A risk table to assist health practitioners assess and prevent the onset of depression in later life

Objective. This study aimed to develop a simple risk table of modifiable factors prospectively associated with depression in later life that could be used to guide the assessment, management and introduction of preventive strategies in clinical practice. Methods. This retrospective cohort study included 4636 men aged 65 to 83 years living in the community who denied history of past diagnosis or treatment for depression. They self-reported information about their physical activity, weight and height, smoking history, alcohol consumption and dietary habits, as well as history of hypertension, diabetes, coronary heart disease and stroke. We calculated the body mass index (BMI) in kg/m(2). Three to 8 years later they were assessed with the Geriatric Depression Scale 15 (GDS-15) and those with a total score of 7 or greater were considered to display clinically significant symptoms of depression. We used binomial exponentiated log-linked general linear models to estimate the risk ratio (RR) and 95% confidence interval (95% Cl) of incident depression after adjusting for age, education, marital status and prevalent medical illnesses. We calculated the probability of depression for each individual combination of risk factors and displayed the results in a risk table. Results. Two hundred and twenty-nine men (4.5%) showed evidence of incident depression 5.7 +/- 0.9 (mean +/- standard deviation) years later. Measured dietary factors showed no association with incident depression. The probability of depression was the highest for older men who were underweight, overweight or obese, physically inactive, risk drinkers and smokers (12.0%, 95% CI = 7.0%, 17.1%), and the lowest for those who had all 4 healthy lifestyle markers: physically active, normal body mass, non-risk drinking and non-smoking (1.6%, 95% CI = 0.6%, 2.5%). The probability of incident depression fell between these two extremes for different combinations of lifestyle practices. Conclusion. Four modifiable lifestyle factors can be used in combination to produce a risk table that predicts the probability of incident depression over a period of 3 to 8 years. The risk table is simple, informative and can be easily incorporated into clinical practice to guide assessment and risk reduction interventions. Crown Copyright (C) 2013 Published by Elsevier Inc All rights reserved.