Snoring and Ischemic Stroke: Understanding a Case-Control Study

A 1991 case-control study investigated whether a history of snoring was associated with ischemic brain infarction, a type of stroke. It found an association, but did not prove that snoring causes stroke or that a product which reduces snoring prevents stroke.

What did the study examine?

Heikki Palomäki studied 177 male patients aged 16–60 with acute brain infarction and selected an age-matched male control for each patient. Snoring history and other potential risk factors were assessed. Habitual or frequent snoring was associated with brain infarction in a multivariable analysis, with an odds ratio of 2.13.

What is an odds ratio?

A case-control study starts with people who have an outcome and compares them with controls. It looks back at factors that might be associated with that outcome. The reported odds ratio is a statistical comparison, not a forecast of a particular person’s future stroke risk.

It would be misleading to describe 2.13 as a percentage or to say that every snorer has twice the future risk. The study design, selection of participants and factors included in the analysis all matter.

What about sleep apnea?

The author proposed that a higher prevalence of obstructive sleep apnea among snorers could help explain the association. That is a possible explanation, not proof that heavy snoring inevitably progresses to sleep apnea. Nor does this study establish the exact contribution of snoring alone.

Why the findings have limits

• The study involved male hospital patients and controls, so it does not directly describe every population.
• Reported snoring history can be incomplete or affected by recall.
• Other health conditions and shared risk factors can influence an observed association.
• No anti-snoring treatment was tested for stroke prevention.

How this differs from the other Finnish study

This investigation compared stroke patients with controls. The separate Finnish cohort study of heart disease and stroke in men followed a larger group over time. Keeping these designs separate avoids mixing their figures or conclusions.

What should readers take away?

Persistent snoring with breathing pauses, gasping or daytime sleepiness warrants a discussion about sleep-apnea assessment. A quieter night alone does not confirm that a breathing disorder is controlled.

Asonor was not evaluated in this study. The findings provide no evidence that it prevents stroke or replaces medical care for sleep apnea.

Source

Palomäki H. Snoring and the risk of ischemic brain infarction. Stroke, 1991;22:1021–1025.

Editorial update: September 2026. This article explains one historical study and its limitations, rather than providing an individual risk assessment.