Medicine (Northwest Academic Centre) - Research Publications

Permanent URI for this collection

Search Results

Now showing 1 - 8 of 8
  • Item
    No Preview Available
    Getting RID of the blues: Formulating a Risk Index for Depression (RID) using structural equation modeling
    Dipnall, JF ; Pasco, JA ; Berk, M ; Williams, LJ ; Dodd, S ; Jacka, FN ; Meyer, D (SAGE PUBLICATIONS LTD, 2017-11)
    OBJECTIVE: While risk factors for depression are increasingly known, there is no widely utilised depression risk index. Our objective was to develop a method for a flexible, modular, Risk Index for Depression using structural equation models of key determinants identified from previous published research that blended machine-learning with traditional statistical techniques. METHODS: Demographic, clinical and laboratory variables from the National Health and Nutrition Examination Study (2009-2010, N = 5546) were utilised. Data were split 50:50 into training:validation datasets. Generalised structural equation models, using logistic regression, were developed with a binary outcome depression measure (Patient Health Questionnaire-9 score ⩾ 10) and previously identified determinants of depression: demographics, lifestyle-environs, diet, biomarkers and somatic symptoms. Indicative goodness-of-fit statistics and Areas Under the Receiver Operator Characteristic Curves were calculated and probit regression checked model consistency. RESULTS: The generalised structural equation model was built from a systematic process. Relative importance of the depression determinants were diet (odds ratio: 4.09; 95% confidence interval: [2.01, 8.35]), lifestyle-environs (odds ratio: 2.15; 95% CI: [1.57, 2.94]), somatic symptoms (odds ratio: 2.10; 95% CI: [1.58, 2.80]), demographics (odds ratio:1.46; 95% CI: [0.72, 2.95]) and biomarkers (odds ratio:1.39; 95% CI: [1.00, 1.93]). The relationships between demographics and lifestyle-environs and depression indicated a potential indirect path via somatic symptoms and biomarkers. The path from diet was direct to depression. The Areas under the Receiver Operator Characteristic Curves were good (logistic:training = 0.850, validation = 0.813; probit:training = 0.849, validation = 0.809). CONCLUSION: The novel Risk Index for Depression modular methodology developed has the flexibility to add/remove direct/indirect risk determinants paths to depression using a structural equation model on datasets that take account of a wide range of known risks. Risk Index for Depression shows promise for future clinical use by providing indications of main determinant(s) associated with a patient's predisposition to depression and has the ability to be translated for the development of risk indices for other affective disorders.
  • Item
    Thumbnail Image
    Statin and Aspirin Use and the Risk of Mood Disorders among Men
    Williams, LJ ; Pasco, JA ; Mohebbi, M ; Jacka, FN ; Stuart, AL ; Venugopal, K ; O'Neil, A ; Berk, M (OXFORD UNIV PRESS, 2016-06)
    BACKGROUND: There is a growing understanding that depression is associated with systemic inflammation. Statins and aspirin have anti-inflammatory properties. Given these agents have been shown to reduce the risk of a number of diseases characterized by inflammation, we aimed to determine whether a similar relationship exists for mood disorders (MD). METHODS: This study examined data collected from 961 men (24-98 years) participating in the Geelong Osteoporosis Study. MD were identified using a semistructured clinical interview (SCID-I/NP). Anthropometry was measured and information on medication use and lifestyle factors was obtained via questionnaire. Two study designs were utilized: a nested case-control and a retrospective cohort study. RESULTS: In the nested case-control study, exposure to statin and aspirin was documented for 9 of 142 (6.3%) cases and 234 of 795 (29.4%) controls (P < .001); after adjustment for age, exposure to these anti-inflammatory agents was associated with reduced likelihood of MD (OR 0.2, 95%CI 0.1-0.5). No effect modifiers or other confounders were identified. In the retrospective cohort study of 836 men, among the 210 exposed to statins or aspirin, 6 (2.9%) developed de novo MD during 1000 person-years of observation, whereas among 626 nonexposed, 34 (5.4%) developed de novo MD during 3071 person-years of observation. The hazard ratio for de novo MD associated with exposure to anti-inflammatory agents was 0.55 (95%CI 0.23-1.32). CONCLUSIONS: This study provides both cross-sectional and longitudinal evidence consistent with the hypothesis that statin and aspirin use is associated with a reduced risk of MD.
  • Item
    Thumbnail Image
    Psychiatric disorders, psychotropic medication use and falls among women: an observational study
    Williams, LJ ; Pasco, JA ; Stuart, AL ; Jacka, FN ; Brennan, SL ; Dobbins, AG ; Honkanen, R ; Koivumaa-Honkanen, H ; Rauma, PH ; Berk, M (BMC, 2015-04-08)
    BACKGROUND: Psychotropic agents known to cause sedation are associated with an increased risk of falls, but the role of psychiatric illness as an independent risk factor for falls is not clear. Thus, this study aimed to investigate the association between psychiatric disorders, psychotropic medication use and falls risk. METHODS: This study examined data collected from 1062 women aged 20-93 yr (median 50 yr) participating in the Geelong Osteoporosis Study, a large, ongoing, population-based study. Depressive and anxiety disorders for the preceding 12-month period were ascertained by clinical interview. Current medication use and falls history were self-reported. Participants were classified as fallers if they had fallen to the ground at least twice during the same 12-month period. Anthropometry, demographic, medical and lifestyle factors were determined. Logistic regression was used to test the associations, after adjusting for potential confounders. RESULTS: Fifty-six women (5.3%) were classified as fallers. Those meeting criteria for depression within the past 12 months had a 2.4-fold increased odds of falling (unadjusted OR = 2.4, 95% CI 1.2-4.5). Adjustment for age and mobility strengthened the relationship (adjusted OR = 2.7, 95% CI 1.4-5.2) between depression and falling, with results remaining unchanged following further adjustment for psychotropic medication use (adjusted OR = 2.7, 95% CI 1.3-5.6). In contrast, past (prior to 12-month) depression were not associated with falls. No association was observed between anxiety and falls risk. Falling was associated with psychotropic medication use (unadjusted OR = 2.8, 95% CI 1.5-5.2), as well as antidepressant (unadjusted OR = 2.4, 95% CI 1.2-4.8) and benzodiazepine use (unadjusted OR = 3.4, 95% CI 1.6-7.3); associations remained unchanged following adjustment for potential confounders. CONCLUSION: The likelihood of falls was increased among those with depression within the past 12 months, independent of psychotropic medication use and other recognised confounders, suggesting an independent effect of depression on falls risk. Psychotropic drug use was also confirmed as an independent risk factor for falls, but anxiety disorders were not. Further research into the underlying mechanisms is warranted.
  • Item
    Thumbnail Image
    Depression following fracture in women: a study of age-matched cohorts
    Williams, LJ ; Berk, M ; Henry, MJ ; Stuart, AL ; Brennan, SL ; Jacka, FN ; Pasco, JA (BMJ PUBLISHING GROUP, 2014)
    OBJECTIVES: High levels of disability, functional impairment and mortality are independently associated with fracture and depression, however the relationship between fracture and depression is uncertain. The aim of this study was to investigate whether fracture is associated with subsequent depressive symptoms in a population-based sample of women. DESIGN: A study of age-matched fracture versus non-fracture cohorts of women. SETTING: Barwon Statistical Division, southeastern Australia. PARTICIPANTS: Two samples of women aged ≥35 years were drawn from the Geelong Osteoporosis Study (GOS). The fracture cohort included women with incident fracture identified from radiology reports and the non-fracture cohort were randomly selected from the electoral roll during 1994-1996. OUTCOME MEASURE: Symptoms of depression for women with and without fracture during the 12-month period 2000-2001 were identified by self-report questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. RESULTS: A total of 296 women with fracture (12 hip, 48 vertebral, 91 wrist/forearm, 17 upper arm, 7 pelvis, 11 rib, 62 lower leg and 48 other fractures) and 590 women without fracture were included. Associations between fracture and depression differed between younger (≤65 years) and older (>65 years) women. Age and weight-adjusted odds ratio for depression following fracture among younger women was 0.62 (0.35 to 1.11, p=0.12) and 3.33 (1.24 to 8.98, p=0.02) for older women. Further adjustment for lifestyle factors did not affect the results. CONCLUSIONS: This study demonstrated that differences in mood status exist between older and younger women following fracture and that fracture is associated with increased depression in older women. Assessment of mood status in both the short and long term following fracture in the elderly seems justified, with early detection and treatment likely to result in improved outcomes.
  • Item
    Thumbnail Image
    Data Integration Protocol In Ten-steps (DIPIT): A new standard for medical researchers
    Dipnall, JF ; Berk, M ; Jacka, FN ; Williams, LJ ; Dodd, S ; Pasco, JA (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2014-10-01)
    INTRODUCTION: The exponential increase in data, computing power and the availability of readily accessible analytical software has allowed organisations around the world to leverage the benefits of integrating multiple heterogeneous data files for enterprise-level planning and decision making. Benefits from effective data integration to the health and medical research community include more trustworthy research, higher service quality, improved personnel efficiency, reduction of redundant tasks, facilitation of auditing and more timely, relevant and specific information. The costs of poor quality processes elevate the risk of erroneous outcomes, an erosion of confidence in the data and the organisations using these data. To date there are no documented set of standards for best practice integration of heterogeneous data files for research purposes. Therefore, the aim of this paper is to describe a set of clear protocol for data file integration (Data Integration Protocol In Ten-steps; DIPIT) translational to any field of research. METHODS AND RESULTS: The DIPIT approach consists of a set of 10 systematic methodological steps to ensure the final data are appropriate for the analysis to meet the research objectives, legal and ethical requirements are met, and that data definitions are clear, concise, and comprehensive. This protocol is neither file specific nor software dependent, but aims to be transportable to any data-merging situation to minimise redundancy and error and translational to any field of research. DIPIT aims to generate a master data file that is of the optimal integrity to serve as the basis for research analysis. CONCLUSION: With linking of heterogeneous data files becoming increasingly common across all fields of medicine, DIPIT provides a systematic approach to a potentially complex task of integrating a large number of files and variables. The DIPIT protocol will ensure the final integrated data is consistent and of high integrity for the research requirements, useful for practical application across all fields of medical research.
  • Item
    Thumbnail Image
    Comparison of self-report and structured clinical interview in the identification of depression
    Stuart, AL ; Pasco, JA ; Jacka, FN ; Brennan, SL ; Berk, M ; Williams, LJ (W B SAUNDERS CO-ELSEVIER INC, 2014-05)
    BACKGROUND: A self-report method seeking a binary response for assessing depression is a cost-effective and time-efficient way to obtain a psychiatric history, yet the reliability of this method is largely unknown. The aim of the study was to compare and assess the validity of two methods for identifying a past history of depression in a population-based study. METHODS: This study examined data collected from 891 men and 1086 women participating in the Geelong Osteoporosis Study. Self-reports of depression were compared with results obtained using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition (SCID-I/NP). RESULTS: Using the SCID-I/NP, 146 (16.4%) men and 285 (26.2%) women met criteria for a lifetime depression. Of those participants, 61.0% (n=263) self-reported a history of depression. The level of agreement between self-reporting depression and the SCID-I/NP depression module was reasonably high; 61% sensitivity, 89.5% specificity and the overall level of agreement (kappa) was 0.5. LIMITATIONS: Results may not be generalizable to other self-report instruments or be suitable for use in clinical samples. CONCLUSION: The SCID-I/NP remains the gold standard for identifying depression; however, given the moderate level of agreement between the self-report questionnaire and SCID-I/NP in our current study, we conclude that simple self-report methods can be used to identify depression with some degree of confidence.
  • Item
    Thumbnail Image
    Atopic disorders and depression: Findings from a large, population-based study
    Sanna, L ; Stuart, AL ; Pasco, JA ; Jacka, FN ; Berk, M ; Maes, M ; O'Neill, A ; Girardi, P ; Williams, LJ (ELSEVIER SCIENCE BV, 2014-02)
    BACKGROUND: Atopy, a common disorder characterized by a sensitivity to allergic reactions, affects a large proportion of the adult population and, as with depression, is associated with immune-inflammatory pathway changes. We sought to determine the role of atopic disorders in depression using data from a randomly-selected, population-based study of men and women. METHODS: Cross-sectional data derived from the Geelong Osteoporosis Study for 942 males and 1085 females were analyzed. Depression [major depressive disorder (MDD), minor depression and dysthymia] was assessed using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition. Data on medical conditions, including atopic disorders (asthma, hay fever and eczema), smoking status, alcohol consumption, socioeconomic status, and physical activity were documented by self-report. Logistic regression modeling was used to explore the associations between atopic disorders and depression. RESULTS: Atopic disorders were associated with a 59% increased likelihood of depression [gender and smoking-adjusted odds ratio (OR) 1:50, 95% CI 1.20-1.97]. Sub-group analyses revealed a similar pattern for those with MDD [gender and smoking-adjusted OR 1:54, 95% CI 1.22-1.94]. These associations were independent of socio-demographic characteristics, clinical and lifestyle factors. LIMITATIONS: Reliance on self-report for allergic symptoms and cross-sectional nature of study. CONCLUSION: This population-based study provides evidence of the potential contribution of allergic disorders to depression. Further research is required to elucidate the direction of this association and to further explicate its underlying physiology, including immune-inflammation markers.
  • Item
    Thumbnail Image
    Dietary intake of fish and PUFA, and clinical depressive and anxiety disorders in women
    Jacka, FN ; Pasco, JA ; Williams, LJ ; Meyer, BJ ; Digger, R ; Berk, M (CAMBRIDGE UNIV PRESS, 2013-06-14)
    Fish and PUFA consumption are thought to play a role in mental health; however, many studies do not take into account multiple sources of PUFA. The present study analysed data from a sample of 935 randomly selected, population-based women aged 20–93 years. A validated and comprehensive dietary questionnaire ascertained the consumption of n-3 and n-6 PUFA. Another assessed fish and energy intake and provided data for a dietary quality score. The General Health Questionnaire-12 (GHQ-12) measured psychological symptoms and a clinical interview (Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition) assessed depressive and anxiety disorders. Median dietary intakes of long-chain n-3 fatty acids (310 mg/d) were below suggested dietary target levels. The only PUFA related to categorical depressive and anxiety disorders was DHA. There was a non-linear relationship between DHA intake and depression; those in the second tertile of DHA intake were nearly 70% less likely to report a current depressive disorder compared to those in the first tertile. The relationship of DHA to anxiety disorders was linear; for those in the highest tertile of DHA intake, the odds for anxiety disorders were reduced by nearly 50% after adjustments, including adjustment for diet quality scores, compared to the lowest tertile. Those who ate fish less than once per week had higher GHQ-12 scores, and this relationship was particularly obvious in smokers. These are the first observational data to indicate a role for DHA in anxiety disorders, but suggest that the relationship between DHA and depressive disorders may be non-linear.