Epidemiologists at the University of Liverpool and the Heart of Mersey have found that approximately half the recent fall in coronary heart disease deaths in the US is due to positive life style changes and a further half to medical therapies.
The team found that a decrease in smoking, cholesterol, blood pressure and physical inactivity contributed to the fall in deaths from coronary heart disease, yet this decrease could have been substantially more had it not been for the increases in obesity and diabetes cases.
Coronary heart disease (CHD) death rates in the US almost halved between 1980 and 2000. To understand how this fall occurred scientists combined information on medical treatments with national changes in the levels of major risk factors, such as smoking and high cholesterol. The UK has seen similar falls in heart disease, but this fall is mainly attributed to healthier diets rather than medication.
From 1980 to 2000, the US death rates for CHD fell from 543 to 267 per 100,000 population among men and from 263 to 134 per 100,000 population among women. Overall there were 341, 745 fewer CHD deaths in 2000 than in 1980.
The team found that this decrease was attributed to reductions in risk factors such as total cholesterol, systolic blood pressure, smoking and physical inactivity. However, they found that this reduction could have been 15% more had it not been for an increase in obesity and diabetes. Approximately half the fall in CHD deaths was also attributed to medical treatments, including medications for heart failure and emergency treatments for heart attacks and angina.
Professor Simon Capewell, from the University of Liverpool's Division of Public Health and Trustee at CHD prevention charity, Heart of Mersey, said: "Using a sophisticated computer model called IMPACT we were able to combine and analyse data on the uptake and effectiveness of specific cardiac treatments and changes in risk factors among adults aged 25 to 84 years in the US. Data included results from trials, official statistics and national surveys.
"We found that CHD death rates halved, and 47% of the fall was attributed to medical treatments and approximately 44% to changes in risk factors. Prevalence of smoking, for example had fallen by 12%. Decreases in physical inactivity however, were offset by increases in body mass index and diabetes."
Robin Ireland, Chief Executive at Heart of Mersey, added: "We have recently seen similar falls in heart disease here in the UK. These changes mainly reflect healthier diets, not tablets. However the increase in obesity and diabetes are a wakeup call. They reflect the increasing consumption of large helpings of junk food. We need legislation to encourage food manufacturers and supermarkets to provide healthier food options."
The research is published in the New England Journal of Medicine.
Notes to editors:
1. The University of Liverpool is one of the UK's leading research institutions. It attracts collaborative and contract research commissions from a wide range of national and international organisations valued at more than £100 million annually.
2. Heart of Mersey is a coronary heart disease charity primarily funded by Greater Merseyside's primary care trusts and local authorities. It aims, through advocacy, campaigns, information and research, to co-ordinate a strategic approach to preventing high rates of heart disease and associated inequalities in Greater Merseyside