Haemorrhoidal disease came with a 24 percent higher rate of dementia over 15 years, and the authors say it is a marker, not a cause

A hazard ratio of 1.243 across 381,031 people is not a borderline result, and the temptation with a finding like this is to dress it up. The research group did the opposite: their own discussion says haemorrhoidal disease may not directly cause dementia and may instead serve as a marker of an underlying systemic condition. That sentence is the reason the study is worth reading, and it is the part that gets dropped when a result like this travels.

The size of it#

Follow-up ran to a median of 15.49 years, with an interquartile range of 12.21 to 18.77, which is long enough for dementia to be a realistic endpoint rather than a rare one: 22.47 percent of the cohort accumulated a diagnosis. A cohort this large and followed this long will detect small effects reliably, and 24 percent is not small.

Why the marker reading is the better one#

No mechanism connects veins at the anal canal to the brain. What does connect them is everything in between: chronic straining, raised intra-abdominal and venous pressure, obesity, low physical activity, hypertension. A separate Korean screening cohort of 194,620 adults found hypertension independently associated with haemorrhoidal disease, and vascular risk factors are established contributors to dementia. Two conditions can share a cause without either causing the other.

What to do with it#

Nothing, clinically, in the direction most readers will expect. There is no case for operating on haemorrhoids to reduce dementia risk, and the study makes no such claim. What it supports is a more modest and more useful habit: haemorrhoidal disease is common enough and cheap enough to observe that it is a reasonable prompt to check the vascular risk factors sitting behind it — blood pressure, weight, activity — in a patient who came in about something else entirely.

Both outcome definitions rest on insurance claims, so severity is invisible in both directions. Two claims under ICD-10 code I84 is a diagnosis of haemorrhoids, not a measure of how bad they were; two claims under F00 to F03, G30 or G31 is a diagnosis of dementia, not a stage of it. Every conclusion here sits at the resolution of diagnoses being recorded.