A prospective observational study on the relationship between sleep deprivation and heart disease was done by Ayas, et al. (Arch Intern Med 2003). Women who slept at most 5 hours a night were
compared to women who slept for 8 hours a night (reference group). After adjusting for potential
confounding variables like smoking, a 95% confidence interval for the relative risk of heart disease
was (1.10, 1.92). Based on this confidence interval, a consistent condusion would be
a. There was no evidence of an association between sleep deprivation and heart disease.
b. Lack of sleep causes the risk of heart disease to increase by 10% to 92%.
c. Sleep deprivation is associated with a modestly decreased risk of heart disease.
d. Sleep deprivation is associated with a modestly increased risk of heart disease.