New European research has found that those who survive a heart attack may be at a higher risk of a second one if they are divorced or have a low socioeconomic status.

Carried out by researchers from Karolinska Institutet, Stockholm, Sweden, the large-scale study looked at 29,226 participants aged 40-76 one year after surviving their first heart attack.

The team recorded the marital status (married, unmarried, divorced, widowed), socioeconomic status (measured by disposable income) and and educational level (nine years or less, 10-12 years, more than 12 years) of each participant, and then continued to follow them for an average of four years.

They found that being divorced and having low socioeconomic status were both significantly associated with a higher risk of a second attack.

Divorced participants had an 18% greater risk of a recurrent event than married patients, while those in the highest household income quintile had a 35% lower risk of a second attack than those in the lowest quintile.

In addition, patients with more than 12 years of education had a 14% lower risk of a recurrent event than those with nine or fewer years of education.

Although unmarried and widowed patients also had higher rates of recurrent attacks than married patients, the associations were not significant, however study author Dr Joel Ohm commented that the proportions of unmarried and widowed patients included in the study may have been too small for the link to be statistically significant.

When they carried out a subgroup analysis, the team also found that unmarried men had a higher risk of recurrence whereas unmarried women had a lower risk, and that although a higher household income was associated with a lower risk of recurrent events in men, there was no association in women.

Dr. Ohm said this could be due to the lower proportion of women in the study (27%), since the maximum age of participants included was 76 years, and women are generally older than men when they have a first heart attack. The difference between the lowest and highest quintiles of household income is also likely to be greater when men have a first heart attack because they and their spouse are still of working age.

"These findings should be interpreted cautiously," Dr Ohm warned. "This was a subgroup analysis and we cannot conclude that women are better off being single and that men should marry and not divorce. Unmarried women had a higher level of education compared to unmarried men, and this difference in socioeconomic status may be the underlying cause."

"The take-home message from this study is that socioeconomic status is associated with recurrent events," said Dr. Ohm. "No matter the reasons why, doctors should include marital and socioeconomic status when assessing a heart attack survivor's risk of a recurrent event. More intense treatment could then be targeted to high risk groups."

The results can be found published online in the European Journal of Preventive Cardiology.