What is a good ApoB to ApoA1 ratio?
There’s no official number. No US guideline sets a goal for the ApoB to ApoA1 ratio. In INTERHEART, a study in 52 countries, people in the top fifth of the ratio had 3.25 times the odds of a heart attack of people in the bottom fifth. ApoB is the half with goals and the half trials can move, so lower your ApoB first.
What we’d do
Look at the two halves separately. If your ApoB is over the goal for your risk, that’s the job. If your ApoB is at goal, the ratio is mostly telling you about ApoA1, which has no goal in the US guideline. Walking, cycling or swimming raise HDL a little, and ApoA1 rides on HDL, so they help that half, along with plenty else.
Two proteins on a scale
ApoB sits on every particle that can carry cholesterol into an artery wall. ApoA1 is the main protein on HDL particles. The ratio divides one by the other, so it goes up when ApoB rises or ApoA1 falls.
In the first beam, an ApoB of 120 and an ApoA1 of 120 give a ratio of 1.00. In the second, 70 and 140 give 0.50. A balance beam shows the idea and the catch. The same ratio can come from very different pairs, and only ApoB has a goal.
What INTERHEART found
INTERHEART compared about 15,000 people who’d just had a heart attack with about 15,000 who hadn’t, across every inhabited continent. In the main 2004 paper, the ratio had the strongest link of the nine risk factors it measured, ahead of smoking. The top fifth of the ratio had 3.25 times the odds of the bottom fifth, against 2.87 times for current smokers compared with people who’d never smoked.
The 2008 lipid paper went further. Of all the blood fat measures, the ratio had the strongest link. Each step of one standard deviation came with 1.59 times the odds, and it accounted for 54% of the heart attacks in the population, against 37% for the LDL to HDL ratio and 32% for total to HDL. It held in every ethnic group, in men and women, and at every age. The blood samples weren’t fasting, which a Copenhagen study of 33,391 adults says is fine, since the ratio didn’t change after a normal meal.
Why there’s no good number
INTERHEART was a case-control study. It shows that the ratio tracks heart attacks very well, but it can’t show that raising ApoA1 prevents them, and the study’s cut points were never turned into a US goal. Exercise raised HDL about 2.5 mg/dL in a 2007 review of 25 trials, which is real but small.
ApoB is different. It has goals in mg/dL, food changes with measured sizes, and medicines that lower it by about a third. What is my ApoB to ApoA1 ratio? works out yours and tells you which half to look at.
5 sources
- Yusuf S and others, Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study), The Lancet, 2004pubmed.ncbi.nlm.nih.gov
- McQueen MJ and others, Lipids, lipoproteins, and apolipoproteins as risk markers of myocardial infarction in 52 countries (the INTERHEART study), The Lancet, 2008pubmed.ncbi.nlm.nih.gov
- Langsted A, Freiberg JJ and Nordestgaard BG, Fasting and nonfasting lipid levels: influence of normal food intake on lipids, lipoproteins, apolipoproteins, and cardiovascular risk prediction, Circulation, 2008pubmed.ncbi.nlm.nih.gov
- Blumenthal RS, Morris PB, Gaudino M and others, 2026 ACC/AHA guideline on the management of dyslipidemia, JACC, 2026doi.org
- Kodama S and others, Effect of aerobic exercise training on serum levels of high-density lipoprotein cholesterol, Archives of Internal Medicine, 2007pubmed.ncbi.nlm.nih.gov
