Lifetime accumulation of affective symptoms associated with increased mortality rate

Lifetime accumulation of affective symptoms appeared linked to an increased rate of mortality, according to study results published in JAMA Psychiatry. Researchers noted that explanatory pathways for this association are dependent on the duration and timing of symptoms.

“Associations between affective problems (anxiety and depression) and premature mortality have been demonstrated among psychiatric, medical and community-based samples and across many causes of death; however, most studies have relied on a single measure of affective symptoms in mid to late adulthood and a relatively short follow-up,” Gemma Archer, PhD, of the Institute of Psychiatry, Psychology & Neuroscience at King’s College London, and colleagues wrote. “Little is known about the long-term association between affective symptoms and mortality, particularly whether associations are determined more by accumulation or timing of symptoms.”

Prior studies that assessed affective symptoms over multiple time points showed estimated increases in mortality corresponding with the frequency of case-level symptoms; however, these studies were conducted in samples of older individuals, with a maximum exposure window of 7 years. Moreover, few studies have included a comprehensive range of potential major explanatory variables, Archer and colleagues noted.

In the current study, the investigators aimed to examine associations between lifetime accumulation and timing of affective symptoms and mortality, as well as to identify potential explanatory factors. They collected data from the Medical Research Council National Survey of Health and Development — a socially stratified, population-based British birth cohort that originally consisted of 5,362 singleton births in England, Wales and Scotland during March 1946. Researchers have followed up the cohort 24 times, most recently from 2014 to 2015. Archer and colleagues analyzed data of individuals flagged for mortality with affective symptoms data available at three or more time points (n = 3,001).

Affective symptoms data were available for participants at ages 13 to 15 years, 36 years, 43 years and 53 years. The researchers considered those scoring in the top 16th percentile as having case-level affective symptoms. Mortality data obtained from the U.K. National Health Service Central Register on participants aged 53 years to 68 years served as the main outcome.

Results showed 235 (7.8%) of 3,001 study members died over a 15-year follow-up. Those who experienced case-level affective symptoms once, twice, and three to four times had 76%, 87% and 134% higher premature mortality rates, respectively, compared with individuals who never experienced case-level symptoms, after adjustment for sex. Case level symptoms among adolescents only (aged 13 to 15 years) were associated with a 94% increased mortality rate, which remained unexplained following full adjustment for covariates (HR = 1.73; 95% CI, 1.1-2.72). Adult health indicators and behaviors predominantly explained associations between participants with case-level symptoms two to four times and mortality. The researchers offered the examples of associations for those with case-level symptoms three to four times being most strongly attenuated by number of health conditions (32.1%), anxiolytic use (28.4%), lung function (24.6%), physical activity (23.9%), smoking (24.6%), antidepressant use (20.1%), diet (16.4%), pulse rate (12.7%) and adult social class (11.2%).

“These findings suggest that policies to reduce the interaction between mental and physical health should be aimed predominately at adults as opposed to earlier in the life course,” the researchers wrote. “This study also highlights the importance of affective symptom history and may help direct future work in elucidating specific causal pathways and points of intervention.” – by Joe Gramigna

Disclosures: Archer reports no relevant financial disclosures. Please see the study for all other authors' relevant financial disclosures.