Table 1.

Characteristics of UK Biobank Study Participants by Category of Circulating IGF1 levels (n = 397,380 participants

Baseline characteristic	IGF1 levels
	Q1	Q2	Q3	Q4	Q5
IGF1, nmol/La	14.3 (2.2)	18.6 (1.1)	21.4 (0.9)	24.1 (1.0)	29.5 (3.9)
Colorectal cancer (n cases)	595	586	528	475	481
Age at recruitment, ya	59.1 (7.2)	57.6 (7.6)	56.3 (7.9)	55.1 (8.2)	53.2 (8.3)
Women (%)	55.5	52.5	52.5	52.5	52.5
Body mass index (kg/m2)a	28.3 (5.4)	27.4 (4.7)	27.1 (4.4)	26.8 (4.2)	26.6 (4.0)
Waist circumference (cm)a	92.7 (14.2)	90.4 (13.1)	89.5 (12.7)	88.9 (12.4)	88.2 (12.2)
Height (cm)a	167.7 (9.2)	168.4 (9.3)	168.9 (9.3)	169.2 (9.3)	169.8 (9.3)
Total physical activity (MET hours per wk) (%)
<10	23.8	21.8	21.1	21.2	21.0
≥60	22.8	23.1	22.7	22.1	21.3
Smoking status (%)
Never	50.3	53.3	55.5	57.2	59.5
Current	11.8	10.9	10.2	10	9.8
Alcohol consumption (%)
Never	9.7	7.4	6.9	6.6	6.7
Daily or almost daily	24.2	22.7	21.4	19.4	16.2
Socioeconomic status (Townsend deprivation index) (%)
Highest quintile	22.2	19.2	18	18	17.8
Family history (first degree relative) of colorectal cancer (%)
Yes	11.5	11.2	10.7	10.5	10.1
Regular aspirin/ibuprofen use (%)
Yes	26.8	25.6	24.8	24.8	24.8
Red and processed meat (%)
<1 occasion per week	10.3	10	9.9	9.9	10.2
≥3 occasions per week	23.4	22.3	21.8	21.2	20.7
Ever menopausal hormone use (%)b
Yes	43.8	38.1	33.8	30	24.9
CRP (mg/L)a	3.4 (5.1)	2.6 (4.1)	2.3 (3.8)	2.1 (3.7)	1.8 (3.8)
Testosterone (nmol/L)a	7.0 (6.3)	6.9 (6.2)	6.8 (6.1)	6.7 (6.1)	6.6 (6.0)
SHBG (nmol/L)a	55.4 (28.6)	52.2 (25.8)	50.5 (24.9)	49.1 (24.2)	46.5 (23.3)
HbA1c (mmol/mol)a	35.9 (5.3)	35.4 (4.5)	35.1 (4.4)	34.9 (4.2)	34.7 (4.5)

MET, metabolic equivalents.

^aMean and SD.

^bAmong women only.