Table 2.

Analyses of smoking risk factors as potential predictors of macular degeneration within SHHEC. Results are presented as Hazard Ratios (HR) with 99% Confidence Intervals (CI), and P values. Two models presented: no adjustment; age, sex, smoking, BMI and alcohol adjusted. Continuous data grouped as quartiles, or as specifically defined groups (i.e. education etc.)

Variable	Grouping	Macular degeneration		Adjusted for + age + sex + smoking + BMI + alcohol
		HR (99% CI)	P value	HR (99% CI)	P value
Current smoker	N = 9,759	Reference		Reference
	Y = 8,348	1.30 (0.93–1.83)	0.047	1.67 (1.17–2.38)	< 0.001
Cigarettes/day	Group 1 = 0	Reference		Reference
	Group 2 = 1–5	0.84 (0.36–1.96)	0.602	0.93 (0.36–2.41)	0.855
	Group 3 = 6–10	1.63 (0.73–3.67)	0.119	1.91 (0.85–4.30)	0.041
	Group 4 = 11–20	1.43 (0.88–2.34)	0.057	1.66 (1.01–2.71)	0.008
	Group 5 > 20	1.30 (0.84–2.00)	0.120	1.86 (1.19–2.91)	< 0.001
Expired Carbon Monoxide (ppm)	Q1 ≤ 1.9	Reference		Reference
	Q2 = 2.0–2.9	1.11 (0.63–1.97)	0.639	1.11 (0.62–1.99)	0.654
	Q3 = 3.0–14.9	1.15 (0.67–1.96)	0.509	1.16 (0.65–2.06)	0.510
	Q4 ≥ 15.0	1.51 (0.87–2.62)	0.055	1.69 (0.81–3.51)	0.065
Cotinine (ng/ml)	Q1 ≤ 0.49	Reference		Reference
	Q2 = 0.5–4.2	0.99 (0.56–1.75)	0.951	1.02 (0.56–1.86)	0.927
	Q3 = 4.3–233.0	0.92 (0.51–1.64)	0.695	1.07 (0.48–2.38)	0.826
	Q4 ≥ 233.1	1.60 (0.94–2.74)	0.024	2.01 (0.78–5.14)	0.056
Thiocyanate (µlmol/L)	Q1 ≤ 32.9	Reference		Reference
	Q2 = 33.0–50.6	1.30 (0.75–2.26)	0.216	1.34 (0.76–2.36)	0.189
	Q3 = 50.7–110.0	1.10 (0.61–1.98)	0.686	1.07 (0.54–2.12)	0.805
	Q4 ≥ 110.1	2.01 (1.17–3.43)	< 0.001	2.14 (0.95–4.81)	0.015