BMI is not related to CHD mortality
Body mass index (BMI=Weight/height2) is the most frequently used indicator of body fatness. In middle-aged men of the Seven Countries Study, BMI was inconsistently related to 10- and 25-year CHD mortality.
Weight fluctuation linked to increased CHD risk
Changes in body weight during the first 10 years of follow-up were related to CHD mortality during the following 15 years. Middle-aged men who gained more than 2 kg, put on an average weight of 7 kg. They had a 20% greater CHD mortality risk (not statistically significant) compared to those whose weight remained stable. A similar result was obtained in men who decreased more than 2 kg weight and lost on average 5 kg. Men were defined as “fluctuating” when their weight at the second examination differed more than 2 kg with their weight at examination 1 or 3. These men lost on average 1 kg and had a significant 50% higher CHD mortality risk compared to those who kept their weight constant. These results indicated that fluctuating weight, the so-called yo-yo effect, rather than BMI per se, was associated with greater CHD risk.