Suicide Risk Highest in Older Men

Older men with multiple health comorbidities have the highest risk for death by suicide, according to a study published in the December 2016 issue of Preventive Medicine.

A team of Australian researchers headed by Osvaldo P. Almeida, PhD, from the School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, conducted a cohort study of 38,170 community-dwelling men, aged 65 to 85 years, with a median age of 72 years, who were followed for up to 16 years. To retrieve subjects’ clinical and demographic data, the researchers used the Western Australian Data Linkage System, which brings together data for all health contacts of Western Australians with inpatient and outpatient mental health services, hospital morbidity data, and death registry. The outcomes of interest were attempted or completed suicides. Methods of self-harm included poison, hanging, firearms, and drowning. Explanatory variables included age as well as mental and medical disorders.

The researchers used a parsimonious logistic regression model to analyze the data, which showed that history of bipolar or depressive disorders and alcohol or substance-related disorders and the number of systems affected by medical comorbidities were all independently associated with past suicide attempts. With the exception of cancer, diseases of all individual health systems were associated with increased odds of a past suicide attempt, with 85% of attempted suicides using poison as their method.

During the median follow-up period of 12.7 years (range, 0-15.7 years), 443 men (1.2%) attempted suicide. Past suicide attempt (hazard ratio [HR], 203.14; 95% CI, 164.10-251.46), bipolar disorder (HR, 1.70; 95% CI, 1.25-2.31), alcohol use disorder (HR, 1.32; 95% CI, 1.02-1.72), and substance use disorder (HR, 1.59; 95% CI, 1.28-1.98) were the baseline variables most closely associated with a new suicide attempt.

The researchers continued the analysis by excluding participants with a history of past suicide attempts and found that, of the conditions affecting those with new suicide attempts, bipolar disorder was the most frequent (HR, 15.46; 95% CI, 9.71-24.62), followed by depressive disorder (HR, 3.65; 95% CI, 2.11-6.00), alcohol use disorder (HR, 1.91; 95% CI, 1.25-2.38), and substance use disorder (HR, 1.72; 95% CI, 1.25-2.38).

During the follow-up, 69 participants died by suicide. Those who completed suicide were actually younger (by 3.6 years [95% CI, 2.3-4.8 years] than those who did not die by suicide, and represented 0.3% of all deaths that occurred in the sample (total deaths, 21,531). Hanging was the most frequently used method to complete suicide (n = 35; 50.7%), followed by poisoning (n = 15; 21.7%).

Past suicide attempt did not turn out to be a robust predictor of future suicide completion (sub-HR, 1.58, 95% CI, 0.39-6.42), nor were the diagnoses of schizophrenia-related disorders (sub-HR, 0.54; 95% CI, 0.06-4.76) or of alcohol (sub-HR, 0.98; 95% CI, 0.44-2.20) and substance use disorders (sub-HR, 0.75; 95% CI, 0.42-1.37).

However, bipolar (sub-HR, 7.82; 95% CI, 3.08-19.90) and depressive disorders (sub-HR, 2.26; 95% CI, 1.14-4.51) were associated with increased risk for suicide completion. The risk for completed suicides also increased with the number of systems affected by disease (sub-HR for 3 to 4 health systems, 6.02 [95% CI, 2.69-13.47]; sub-HR for ≥5 health systems, 11.18 [95% CI, 4.89-25.53]).

The researchers observe that the rates of new suicide attempts during the 16 years of follow-up increased with age, as did the rates of suicide completion. Although poisoning was the most frequent method of suicide attempts, hanging was the most frequent method used in completed suicides. The rates of suicide completion were high among men with bipolar and depressive disorders, although most men who died from suicide actually had no psychiatric diagnosis.

Suicide prevention strategies targeting older men have typically focused on improving the detection of depression and suicide ideation in the community, as depression has been regarded as the key contributor, the researchers observe. However, because their study showed that only about 17% of all cases of completed suicide were associated with mood disorders, the researchers suggest that “preventive strategies that are restricted to the detection and management of mood disorders may not substantially reduce the rates of completed suicides in the community.”

They comment that their study highlights the “potential contribution of chronic diseases to suicide behaviour,” noting that “having 5 or more health systems affected by disease during the study period increased by >11 times the risk for suicide, and that the presence of this multiplicity of morbidities accounted for about [75%] of the deaths by suicide.” They add, “If this relationship is truly causal, then deteriorating physical health and frailty may be major drivers of suicide among older men,” noting that the proportion of people affected by multiple health morbidities increases with increasing age.

“It follows that strategies designed to decrease the incidence of suicide among older men may need to extend beyond the diagnosis and management of mood disorders and include effective measures to decrease morbidity and enhancing coping,” the authors suggest.

Antidepressants are frequently used in this population and may indeed be associated with decreasing rates of suicide in the 1990s. However, no further strides in suicide reduction have been observed since 2000, despite the “unrelenting rise in the prescription of antidepressants.” The researchers discuss other potential interventions, including psychotherapy, decreasing the incidence of frailty, and increasing physical activity. Improving the overall health of the population may be the most effective way of decreasing suicide rates in older age, they suggest.

“[G]iven that older adults are frequent users of health services, contact with health care providers offers a unique window of opportunity for the introduction of interventions for suicide prevention,” they conclude.

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Almeida OP, McCaul K, Hankey GJ, et al. Suicide in older men: the health in men cohort study (HIMS). Prev Med. 2016;93:33-38. doi: 10.1016/j.ypmed.2016.09.022