Threat of unemployment and cardiovascular risk factors: longitudinal study of quality of sleep and serum cholesterol concentrations in men threatened with redundancy. OBJECTIVE--To assess whether the threat of unemployment affects risk factors for cardiovascular disease. DESIGN--Longitudinal study of a cohort of middle aged shipyard workers followed up for a mean of 6.2 (SD 1.9) years and a group of controls observed for the same period. The first investigation took place during a period of relative economic stability for the shipyard and the second during the phase of its closure. SETTING--An age cohort health screening programme in Malmo, Sweden. PARTICIPANTS--715 Male shipyard workers and 261 age matched male controls. MAIN OUTCOME MEASURES--Changes in 19 variables related to the risk of cardiovascular disease, and psychological variables, alcohol consumption, smoking, and dietary habits as assessed by questionnaire. RESULTS--Serum cholesterol concentrations increased more (mean 0.25 (SD 0.68) mmol/l v 0.08 (0.66) mmol/l) and serum calcium concentrations decreased less (-0.06 (0.10) mmol/l v -0.08 (0.09) mmol/l) in the shipyard workers than in the controls. A correlation was found between scores for sleep disturbance and changes in serum cholesterol concentration. In the whole series there was a greater increase in serum cholesterol concentrations among men threatened with unemployment (437/976; 44.8%) than among those who were not. In stepwise regression analysis the change in serum cholesterol concentration was correlated with changes in haemoglobin concentration, body weight, and serum triglyceride and calcium concentrations. A positive correlation was found between change in cholesterol concentration and change in blood pressure, indicating that the overall risk profile had worsened among men with increased serum cholesterol concentrations. CONCLUSIONS--Risk of unemployment increases the serum cholesterol concentration in middle aged men, the increase being more pronounced in those with sleep disturbance. The increase in serum cholesterol is related to changes in other established risk factors for cardiovascular disease. These findings might partly explain the excessive mortality due to cardiovascular disease recorded among the unemployed and people with sleep disturbance. 