Table 2.

Odds ratio for colorectal cancer by KRAS mutation status according to plasma adiponectin level in the Nurses’ Health Study and the Health Professionals Follow-up Study

Colorectal cancer subtype	Tertile 3	Tertile 2	Tertile 1	P trend*	P heterogeneity†
Women (NHS)
KRAS wild-type
No. of case patients/control individuals (82/161)	26/50	26/58	30/53
Age-adjusted OR (95% CI)‡	1 (referent)	0.89 (0.48 to 1.67)	1.14 (0.57 to 2.24)	.79
Multivariable-adjusted OR (95% CI)§	1 (referent)	0.79 (0.39 to 1.60)	0.98 (0.44 to 2.14)	.86
KRAS-mutant
No. of case patients/control individuals (70/136)	17/44	20/43	33/49
Age-adjusted OR (95% CI)‡	1 (referent)	1.21 (0.55 to 2.66)	1.92 (0.86 to 4.26)	.12
Multivariable-adjusted OR (95% CI)§	1 (referent)	1.34 (0.56 to 3.19)	1.97 (0.82 to 4.75)	.14	.21
Men (HPFS)
KRAS wild-type
No. of case patients/control individuals (89/171)	29/57	27/51	33/63
Age-adjusted OR (95% CI)‡	1 (referent)	1.04 (0.53 to 2.03)	1.10 (0.55 to 2.18)	.80
Multivariable-adjusted OR (95% CI)§	1 (referent)	0.86 (0.40 to 1.89)	0.92 (0.40 to 2.09)	.81
KRAS-mutant
No. of case patients/control individuals (66/125)	13/47	26/43	27/35
Age-adjusted OR (95% CI)‡	1 (referent)	2.28 (1.00 to 5.21)	3.17 (1.30 to 7.75)	.01
Multivariable-adjusted OR (95% CI)§	1 (referent)	2.69 (1.04 to 6.93)	4.21 (1.52 to 11.6)	.005	.02
Combined (women [NHS] and men [HPFS])
KRAS wild-type
No. of case patients/control individuals (171/332)	55/107	53/109	63/116
Age-adjusted OR (95% CI)‡	1 (referent)	0.96 (0.60 to 1.51)	1.11 (0.68 to 1.80)	.72
Multivariable-adjusted OR (95% CI)§	1 (referent)	0.89 (0.54 to 1.45)	0.83 (0.49 to 1.43)	.48
KRAS-mutant
No. of case patients/control individuals (136/261)	30/91	46/86	60/84
Age-adjusted OR (95% CI)‡	1 (referent)	1.65 (0.94 to 2.89)	2.42 (1.34 to 4.37)	.005
Multivariable-adjusted OR (95% CI)§	1 (referent)	1.88 (1.03 to 3.42)	2.83 (1.50 to 5.34)	.002	.004

* Tests for trend (the Wald statistics, two-sided) were conducted using the median values for each tertile of plasma adiponectin. CI = confidence interval; HPFS = Health Professionals Follow-up Study; NHS = Nurses’ Health Study; OR = odds ratio.

† Likelihood ratio tests (two-sided) were used to test for heterogeneity (comparing the associations across tumor subtypes).

‡ Results were based on conditional logistic regression analysis with adjustment for age at blood draw and date of blood collection.

§ Results were based on conditional logistic regression analysis (which accounted for age at blood draw and date of blood collection) with additional adjustment for fasting status (<8 hours, ≥8 hours since last meal), body mass index (continuous, kg/m²), physical activity level (continuous, metabolic equivalent hour per week), family history of colorectal cancer (yes, no), multivitamin use (yes, no), regular aspirin use (yes, no), hormone replacement therapy (yes, no; NHS only), history of previous lower endoscopy (yes, no), pack-years of smoking before age 30 years (continuous), intake of total calorie (continuous, kcal/day), red meat intake (continuous, serving/day), processed meat intake (continuous, serving/day), calcium intake (continuous, mg/day), folate intake (continuous, μg/day), alcohol consumption (continuous, g/day), and plasma 25-hydroxyvitamin D (tertile, ng/mL).

The median (range) levels of plasma adiponectin across tertiles among controls are as follows:

Women (NHS) (Batch 1): 12.1 (10.0 to 26.0) μg/mL (Tertile 3), 8.2 (6.7 to 10.0) μg/mL (Tertile 2), 5.0 (1.8 to 6.7) μg/mL (Tertile 1)

Women (NHS) (Batch 2): 11.5 (9.3 to 27.0) μg/mL (Tertile 3), 8.1 (6.6 to 9.3) μg/mL (Tertile 2), 4.6 (1.4 to 6.6) μg/mL (Tertile 1)

Men (HPFS): 9.2 (6.7 to 28.0) μg/mL (Tertile 3), 5.4 (4.2 to 6.7) μg/mL (Tertile 2), 3.3 (1.3 to 4.2) μg/mL (Tertile 1)