Hammerfest: occupational medicine at 70° north.

doi:10.1093/occmed/kqu132 22. Cloninger CR, Svrakic DM, Przybeck TR. Can personality assessment predict future depression? A twelvemonth follow-up of 631 subjects. J Affect Disord 2006;92:35–44. 23. Kai Y, Nagamatsu T, Yamaguchi. Y, Tokushima S. Effect of leisure-time physical activity and commuting by walking on depressive symptoms among Japanese workers. Bull Phys Fitness Res Inst 2011;109:1–8. 24. Bonde JP. Psychosocial factors at work and risk of depression: a systematic review of the epidemiological evidence. Occup Environ Med 2008;65:438–445. 25. Nakata A. Work hours, sleep sufficiency, and prevalence of depression among full-time employees: a community-based cross-sectional study. J Clin Psychiatr 2011;72:605–614. 26. Bara AC, Arber S. Working shifts and mental health—findings from the British Household Panel Survey (1995– 2005). Scand J Work Environ Health 2009;35:361–367. 27. Gea A, Beunza JJ, Estruch R et al. Alcohol intake, wine consumption and the development of depression: the PREDIMED study. BMC Med 2013;11:192. 28. Kang E, Lee J. A longitudinal study on the causal association between smoking and depression. J Prev Med Publ Health 2010;43:193–204. 29. Park J, Kim Y, Chung HK, Hisanaga N. Long working hours and subjective fatigue symptoms. Ind Health 2001;39:250–254. 30. Nakashima M, Morikawa Y, Sakurai M et al. Association between long working hours and sleep problems in whitecollar workers. J Sleep Res 2011;20:110–116.