MedWire News: The clinically significant weight gain observed in bipolar disorder patients begins with the first manic episode, regardless of previous episodes, and may be due to the treatment required, say Canadian researchers.
Many studies have shown that bipolar disorder is associated with obesity, but these investigations have typically been retrospective or cross-sectional in design and focused on patients with long-term illnesses.
To determine the patterns of weight gain in early bipolar disorder, Lakshmi Yatham and colleagues from the University of British Columbia in Vancouver obtained weight gain data and laboratory metabolic measurements over a 12-month period from 47 bipolar disorder patients receiving maintenance therapy after their first manic episode and 24 age- and gender-matched healthy controls.
At baseline, there were no significant differences between patients and controls in terms of average body mass index (BMI), rates of overweight and obesity, and laboratory metabolic indices.
Over the first 6 months of follow-up, 46.8% of patients and 4.2% of controls gained ≥7% over their baseline weight, at an average weight gain of 4.57 kg and 0.51 kg, respectively. However, rates of overweight and obesity did not differ significantly between patients and controls.
On logistic regression analysis, significant weight gain was associated with lower initial weight, male gender, and treatment with olanzapine and risperidone. Obese patients had significantly greater average serum triglyceride and fasting glucose levels than non-obese patients.
At 12 months, 19% of patients and 4% of controls gained ≥15% over their baseline weight, and the average weight gain was 4.76 kg and 1.50 kg, respectively. Interestingly, the changes at 12 months were primarily due to changes over the first 6 months, as average weight change during the second 6 months was 0.19 kg for patients and 0.98 kg for controls, and 13% and 8.3%, respectively, gained ≥7% over their 6-month body weight.
There were no significant associations between significant weight gain from 6–12 months and any of the variables analyzed, the team notes in the Journal of Affective Disorders.
They write: “Given the long-term health consequences of overweight and obesity, these findings underscore the importance of considering weight and metabolic factors when making even the earliest treatment decisions for patients with bipolar disorder, and of frequently monitoring for and addressing weight gain.”
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