Table 2. Mean levels of 3-(2-deoxy-β-d-erythro-pentafuranosyl)pyrimido[1,2-α]purin-10(3H)-one deoxyguanosine (M₁dG) adducts per 10⁸ normal nucleotides in the nasal epithelia of workers occupationally exposed to formaldehyde compared to the controls, and according to study variables.

Nasal epithelia M1dG adducts
	N	Mean levels ± SE	P-values a
Age
<42 years b	31	90 ± 15
42–49 years	35	87 ± 16	0.841
>49 years	29	68 ± 10	0.492
P-value for trend			0.348
Tobacco smoking
Non-smokers b	57	82.4 ± 11
Smokers	38	82.0 ± 12	0.637
Jobs
Controls b	45	49.6 ± 3.4
Plastic laminate plant workers	50	111.6 ± 14.3	<0.001
Personal formaldehyde exposure
<25 b μg m–3	23	47.6 ± 4.4
25–66 μg m–3	19	59.2 ± 11.6	0.703
>66 μg m–3	53	105.5 ± 13.4	0.001
P-value for trend			0.002

^a P-values after adjusting for confounding factors.

^bReference level.