Coronary heart disease (CHD) increases with BMI, as well as with age, finds an article published in BioMed Central's open access journal BMC Medicine. The research from the Million Women Study indicates that increased weight increases risk of CHD equivalent to that caused by getting older.

Researchers from the University of Oxford followed the health of 1.2 million women from England and Scotland for (on average) almost a decade. Analysis of the data showed that the occurrence of CHD increases with BMI so that every 5 unit increase in BMI, calculated as weight/height2, increases incidence by 23%, which is equivalent to the risk conferred by getting older by 2.5 years.

The results showed that one in eleven lean middle aged women (with an average BMI of 21) will be admitted to hospital or will have died from CHD between the ages of 55 to 74. This risk progressively increases with BMI, and it reaches one in six, for obese women (with an average BMI of 34).

Dr Dexter Canoy, who led this study explained, "The risk of developing CHD increases even with small incremental increases in BMI, and this is seen not only in the heaviest but also in women who are not usually considered obese. Small changes in BMI, together with leading a healthy lifestyle by not smoking, avoiding excess alcohol consumption, and being physically active could potentially prevent the occurrence of CHD for a large number of people in the population."