Background: High plasma fibrinogen concentration is associated with an increased risk of coronary heart disease. We have investigated associations between plasma fibrinogen and factors operating in childhood and in adulthood, including the psychosocial characteristics.
Methods: In a cross-sectional study of Civil Servants in London, UK, 2095 men and 1202 women aged 45-55 years provided blood samples for fibrinogen measurement at the time of the Whitehall II study baseline. The participants completed a questionnaire on demographic characteristics, education, employment grade, parents' occupation, health behaviours, and work characteristics.
Findings: Measures of childhood environment (adult height, father's social class, and participant's education) were inversely associated with adult plasma fibrinogen concentration in both sexes. Lower socioeconomic status (as shown by employment grade) was associated with higher fibrinogen concentrations, with differences from top to bottom grade of 0.22 g/L (95% Cl 0.13-0.31) in men and 0.37 g/L (0.18-0.56) in women (p<0.0001, both sexes). This association was not accounted for by measures of childhood circumstances. Control over work, assessed by personnel managers, was inversely related to fibrinogen in both sexes, and a similar relation was seen for self-rated control over work among men but not women. Men in the bottom third of the distribution for self-rated and externally assessed control over work had higher fibrinogen concentrations than those in the top third for both measures (difference 0.16 g//L [0.07-0.26]; p<0.001.) There was no difference between these extremes among women (0.02 g/L [0.16 to 0.19]). Current smokers had higher fibrinogen concentrations than non-smokers, and moderate alcohol consumers had lower concentrations than those who drank occasionally or never.
Interpretation: Although our study was cross-sectional, it provides evidence that adult fibrinogen concentration is determined by factors operating throughout life. Fibrinogen may be a marker of the biological pathways that mediate the inverse socioeconomic gradient in coronary disease.