Table 4.

Cumulative average LAN and breast cancer risk stratified by menopausal status at the time of an event in the Nurses’ Health Study II ($n=\mathrm{109,155}$)^a.

Exposure	Premenopausal		Postmenopausal
	Cases (n)	Fully adjusted HR (95% CI)b	Cases (n)	Fully adjusted HR (95% CI)b
LAN quintile 1 (Median $4.3{\text{nW}/\mathrm{cm}}^2/\text{sr}$)	282	Reference	223	Reference
LAN quintile 2 (Median $12.4{\text{nW}/\mathrm{cm}}^2/\text{sr}$)	367	1.02 (0.87, 1.19)	242	0.96 (0.80, 1.16)
LAN quintile 3 (Median $22.9{\text{nW}/\mathrm{cm}}^2/\text{sr}$)	415	1.08 (0.92, 1.26)	229	0.92 (0.77, 1.11)
LAN quintile 4 (Median $37.2{\text{nW}/\mathrm{cm}}^2/\text{sr}$)	447	1.12 (0.96, 1.31)	248	0.99 (0.82, 1.19)
LAN quintile 5 (Median $64.0{\text{nW}/\mathrm{cm}}^2/\text{sr}$)	462	1.20 (1.02, 1.41)	230	0.95 (0.78, 1.15)
Continuous LAN (per IQR increasec)		1.07 (1.01, 1.14)		1.00 (0.91, 1.09)
p for interaction	0.08

Note: BMI, body mass index; CI, confidence interval; HR, hazard ratio; IQR, interquartile range; LAN, light at night; PM_2.5, particulate matter with aerodynamic diameter $<2.5\mathrm{\mu }\mathrm{m}$.

See Figure S1 for a graphical representation of this table.

^aThere were 404 cases who were missing menopausal status at the time of an event. These observations are excluded from this analysis.

^bHazard ratios are adjusted for benign breast disease history, family history of breast cancer, age at menarche, parity and age at first birth, height, white race, BMI, BMI at age 18, oral contraceptive use, mammography screening, smoking status, alternative healthy eating index, physical activity, marital status, living alone, personal income, shift work after 1989, region, ${\text{PM}}_{2.5}$, census-tract median home value, income, and population density.

^cAn IQR increase in cumulative average LAN is $31.6{\text{nW}/\mathrm{cm}}^2/\text{sr}$.