Day of the week and ischemic stroke: is it Monday high or Sunday low?

Abstract

Background and purpose: The study aim was to examine the incidence of ischemic stroke (IS) by day of the week and its relationship with age, sex, and socioeconomic status (SES).

Methods: A total of 12,801 IS events in men and women aged 25 to 99 years was recorded in a population-based stroke register (FINMONICA), which was functioning in Finland from 1982 to 1992. We analyzed the weekly variation in IS incidence by pooling the data and stratifying by sex and age. Taxable income and level of education were used as indicators of SES.

Results: We observed a significant weekly variation in IS occurrence, but the analysis by age group demonstrated a difference by weekday only in the age group 60 to 74, both in men and women (P<0.001 and P=0.02, respectively). The increase in the number of IS events from Sunday to Monday was pronounced in men (29.2% increase from Sunday to Monday). When stratifying by age, Monday excess in IS incidence was associated with lower SES among persons >59 years of age. No Monday excess was observed in persons with high SES.

Conclusions: Because the incidence of IS is much higher in persons with low SES than in those with high SES, the Monday excess in persons with low SES is of substantial public health interest. This finding may suggest reasons for the higher IS incidence in persons with low socioeconomic positions and open up some possibilities for prevention.