US cholesterol levels drop over past decade

The proportion of US adults with high cholesterol dropped by about five percentage points over the past decade, according to new data from the Centers for Disease Control and Prevention (CDC), even as waistlines have expanded.

The new CDC data show that about 13.4% of US adults in 2009 to 2010 had high cholesterol – considered to be a major risk factor for heart disease – compared to 18.3% in 1999. That is a 27% drop, and comfortably beats the government’s target of reducing the number of people with high cholesterol to less than 17% of the population by 2010. Meanwhile, more than two-thirds of the population is overweight or obese, although there is some evidence to suggest that rates have leveled off during the past ten years.

The CDC researchers did not offer any possible explanations for the drop, but there are several known risk factors for heart disease that have shifted during this time, including patterns of dietary fat consumption. Food manufacturers have cut artificial trans fats from their products over the past decade which, in the form of partially hydrogenated vegetable oils, have been linked to increased levels of low-density lipoprotein in the blood, also known as LDL or ‘bad’ cholesterol, and trans fats are also thought to simultaneously lower levels of HDL ‘good’ cholesterol.

According to a research letter published in the Journal of the American Medical Association in February, trans fat consumption among US adults has fallen 58% over the past decade, coinciding with regional bans and federal government regulation requiring labeling of artificial trans fats. 

But while public health measures and messages related to diet may be making a difference, prescriptions for cholesterol-lowering drugs have increased dramatically during this time, with 260m prescriptions dispensed in the United States last year, according to IMS Health, and smoking rates have also declined over the ten-year period.

However, the FDA released new safety advice about statins in February this year, saying that cholesterol-lowering drugs may cause a number of unwanted side-effects if prescribed to otherwise healthy individuals, although it emphasized that they are still useful for reducing cholesterol, particularly in cases where diet and exercise alone have failed.