Research on older adults’ health outcomes is common, and the higher incidence of disease and chronic conditions among seniors often makes close monitoring of senior care a matter of critical importance. Despite this interest in the health of seniors, researchers typically pay less attention to the 90-plus crowd, but an initiative called the “90+ Study” is closing the gap.

Fast-growing population 
People above age 90 are relatively unstudied by researchers and little understood even by doctors. However, the health of people in this advanced age bracket is as worthy of notice as that of any other group, and their health issues are likely only to become more prominent. Data from the U.S. Census Bureau showed that the over-90 population is growing rapidly, nearly tripling to 1.9 million members between 1980 and 2010. In the same time frame, the group grew to represent a larger portion of the senior population, increasing from 2.8 to 4.7 percent of the demographic. By 2050, the Census Bureau expects people 90 and older to account for 10 percent of people over 65.

The agency revealed some additional information that shines a light on who exactly makes up this population. There are nearly three times as many women than men alive past 90, for instance, and 20 to 30 percent of the entire group lives in retirement communities. This is likely due to the increasing risk of disability that typically accompanies growing older. More than 98 percent of those over 90 in senior living communities have some form of disability. Even among those who are able to live on their own, more than 80 percent have a disabling condition.

Landmark study 
Beyond that, more nuanced research is needed to determine the characteristics of people over 90. To date, the most thorough source of information comes from the 90+ Study, a study that began in 2003, and is still running today. The 90+ Study actually has its roots in a 1981 survey of 14,000 seniors living in a retirement community called Leisure World. In 2003, researchers found 1,600 of the study’s participants and enrolled them in another program to track what happened to them as they aged beyond 90.

Some of the results of the 90+ Study have confirmed or strengthened previous research, while others have presented new findings or highlighted complications and gaps in the understanding of the elder population. For example, exercise was correlated with longevity, as expected, but the upper limits of its effectiveness were unexpected. Those who got 45 minutes of physical activity per day were the healthiest group, surpassing even those who exercised more.

Unforeseen consequences 
People who drank moderate amounts of caffeine and alcohol were also more likely to survive past 90 than others. While this is widely expected, recent research has shown that alcohol’s supposed benefits to heart health may in fact be a myth, leaving its link to longevity unclear.

Many findings were more surprising, even to researchers. People who were overweight in their 70s were found to live longer their those who were underweight or of average weight, though researchers couldn’t say why. Once participants entered their 90s, some aspects of their health became even more inexplicable. One researcher, Claudia Kawas, told 60 Minutes that people who had high blood pressure in their 90s had a lower risk of dementia, but the effect was not seen in those whose high blood pressure developed earlier.

Room for research 
Kawas also revealed gaps in researchers’ understanding of memory loss. Some patients who exhibited symptoms thought to indicate Alzheimer’s disease were found to have none of the brain plaques and tangles considered to be hallmarks of the degenerative illness. Instead, many of them have tiny strokes in the brain, called microinfarcts, which may explain their memory loss. Some participants were even found to have enough plaques that they should, by current understanding, have Alzheimer’s, but exhibited no symptoms.