Table 3.

Thickness Differences of the Photoreceptor and RPE–BM Layers Estimated through Multivariable Linear Mixed Effects Models

Variable	PRL (μm)		RPE–BM (μm)
	Thickness Difference (95% CI)	P Value	Thickness Difference (95% CI)	P Value
Very severe periodontitis
Absent	Reference		Reference
Present	−0.55 (−0.97 to −0.12)	0.013	0.00 (−0.12 to 0.13)	0.97
Age
Per decile	−0.99 (−1.11 to −0.88)	< 0.001	0.22 (0.19–0.25)	< 0.001
Sex
Female	Reference		Reference
Male	1.91 (1.74–2.09)	< 0.001	0.32 (0.27–0.37)	< 0.001
Ethnicity
White	Reference		Reference
Asian (South)	−3.94 (−4.49 to −3.39)	< 0.001	0.31 (0.14–0.47)	< 0.001
Black	−5.85 (−6.41 to −5.29)	< 0.001	1.57 (1.41–1.73)	< 0.001
Other	−2.29 (−2.81 to −1.77)	< 0.001	0.47 (0.32–0.62)	< 0.001
Socioeconomic status
Per SD increase	−0.28 (−0.37 to −0.19)	< 0.001	0.00 (−0.03 to 0.02)	0.92
Diabetes mellitus
Absent	Reference		Reference
Present	−1.55 (−2.03 to −1.06)	< 0.001	0.05 (−0.10 to 0.19)	0.52
Hypertension
Absent	Reference		Reference
Present	−0.82 (−1.04 to −0.61)	< 0.001	−0.02 (−0.08 to 0.05)	0.62
Alcohol drinker status
Never	Reference		Reference
Previous	0.65 (0.00–1.30)	0.05	0.00 (−0.19 to 0.19)	0.97
Current	1.09 (0.64–1.53)	< 0.001	−0.02 (−0.15 to 0.11)	0.81
Smoking status
Never	Reference		Reference
Previous	0.07 (−0.13 to 0.26)	0.50	0.01 (−0.04 to 0.07)	0.60
Current	−0.73 (−1.04 to −0.42)	< 0.001	−0.12 (−0.21 to −0.03)	0.008
Refractive error
Per diopter	1.69 (1.62–1.76)	< 0.001	−0.12 (−0.14 to −0.09)	< 0.001
Previous cataract surgery
Absent	Reference		Reference
Present	0.44 (−0.95 to 1.82)	0.54	0.21 (−0.34 to 0.77)	0.45

Figures in bold were considered statistically significant.

CI = confidence interval; PRL = photoreceptor layer; RPE–BM = retinal pigment epithelium–basement membrane; SD = standard deviation.