Summary: According to a new study, certain behavioral risk factors strongly predict the likelihood of a person developing depression, and these risk factors change as we age.
Behavioral risk factors including smoking, obesity, limited physical activity and a less healthy diet strongly predict the likelihood of depression — and that likelihood increases with each additional risk factor a person possesses. Additionally, the risk factors most strongly linked to depression change with age.
Previous studies had identified behavioral risk factors for depression, but it was unclear how these variables changed across the lifespan. This study sought to identify how the risk factors varied among three age groups: younger (18-39 years old), middle-aged (40-59) and older (60-99) adults.
The researchers collected data from more than 30,000 survey respondents, who answered questions about their lifestyle, including smoking, weight, physical activity and diet, as well as their history of depression. The team looked for correlations between the risk factors and depression, controlling for variables such as gender, ethnicity and socioeconomic status.
Sixteen percent of all participants had a prior diagnosis of depression. Smoking was most strongly associated with depression, especially in younger people: Younger smokers had 2.7 times’ greater odds of having had depression, while middle-aged and older smokers had 1.8 times the odds, compared to nonsmokers of the corresponding age. Obesity was the next most important risk factor: younger, middle-aged and older obese respondents had 65 percent, 54 percent, and 67 percent greater likelihood of depression, respectively, compared to non-obese counterparts.
Participants who had little physical activity were more likely to have depression as they grew older. And a less healthy diet was linked to depression in the middle-aged and older groups only.
Importantly, compared to having no risk factors, having one risk factor increased the odds of having had depression (1.7 times). When a person had two risk factors, the odds of developing depression more than doubled. Having three risk factors increased the odds of developing depression by more than threefold, and a person with all four risk factors had almost six times the likelihood of depression.
The study is the largest yet to examine the behavioral risk factors for depression across age groups. Given the psychological, social and economic toll of depression, as well as its growing prevalence, predicting a person’s risk at any age is critical, as are age-specific prevention programs, according to the authors. They said further research about nuanced risk factors, including gender and ethnicity, are warranted.
Funding: The work was funded by the Gallup Organization, the Parlow-Solomon Professorship on Aging, and the UCLA Longevity Center.
Source: Emily Packer – UCLA
Publisher: Organized by NeuroscienceNews.com.
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Original Research: Abstract for “Behavioral risk factors for self-reported depression across the lifespan” by Natacha D. Emerson, Gary W. Small, David A. Merrill, Stephen T. Chen, Fernando Torres-Gil, and Prabha Siddarth in Mental Health & Prevention. Published September 21 2018.
Behavioral risk factors for self-reported depression across the lifespan
While behavioral risk factors for depression have been assessed in select samples, previous research is limited in addressing such correlates across the lifespan. To this end, we assessed the relationship between self-reported depression and four behavioral risk factors (smoking, obesity, limited physical activity, and less healthy diet) in a representative United States adult sample.
Data were drawn from 30,116 Gallup-Healthways survey respondents, and stratified according to younger (18–39), middle-aged (40–59), and older (60–99) adults. The survey included demographic information, questions relating to the four risk factors, and an item on self-reported depression. Weighted multivariable logistic regressions, controlling for sex, ethnicity, and socioeconomic variables, were used to calculate odds ratios (OR) and confidence intervals (CI) for each correlate.
Sixteen percent of respondents endorsed a prior diagnosis of depression; 17% smoked; 26% were obese; 50% engaged in limited physical activity; and 41% had a less healthy diet. Smoking was most strongly associated with risk for depression (OR: 2.71, 95% CI [2.41–3.04], 1.81 [1.62–2.02] and 1.82 [1.55–2.15] for younger, middle-aged and older age groups, respectively), followed by obesity (OR = 1.65 [1.45-1.86], 1.54 [1.39–1.71], 1.67 [1.46–1.90]), limited physical activity (OR = 1.32 [1.18–1.48], 1.48 [1.35–1.66], 1.61 [1.41–1.82]), and a less healthy diet (OR = 1.20 [1.08–1.32], 1.21 [1.06–1.37] for middle-aged and older groups). Depression rates increased with the number of risk factors.
Behavioral risk factors are associated with an increased risk for depression across the lifespan with some variability according to age groups.