Exercise, Chronic Diseases and Dementia
Healthy lifestyles based on non-smoking, an acceptable BMI, a high fruit and vegetable intake, regular physical activity, and low/moderate alcohol intake, are associated with reductions in the incidence of certain chronic diseases, but to date there is limited evidence on cognitive function and dementia.
In 1979 healthy behaviours were recorded on 2,235 men aged 45–59 years in Caerphilly, UK. During the following 30 years incident diabetes, vascular disease, cancer and death were recorded, and in 2004 cognitive state was determined.
Men who followed four or five of the behaviours had an odds ratio (OR) and confidence intervals (CI) for diabetes, corrected for age and social class, of 0.50 (95% CI: 0.19, 1.31; P for trend with increasing numbers of healthy behaviours <0.0005). For vascular disease the OR was 0.50 (95% CI: 0.30, 0.84; P for trend <0.0005), and there was a delay in vascular disease events of up to 12 years. Cancer incidence was not significantly related to lifestyle although there was a reduction associated with non-smoking (OR: 0.65; 95% CI: 0.54, 0.79). All-cause mortality was reduced in men following four or five behaviours (OR 0.40; 95% CI: 0.24, 0.67; P for trend <0.005).
After further adjustment for NART, the OR for men following four or five healthy behaviours was 0.36 (95% CI: 0.12, 1.09; P for trend <0.001) for cognitive impairment, and 0.36 (95% CI: 0.07, 1.99; P for trend <0.02) for dementia.
The adoption of a healthy lifestyle by men was low and appears not to have changed during the subsequent 30 years, with under 1% of men following all five of the behaviours and 5% reporting four or more in 1979 and in 2009.
A healthy lifestyle is associated with increased disease-free survival and reduced cognitive impairment but the uptake remains low.
From press release:
The study identifies five healthy behaviors as being integral to having the best chance of leading a disease-free lifestyle: taking regular exercise, non-smoking, a low body weight, a healthy diet and a low alcohol intake.
The people who consistently followed four or five of these behaviors experienced a 60 per cent decline in dementia and cognitive decline -- with exercise being the strongest mitigating factor -- as well as 70 per cent fewer instances of diabetes, heart disease and stroke, compared with people who followed none.
"The size of reduction in the instance of disease owing to these simple healthy steps has really amazed us and is of enormous importance in an aging population," said Principle Investigator Professor Peter Elwood from Cardiff University's School of Medicine. "What the research shows is that following a healthy lifestyle confers surprisingly large benefits to health -- healthy behaviors have a far more beneficial effect than any medical treatment or preventative procedure.
"Taking up and following a healthy lifestyle is however the responsibility of the individual him or herself. Sadly, the evidence from this study shows that very few people follow a fully healthy lifestyle. Furthermore, our findings reveal that while the number of people who smoke has gone down since the study started, the number of people leading a fully healthy lifestyle has not changed," he added.
Recent surveys indicate that less than one per cent of people in Wales follow a completely healthy lifestyle, based on the five recommended behaviors, and that five per cent of the population follow none of the healthy behaviors; roughly equating to a city with a population the size of Swansea (240,000).
Professor Elwood continued: "If the men had been urged to adopt just one additional healthy behavior at the start of the study 35 years ago, and if only half of them complied, then during the ensuing 35 years there would have been a 13 per cent reduction in dementia, a 12 per cent drop in diabetes, six per cent less vascular disease and a five per cent reduction in deaths."
The Caerphilly Cohort Study recorded the healthy behaviors of 2,235 men aged 45-59 in Caerphilly, South Wales. The study had multiple aims and has been the basis for over 400 research papers in the medical press. One of the most important aims was to examine the relationship between healthy lifestyles, chronic disease and cognitive decline over a 35-year period; and to monitor changes in the take-up of healthy behaviors.
Dr Doug Brown, Director of Research and Development at the Alzheimer's Society, said: "We have known for some time that what is good for your heart is also good for your head, and this study provides more evidence to show that healthy living could significantly reduce the chances of developing dementia. These large, longitudinal studies are expensive and complicated to run, but are essential to understand how dementia can be prevented. We are calling on the G8 Summit next week to commit to greater funding of important studies such as this one which give us hope for reducing the impact of dementia in the future."
Christopher Allen, Senior Cardiac Nurse at the British Heart Foundation, which part-funded the study, said: "The results of this study overwhelmingly support the notion that adopting a healthy lifestyle reduces your risk of cardiovascular disease and dementia. These findings will hopefully go a long way in encouraging people to carefully consider their lifestyle and how it will impact on their health in later years."
Unhealthy living has accounted for around 10 per cent of the costs of the NHS in Wales since the study first started, while the annual expenditure on prevention and public health services in Wales is estimated to have been £280M.
Peter Elwood, Julieta Galante, Janet Pickering, Stephen Palmer, Antony Bayer, Yoav Ben-Shlomo, Marcus Longley, John Gallacher.
Healthy Lifestyles Reduce the Incidence of Chronic Diseases and Dementia: Evidence from the Caerphilly Cohort Study