The sense of coherence and risk of injuries: role of alcohol consumption and occupation

Study objective: To test the hypothesis that individuals with a strong sense of coherence (SOC) have a decreased incidence of external cause injuries and to study the role of alcohol consumption and occupational category in that association. Design: Participants of the Helsinki Heart Study were followed up for injuries for eight years through the national hospital discharge register and cause of death statistics. Cox proportional hazards models were used to calculate the relative risks. Setting: The Helsinki Heart Study, a clinical trial to prevent coronary heart disease. Participants: 4405 Finnish middle-aged employed men. Main results: The SOC was inversely associated with the risk of injuries, with a significant 25% lower incidence in the highest tertile of SOC (7.6 per 1000 person-years) compared with the lowest (10.2 per 1000 person-years). The association remained significant if adjusted for age, but not if adjusted additionally for alcohol consumption or occupation. When considered jointly with occupational category, the injury risk showed a decreasing trend (p= 0.02) with increasing SOC among blue collar but not among white collar workers. The use of alcohol had a great impact on injury risk among those with weak SOC, with incidences of 7.7, 10.2, and 14.9 per 1000 person-years in the non/light, medium, and heavy categories of consumption (p for trend 0.01). No such trend was seen in other SOC tertiles. Conclusions: There was an effect of SOC on the incidence of injury especially among blue collar workers. A substantial part of the effect was mediated by alcohol consumption.