Table 3.

Comparison between ORs of skin SCC and quartiles of RBC fatty acids among participants in the Southeastern Arizona Health Study by inclusion of all controls (OR1) and only those without history of prior actinic keratoses (OR2)

Level of fatty acid*
P for trend
1st quartile2nd quartile3rd quartile4th quartile
Saturated fatty acids
16:00OR11.000.59 (0.36-0.96)0.68 (0.42-1.10)0.46 (0.26-0.82)0.003
OR21.000.92 (0.56-1.51)0.61 (0.36-1.04)0.34 (0.18-0.64)
18:00OR11.001.01 (0.51-1.99)1.04 (0.51-2.12)0.96 (0.45-2.03)0.311
OR21.001.05 (0.52-2.14)1.13 (0.54-2.38)1.20 (0.55-2.65)
Monounsaturated fatty acids
16:1n-7OR11.000.82 (0.49-1.36)0.70 (0.42-1.18)0.51 (0.30-0.89)0.066
OR21.001.03(0.60-1.76)0.84 (0.48-1.46)0.78 (0.44-1.39)
18:1n-7cOR11.000.67 (0.33-1.35)0.34 (0.15-0.79)0.34 (0.14-0.78)0.042
OR21.000.67 (0.33-1.36)0.32 (0.14-0.76)0.24 (0.10-0.57)
18:1n-9cOR11.001.42 (0.88-2.27)0.73 (0.41-1.30)0.91 (0.45-1.85)0.278
OR21.001.25 (0.73-2.12)0.95 (0.53-1.70)0.92 (0.44-1.91)
18:1n-9tOR11.001.19 (0.70-2.03)0.91 (0.55-1.49)0.87 (0.53-1.44)0.286
OR21.001.05 (0.60-1.85)0.65 (0.36-1.17)0.64 (0.36-1.12)
Polyunsaturated fatty acids
18:2n-6cOR11.001.07 (0.65-1.76)1.36 (0.83-2.25)0.96 (0.55-1.66)0.735
OR21.001.00 (0.59-1.69)1.39 (0.82-2.38)0.99 (0.56-1.75)
18:2n-6tOR11.000.45 (0.27-0.76)0.003
OR21.000.71 (0.42-1.19)0.780
18:3n-3OR10.753
OR21.001.28 (0.87-1.89)
20:2n-9OR11.001.47 (0.87-2.49)1.30 (0.77-2.20)1.26 (0.74-2.13)0.560
OR21.001.64 (0.95-2.83)1.43 (0.84-2.45)1.03 (0.61-1.74)
20:3n-9OR11.001.31 (0.78-2.21)0.88 (0.51-1.50)1.45 (0.88-2.39)0.450
OR21.001.24 (0.72-2.13)0.83 (0.48-1.43)1.96 (1.12-3.42)
20:4n-6OR11.000.98 (0.58-1.64)1.09 (0.65-1.85)1.52 (0.91-2.52)0.001
OR21.001.61 (0.92-2.80)1.40 (0.79-2.49)2.38 (1.37-4.12)
Long-chain N-3 polyunsaturated fatty acids
20:5n-3OR11.001.60 (0.94-2.73)1.60 (0.95-2.70)1.22 (0.72-2.08)0.448
OR21.001.87 (1.07-3.24)2.28 (1.31-3.95)1.54 (0.91-2.60)
22:6n-3OR11.001.61 (0.96-2.72)1.66 (0.97-2.86)1.71 (0.99-2.94)0.726
OR21.001.37 (0.80-2.33)1.61 (0.92-2.81)1.17(0.67-2.05)
P/S ratioOR11.001.55 (1.02-2.36)1.19 (0.71-1.99)1.94 (1.02-3.66)0.020
OR21.001.56 (0.92-2.63)1.89 (1.11-3.21)1.28 (0.76-2.17)
N3/N6 ratioOR11.001.45 (0.85-2.47)1.38 (0.80-2.39)1.28 (0.73-2.25)0.731
OR21.001.53 (0.88-2.64)1.45 (0.82-2.56)1.32 (0.74-2.35)
  • NOTE: OR1 is OR adjusted for age, sex, lab, tanning ability, freckles, history of actinic keratosis and includes all cases and controls (n = 657). OR2 is OR adjusted for age, sex, lab, tanning ability, freckles and excludes 94 controls with history of prior actinic keratosis (n = 563).

  • * Quartiles defined by control group (all controls for OR1 and controls without AK for OR2); for 18:2n6t and 18:3n3 groups were categorized as detectable or not.