (gender, age, diagnostic criteria, and area of residence) and measurement issues have an effect on the association, we conducted a meta-analysis of studies that have been published on this subject.
Section snippets
Literature search
We conducted a systematic literature search. First, we conducted systematic searches in major bibliographical databases (Pubmed, PsycInfo and Embase; the end date of the search was 20 September 2007). In these databases we combined keywords and text words referring to obesity (obesity, BMI, body mass index and overweight) and depression (depressi⁎, depressed, depressive and depression). We used no language restrictions. We studied all 5771 abstracts (1909 Pubmed, 679 Embase and 3183 PsycInfo).
Included studies
A total of 17 studies met the inclusion criteria (Stewart and Brook, 1983, Istvan et al., 1992, Ross, 1994, Palinkas et al., 1996, Carpenter et al., 2000, Haukkala and Uutela, 2000, Roberts et al., 2002, Onyike et al., 2003, John et al., 2005, Ohayon and Hong, 2006, Ohayon, 2007, Hach et al., 2006, Johnston et al., 2004, Herva et al., 2006, McIntyre et al., 2006, Simon et al., 2006, Scott et al., 2007) and selected characteristics of these studies are presented in Table 1. In these 17 studies a
Discussion
In the meta-analysis of 17 community-based studies with a total of 204,507 participants, we found a significant association between depression and obesity (OR = 1.26; 95% CI; 1.17–1.36, P ≤ 0.001) in a moderately heterogeneous group (I2 = 46.18). All the potential moderators (age, continent of residence, year of publication and differences in measurement methods) did not influence this association, with the exception of gender. The association between depression and obesity was more clearly present
References (41)
- et al.
‘Jolly fat’ revisited
Journal of Psychosomatic Research
(1980) - et al.
Obesity-depression associations in the population
Journal of Psychosomatic Research
(2002) - et al.
Associations between waist circumference and depressive disorders
Journal of Affective Disorders
(2006) - et al.
Association between obesity and depressive symptoms among U.S. military active duty service personnel, 2002
Jounal of Psychosomatic Research
(2006) Epidemiology of depression and its treatment in the general population
Journal of Psychiatric Research
(2007)- et al.
Prevalence of major depressive disorder in the general population of South Korea
Journal of Psychiatric Research
(2006) - et al.
Depressive symptoms in the overweight and obese older adults: a test of the ‘jolly fat’ hypothesis
Journal of Psychosomatic Research
(1996) - et al.
Depression and obesity
Biological Psychiatry
(2003) - et al.
The direct health care costs of obesity in the United States
American Journal of Public Health
(1999) - et al.
Mental disorders in patients with obesity in comparison with healthy probands
International Journal of Obesity
(2007)
Does depression cause obesity?: A meta-analysis of longitudinal studies of depression and weight control
Journal of Health Psychology
Relationships between obesity and DSM-VI Major depressive disorder, suicide ideation, suicide attempts: results from a general population study
American Journal of Public Health
Jolly fat: relation between obesity and psychoneurosis in general population
British Medical Journal
Health and disability costs of depressive illness in a major US corporation
American Journal of Psychiatry
Mood disorders and obesity
Current Opinion Psychiatry
Does adolescent depression predict obesity in black and white young adult women?
Psychological Medicine
Psychological correlates of obesity: moving to the next generation
Psychological Bulletin
Depressive symptoms during childhood and adult obesity
Molecular Psychiatry
Clinical hostility, depression, and obesity: the moderating role of education and gender
International Journal of Eating Disorders
Obesity and depression: results from the longitudinal northern Finland 1966 birth cohort study
International Journal of Obesity
Cited by (0)
- ☆
A study examining the association between obesity and depression in the general population and exploring potential moderating (demographic) factors.