1. Tjepkema M. Insomnia. Health Reports 2005; 17(1): 9-25.
2. Ferrie JE, Kumari M, Salo P, et al. Sleep epidemiology—a rapidly growing field. International Journal of Epidemiology 2011; 40: 1431-7.
3. Foley D, Ancoli-Israel S, Britz P, Walsh J. Sleep disturbances and chronic disease in older adults: results of the 2003 National Sleep Foundation Sleep in America Survey. Journal of Psychosomatic Research 2004; 56(5): 497-502.
4. Stranges S, Dorn JM, Shipley MJ, et al. Correlates of short and long sleep duration: cross-cultural comparison between UK and US. The Whitehall II Study and the Western New York Health Study. American Journal of Epidemiology 2008; 168: 1353-64.
5. Stranges S, Tigbe W, Gómez-Olivé XF, et al. Sleep problems: an emerging global epidemic? Findings from the INDEPTH WHO-SAGE study among over 40,000 older adults from eight countries across Africa and Asia. Sleep 2012; 35: 1173-81.
6. Gallicchio L, Kalesan B. Sleep duration and mortality: a systematic review and meta-analysis. Journal of Sleep Research 2009; 18(2): 148-58.
7. Cappuccio FP, D’Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 2010; 33(5): 585-92.
8. Grandner MA, Patel NP, Gehrman PR, et al. Problems associated with short sleep: Bridging the gap between laboratory and epidemiological studies. Sleep Medicine Reviews 2010; 14(4): 239-47.
9. Alvarez GG, Ayas NT. The impact of daily sleep duration on health: a review of the literature. Progress in Cardiovascular Nursing 2004; 19(2): 56-9.
10. Heslop P, Smith GD, Metcalfe C, et al. Sleep duration and mortality: the effect of short or long sleep duration on cardiovascular and all-cause mortality in working men and women. Sleep Medicine 2002; 3: 305-14.
11. Ferrie J, Shipley MJ, Cappuccio FP, et al. Sleep duration and change in sleep duration: associations with mortality in the Whitehall II cohort. Sleep 2007; 30: 1659-66.
12. Hublin C, Partinen M, Koskenvuo M, Kaprio J. Sleep and mortality: a population-based 22-year follow-up study. Sleep 2007; 30: 1245-53.
13. Buysse DJ, Grunstein R, Horne J, Lavie P. Can an improvement in sleep positively impact on health? Sleep Medicine Reviews 2010; 14: 405-10. Doi:10.1016/j.smrv.2010.02.001
14. Marshall NS, Stranges S. Sleep duration: risk factor or risk marker for ill health? In: Cappuccio FP, Miller MA, Lockley SW, eds. Sleep, Health, and Society. Oxford: Oxford University Press, 2010.
15. Horne J. The end of sleep: ‘Sleep debt’ versus biological adaptation of human sleep to waking needs. Biological Psychology 2011; 87: 1-4.
16. Bin Y, Marshall NS, Glozier N. Secular trends in adult sleep duration: A systematic review. Sleep Medicine Reviews 2011; 1-8. Doi:10.1016/j.smrv.2011.07.003
17. Knutson KL, Van Cauter E, Rathouz PJ, et al. Trends in the prevalence of short sleepers in the USA : 1975-2006. Sleep 2010; 33(1): 37-45.
18. Pilcher JJ, Ginter DR, Sadowsky B. Sleep quality versus sleep quantity: relationships between sleep and measures of health, well-being and sleepiness in college students. Journal of Psychosomatic Research 1997; 42(6): 583-96.
19. Nagin DS. Group-based Modeling of Development. Cambridge Massachusetts: Harvard University Press, 2005.
20. Swain L, Catlin G, Beaudet MP. The National Population Health Survey–its longitudinal nature. Health Reports 1999; 10(4): 62-82.
21. Tambay J-L, Catlin G. Sample design of the National Population Health Survey. Health Reports 1995; 7(1): 29-38.
22. Jones BL, Nagin DS, Roeder K. A SAS procedure based on mixture models for estimating developmental trajectories. Sociological Research and Methods 2001; 29(3): 374-93.
23. Jones BL, Nagin DS. Advances in group-based trajectory modeling and a SAS procedure for estimating them. Sociological Methods and Research 2007; 35: 542-71.
24. Ryu SY, Kim KS, Han MA. Factors associated with sleep duration in Korean adults : Results of a 2008 Community Health Survey in Gwangju Metropolitan City, Korea. Journal of Korean Medical Sciences 2011; 26: 1124-31.
25. Krueger PM, Friedman EM. Sleep duration in the United States: a cross-sectional population-based study. American Journal of Epidemiology 2009; 169: 1052-63.
26. Hale L, Do P. Racial differences in self-reports of sleep duration in a population-based study. Sleep 2007; 30(9): 1096-103.
27. Magee CA, Iverson DC, Caputi P. Factors associated with short and long sleep. Preventive Medicine 2009; 49: 461-7.
28. Ohayon MM, Carskadon MA, Guilleminault C, Vitiello MV. Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: Developing normative sleep values across the human life span. Sleep 2004; 27(7): 1255-73.
29. Williams C. You snooze, you lose?—Sleep patterns in Canada. Canadian Social Trends (Statistics Canada, Catalogue 11-008) 2001; 60(Spring): 10-4.
30. Hurst M. Who gets any sleep these days? Sleep patterns of Canadians. Canadian Social Trends (Statistics Canada, Catalogue 11-008) 2008; 85(Summer): 39-45.
31. Kronholm E, Härma M, Hublin C, et al. Self-reported sleep duration in Finnish general population. Journal of Sleep Research 2006; 15(4): 276-90.
32. Ursin R, Bjorvatn B, Holsten F. Sleep duration, subjective sleep need, and sleep habits of 40- to 45-year-olds in the Hordaland Health Study. Sleep 2005; 28: 1260-9.
33. Baldwin CM, Kapur VK, Holberg CJ, et al. Associations between gender and measures of daytime somnolence in the Sleep Heart Health Study. Sleep 2004; 27: 305-11.
34. Lauderdale DS, Knutson KL, Yan LL, et al. Self-reported and measured sleep duration: how similar are they? Epidemiology 2008; 19(6): 838-45.
35. Silva GE, Goodwin JL, Sherrill DL, et al. Relationship between reported and measured sleep times: The Sleep Heart Health Study (SHHS). Journal of Clinical Sleep Medicine 2007; 3(6): 622-30.