Not smoking and remaining socially engaged are significant markers of living past 100, according to a New Zealand analysis of 292 centenarians, while a Washington State University study suggested living in highly walkable, mixed-age communities was important.
When it comes to living to the ripe old age of 100, good genes help but don’t tell the full story. Where you live has a significant impact on the likelihood that you will reach centenarian age, suggests a new study conducted by scientists at Washington State University’s Elson S Floyd College of Medicine. Based on Washington State mortality data, the research team’s findings suggest that Washingtonians who live in highly walkable, mixed-age communities may be more likely to live to their 100th birthday. They also found socioeconomic status to be correlated, and an additional analysis showed that geographic clusters where the probability of reaching centenarian age is high are located in urban areas and smaller towns with higher socioeconomic status, including the Seattle area and the region around Pullman, Washington.
“Our study adds to the growing body of evidence that social and environmental factors contribute significantly to longevity, said study author Rajan Bhardwaj, a second-year WSU medical student who took an interest in the topic after serving as a home care aide to his aging grandfather. Earlier research, he said, has estimated that heritable factors only explain about 20% to 35% of an individual’s chances of reaching centenarian age.
“We know from previous research that you can modify, through behaviour, your susceptibility to different diseases based on your genetics,” explained Ofer Amram, the study’s senior author and an assistant professor who runs WSU’s Community Health and Spatial Epidemiology (CHaSE) lab.
In other words, when you live in an environment that supports healthy aging, this likely impacts your ability to successfully beat your genetic odds through lifestyle changes. However, there was a gap in knowledge as to the exact environmental and social factors that make for an environment that best supports living to centenarian age, which this study helped to address.
In collaboration with co-authors Solmaz Amiri and Dedra Buchwald, Bhardwaj and Amram looked at state-provided data about the deaths of nearly 145,000 Washingtonians who died at age 75 or older between 2011 and 2015. The data included information on each person’s age and place of residence at the time of death, as well as their sex, race, education level and marital status.
Based on where the person lived, the researchers used data from the American Community Survey, Environmental Protection Agency, and other sources to assign a value or score to different environmental variables for their neighbourhood. The variables they looked at included poverty level, access to transit and primary care, walkability, percentage of working age population, rural-urban status, air pollution, and green space exposure. Subsequently, they conducted a survival analysis to determine which neighbourhood and demographic factors were tied to a lower probability of dying before centenarian age.
They found that neighbourhood walkability, higher socioeconomic status, and a high percentage of working age population (a measure of age diversity) were positively correlated with reaching centenarian status. “These findings indicate that mixed-age communities are very beneficial for everyone involved,” said Bhardwaj. “They also support the big push in growing urban centres toward making streets more walkable, which makes exercise more accessible to older adults and makes it easier for them to access medical care and grocery stores.”
Amram added that neighbourhoods that offer more age diversity tend to be in urban areas, where older adults are likely to experience less isolation and more community support.
Meanwhile, Bhardwaj said their findings also highlight the importance of continuing efforts to address health disparities experienced by racial minorities, such as African Americans and Native Americans. Consistent with previous research findings, for example, the data shows being white is correlated with living to 100. Looking at gender, the researchers also found that women were more likely to reach centenarian age.
Finally, the researchers wanted to see in which areas of the state people had a higher probability of reaching centenarian age. For each neighbourhood, they calculated the years of potential life lost, or the average number of years deceased individuals would have had to continue living to reach age 100. Neighbourhoods with lower values for years of potential life lost were considered to have a higher likelihood of reaching centenarian age, and vice versa.
When they mapped the years of potential life lost for all neighbourhoods across the state, they saw clusters with high likelihood of living to centenarian age in higher socioeconomic areas in urban centres and small towns across the state, including the greater Seattle area and the Pullman region.
While more research is needed to expand upon their findings, the researchers said the study findings could eventually be used to create healthier communities that promote longevity in older adults.
Objective: This study examined the association of several social and environmental factors on the likelihood of reaching centenarian age for older adults in Washington State.
Methods: A survival analysis of reaching centenarian age for older adults aged 75 years and above was performed using Washington State mortality data from 2011−2015. Models were adjusted for sex, race, education, marital status, and neighborhood level social and environmental variables at the block group level. Geographic clusters of increased chance of becoming a centenarian were also mapped.
Results: In the adjusted model, increased neighborhood walkability, lower education level, higher socioeconomic status, and a higher percent of working age population were positively associated with reaching centenarian age. Being widowed, divorced/separated, or never married were also positively correlated compared to being married. Additionally, being white or female were positively correlated with reaching centenarian status.
Discussion: Several social and environmental factors are correlated with becoming a centenarian in Washington State. In this study, we explore findings that are consistent with previous research, as well as some that have not been previously explained. More research is needed to expand upon these findings in this rapidly growing field.
Rajan Bhardwaj, Solmaz Amiri Dedra Buchwald, Ofer Amram
University of Otago researchers have discovered some of the secrets to longevity with new research revealing not smoking and being social engaged throughout older age are common traits of New Zealand centenarians.
Associate Professor Yoram Barak, a consultant psycho-geriatrician, says the results show people can have some control over the ageing process. “Electing not to smoke and committing to maintain social networking will be the best investment one can make towards successful ageing,” he says. Being socially active means physically going out of your home and away from families and interacting with people whether that is visiting friends, volunteering or participating in activities such as attending a concert or playing golf, Barak says.
Together with his colleague Professor Paul Glue, from the department of psychological medicine, and Dr Sharon Leitch from the department of general practice and rural health, Barak set out to investigate the variables associated with exceptionally healthy extreme old age.
“This is so we can make some recommendations to try and help people age well.” The researchers examined data relating to 292 centenarians who were free of common chronic diseases such as diabetes, depression, dementia and hypertension. They also included information relating to a further 103,377 older people aged over 60. All of these people were living in private accommodation in the community and not in aged residential care.
Results showed social engagement of participants, whereby they are participating in social activities of long-standing interest was similar across all age groups. Rates of depression and diabetes declined steadily with increasing age and rates of dementia declined after the age of 80. Hypertension rates increased by nearly 30% from age 60 to 100 years.
There is evidence that exercise improves health and length of life but in this study most participants had a similar profile of physical activity and there was not sufficient spread of duration or intensity of physical activities to test the effects on ageing.
However, among those surveyed the highest physical activity groups were at the lowest risk of dementia.
As of 2011, there are estimated to be between 400 to 500 centenarians living in New Zealand. Of these, fewer than 40 would be aged over 105. The mean age of those interviewed in the study was 101.
The centenarians were more likely to be female (75%) and in any age group, women were more likely to be free of the common chronic diseases outlined above.
“Women have a longer life expectancy and are therefore more likely to be represented in centenarian studies. However, after correcting for this advantage, men who do make it to 100 years of age are more likely to be free of common illnesses,” Barak says.
This study found higher rates of centenarians free of common chronic diseases in New Zealand than reported in other countries. However, one explanation is that this survey considered only centenarians living in the community, who were likely to be in better health compared with those living in residential care or hospital settings.
Barak explains the biopsychosocial foundations of remarkable health and longevity among centenarians is unclear. Genetic factors, certain geographical locations and life-style characteristics have all been studied in an effort to identify potential predisposing factors of exceptional longevity
Background: Centenarians escapers are those who reached 100 years of age without the diagnosis of any of the common age-related diseases and exploring their characteristics will inform about successful ageing. No previous study has examined centenarians free of common chronic diseases amongst New Zealand centenarians.
Methods: Retrospective observational cross-sectional review of a national dataset determining the prevalence of depression, dementia, diabetes and hypertension, smoking, physical activity and social relationships among older adults (aged 60–99 years) and centenarians. Participants were all older New Zealanders living independently in the community who completed the international Residential Assessment Instrument–Home Care (interRAI-HC) assessment during the study’s 5-year period (July 2013–June 2018).
Results: The assessments of 292 centenarians (mean age 101.03, SD 1.27 years) and 103,377 elderly (mean age 81.7, SD 5.7 years) were analysed. Compared to the elderly, centenarians were more likely to be female (74.7%, compared with 59.3% elderly, p < 0.001). Centenarians free of common chronic diseases did not differ from other centenarians on any of the analysed variables. Reduction in smoking rates and steady high rates of social engagement were associated with reaching a centenarian status free of common chronic diseases compared with older adults.
Conclusions: Not smoking and being socially engaged throughout older age were associated with being a centenarian free of common chronic diseases. This study adds to our understanding the complexities of attaining exceptional longevity.
Yoram Barak, Sharon Leitch, Paul Glue
Floyd College of Medicine, Washington State University material
The International Journal of Environmental Research and Public Health abstract
Otago University material
Aging Clinical and Experimental Research abstract