Table 2. Association between different levels of birth weight and occurrence of melanoma in the study population: Mantel–Haenszel test of linear trend.

Birth weight (grams) categories	Cases (N=709)	Controls (N=108 209)	OR	95% CI
<2500	23	4043	1.00
2500–3189	160	22 909	1.23	(0.79–1.90)
3190–3519	176	26 664	1.16	(0.75–1.79)
3520–3859	167	27 506	1.07	(0.69–1.65)
⩾3860	183	27 087	1.19	(0.77–1.84)
P for trend=0.871

CI=confidence interval; OR=odds ratio.