چاقی و آغاز افسردگی در میان میانسال وسالمندان ایالات متحده

Objectives This paper aims to examine the relationship between obesity and onset of depression among U.S. middle-aged and older adults. Methods Data came from 1994 to 2010 waves of the Health and Retirement Study. Study sample consisted of 6514 community-dwelling adults born between 1931 and 1941 who were free of clinically relevant depressive symptoms in 1994. Body mass index (BMI) was calculated from self-reported height/weight. Body weight status was classified into normal weight (18.5 kg/m2 ≤ BMI < 25 kg/m2), overweight (25 kg/m2 ≤ BMI < 30 kg/m2), and obesity (BMI ≥ 30 kg/m2). A score of ≥ 3 on the 8-item Center for Epidemiologic Studies Depression Scale was used to define clinically relevant depressive symptoms. Kaplan–Meier estimator and time-dependent Cox proportional hazards model were performed to examine the association between body weight status and onset of clinically relevant depressive symptoms. Results Unhealthy body weight was associated future onset of depression. Compared with their normal weight counterparts, overweight and obese participants were 13% (hazard ratio [HR] = 1.13, 95% confidence interval [CI] = 1.04–1.23) and 9% (HR = 1.09, 95% CI = 1.01–1.18) more likely to have onset of clinically relevant depressive symptoms during the 16 years of follow-up, respectively. The relationship between obesity and depression onset appeared stronger among females and non-Hispanic whites than their male and racial/ethnic minority counterparts. Conclusions Health care providers should be aware of the potential risk for depression among obese older adults.

Obesity is a leading public health concern in the U.S. and worldwide [1]. Over one-third of American adults are obese and another one-third overweight [2]. The growth rate of adult obesity, especially severe or morbid obesity, does not appear to begin leveling off [3]. While the consequences of obesity on physical health have been well documented [1] and [4], its link to psychiatric disorders remains unclear. Depression is one of the most prevalent psychiatric disorders and a major contributor to the U.S. burden of disease [5]. Systematic reviews and meta-analyses of cross-sectional studies have suggested an association between obesity and depression [6], [7] and [8]. One meta-analysis of prospective studies reported obesity at baseline to predict depression onset during follow-up [9], whereas another meta-analysis found no robust evidence [10]. It is not clear to what extent these inconsistencies can be explained by possible heterogeneity in the relationship between obesity and depression across population subgroups [10]. Most prospective, longitudinal studies examining the impact of obesity on depression have focused on children and youth [11], [12], [13] and [14]. Few studies have examined the prospective impact of obesity on depression in the aging process [15], [16], [17] and [18]. Midlife and older adulthood may be a critical period for the emergence and progression of the psychological risks of obesity. Across the life span, the prevalence of overweight and obesity peaks in midlife (roughly between 40 and 60 years of age) [2]. Midlife is also a period when host immunity begins to decline and the effects of unhealthy body weight and other poor health habits accumulate [19]. The declined immunity may make middle-aged and older adults particularly vulnerable to the psychological consequences of obesity. However, previous studies specifically focusing on middle-aged and older adults used regional samples and had relatively short follow-up period [15], [16], [17] and [18]. Their assessments of body weight and depression were undertaken at only one point in time [15], [16] and [17]. In addition, most of these studies estimated odds ratio [15] and [17], which can dramatically overstate the relative risk for common outcomes [20]. The relationships between obesity and depression may also differ by sex and race/ethnicity. Previous studies have documented a stronger relationship between obesity and depression in women [7], [11], [21], [22] and [23]. However, these studies have primarily focused on youth. It is less clear whether similar moderating effects of sex exist in older adulthood [23]. Only a few studies have examined the differential impacts of obesity on depression by race/ethnicity with mixed findings reported [16], [21], [24] and [25]. Population-based prospective studies are warranted to identify population subgroups that are most vulnerable to the psychological consequences of obesity. The present study examined the association of obesity and onset of clinically relevant depressive symptoms using data from a nationally representative longitudinal survey of U.S. middle-aged and older adults. The uniquely large and diverse study sample with extended follow-up periods (up to 16 years from 1994 to 2010) allowed us to examine the long-term psychological risks of obesity in the aging process and the differential impacts of obesity across sex and racial/ethnic subgroups.

Table 1 presents the descriptive statistics of the study sample stratified by baseline body weight status. Participants were on average 57.8 years of age in 1994 and predominantly non-Hispanic white (84.5%). Individual sociodemographics, health behavior, and chronic conditions differed substantially by body weight status. During the 16 years of follow-up, 37% (95% confidence interval [CI] = 35.5%–38.5%, N = 2458) of the initially depression-free sample experienced the onset of clinically relevant depressive symptoms. The rates of depression onset increased monotonically with body weight status, from 34.3% (95% CI = 31.8%–36.8%) among normal weight participants to 37.2% (95% CI = 35.2%–39.2%) among overweight participants and 40.9% (95% CI = 38.6%–43.3%) among obese participants.