Study of 1.8 million finds hypertension more dangerous than cholesterol, blood glucose.
High blood pressure, serum cholesterol and blood glucose explain approximately 50 percent of the increased risk of heart disease and three-quarters of the increased risk of stroke among overweight or obese individuals, according to a new international study published in The Lancet journal.
Body-mass index (BMI) and diabetes have increased worldwide, whereas global average blood pressure and cholesterol have decreased or remained unchanged. This lead a group of researchers to try calculate how much of the effects of BMI on coronary heart disease (CHD) and stroke are mediated through blood pressure, cholesterol, and glucose.
For their study, they gathered data from 97 prospective cohort studies that collectively enrolled 1.8 million participants between 1948 and 2005. The data included 57,161 incidences of CHD and 31,093 strokes. For each cohort, they excluded participants who were younger than 18 years, had a BMI of lower than 20 kg/m2, or who had a history of CHD or stroke. They estimated the hazard ratio (HR) of BMI on CHD and stroke with and without adjustment for all possible combinations of blood pressure, cholesterol, and glucose.
They found that of the three metabolic factors examined, high blood pressure poses the biggest risk, accounting for 31 percent of the increased risk of heart disease and 65 percent of the increased risk of stroke among overweight or obese individuals.
The percentage excess risks mediated by the three did not differ significantly between Asian and Western countries (North America, Western Europe, Australia, and New Zealand).
Based on their findings, the researchers concluded that “interventions that reduce high blood pressure, cholesterol, and glucose might address about half of excess risk of coronary heart disease and three-quarters of excess risk of stroke associated with high BMI. Maintenance of optimum bodyweight is needed for the full benefits.”
The study was funded by the U.S. National Institute of Health, UK Medical Research Council, National Institute for Health Research Comprehensive Biomedical Research Centre at Imperial College Healthcare NHS Trust, Lown Scholars in Residence Program on cardiovascular disease prevention, and Harvard Global Health Institute Doctoral Research Grant.