Incidence of ischaemic stroke according to income level among older people: the 3C study

stroke has been shown to follow a social gradient with incidence rising as socioeconomic status decreases.

to examine the relationship between socioeconomic status and ischaemic stroke risk amongst older people.

the Cities of Bordeaux, Dijon and Montpellier in France.

nine thousand and two hundred and ninety-four non-institutionalised persons aged 65 years or more followed for 6 years.

the distribution of cardiovascular risks factors was consistent with the classical finding of more favourable risk profiles among the advantaged socioeconomic groups. One hundred and thirty-six individuals developed a first ever ischaemic stroke (incidence rate: 3.2 per 1,000 py (person-years), 95% CI 2.7-3.8). The age- and sex-adjusted incidence of ischaemic stroke increased with increasing level of income (from 2.4 to 4.1 per 1,000 py, P = 0.04). In the multivariable analysis adjusting for cardiovascular risk factors, the higher income group displayed a 80% increased risk of ischaemic stroke compared with less wealthy participants (hazards ratio 1.77, 95% CI 1.20-2.61).

in this community-based sample of older individuals, a higher level of household income was associated with a higher risk of ischaemic stroke, a reversal of the social gradient usually reported in younger age groups. Selective survival is one of the potential explanations for this unexpected finding.