Most people would like to live long and healthy lives. We now pretty much know how this can be achieved, barring accidents, and it is very simple: adopt a lifestyle designed to minimise risk of ill-health. Thelatest study in this area has just been published by Yanping Li and others in Circulation, and reports that adopting five simple and well-known lifestyle habits can lengthen a woman's life expectancy at the age of 50 by 14 years and a man's life by 12 years.
The researchers analysed data from two large studies of American health professionals, the Nurses Health Study (NHS) and the Health Professionals Follow-Up study (HPFS), using a sample size of about 79,000 women and 44,300 men. The NHS began in 1976 and the HPFS in 1986. Participants studied completed detailed questionnaires every two to four years and the researchers monitored the five lifestyle behaviours.
The five low-risk lifestyle factors followed in the study are: healthy diet; regular physical exercise, moderate drinking, non-smoking and maintaining healthy body weight.
Low-risk smoking was defined as never smoking. Low-risk physical exercise was defined as at least 30 minutes per day of moderate to vigorous activities – for example, brisk walking. Healthy diet was assessed according to the American Alternate Healthy Eating Index, which stresses eating plenty of vegetables, fruit, whole grains, nuts and legumes, polyunsaturated fats and fatty fish and low intake of sugar-sweetened beverages, red meat, salt and alcohol.
Low-risk alcohol consumption was defined as 5-15 g of alcohol per day for women and 5-30 g per day for men – basically no more than one standard drink (eg half a pint of beer) for women or two standard drinks for men per day.
The health benefits of moderate alcohol consumption have been observed consistently in large studies
Low-risk body weight was defined as a body mass index (BMI) in the range 18.5-24.9 kilograms per metre squared. A BMI of 25 to 29.9 is considered overweight and a BMI of 30 and over is considered obese. BMI is defined as body mass in kilograms divided by the square of body height in metres.
The researchers followed the NHS and HPFS groups for up to 34 years, during which time more than 42,000 people died. Cancer accounted for almost 14,000 of these deaths and cardiovascular disease for almost 10,700 deaths.
However, those people who practised all five of the good health habits were 74 per cent less likely overall to die during this period than those who followed none of the healthy habits and specifically were 82 per cent less likely to die of cardiovascular disease and 65 per cent less likely to die from cancer.
A brief word about alcohol consumption. The Circulation study reports that people who drank two standard drinks per day had the same risk of death as those who had one drink. Those who drank three or more drinks per day had a 25 per cent greater risk of death than those who had one drink. But those who drank no alcohol also had a higher risk of death by 27 per cent than those who drank one drink. It seems there is nothing wrong with moderate alcohol consumption. Indeed, the cardiovascular benefits of moderate alcohol consumption have been observed consistently in large studies.
The results reported in this study are very significant for the United States – the richest country in the world – ranking number one globally for health expenditure as a percentage of gross domestic product, but where life expectancy lags considerably behind that of many other wealthy nations. Achieving 10 extra years of life by making such simple, small changes in daily health habits would be a huge leap forward for the US.
The American healthcare system does not concentrate on prevention of disease, focusing primarily on discovery of new drugs and treatment of disease. Although the results reported in Circulation are of particular importance for the US they are also of great international significance. Research covering 17 countries has indicated that about 60 per cent of premature deaths can be attributed to unhealthy lifestyles, including smoking, excessive alcohol intake, physical inactivity, poor diet and obesity, and are therefore preventable. Prevention should be the top priority for national health policies.
William Reville is an emeritus professor of biochemistry at UCC