TABLE 4.

Relationship Between Caffeine Intake (Per 100 mg/d) and WHS-Defined DED, Stratified by Sleep Quality and Stress at Work

Good Sleepers (PSQI <5.5) (N = 58,262, Mean Caffeine Intake: 290 mg/d)				Poor Sleepers (PSQI≥5.5) (N = 13,222, Mean Caffeine Intake: 268 mg/d)
OR (95% CI), Model 2*	P	OR (95% CI), Model 3†	P	OR (95% CI), Model 2*	P	OR (95% CI), Model 3†	P
0.976 (0.957–0.994)	0.01	0.988 (0.969–1.008)	0.23	0.967 (0.937–0.998)	0.04	0.983 (0.951–1.016)	0.30

“Not” Stressed at Work (N = 50,104, Mean Caffeine Intake: 285 mg/d)				“Slightly” or “Very” Stressed at Work (N = 26,368, Mean Caffeine Intake: 288 mg/d)
OR (95% CI), Model 2*	P	OR (95% CI), Model 3†	P	OR (95% CI), Model 2*	P	OR (95% CI), Model 3†	P
0.975 (0.956–0.994)	0.01	0.992 (0.972–1.012)	0.41	0.952 (0.926–0.9878)	<0.001	0.966 (0.940–0.994)	0.02

Bolded items indicate statistical significance (P < 0.05).

^*Model 2: corrected for age, sex, body mass index, alcohol intake, smoking status, education level, and net monthly household income.

^†Model 3: corrected for age, sex, body mass index, alcohol intake, smoking status, education level, net monthly household income, and 48 comorbidities associated with dry eye, N (good sleepers) = 57,547, N (poor sleepers) = 12,966, N (not stressed at work) = 49,163, N (stress at work) = 26,218.

PSQI, pittsburgh sleep quality index.