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Unlocking natural keys to longevity

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*People who live in walkable, mixed-age communities likely to live 100 years
*Physical activity prevents almost four million premature deaths worldwide yearly
*Replacing sitting time with 30 minutes of activity linked with lower cancer deaths
*Not smoking, being socially engaged in older age are common traits of centenarians

Scientists have made several advances in the search for natural keys to longevity.

Top of the pack are: people who live in highly walkable, mixed-age communities may be more likely to live to their 100th birthday; at least 3.9 million early deaths are being averted worldwide every year by people being physically active. Sedentary behaviour independently predicts cancer mortality but replacing sitting time with 30 minutes of activity was associated with a lower risk of cancer death, and not smoking and being socially engaged throughout older age are common traits of New Zealand centenarians.

The new study conducted by scientists at Washington State University’s Elson S. Floyd College of Medicine, United States (U.S.) suggests that where people live has a significant impact on the likelihood that they will reach centenarian age.

Published in the International Journal of Environmental Research and Public Health and 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, Wash.

Study author, a second-year WSU medical student who took an interest in the topic after serving as a home care aide to his ageing grandfather, Rajan Bhardwaj, said: “Our study adds to the growing body of evidence that social and environmental factors contribute significantly to longevity.”

Earlier research, he said, has estimated that heritable factors only explain about 20 to 35 per cent of an individual’s chances of reaching centenarian age.

The study’s senior author and an assistant professor who runs WSU’s Community Health and Spatial Epidemiology (CHaSE) lab, Ofer Amram, said: “We know from previous research that you can modify, through behaviour, your susceptibility to different diseases based on your genetics.”

In other words, when you live in an environment that supports healthy ageing, 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 neighborhood. The variables they looked at the included poverty level, access to transit and primary care, walkability, percentage of the working-age population, rural-urban status, air pollution, and green space exposure. Subsequently, they conducted a survival analysis to determine which neighborhood and demographic factors were tied to a lower probability of dying before the centenarian age.

They found that neighborhood walkability, higher socioeconomic status, and a high percentage of the working-age population (a measure of age diversity) were positively correlated with reaching centenarian status.

Also, according to a new study, people being physically active are averting at least 3.9 million early deaths worldwide every year. The study was published in The Lancet Global Health, last week, by researchers at the Universities of Cambridge and Edinburgh.

The team behind the study argued that too often people focus on the negative health consequences of poor levels of physical activity when they could be celebrating the achievements of physical activity.

The team looked at previously published data for 168 countries, on the proportion of the population meeting World Health Organisation (WHO) global recommendation of at least 150 minutes of moderate-intensity aerobic activity throughout the week, or 75 minutes of vigorous-intensity activity, or an equivalent combination. The proportion of the population meeting the recommended amount of physical activity varied substantially between countries, from 33 per cent for Kuwait to 64 per cent for the United Kingdom, to 94 per cent for Mozambique.

By combining these data with estimates of the relative risk of dying early for active people compared to inactive people, the authors were able to estimate the proportion of premature deaths that were prevented because people are physically active.

They found that globally, due to physical activity the number of premature deaths was an average (median) of 15 per cent lower than it would have been – 14 per cent for women and 16 per cent for men — equating to approximately 3.9 million lives saved per year.

Despite considerable variation in physical activity levels between countries, the positive contribution of physical activity was remarkably consistent across the globe, with a broad trend towards a greater proportion of premature deaths averted for low- and middle-income countries. In low-income countries, an average of 18 per cent of premature deaths was averted compared to 14 per cent for high-income countries.

Meanwhile, another study found that sedentary behavior independently predicts cancer mortality but replacing sitting time with 30 minutes of activity was associated with a lower risk of cancer death.

In the first study to look at objective measures of sedentary behavior and cancer mortality, researchers from The University of Texas MD Anderson Cancer Center, United States (U.S.), found that greater inactivity was independently associated with a higher risk of dying from cancer. The most sedentary individuals had an 82 per cent higher risk of cancer mortality compared to the least sedentary individuals. An accelerometer was used to measure physical activity, rather than relying on participants to self-report their activity levels

Researchers also found that replacing 30 minutes of sedentary time with physical activity was associated with a 31 per cent lower risk of cancer death for moderate-intensity activity, such as cycling, and an eight per cent lower risk of cancer death for light-intensity activity, such as walking.

The study also found that engaging in either light or moderate to vigorous physical activity made a difference. Investigators assessed sedentary time; light-intensity physical activity (LIPA) and moderate to vigorous physical activity (MVPA) in the same model and found that LIPA and MVPA, not sedentary behavior, remained significantly associated with cancer mortality.

Meanwhile, University of Otago researchers have discovered some of the secrets to longevity with new research revealing not smoking and being socially engaged throughout older age are common traits of New Zealand centenarians.

A consultant psychogeriatrician and Associate Professor, Yoram Barak, said the results showed people could have some control over the ageing process.

Psychogeriatrician is a psychiatrist sub-specialising in the assessment and treatment of elderly people.

“Electing not to smoke and committing to maintain social networking will be the best investment one can make towards successful ageing,” he said.

Barak said being socially active means physically going out of your home and away from families and interacting with people whether visiting friends, volunteering or participating in activities such as attending a concert or playing golf.

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 the 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 and hypertension rates increased by nearly 30 per cent 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 per cent) 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 said.

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 explained 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.

The biopsychosocial model is an interdisciplinary model that looks at the interconnection between biology, psychology, and socio-environmental factors. The model specifically examines how these aspects play a role in topics ranging from health and disease models to human development.


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