Early life characteristics, social mobility during childhood and risk of stroke in later life: findings from a Swedish cohort.

AIMS: To investigate if early life characteristics and social mobility during childhood are associated with incident thrombotic stroke (TS), haemorrhagic stroke (HS) and other stroke (OS).

METHODS: Our study population consists of all live births at Uppsala University Hospital in 1915-1929 (Uppsala Birth Cohort; n = 14,192), of whom 5532 males and 5061 females were singleton births and lived in Sweden in 1964. We followed them from 1 January 1964 until first diagnosis of stroke (in the National Patient Register or Causes of Death Register), emigration, death, or until 31 December 2008. Data were analysed using Cox regression, stratifying by gender.

RESULTS: Gestational age was negatively associated with TS and OS in women only. Women had increased risk of TS if they were born early preterm (<35 weeks) (HR 1.54 (95% CI 1.02-2.31)) or preterm (35-36 weeks) (HR 1.37 (95% CI 1.03-1.83)) compared to women born at term. By contrast, only women who were early preterm (HR 1.98 (95% CI 1.27-3.10) had an increased risk of OS. Men who were born post-term (⩾42 weeks) had increased risk of HS (HR 1.45 (95% CI 1.04-2.01)) compared with men born at term, with no association for women. TS was associated with social mobility during childhood in women: women whose families were upwardly or downwardly mobile had increased risk of TS compared to women who were always advantaged during childhood.

CONCLUSIONS: Gestational age and social mobility during childhood were associated with increased risk of stroke later in life, particularly among women, but there was some heterogeneity between stroke subtypes.