Is the association between job strain and carotid intima-media thickness attributable to pre-employment environmental and dispositional factors?: The Cardiovascular Risk in Young Finns Study

Objectives: Most previous studies of job strain and cardiovascular risk have been limited to adult data. It remains unclear whether this association might be explained by factors already present before entering the labour market. This study examined whether pre-employment family factors and participants' own dispositional factors contribute to the relationship between job strain and carotid intima-media thickness (CIMT) among male employees. Methods: The sample consisted of 494 men from the Cardiovascular Risk in Young Finns Study. Parental socioeconomic position and parental life dissatisfaction were assessed at 9-21 years of age and components of type A behaviour (Hunter-Wolf) were assessed at 12 24 years of age before the participants had entered the labour market. Job strain, education and CIMT were assessed at 27-39 years of age when all participants were employed. Results: There was an association between higher job strain and increased CIMT in adulthood (mean 0.59 mm; 95% CI 0.42 to 0.76) which was only slightly affected on adjustment for parental socioeconomic position and parental life dissatisfaction as well as participants' education. However, the job strain/CIMT relationship attenuated by 17% to non-significant after taking into account the effect of the participants' type A behaviour components. Conclusions: In this contemporary cohort of men, lack of leadership (a type A behaviour component) contributed to the association between job strain and CIMT 15 years later, whereas pre- employment family factors had only a modest effect on this association.