Improving Sleep Quality May Reduce Cardiovascular Risk in Bipolar Disorder
A significant correlation was observed between lower sleep efficacy and higher triglyceride levels.
According to a study published in Acta Psychiatrica Scandinavica, monitoring the metabolic health of individuals with bipolar disorder and treating persistent sleep or circadian rhythm disturbances with medications or psychosocial methods is important in preventing metabolic syndrome and reducing cardiovascular risk in this vulnerable population.
The study sample included 124 remitted patients with bipolar disorder recruited from 2 university psychiatric departments in Paris, France. The study participants were diagnosed with bipolar disorder according to DSM-IV criteria; remission was defined as the absence of a major mood episode within 3 months. Actigraphy measures were captured continually for 3 weeks in which the patients wore an Actiwatch device that accurately characterized their activity and sleep patterns. Actigraphic parameters were selected that related to sleep quality and circadian rhythms and were examined in association with metabolic parameters.
Of the 124 patients, 67 fit the study criteria of having 3 weeks of actigraphy recording and receiving metabolic syndrome assessments within the appropriate period of time. A significant correlation was observed among specific actigraphic and metabolic parameters: lower sleep efficiency with higher triglyceride levels, and higher fragmentation index with higher systolic blood pressure. These correlations were independent of most confounding factors, including sleep apnea risk, atypical antipsychotic intake, and tobacco use.
Limitations of the study included a modest sample size and the absence of a control group. Furthermore, the nature of a cross-sectional study design does not support the implication that sleep abnormalities actually cause metabolic disturbances.
The association between sleep efficiency and triglyceride levels is a new observation of the study and extends current literature describing associations between sleep disturbances and metabolic syndrome in bipolar disorder. Elevated blood pressure at night (associated with repetitive sympathetic arousals during sleep, or a high fragmentation index) was shown to increase cardiovascular risk in elderly as well as patients with bipolar disorder. Health professionals should recommend interventions that improve sleep quality and regulate circadian rhythm in reducing cardiovascular risk for individuals with bipolar disorder.
Brochard H, Godin O, Geoffroy PA, et al. Metabolic syndrome and actigraphy measures of sleep and circadian rhythms in bipolar disorders during remission [published online May 30, 2018]. Acta Psychaitr Scand. doi: 10.1111/acps.12910