Biomarkers in geriatric psychiatry: searching for the holy grail?

Insulin-like growth factor 1 and risk of depression in older people: the English Longitudinal Study of Ageing

Depressive disorders are a leading cause of disability in older age. Although the role of psychosocial and behavioural predictors has been well examined, little is known about the biological origins of depression. Findings from animal studies have implicated insulin-like growth factor 1 (IGF-1) in the aetiology of this disorder. A total of 6017 older adults (mean age of 65.7 years; 55% women) from the English Longitudinal Study of Ageing provided serum levels of IGF-1 (mean=15.9 nmol l(-1), s.d. 5.7) during a nurse visit in 2008. Depression symptoms were assessed in the same year and again in 2012 using the eight-item Center for Epidemiologic Studies Depression Scale. Self-reports of a physician-diagnosis of depression were also collected at both time points. In separate analyses for men and women, the results from both the cross-sectional and longitudinal analyses revealed a 'U'-shaped pattern of association, such that lower and higher levels of IGF-1 were associated with a slightly elevated risk of depression, whereas the lowest risk was seen around the median levels. Thus, in men, with the lowest quintile of IGF-1 as the referent, the age-adjusted odds ratios (95% confidence interval) of developing depression symptoms after 4 years of follow-up, for increasing quintiles of IGF-1, were: 0.51 (0.28-0.91), 0.50 (0.27-0.92), 0.63 (0.35-1.15) and 0.63 (0.35-1.13) (P-value for quadratic association 0.002). Some attenuation of these effects was apparent after adjustment for co-morbidity, socioeconomic status and health behaviours. In conclusion, in the present study of older adults, there was some evidence that moderate levels of IGF-1 levels conferred a reduced risk of depression.

Major depressive disorder and cardiometabolic disease risk among sub-Saharan African adults

OBJECTIVE

We sought to evaluate the extent to which major depressive disorder (MDD) is associated with cardiometabolic diseases and risk factors.

METHODS

This was a cross-sectional epidemiologic study of 1924 employed adults in Ethiopia. Structured interview was used to collect sociodemographic data, behavioral characteristics and MDD symptoms using a validated Patient Health Questionnaire-9 (PHQ-9) depression scale. Fasting blood glucose, insulin, C-reactive protein, and lipid concentrations were measured using standard approaches. Multivariate logistic regression models were fitted to estimate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

A total of 154 participants screened positive for MDD on PHQ-9 (8.0%; 95% CI: 6.7-9.2%). Among women, MDD was associated with more than 4-fold increased odds of diabetes (OR=4.14; 95% CI: 1.03-16.62). Among men the association was not significant (OR=1.12; 95% CI: 0.63-1.99). Similarly, MDD was not associated with metabolic syndrome among women (OR=1.51; 95% CI: 0.69-3.29) and men (OR=0.61; 95% CI: 0.28-1.34). Lastly, MDD was not associated with increased odds of systemic inflammation.

CONCLUSION

The results of our study do not provide convincing evidence that MDD is associated with cardiometabolic diseases among Ethiopian adults. Future studies need to evaluate the effect of other psychiatric disorders on cardiometabolic disease risk.

Aging changes and medical complexity in late-life bipolar disorder: emerging research findings that may help advance care

Demographic trends globally point in the direction of increasing numbers of older people with serious and chronic mental disorders, such as bipolar disorder (BD). While there has been growing sophistication and understanding in treatments for BD generally, data specific to older people with BD are limited. Recent reviews, secondary analyses and some new research confirm complexity and aging-related issues relevant to later-life BD. Confounding variables that must be considered when studying older BD individuals include clinical heterogeneity, medical comorbidity, cognitive impairment and concomitant psychotropic medication. This article will review current and emerging data on aging- and disease-related issues that complicate assessment and treatment of older individuals with BD. We will discuss common comorbid medical conditions that affect BD elders, how aging may affect cognition and treatment, including the effects of lithium and other psychotropic drugs on the aging brain, and recent research using neuroimaging techniques that may shed light on understanding the mechanisms of illness progression and on treatment response. Finally, we will discuss implications for future work in geriatric BD.