Background: Both weight gain and weight loss have been associated with increased risk of cardiovascular disease mortality in recent studies from the US. This finding has led to concern and uncertainty about appropriate advice for overweight and obese subjects.
Methods: In a prospective study of cardiovascular disease, the relationship between weight change over a 5-year period and subsequent risk of a heart attack during a further 6.5 year follow-up was examined in 7100 middle-aged British men.
Results: Over half of the men remained stable (< 4% change in bodyweight) and served as the reference group; 31% gained weight and 13% lost weight. The 6445 men free from a history of coronary heart disease experienced 318 heart attacks, fatal and non-fatal, during the 6.5 years. Men who gained 4-10% bodyweight had the lowest rate of heart attack, although this was not significantly different from the stable group. The men who lost weight had an increased risk of heart attack, which after adjustment (for age, recall of doctor-diagnosed hypertension and diabetes and other coronary risk factors i.e. serum total cholesterol, blood pressure, social class, initial body mass index (BMI) and lung function (FEV1), and smoking status at screening and 5 years later), was of a similar level of risk to the stable group. The men who gained > 10% bodyweight had a significantly increased risk of a heart attack after the above adjustment (P < 0.05). When the effect of weight change was examined according to initial BMI, those men with a BMI < 25 kg/m2 who lost weight had a marginally increased relative risk of heart attack after full adjustment (P = 0.06), while men who were overweight (BMI 25-27.9 kg/m2) or obese (BMI > or = 28 kg/m2) showed no benefit from weight loss. A small amount of weight gain (4-10%) in the overweight or obese men was associated with decreased risk, whereas considerable weight gain (> 10%) was associated with increased risk, both findings reaching statistical significance in the overweight men (P < 0.05 and P < 0.001 respectively).
Conclusions: Considerable weight gain (> 10%) in middle-aged men is associated with increased risk of a heart attack, but weight loss does not appear to reduce risk even in the overweight or obese.