The impact of psychosocial and behavioral factors on serum lipids was examined in 46 male and 47 female students with a mean age of 23 years. Subjects were recruited from the University of Stockholm and the study was performed with the Student Health Care Organization in order to have a basis for intervention programs. Significant associations between serum lipids and parental education, regularity of breakfast habits, nourishing eating, social support, depressive feelings and quality of life are found. However, there is no consistent pattern for these associations in men and women. Thus, some associations are significant for men and some for women. Women with parents having higher levels of education had lower values of cholesterol, triglycerides and apo B, and higher values of apo A-1 (representing the 'good' cholesterol) than women whose parents were not highly educated. When controlling the associations for confounding factors such as age, body mass index, physical activity, coffee, alcohol, smoking habits, nourishing eating and quality of life, the associations were strongly confirmed. No similar associations were found in men. Men who reported low social support or social integration and a low perceived quality of life showed a tendency to higher levels of lipids compared to those who reported high integration and quality of life. Regularity of dietary habits was found to be associated to serum lipids in men, the greater the regularity, the lower the lipid levels. The strongest association was found for regularity of breakfast habits. This association was also strongly significant in the regression analysis after controlling for the described confounding factors.(ABSTRACT TRUNCATED AT 250 WORDS)