Table 4.

Associations between IGF-I levels and malignant melanoma, stratified by disease stage and various risk factors

	Cases	Controls	OR	Cases	Controls	OR (95% CI)a	P-value	Pinteraction
			IGF-I < 300.4 ng/mL			IGF-I ≥ 300.4 ng/mL
Tumor stage
In situ	67	144	1.0	34	145	0.48 (0.26–0.89)	0.019
Localized	80	144	1.0	87	145	0.74 (0.45–1.2)	0.23	0.28
Tumor site
Face	30	144	1.0	12	145	0.43 (0.17–1.1)	0.072
Upper limbs	44	144	1.0	32	145	0.67 (0.34–1.3)	0.24
Trunk	48	144	1.0	51	145	0.85 (0.47–1.5)	0.59
Lower Limbs	33	144	1.0	29	145	0.54 (0.25–1.2)	0.12	0.62
Blistering sunburn
No	55	60	1.0	31	67	0.48 (0.22–1.1)	0.075
Yes	103	83	1.0	96	78	0.76 (0.45–1.3)	0.31	0.073
Mole removed
Never	52	83	1.0	43	97	0.42 (0.22–0.82)	0.011
Ever	106	60	1.0	84	48	0.78 (0.40–1.5)	0.45	0.30
Personal history of non-melanoma skin cancerb
No	112	119	1.0	79	133	0.39 (0.24–0.65)	<0.001
Yes	41	24	1.0	44	12	3.6 (1.0–13)	0.049	0.0035
Family history of skin cancerb
No	113	115	1.0	76	108	0.57 (0.34–0.96)	0.034
Yes	29	20	1.0	42	27	0.73 (0.25–2.13)	0.57	0.33
Smoking status
Never	73	53	1.0	63	67	0.43 (0.22–0.84)	0.014
Ever	85	90	1.0	64	78	0.87 (0.48–1.6)	0.65	0.52
Alcohol intake
Never	45	43	1.0	26	46	0.22 (0.08–0.57)	0.0018
Ever	113	100	1.0	101	99	0.82 (0.50–1.4)	0.45	0.22
BMI (kg/m2)
<25	74	60	1.0	75	66	0.63 (0.32–1.25)	0.19
≥ 25	84	83	1.0	52	79	0.59 (0.33–1.1)	0.074	0.23
Calories (kcal)
<1921.0	82	81	1.0	63	61	0.66 (0.36–1.24)	0.20
≥1921.0	76	62	1.0	64	84	0.54 (0.29–0.99)	0.047	0.23

^aAdjusted for age, race, sex, energy intake, number of lifetime blistering sunburns, height, BMI, ability to tan, education, hair color, smoking and drinking status and IGFBP-3.

^bNine cases had missing personal history of non-melanoma skin cancer and 26 cases & 18 controls had missing family history of skin cancer