Previous research has established a connection between metabolic syndrome and depression, but data on the increased risk for depressed individuals to develop metabolic syndrome (MetS) are lacking, wrote Lara Onofre Ferriani, PhD, of Federal University of Espírito Santo, Vitoria, Brazil, and colleagues.
“Individuals with MetS and depression have increased levels of inflammatory markers, and it is speculated that inflammation could mediate this comorbidity,” they said.
Dr. Lara Onofre Ferriani
In a study published in the Journal of Psychiatric Research, the investigators reviewed data from 13,883 participants in the Brazilian Longitudinal Study of Adult Health; all were civil servants at universities in Brazil. The participants ranged from 35 to 74 years of age, with a mean age of 51.9 years; 54.3% were women; and 52.4% were white; the mean follow-up period was 3.8 years.
The primary outcome was the association between depression diagnosis and severity on components of MetS at baseline and over a 4-year period. Participants were classified by MetS trajectory as recovered, incident, or persistent, and classified by depression status as without depression or with a mild, moderate, or severe current depressive episode. Depression status was based on the Clinical Interview Schedule Revised. MetS components and diagnosis were based on the National Cholesterol Education Program Adult Treatment Panel III.
In a logistic regression analysis, baseline depression was positively associated with recovered, incident, and persistent MetS (odds ratios, 1.59, 1.45, and 1.70, respectively).
Depression at baseline also was significantly associated with separate components of MetS: large waist circumference, high triglycerides, low high-density lipoprotein cholesterol, and hyperglycemia, with odds ratios of 1.47, 1.23, 1.30, and 1.38, respectively.
Although not seen at baseline, a significant positive association between baseline depression and the presence of three or more MetS components was noted at follow-up, with a positive dose-response effect, the researchers wrote in their discussion.
Not all associations were statistically significant, but this was mainly because of the small number of cases of moderate and severe depression, they said. However, the magnitude of associations was greater in severe depression, when compared with moderate and mild, which suggests that the risk of MetS may be higher in this population, they added.
The study findings were limited by several factors including the possible misclassification of depression, inability to differentiate among depressive subtypes, and the potential lack of generalizability to other populations beyond Brazilian civil servants, the researchers noted.
However, the results were strengthened by the large sample size and support the role of depression as a risk factor for MetS, they said. More research is needed to determine a bidirectional relationship and to assess the trajectory of depression after MetS develops, but the findings “highlight the need to investigate and manage metabolic and cardiovascular alterations in the presence of depression in clinical settings,” they concluded.
The study was supported by the Brazilian Ministry of Health (Science and Technology Department) and the Brazilian Ministry of Science, Technology and Innovation FINEP and CNPq, and by the Coordenaçaõ de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES). The researchers had no financial conflicts to disclose.