How Could Sensor-Based Measurement of Physical Activity Be Used in Cardiovascular Healthcare?

Physical activity and cardiovascular disease (CVD) are intimately linked. Low levels of physical activity increase the risk of CVDs, including myocardial infarction and stroke. Conversely, when CVD develops, it often reduces the ability to be physically active. Despite these largely understood relationships, the objective measurement of physical activity is rarely performed in routine healthcare. The ability to use sensor-based approaches to accurately measure aspects of physical activity has the potential to improve many aspects of cardiovascular healthcare across the spectrum of healthcare, from prediction, prevention, diagnosis, and treatment to disease monitoring. This review discusses the potential of sensor-based measurement of physical activity to augment current cardiovascular healthcare. We highlight many factors that should be considered to maximise the benefit and reduce the risks of such an approach. Because the widespread use of such devices in society is already a reality, it is important that scientists, clinicians, and healthcare providers are aware of these considerations.

Behavioral Approach System and Behavioral Inhibition System sensitivities and bipolar spectrum disorders: prospective prediction of bipolar mood episodes.

OBJECTIVES: Research has found that bipolar spectrum disorders are associated with Behavioral Approach System (BAS) hypersensitivity and both unipolar and bipolar depression are associated with high Behavioral Inhibition System (BIS) sensitivity, but prospective studies of these relationships are lacking. We tested whether BAS and BIS sensitivities prospectively predicted the time to new onsets of major depressive and hypomanic and manic episodes in bipolar spectrum individuals. METHODS: We followed 136 bipolar II or cyclothymic and 157 demographically matched normal control individuals prospectively for an average of 33 months. Participants completed the BIS/BAS scales and symptom measures at Time 1 and semi-structured diagnostic interviews every four months of follow-up. RESULTS: The bipolar spectrum group exhibited higher Time 1 BAS, but not BIS, scores than the normal controls, controlling for Time 1 symptoms. Among bipolar spectrum participants, high BAS sensitivity prospectively predicted a shorter time to onset of hypomanic and manic episodes, whereas high BIS sensitivity predicted less survival time to major depressive episodes, controlling for initial symptoms. CONCLUSIONS: Consistent with the BAS hypersensitivity model of bipolar disorder, a highly responsive BAS provides vulnerability to onsets of (hypo)manic episodes. In addition, a highly sensitive BIS increases risk for major depressive episodes.

Anxiety and somatic symptoms as predictors of treatment-related adverse events in major depressive disorder.

The purpose of this study was to examine the relationship between the degree of anxiety or somatic symptoms present before treatment with the subsequent diagnosis of treatment-related adverse events (TRAEs) in patients with major depressive disorder (MDD) enrolled in an 8-week open trial of fluoxetine (20 mg). Baseline symptom questionnaires (SQ) were completed by 170 MDD patients enrolled in the trial. We then tested whether pre-treatment scores for anxiety and somatic symptoms predicted (1) whether patients were subsequently diagnosed with TRAEs; (2) whether they were subsequently diagnosed with moderate or severe TRAEs; or (3) whether a greater number of TRAEs were diagnosed during the trial. We found that depressed patients who presented with prominent somatic symptoms were significantly more likely to report at least one moderate or severe side effect during the course of treatment, but not more likely to report a greater number of side effects. Pre-treatment anxiety was not related to the development of side effects.

Serum cholesterol and serotonergic function in major depressive disorder.

Studies have revealed a relationship between serum cholesterol levels and serotonergic (5HT) function in healthy young adults. Patients with major depressive disorder (MDD) may have significant differences in cholesterol levels compared with healthy adults, while MDD patients with elevated cholesterol have a poorer prognosis for treatment response. The goal of the present study is to examine (1) the relationship between serum cholesterol levels and central 5HT function by way of the cortisol and prolactin response to the 5HT-selective agonist DL-fenfluramine in MDD patients and (2) differences in 5HT-function between MDD patients who present with and without elevated cholesterol. Fasting serum cholesterol levels were measured in 21 outpatients with MDD. After oral administration of 60 mg of DL-fenfluramine in these patients, cortisol and prolactin responses were measured to test whether cholesterol levels predicted the degree of cortisol or prolactin response. Cortisol and prolactin responses were compared between patients with and without elevated cholesterol levels, defined as >/=200 mg/dl. MDD patients with elevated cholesterol levels were more likely to demonstrate an attenuated cortisol response. There was no relationship between cholesterol levels and cortisol or prolactin response. Excess cholesterol may adversely affect the function of membrane-bound serotonergic structures, and this may explain why MDD patients with elevated cholesterol are more likely to exhibit attenuated neuroendocrine responses, less likely to respond to treatment and more likely to relapse.

Functioning and interpersonal relationships as predictors of response in treatment-resistant depression.

The purpose of this study was to examine whether occupational functioning or the quality of interpersonal relationships is predictive of clinical response to a 6-week open trial of nortriptyline (NT) in patients with treatment-resistant depression (TRD). Ninety-two subjects with TRD were treated openly with NT for 6 weeks. The longitudinal interval follow-up evaluation (LIFE) scale was administered at baseline. A logistic regression was performed using occupational functioning and interpersonal relationships (over the past month and over the past 5 years) as predictors of treatment response. Unpaired t tests were performed to examine mean composite LIFE score values between responders and nonresponders. The composite scores that were statistically significant were used as single predictors of treatment status in separate logistic regression equations. Better occupational function over the past 5 years predicted better response to treatment with NT in patients with TRD. Beyond a history of nonresponse to antidepressants, long-term occupational function may be a predictor of outcome in the treatment of TRD.