October 27, 2022 | Press Release

Increased Obesity Prevalence Exacerbates Depression Risk for Baby Boomers: A Counterfactual Study

MPIDR PhD-Student Maria Gültzow and colleagues used a counterfactual analysis in their recent study published in “Epidemiology” to assess the influence of generational differences in health behavior on the depression risk in the United States of Baby Boomers, and the Great and Silent generations.

More recent birth cohorts are at a higher risk of depression than those born in the early 20th century. “We are investigating to what extent changes in alcohol consumption, smoking, physical activity and obesity, contribute to these different depression risks,” says Maria Gültzow, a PhD-Student at the Max Planck Institute for Demographic Research (MPDIR) in Rostock, Germany and at the Public Health Department at the Erasmus Medical Center, Rotterdam, the Netherlands, and author of the paper recently published in the journal Epidemiology.

Gültzow and her colleagues used panel data from US adults who were born between 1916 and 1966 and who took part in the Health and Retirement Study to perform a so-called “counterfactual decomposition analysis”. This analysis allowed them to compare the predicted probability of elevated depressive symptoms to a counterfactual scenario where all birth cohorts had the health behavior of the 1945 birth cohort.

Obesity particularly plays a role for women’s depression risk

The depression risk of the Great and Silent generations, born between 1916 and 1949, would be on average 2% higher had they had the alcohol consumption levels equal to that of the 1945 cohort. The Baby Boomer generation, born between 1950 and 1966, would have a 0.5% higher depression risk on average had they had the alcohol consumption levels of the 1945 cohort. That indicates that depression risk for the Baby Boomers fell by 0.5% because of differences in alcohol consumption of Baby Boomers compared to the 1945 cohort.

In the counterfactual scenario where the 1945 Body Mass Index (BMI) distribution was applied to all generations, depression risk was on average 2.1% higher for the Great and Silent generations and 1.8% lower for the Baby Boomers. That indicates that depression risk for the Baby Boomers rose by 1.8% because of the higher obesity prevalence in that cohort.

For smoking and physical activity, the researchers didn’t find differences in depression risks between the natural course and counterfactual scenario. They highlight that alcohol consumption has a greater influence on the depression risk of whites than of other races and ethnic groups, while obesity particularly influences the depression risk of women.

Alcohol consumption is a more important risk factor for the Great and Silent generations

“As far as we know, our study is the first to investigate possible causes for the differences in depression risk across generations with the use of models embedded in the causal inference framework,” says Maria Gültzow.

In that way the study shows that obesity contributes on average 5.5% to depression risk in the Baby Boomers, whereas alcohol consumption is a more important risk factor for the Great and Silent generations, with average contributions of 7.5%.

Maria Gültzow concludes: “Though previous research suggests that lifestyle changes might explain increased depression risk in recent cohorts, our study finds only small contributions of alcohol consumption, physical activity, smoking, and obesity. Instead, the increased depression risk might, for example, be explained by the simultaneous rise in noncommunicable diseases, leading to increased multimorbidity.”

Original Publication

Gültzow, M.; Bijlsma, M. J.; van Lenthe, F. J.; Myrskylä, M.: The contribution of health behaviors to depression risk across birth cohorts. Epidemiology (2022). DOI: 10.1097/EDE.0000000000001524