Why You Should Start Thinking About Your Cholesterol Earlier

High cholesterol is known to be one of the primary risk factors for heart disease, since it can contribute to plaque buildup in the arteries. But even though the U.S. Centers for Disease Control and Prevention recommends regular cholesterol testing starting around age 20, many Americans don’t give cholesterol—or heart disease, for that matter—much thought until later in life.

A new modeling study published in the Lancet gives extra reason not to put off cholesterol screening and treatment. It confirms that high blood levels of “bad” (or non-HDL) cholesterol are associated with a greater risk of developing cardiovascular issues including stroke and heart disease.

The researchers collected data from 38 studies conducted in North America, Europe and Australia, comprising about 400,000 people without cardiovascular disease, a third of whom were younger than 45. At the start of each study, participants’ cholesterol levels were measured, and they answered questions about their medical histories, lifestyle and demographics. During a follow-up period of up to 43 years, almost 55,000 of the study participants developed heart disease or stroke.

The researchers used that information both to find connections between baseline cholesterol levels and later heart issues, and to create a model for predicting a person’s risk of heart problems based on their sex, age and common risk factors, including smoking status, blood pressure, body mass index, diabetes diagnosis and medication regimens.

Based on that model, the authors estimated that a man younger than 45 with non-HDL cholesterol between 145-185 mg/dL—levels below 130 mg/dL are considered healthy—and at least two other heart disease-risk factors has a 29% chance of having a heart problem by age 75. Meanwhile, a man older than 60 with exactly the same characteristics has a 21% probability of having a heart problem by age 75. For women, those numbers were 16% and 12%, respectively.

One explanation, the authors say in a statement, is that younger adults who already have high cholesterol can expect damage to accumulate over a longer period of time, whereas older adults may have developed the issue later on, and so have had less time for the progression to reach critical levels.

It’s also possible that older adults who met the study’s initial criteria of not having cardiovascular disease were in better health than their peers overall.

While any modeling estimate leaves room for error, the study emphasizes the importance of lowering high cholesterol early and, ideally, preventing it in the first place. The study authors estimate that a man younger than 45 who halves his non-HDL cholesterol levels could slash his chance of later heart problems from 29% to 6%, while a younger woman’s probability could drop from 16% to 4%.

Doctors can prescribe medications—often statins—to lower cholesterol, but lifestyle choices can also make a big difference. Diet is among the most important interventions. There’s some debate about whether foods that contain dietary cholesterol, such as eggs, actually raise blood cholesterol; U.S. federal dietary guidelines no longer explicitly cap daily cholesterol intake. But they do still recommend limiting high-cholesterol foods, such as fatty meats and high-fat dairy, for a variety of health reasons.

Instead, people should eat plenty of produce, whole grains and healthy fats, like those from fish and avocados. Exercising regularly, relieving stress, getting plenty of sleep and avoiding smoking can also help keep cholesterol in check.