A new study involving more than 300,000 people finds that being overweight independently increases a person's risk of coronary disease.
In other words, even if doctors could get an overweight person's blood pressure and cholesterol down to normal, that patient would still be at higher heart risk. This Dutch analysis involved data from 21 previous studies that included more than 302,000 people.
Of those people, 18,000 suffered heart events or deaths during the studies. After factoring in age, sex, physical activity levels and smoking, the team concluded that moderately overweight people had a 32 percent increased risk of heart disease and obese people an 81 percent increased risk compared to those who weren't overweight.
The researchers, from the National Institute for Public Health and the Environment, in Bilthoven, The Netherlands, then adjusted further for blood pressure and cholesterol levels. They found that this reduced the increased risk of heart disease among moderately overweight people to 17 percent, and to 49 percent for obese people.
Before adjusting for blood pressure and cholesterol, every five units of body mass index (BMI) increase was associated with a 29 percent increased risk for heart disease. After adjusting for blood pressure and cholesterol, there was still a 16 percent increased risk for every five units of BMI increase.
"Hence, the present study indicates that adverse effects of overweight on blood pressure and cholesterol levels could account for about 45 percent of the increased risk of coronary heart disease, and that there is still a significantly increased risk of coronary heart disease that is independent of these effects," wrote the study authors.
This implies that, even under the theoretical scenario that optimal treatment would be available against hypertension and hypercholesterolemia in overweight persons, they would still have an elevated risk of coronary heart disease.