Table 2.

Results from regression analyses of melatonin and reproductive hormone levels during day sleep (night shift workers), relative to night sleep (day shift workers), all participants (n = 151 day and 170 night shift workers)

Urinary hormonea% increase (+) or decrease (−) in NSW hormone levels, relative to DSW levelsb95% confidence interval
6-Sulfatoxymelatonin−62.5%c(−69.8% to −55.1%)
FSH+61.6%d(+23.6% to +99.6%)
LH+58.4%d(+24.2% to +92.6%)
E1C+4.1%(−6.1% to +14.2%)

Abbreviations: DSW, day shift workers; NSW, night shift workers.

  • aAnalyzed using the natural log transformation.

  • bAdjusted for the effects of age, hours of darkness, BMI, number of pregnancies, number of alcoholic beverages consumed, and use of psychotherapeutics.

  • cP ≤ 0.0001, using 2-sided t test.

  • dP < 0.01, using 2-sided t test.