Background/Purpose: General population studies have found significant relationships between obesity and depression, including identifying obesity as a risk factor for onset of depression.  In SLE, rates of depression are high, and depression can be a neuropsychiatric manifestation of SLE.  The role of obesity as an independent risk factor for depression in SLE has not been studied.  In this analysis, we examine the risk of depression onset for obese and non-obese women with SLE.

Methods: Analyses use data from the Lupus Outcomes Study (2004-2014) obtained through annual structured telephone interviews. All participants have physician-confirmed SLE. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression scale (CESD).  Possible and probable depression were estimated using validated SLE-specific cut-points (20 and 24, respectively).  Body mass index (BMI) was calculated from self-reported height and weight, and obesity was defined using a validated SLE-specific BMI cut-point of ≥26.8.  (A sensitivity analysis also examined the standard BMI obesity cut-point of 30.)  Cox proportional hazard models were used to estimate the risk of becoming depressed associated with obesity at baseline.  Models were calculated for both possible and probable depression.  Multivariate analyses adjusted for age, race (white non-Hispanic vs. other), baseline disease activity (Systemic Lupus Activity Questionnaire, SLAQ), current smoking, prednisone use, and baseline functioning (SF-36 Physical Component Score).  Only women were included in the analysis because the number of men was relatively small.  Women who had BMI <18.5 or who met the depression criterion at baseline were excluded from analysis.

Results: Data from 718 women were available for analysis, of whom 32 had BMI<18.5.  At baseline, 211 met the criterion for possible depression (CESD ≥ 20) and 171 for probable depression (CESD ≥ 24), leaving 471 and 515 in the analyses for possible and probable depression, respectively.  BMIs ranged from 18.6 — 54.9.  Mean follow-up time was 9 years (range 2-11 years). In the analysis for possible depression, 31.6% of those who were not obese became depressed, compared to 48.1% of those who were obese (table).  The adjusted HR (95% CI) for possible depression associated with obesity was 1.56 (1.15, 2.11).  In the analysis of probable depression, 25.9% of those not obese became depressed compared to 42.6% of those who were obese.  The adjusted HR (95% CI) for probable depression was 1.69 (1.23, 2.30). Using the standard BMI cut-point for obesity yielded similar results.

Conclusion:   Obesity appears to be a risk factor for development of depression among women with SLE, even after controlling for disease activity and other relevant factors.  This is a clinically important finding, as obesity is modifiable, and reducing obesity is likely to lead to additional health benefits such as reduced cardiovascular disease.

 

Risk of depression onset associated with obesity* among women with SLE
	Possible depression (CESD ≥20)	Probable depression (CESD ≥24)
Total n for analysis	471	515
Obese at baseline	38.9%	39.2%
Became depressed
Not obese	31.6% (91)	25.9% (81)
Obese	48.1% (88)	42.6% (86)
Multivariate HR (95% CI) for obesity†	1.56 (1.15, 2.11)	1.69 (1.23, 2.30)
Women who met criteria for depression at baseline were excluded.  * Obesity defined as BMI ≥ 26.8. † HR = Hazard ratio. Multivariate model adjusted for age race, baseline disease activity (SLAQ), smoking, and baseline physical functioning.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/obesity-is-a-risk-factor-for-depression-in-systemic-lupus-erythematosus-sle/