Table 5.

Association between shiftwork and total prostate-specific antigen (PSA) of 4.0ng/mL or greater and between shiftwork and total PSA of 4.0ng/mL or greater with free PSA less than or equal to 25% among 2005 to 2006 National Health and Nutrition Examination Survey participants*

Exposure	Total PSA ≥ 4.0, odds ratio (95% CI)	P†
Shiftwork, age-adjusted	4.58 (1.10 to 19.14)	.04
Shiftwork, confounder adjusted‡	5.11 (1.59 to 16.38)	.006
	Total PSA ≥ 4.0, free PSA ≤ 25%, odds ratio (95% CI)	P†
Shiftwork, age-adjusted	5.16 (1.25 to 21.31)	.02
Shiftwork, confounder adjusted‡	5.58 (1.87 to 16.68)	.002

* CI = confidence interval.

† All statistical tests were two-sided. P values were calculated using logistic regression models. Nonshiftworkers were the reference group.

‡ Adjusted for age (continuous), body mass index (continuous), race (white, black, Hispanic, other), health insurance (yes/no), hours of sleep per night (continuous), months on the current job (continuous), and history of PSA test (ever/never).