Should you need another arrow in your quiver of arguments for why clients should retire later rather than sooner, here’s one from a longintudinal study whose findings were published in March in the international Journal of Epidemiology and Community Health (abstract is here; payment required for full report).

The stated aim of the research was to “examine the association between retirement age and mortality among healthy and unhealthy retirees and to investigate whether sociodemographic factors modified this association.” It turns out there was an association. Among nearly 3,000 Americans who were followed over 18 years, it turned out that among healthy retirees, there was an 11% lower risk of all-cause mortality for those who were at least one year older at retirement. But even among unhealthy retirees, there was a lower death risk when they retired later.

That was the case, the researchers found, “independent of a wide range of sociodemographic, lifestyle and health confounders.” (What’s a confounder? It’s essentially a third variable that may be responsible for a correlation between two other variables. So people who work longer tend to live longer. Great. But is there another variable that confounds that correlation? The researchers looked and didn’t find any. For all you non-statistics persons out there, please see this sidebar.) 

The deadpan conclusion of the researchers? “Early retirement may be a risk factor for mortality, and prolonged working life may provide survival benefits among U.S. adults.” 

The paper first looks at prior research seeking a link between retirement age and longevity and concludes there is no such consensus (some studies showed greater longevity among early retirees, others just the opposite). Lead researcher Chenkai Wu and colleagues were also cognizant of another big issue when looking at retirement and death: the “healthy worker bias.”

That is the statistical bias arising when a worker retires early because of poor health, which may increase the death rates for said retirees, or in the paper’s words, poor health is a “a well-established risk factor for mortality.” So the researchers only followed participants in a broader longitudinal study who said their health had “no impact on their decision to retire.”

That netted the 2,956 survey participants, 1,934 who were healthy and 1,022 who were unhealthy. Over an average follow-up period of 16.9 years, 234 (12.1%) healthy and 262 (25.6%) unhealthy retirees died. 

Conclusions and Causes

First, a word about who was healthy and who was not. The healthy retirees were “more often men and white, more highly educated and more likely married.” In addition, the healthy “had more wealth than unhealthy retirees,” and tended to be more physically active, had a lower body mass index, fewer chronic conditions and were less likely to engage in unhealthy behaviors like smoking, leading the researchers to conclude that “overall, healthy retirees had relatively advantaged socioeconomic, behavioral and health profiles.” However, while “unhealthy retirees had an 84% higher mortality risk than healthy retirees, the association of retirement age with mortality did not differ between these subgroups.” Even when the unhealthy retirees were analyzed separately, retiring one year later (using the average retirement age of 65) “was associated with a 9% lower mortality risk.” For healthy retirees in the study, retiring one year later produced an “11% lower risk of all-cause mortality.” 

The big question is why retiring even one year later than average reduces mortality. The researchers cited several potential answers. One, they said, is that employment “is a key component of individuals’ identity that provides them with substantial nancial, psychosocial and cognitive resources.” Another could be that retirement itself is a “stressful life event.”

They also speculate that delaying retirement, “and continued participation in volunteer activities and paid work in old age after retirement could delay the declines in physical, cognitive and mental functioning and reduce the risk of morbidities, which leads to better survival.” Finally, they suggest “this may be particularly true for individuals in work-oriented countries, where work is highly valued and is considered a necessary part of life.”

The study — Association of retirement age with mortality: a population-based longitudinal study among older adults in the USA — was conducted by Chenkai Wu and colleagues Michelle Odden and Robert Stawski at Oregon State University and Gwenith Fisher of Colorado State University.

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